CA2433891C - Policy-based forwarding in open shortest path first (ospf) networks - Google Patents
Policy-based forwarding in open shortest path first (ospf) networks Download PDFInfo
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- CA2433891C CA2433891C CA2433891A CA2433891A CA2433891C CA 2433891 C CA2433891 C CA 2433891C CA 2433891 A CA2433891 A CA 2433891A CA 2433891 A CA2433891 A CA 2433891A CA 2433891 C CA2433891 C CA 2433891C
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L45/00—Routing or path finding of packets in data switching networks
- H04L45/02—Topology update or discovery
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L45/00—Routing or path finding of packets in data switching networks
- H04L45/02—Topology update or discovery
- H04L45/04—Interdomain routing, e.g. hierarchical routing
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L45/00—Routing or path finding of packets in data switching networks
- H04L45/02—Topology update or discovery
- H04L45/03—Topology update or discovery by updating link state protocols
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L45/00—Routing or path finding of packets in data switching networks
- H04L45/02—Topology update or discovery
- H04L45/033—Topology update or discovery by updating distance vector protocols
Abstract
Policy-based traffic forwarding in a data network is implemented using policy-based control over propagation of LSA messages through the data network. A route tag is asserted in respect of a link state advertisement (LSA) message advertising a network address. Propagation of the LSA through the data network is controlled using the asserted internal route tag. At each hop, a policy decision affecting the forwarding of the LSA is made. Exemplary policy decisions include, Pass and Discard. In addition, the forwarding table may be updated using the route and address information contained in the LSA. In this case, routes entered in the forwarding table may be tagged as an inclusion route or an exclusion route. This may be based on the value of an exclusion route flag, such as a binary "0" or "1" inserted into an unused portion of the options field of the LSA.
Description
POLICY-BASED FORWARDING IN OPEN SHORTEST PATH
FIRST (OSPF) NETWORKS
TECHNICAL FIELD
The present invention relates to routing protocols for connectionless traffic in a data network, and in particular to policy-based forwarding in Open Shortest Path-First (OSPF) networks.
BACKGROUND OF THE INVENTION
The modern data network space is made up of a plurality of Autonomous Systems (ASs) that are directly or indirectly linked to a communications network, such as the public internet. In this respect, it will be noted that the classical definition of an "autonomous system" refers to a set of one or more routers under a single technical administration, using an Interior Gateway Protocol (IGP) and common metrics to route packets within the autonomous system, and using an Exterior Gateway Protocol (EGP) to route packets to other autonomous systems. Since this classic definition was developed, it has become common for single autonomous systems to use several interior gateway protocols and sometimes several different sets of metrics within the AS. In the present application, the term Autonomous System (AS) is used to emphasize the fact that, even when multiple IGPs and metrics are used, the technical administration of an AS appears to other autonomous systems to have a single coherent interior routing plan and presents a consistent picture of what destinations are reachable through it.
FIG. 1 is a block diagram showing a typical autonomous system 2 having three areas 4a-c (Area 0Ø0.1, Area 0Ø0.2 and Area 0Ø0.3) that are linked to a backbone network 6 via two Area Border Routers (ABRs) 8 and
FIRST (OSPF) NETWORKS
TECHNICAL FIELD
The present invention relates to routing protocols for connectionless traffic in a data network, and in particular to policy-based forwarding in Open Shortest Path-First (OSPF) networks.
BACKGROUND OF THE INVENTION
The modern data network space is made up of a plurality of Autonomous Systems (ASs) that are directly or indirectly linked to a communications network, such as the public internet. In this respect, it will be noted that the classical definition of an "autonomous system" refers to a set of one or more routers under a single technical administration, using an Interior Gateway Protocol (IGP) and common metrics to route packets within the autonomous system, and using an Exterior Gateway Protocol (EGP) to route packets to other autonomous systems. Since this classic definition was developed, it has become common for single autonomous systems to use several interior gateway protocols and sometimes several different sets of metrics within the AS. In the present application, the term Autonomous System (AS) is used to emphasize the fact that, even when multiple IGPs and metrics are used, the technical administration of an AS appears to other autonomous systems to have a single coherent interior routing plan and presents a consistent picture of what destinations are reachable through it.
FIG. 1 is a block diagram showing a typical autonomous system 2 having three areas 4a-c (Area 0Ø0.1, Area 0Ø0.2 and Area 0Ø0.3) that are linked to a backbone network 6 via two Area Border Routers (ABRs) 8 and
2 -to a communications network 10 such as the public internet via an Autonomous System Border Router (ASBR) 12. Each area 4 includes one or more Internal Routers (IRs) 14, which control the forwarding of traffic among user machines 16 (e.g. client PCs and content servers) and respective ABRs 8 hosting the area 4. Each of the routers 8,14 are coupled together via links 18 (which may be physical or logical links) through which packetized data is forwarded.
The topology of the autonomous system 2 illustrated in FIG. 1 is typical of that set up within an enterprise or campus Local Area Network (LAN) to connect various domains (e.g. departmental LANs) represented by each area 4 to the communications network 10. Traffic forwarding external to the autonomous system 2 (both to and from the autonomous system 2), is controlled by the ASBR 12 using an Exterior Gateway Protocol (EGP) such as Border Gateway Protocol (BGP) in a manner known in the art. Within the autonomous system 2, traffic forwarding is controlled using an Interior Gateway Protocol (IGP) such as Open Shortest Path First (OSPF) protocol.
Using this arrangement, information concerning addresses located outside the autonomous system 2, and reachable through the communications network 10, can. be obtained using BGP messages received by the ASBR 12. BGP
route information received in this manner is checked against predetermined OSPF policies, which control the generation of Type-5 (and/or Type-7, if the autonomous system 2 is an NSSA area) Link State Advertisement (LSA) messages by the ASBR 12. The BGP route information is then propagated through the autonomous system 2 by flooding the Type-5 (or Type-7) LSAs into the autonomous system 2, such that each router 8,12,14 in the autonomous system 2 obtains
The topology of the autonomous system 2 illustrated in FIG. 1 is typical of that set up within an enterprise or campus Local Area Network (LAN) to connect various domains (e.g. departmental LANs) represented by each area 4 to the communications network 10. Traffic forwarding external to the autonomous system 2 (both to and from the autonomous system 2), is controlled by the ASBR 12 using an Exterior Gateway Protocol (EGP) such as Border Gateway Protocol (BGP) in a manner known in the art. Within the autonomous system 2, traffic forwarding is controlled using an Interior Gateway Protocol (IGP) such as Open Shortest Path First (OSPF) protocol.
Using this arrangement, information concerning addresses located outside the autonomous system 2, and reachable through the communications network 10, can. be obtained using BGP messages received by the ASBR 12. BGP
route information received in this manner is checked against predetermined OSPF policies, which control the generation of Type-5 (and/or Type-7, if the autonomous system 2 is an NSSA area) Link State Advertisement (LSA) messages by the ASBR 12. The BGP route information is then propagated through the autonomous system 2 by flooding the Type-5 (or Type-7) LSAs into the autonomous system 2, such that each router 8,12,14 in the autonomous system 2 obtains
3 -the BGP route information, and can write appropriate entries into its respective forwarding table (not shown).
Typically, information concerning addresses within an area in the autonomous system 2 is propagated throughout the autonomous system 2 by flooding Type-3 LSAs into the autonomous system 2 from the ABR 8 hosting the involved address. This enables each router 8,12,14 in the autonomous system 2 to obtain the internal route information, and write appropriate entries into its 10, respective forwarding table.
As is well known in the art, the routing of traffic within the autonomous system 2 is controlled by the forwarding table maintained by each router, which maps packets received by a router 8,12,14 to downstream links 18 connected to the router, typically on the basis of the contents of the destination address field of the traffic header. Exemplary data fields within the forwarding table include: IP Address; Mask; Next Hop and Next Hop Interface.
As each packet arrives at a router, its destination address is read and used to query the forwarding table. If a matching route in the forwarding table is located, the corresponding Next Hop and Next Hop Interface fields are used to forward the packet to a downstream link towards its destination. Otherwise, the packet is discarded.
The routes identified in a conventional forwarding table are always "inclusionary", in the sense that a router can forward packets to any route (or address) identified in the forwarding table. Conversely, the router is unable to forward packets to any routes (or addresses) that are not identified in the forwarding table. Typically, the forwarding table contains a list of explicitly defined routes to which packets may be forwarded, and/or a default
Typically, information concerning addresses within an area in the autonomous system 2 is propagated throughout the autonomous system 2 by flooding Type-3 LSAs into the autonomous system 2 from the ABR 8 hosting the involved address. This enables each router 8,12,14 in the autonomous system 2 to obtain the internal route information, and write appropriate entries into its 10, respective forwarding table.
As is well known in the art, the routing of traffic within the autonomous system 2 is controlled by the forwarding table maintained by each router, which maps packets received by a router 8,12,14 to downstream links 18 connected to the router, typically on the basis of the contents of the destination address field of the traffic header. Exemplary data fields within the forwarding table include: IP Address; Mask; Next Hop and Next Hop Interface.
As each packet arrives at a router, its destination address is read and used to query the forwarding table. If a matching route in the forwarding table is located, the corresponding Next Hop and Next Hop Interface fields are used to forward the packet to a downstream link towards its destination. Otherwise, the packet is discarded.
The routes identified in a conventional forwarding table are always "inclusionary", in the sense that a router can forward packets to any route (or address) identified in the forwarding table. Conversely, the router is unable to forward packets to any routes (or addresses) that are not identified in the forwarding table. Typically, the forwarding table contains a list of explicitly defined routes to which packets may be forwarded, and/or a default
- 4 -route to which the router can forward packets that do not match pay of the explicitly defined routes.
A method of controlling traffic within a Border Gateway Protocol (BGP) network uses "exclusion" routes, which can be entered into the forwarding table in a conventional manner, but which explicitly define routes to which traffic may not be forwarded. This modifies the effect of default routes, thereby allowing control over traffic flows within the network, while at the same time maximizing performance by minimizing he size of the forwarding table maintained by each BGP router. For example, an exclusion route can be defined in the forwarding table of the ASBR 12(which is a BGP router) such that packets originating in the autonomous system 2 and destined for one or more "restricted" addresses in the communications network 10 are discarded by the ASBR 12.
Similarly, exclusion routes may be defined such that packets originating in the communications network 10 and destined for selected addresses in the autonomous system 2 are discarded by the ASBR 12.
The use of explicitly defined exclusion routes, as described above provides enhanced control over BGP traffic, and thus can be used for engineering and policing of traffic entering and leaving the autonomous system 2.
A limitation of the above arrangement is that the implementation of policy-based traffic forwarding by means of BGP exclusion routes affects the entire autonomous system equally. In the many instances, it is desirable to implement different policy-based traffic forwarding regimes (e.g. providing 40255597.1
A method of controlling traffic within a Border Gateway Protocol (BGP) network uses "exclusion" routes, which can be entered into the forwarding table in a conventional manner, but which explicitly define routes to which traffic may not be forwarded. This modifies the effect of default routes, thereby allowing control over traffic flows within the network, while at the same time maximizing performance by minimizing he size of the forwarding table maintained by each BGP router. For example, an exclusion route can be defined in the forwarding table of the ASBR 12(which is a BGP router) such that packets originating in the autonomous system 2 and destined for one or more "restricted" addresses in the communications network 10 are discarded by the ASBR 12.
Similarly, exclusion routes may be defined such that packets originating in the communications network 10 and destined for selected addresses in the autonomous system 2 are discarded by the ASBR 12.
The use of explicitly defined exclusion routes, as described above provides enhanced control over BGP traffic, and thus can be used for engineering and policing of traffic entering and leaving the autonomous system 2.
A limitation of the above arrangement is that the implementation of policy-based traffic forwarding by means of BGP exclusion routes affects the entire autonomous system equally. In the many instances, it is desirable to implement different policy-based traffic forwarding regimes (e.g. providing 40255597.1
- 5 -different levels of access and security) in different areas of an autonomous system. For example, an enterprise may wish to partition its enterprise LAN into discrete areas, each having respective different levels of security and public access. In the Autonomous system illustrated in FIG. 1, for example, Area 0Ø0.1 4a may be used to provide secure space for employees, and Area 0Ø0.2 4b used by accounting and corporate finance departments. Both of these areas 4a,4b must therefore be carefully protected against unauthorized access. On the other hand, Area 0Ø0.3 4c may be used for distribution of product information, and handling customer inquiries and product orders, and therefore must be readily accessible from the communications network 10. It is desirable for internal routers 14 located in Areas 0Ø0.1 and 0Ø0.2 4a and 4b, respectively, to obtain route information concerning addresses within Area 0Ø0.3 4c, in order to enable maintenance and other administrative functions. However, in order to maintain security, it is important that internal routers 14 within Area 0Ø0.3 4c be unable to access addresses within Areas 0Ø0.1 and 0Ø0.2 4a and 4b.
One method of accomplishing this is to manually configure the respective forwarding tables of ABR(A) 8a and ABR(B) 8b to include only explicitly defined inclusion routes to which traffic may be forwarded. However OSPF
normally operates to advertise new and/or changed addresses throughout the autonomous system by flooding LSAs from the router hosting the new addresses. Thus manually configuring the respective forwarding tables of ABR(A) 8a and ABR(B) 8b with explicitly defined routes requires that the conventional route-learning functionality of OSPF be defeated. This creates scalability and network maintenance difficulties as the configuration of the autonomous system changes.
One method of accomplishing this is to manually configure the respective forwarding tables of ABR(A) 8a and ABR(B) 8b to include only explicitly defined inclusion routes to which traffic may be forwarded. However OSPF
normally operates to advertise new and/or changed addresses throughout the autonomous system by flooding LSAs from the router hosting the new addresses. Thus manually configuring the respective forwarding tables of ABR(A) 8a and ABR(B) 8b with explicitly defined routes requires that the conventional route-learning functionality of OSPF be defeated. This creates scalability and network maintenance difficulties as the configuration of the autonomous system changes.
- 6 -Request for Comments (rfc)-2740 describes OSPF for IP
version 6, which attempts to overcome some of the limitations of autonomous system-wide propagation of LSAs, by allowing a router originating the LSA to restrict propagation of the LSA to a link, a local area, or the entire autonomous system. However, this functionality cannot accommodate a situation in which it is desired to selectively propagate an LSA into some areas of the autonomous system, but not others. For example, the autonomous system, of FIG. 1 contains three areas 4, and it is desired that LSAs originating in Area 0Ø0.1, be propagated to Area 0Ø0.2 to enable nodes in Area 0Ø0.2 to access addresses in Area 0Ø0.1. However, it is important that these same LSAs be prevented from propagating into Area 0Ø0.3, and so prevent unauthorized access to addresses in Area 0Ø0.1 from the (publicly accessible) Area 0Ø0.3.
Accordingly, a method and apparatus for enabling flexible control of traffic forwarding within an OSPF
network, while ensuring a high level of security and scalability, remains highly desirable.
SUMMARY OF THE INVENTION
An object of the invention is to provide a method of policy-based control of traffic forwarding within a data network.
This object is met by the features of the invention defined in the appended independent claims. Optional features of various embodiments of the invention are defined in the subsidiary claims.
Accordingly, an aspect of the present invention provides a method of enabling policy-based traffic forwarding in a data network. A route tag is asserted in
version 6, which attempts to overcome some of the limitations of autonomous system-wide propagation of LSAs, by allowing a router originating the LSA to restrict propagation of the LSA to a link, a local area, or the entire autonomous system. However, this functionality cannot accommodate a situation in which it is desired to selectively propagate an LSA into some areas of the autonomous system, but not others. For example, the autonomous system, of FIG. 1 contains three areas 4, and it is desired that LSAs originating in Area 0Ø0.1, be propagated to Area 0Ø0.2 to enable nodes in Area 0Ø0.2 to access addresses in Area 0Ø0.1. However, it is important that these same LSAs be prevented from propagating into Area 0Ø0.3, and so prevent unauthorized access to addresses in Area 0Ø0.1 from the (publicly accessible) Area 0Ø0.3.
Accordingly, a method and apparatus for enabling flexible control of traffic forwarding within an OSPF
network, while ensuring a high level of security and scalability, remains highly desirable.
SUMMARY OF THE INVENTION
An object of the invention is to provide a method of policy-based control of traffic forwarding within a data network.
This object is met by the features of the invention defined in the appended independent claims. Optional features of various embodiments of the invention are defined in the subsidiary claims.
Accordingly, an aspect of the present invention provides a method of enabling policy-based traffic forwarding in a data network. A route tag is asserted in
7 -respect of a Link State Advertisement (LSA) message.
Propagation of the LSA through the data network is controlled using the asserted internal route tag.
Another aspect of the present invention provides a router adapted for enabling policy-based traffic forwarding in a data network. The router comprises means for controlling propagation of a link state advertisement (LSA) message through the data network using a route tag asserted in respect of the LSA.
In embodiments of the invention, the data network is an Open Shortest Path first (OSPF) network. The router may be an Autonomous System Border Router (ASBR) or an Area Border router (ABR) of the OSPF network.
The route tag may include either one of: an internal route tag associated with an address located within an autonomous system of the data network; and an external route tag associated with an address located outside the autonomous system.
Assertion of the route tag may include: setting a route tag value respecting the LSA; and inserting the route tag valve into a predetermined field of the LSA. The route tag value may be set by a policy having a match criteria corresponding to a predetermined parameter of the LSA. The predetermined parameter may include any one or more of: a source address; a source area; a destination address; and a destination area.
Control over propagation of the LSA may include implementing a forwarding policy having a match criteria corresponding to the asserted route tag. The forwarding policy may correspond to one of: a pass decision, in which the LSA is forwarded to a downstream link; and a discard decision, in which the LSA is discarded without forwarding.
Propagation of the LSA through the data network is controlled using the asserted internal route tag.
Another aspect of the present invention provides a router adapted for enabling policy-based traffic forwarding in a data network. The router comprises means for controlling propagation of a link state advertisement (LSA) message through the data network using a route tag asserted in respect of the LSA.
In embodiments of the invention, the data network is an Open Shortest Path first (OSPF) network. The router may be an Autonomous System Border Router (ASBR) or an Area Border router (ABR) of the OSPF network.
The route tag may include either one of: an internal route tag associated with an address located within an autonomous system of the data network; and an external route tag associated with an address located outside the autonomous system.
Assertion of the route tag may include: setting a route tag value respecting the LSA; and inserting the route tag valve into a predetermined field of the LSA. The route tag value may be set by a policy having a match criteria corresponding to a predetermined parameter of the LSA. The predetermined parameter may include any one or more of: a source address; a source area; a destination address; and a destination area.
Control over propagation of the LSA may include implementing a forwarding policy having a match criteria corresponding to the asserted route tag. The forwarding policy may correspond to one of: a pass decision, in which the LSA is forwarded to a downstream link; and a discard decision, in which the LSA is discarded without forwarding.
8 -Implementation of the forwarding policy may also include updating a forwarding table using information contained in the LSA as one of: an inclusion route; and an exclusion route.
Thus the present invention provides a method and apparatus for policy-based control of traffic forwarding by the use of policies implemented to control the propagation of LSAs containing route information. LSAs containing information concerning restricted or prohibited addresses can be discarded by an ABR, in response to a policy decision, so that downstream nodes remain unaware of the restricted addresses. This functionality can be used, for example, to prevent information concerning an address within Area 0Ø0.1 being propagated to any nodes beyond ABR(A), so that nodes within Area 0Ø0.3 remain unaware of (and thus cannot forward traffic to) that address.
BRIEF DESCRIPTION OF THE DRAWINGS
Further features and advantages of the present invention will become apparent from the following detailed description, taken in combination with the appended drawings, in which:
FIG. 1 is a block diagram schematically illustrating an autonomous system in which the present invention may be utilized;
FIG. 2 is a block diagram schematically illustrating exemplary elements of a router in accordance with the present invention; and FIGs. 3a-3c are block diagrams schematically illustrating fields of exemplary LSA messages usable in the present invention.
Thus the present invention provides a method and apparatus for policy-based control of traffic forwarding by the use of policies implemented to control the propagation of LSAs containing route information. LSAs containing information concerning restricted or prohibited addresses can be discarded by an ABR, in response to a policy decision, so that downstream nodes remain unaware of the restricted addresses. This functionality can be used, for example, to prevent information concerning an address within Area 0Ø0.1 being propagated to any nodes beyond ABR(A), so that nodes within Area 0Ø0.3 remain unaware of (and thus cannot forward traffic to) that address.
BRIEF DESCRIPTION OF THE DRAWINGS
Further features and advantages of the present invention will become apparent from the following detailed description, taken in combination with the appended drawings, in which:
FIG. 1 is a block diagram schematically illustrating an autonomous system in which the present invention may be utilized;
FIG. 2 is a block diagram schematically illustrating exemplary elements of a router in accordance with the present invention; and FIGs. 3a-3c are block diagrams schematically illustrating fields of exemplary LSA messages usable in the present invention.
9 PCT/CA01/01827 It will be noted that throughout the appended drawings, like features are identified by like reference numerals.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The present invention provides a method and a system (which may take the form of, for example, a router and/or a computer program adapted for controlling the router) for policy-based control of traffic forwarding within an autonomous system. FIG. 1 illustrates an exemplary autonomous system 2 in which the present invention may be deployed. In the embodiment of FIG. 1, the autonomous system 2 includes three areas (Area 0Ø0.1, Area 0Ø0.2 and Area 0Ø0.3) 4a-4c that are linked to a backbone network 6 via one or more respective Area Border Routers (ABRs) 8. The autonomous system 2 is coupled to an external communications network 10 (such as the public internet) via an Autonomous System Border Router (ASBR) 12.
Each area 4 includes one or more Internal Routers (IRs) 14, which control the forwarding of traffic among user machines 16 (e.g. PCs, not shown) and the. ABRs 8 hosting the area 4. The routers 8,12,14 are coupled together by links 18 (which may be physical or logical links) through which packetized data traffic is forwarded.
The topology of the autonomous system 2 illustrated in FIG. 1 is typical of enterprise and/or campus Local Area Networks (LANs), in which various network areas 4 (e.g.
department-specific LANs) are connected to each other, and to an external communications network 10, such as a Wide Area network (WAN) and/or the public internet, via a backbone 6. In the embodiment of FIG. 1, three areas 4 are illustrated. These areas 4 are connected to the backbone 6 via two ABRs 8, namely: ABR(A) 8a, which connects Areas 0Ø0.1 and 0Ø0.2 4a and 4b, respectively, to the
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The present invention provides a method and a system (which may take the form of, for example, a router and/or a computer program adapted for controlling the router) for policy-based control of traffic forwarding within an autonomous system. FIG. 1 illustrates an exemplary autonomous system 2 in which the present invention may be deployed. In the embodiment of FIG. 1, the autonomous system 2 includes three areas (Area 0Ø0.1, Area 0Ø0.2 and Area 0Ø0.3) 4a-4c that are linked to a backbone network 6 via one or more respective Area Border Routers (ABRs) 8. The autonomous system 2 is coupled to an external communications network 10 (such as the public internet) via an Autonomous System Border Router (ASBR) 12.
Each area 4 includes one or more Internal Routers (IRs) 14, which control the forwarding of traffic among user machines 16 (e.g. PCs, not shown) and the. ABRs 8 hosting the area 4. The routers 8,12,14 are coupled together by links 18 (which may be physical or logical links) through which packetized data traffic is forwarded.
The topology of the autonomous system 2 illustrated in FIG. 1 is typical of enterprise and/or campus Local Area Networks (LANs), in which various network areas 4 (e.g.
department-specific LANs) are connected to each other, and to an external communications network 10, such as a Wide Area network (WAN) and/or the public internet, via a backbone 6. In the embodiment of FIG. 1, three areas 4 are illustrated. These areas 4 are connected to the backbone 6 via two ABRs 8, namely: ABR(A) 8a, which connects Areas 0Ø0.1 and 0Ø0.2 4a and 4b, respectively, to the
- 10 -backbone 6; and ABR(B) 8b, which connects Area 0Ø0.3 4c to the backbone 6. A single ASBR 12 is provided to enable traffic flow between the autonomous system 2 and the external communications network 10. It will be appreciated, however, that the present invention may be successfully deployed in networks 2 having any number of areas 4, each of which may be connected to the backbone 6 via one or more ABRs 8, which may be shared with one or more other areas 4. Accordingly, the autonomous system 2 of FIG. 1 shall be viewed as being illustrative, rather than limitative, of the types of ASs in which the present invention may be deployed.
FIG. 2 is a block diagram schematically illustrating elements of an exemplary router 20 in accordance with the present invention. The router 20 may be deployed as any ABR 8, ASBR 12, or IR 14, and operates to control the forwarding of traffic through the autonomous system 2. As shown in FIG. 2, the router 20 generally comprises at least one ingress network interface 22, each of which provides one or more ingress ports 24 for receiving data traffic through upstream links 18 of the AS 2; at least one egress network interface 26, each of which provides a plurality of egress ports 28 for launching data traffic into downstream links 18 of the AS 2; a switch fabric 30' for mapping traffic received at an ingress port 24 to a selected egress port 28 for forwarding to an appropriate downstream link 18; and a control unit 32 for controlling operations of the ingress and egress interfaces 22,26 and ports 24,28, and the switch fabric 30.
The router 20 may be implemented as physical hardware or as a virtual router instantiated in a server (not shown), for example. Similarly, the ingress and egress interfaces 22,26 and ports 24,28, switch fabric 30, and the control unit 32 may be implemented by any suitable
FIG. 2 is a block diagram schematically illustrating elements of an exemplary router 20 in accordance with the present invention. The router 20 may be deployed as any ABR 8, ASBR 12, or IR 14, and operates to control the forwarding of traffic through the autonomous system 2. As shown in FIG. 2, the router 20 generally comprises at least one ingress network interface 22, each of which provides one or more ingress ports 24 for receiving data traffic through upstream links 18 of the AS 2; at least one egress network interface 26, each of which provides a plurality of egress ports 28 for launching data traffic into downstream links 18 of the AS 2; a switch fabric 30' for mapping traffic received at an ingress port 24 to a selected egress port 28 for forwarding to an appropriate downstream link 18; and a control unit 32 for controlling operations of the ingress and egress interfaces 22,26 and ports 24,28, and the switch fabric 30.
The router 20 may be implemented as physical hardware or as a virtual router instantiated in a server (not shown), for example. Similarly, the ingress and egress interfaces 22,26 and ports 24,28, switch fabric 30, and the control unit 32 may be implemented by any suitable
- 11 -combination of hardware and/or software. In order to simplify illustration and description of the present invention, FIG. 2 shows only one each ingress and egress interface 22,26, each of which provides three respective ports 24,28. However, it will be understood that, in general, a router 20 will include multiple ingress and egress interfaces, and each interface will provide multiple ports. Similarly, in order to simplify description, a unidirectional traffic flow is illustrated within the router. Thus inbound data traffic is received from an upstream link 18 by an ingress interface 22 through a respective ingress port 24, mapped through the switch fabric 30 to an egress interface 26, and then launched into a downstream link 18 through an egress port 28. It will be appreciated, however, that traffic flows will, in general, be bi-directional. Accordingly, the router 20 of FIG. 2 shall be viewed as being illustrative, rather than limitative, of routers in accordance with the present invention.
The control unit 32 is logically connected to a database 34, which contains one or more forwarding tables, translation tables, policies, and/or any other information used for enabling flow-specific processing of data traffic through the router 20. The database 34 may be co-resident with the router 20, or remotely located and accessible by the router 20 through the AS 2. As is known in the art, the control unit 32 operates, typically under software control, to update the contents of the database 34 (principally the forwarding table), based on the contents of Link State Advertisement (LSA) messages advertised by other routers. As data packets are received at an ingress port 24, the contents of the packet header (e.g. the destination address) are read by the ingress interface 22 and used to query the database 32 in order to determine how the packet should be routed. Based on the query result,
The control unit 32 is logically connected to a database 34, which contains one or more forwarding tables, translation tables, policies, and/or any other information used for enabling flow-specific processing of data traffic through the router 20. The database 34 may be co-resident with the router 20, or remotely located and accessible by the router 20 through the AS 2. As is known in the art, the control unit 32 operates, typically under software control, to update the contents of the database 34 (principally the forwarding table), based on the contents of Link State Advertisement (LSA) messages advertised by other routers. As data packets are received at an ingress port 24, the contents of the packet header (e.g. the destination address) are read by the ingress interface 22 and used to query the database 32 in order to determine how the packet should be routed. Based on the query result,
- 12 -the control unit 32 interacts with the ingress interface 22, switch fabric 30 and/or the egress interface 26, to either forward the packet to an appropriate downstream link 18, or, under some conditions, discard the packet.
Traffic forwarding between the autonomous system 2 and the external communications network 10 is controlled by the ASBR 12 using route information contained in update messages conforming to an Exterior Gateway Protocol (EGP) such as, for example, Border Gateway Protocol (BGP) in a manner known in the art. Thus, for example, the ASBR 12 may obtain information concerning addresses and routes within the external communications network via BGP update messages received from the external communications network 10. Conversely, the ASBR 12 may advertise information concerning addresses and routes within the autonomous system 2 by formulating and launching BGP update messages into the external communications network 10.
Traffic forwarding within the autonomous system 2 is controlled by the ABRs 8 and IRs 14 using respective forwarding tables, which are populated with route information using an Interior Gateway Protocol (IGP) such as, for example, Open Shortest Path First (OSPF) protocol.
Thus, for example, the ASBR 12 can advertise information concerning external addresses and routes (i.e. those outside the autonomous system 2) to the autonomous system 2 using Type-5 (and/or Type-7) OSPF Link State Advertisement (LSA) messages. Similarly, ABR(A) 8,a may advertise information concerning addresses and routes within Areas 0Ø0.1 4a and 0Ø0.2 4b to other portions of the autonomous system 2, and to the ASBR 12, using Type-3 LSA
messages. Under conventional OSPF, LSA messages can be originated by the ASBR 12, ABRs 8 or IRs 14, and are "flooded" into the autonomous system 2. In this respect, the term "flooded" means that the LSA message is launched
Traffic forwarding between the autonomous system 2 and the external communications network 10 is controlled by the ASBR 12 using route information contained in update messages conforming to an Exterior Gateway Protocol (EGP) such as, for example, Border Gateway Protocol (BGP) in a manner known in the art. Thus, for example, the ASBR 12 may obtain information concerning addresses and routes within the external communications network via BGP update messages received from the external communications network 10. Conversely, the ASBR 12 may advertise information concerning addresses and routes within the autonomous system 2 by formulating and launching BGP update messages into the external communications network 10.
Traffic forwarding within the autonomous system 2 is controlled by the ABRs 8 and IRs 14 using respective forwarding tables, which are populated with route information using an Interior Gateway Protocol (IGP) such as, for example, Open Shortest Path First (OSPF) protocol.
Thus, for example, the ASBR 12 can advertise information concerning external addresses and routes (i.e. those outside the autonomous system 2) to the autonomous system 2 using Type-5 (and/or Type-7) OSPF Link State Advertisement (LSA) messages. Similarly, ABR(A) 8,a may advertise information concerning addresses and routes within Areas 0Ø0.1 4a and 0Ø0.2 4b to other portions of the autonomous system 2, and to the ASBR 12, using Type-3 LSA
messages. Under conventional OSPF, LSA messages can be originated by the ASBR 12, ABRs 8 or IRs 14, and are "flooded" into the autonomous system 2. In this respect, the term "flooded" means that the LSA message is launched
- 13 -towards every adjacent router, and thereafter propagates, hop-by-hop, through the entire autonomous system 2. At each router, the respective forwarding table is updated based on the contents of the LSA message. Under OSPF for IP version 6 (described in rfc-2740), this flooding behavior is modified by enabling the originating router to restrict propagation of the LSA to a single hop, the local area 4 within which the originating router resides, or the entire autonomous system 2.
The present invention enables policy-based control over traffic forwarding within the autonomous system 2, by implementing policy-based control over the propagation of LSA messages. This policy-based control is implemented on a per-router basis, so that it is possible to define different forwarding policies for respective different routers. Thus, for example, different policies can be defined for each of ABR(A) 8a and ABR (B) 8b, so that LSAs originating from the ASBR 12 are treated differently by each of these ABRs 8. In general, policy-based forwarding of LSAs can be implemented in the ASBR 12 and ABRs 8, while conventional flooding is used within each individual area 4, and within the backbone 6. In this case, policies need only be defined in respect of Type-5 and Type-7 LSAs (originated by the ASBR 12 to advertise external route information) and Type-3 LSAs (originated by each ABR 8 to advertise internal route information). Each of these cases is described in greater detail below with reference to FIGS. 3a-3c.
FIG. 3a is a block diagram illustrating the fields of a standard OSPF LSA header 36. These fields are described in detail in Moy, J., "OSPF Version 211, STD 54, RFC-2328, April 1998, and summarized as follows:
The present invention enables policy-based control over traffic forwarding within the autonomous system 2, by implementing policy-based control over the propagation of LSA messages. This policy-based control is implemented on a per-router basis, so that it is possible to define different forwarding policies for respective different routers. Thus, for example, different policies can be defined for each of ABR(A) 8a and ABR (B) 8b, so that LSAs originating from the ASBR 12 are treated differently by each of these ABRs 8. In general, policy-based forwarding of LSAs can be implemented in the ASBR 12 and ABRs 8, while conventional flooding is used within each individual area 4, and within the backbone 6. In this case, policies need only be defined in respect of Type-5 and Type-7 LSAs (originated by the ASBR 12 to advertise external route information) and Type-3 LSAs (originated by each ABR 8 to advertise internal route information). Each of these cases is described in greater detail below with reference to FIGS. 3a-3c.
FIG. 3a is a block diagram illustrating the fields of a standard OSPF LSA header 36. These fields are described in detail in Moy, J., "OSPF Version 211, STD 54, RFC-2328, April 1998, and summarized as follows:
- 14 -= LS age 38: The time in seconds since the LSA was originated.
= Options 40: The optional capabilities supported by the described portion of the routing domain.
= LS Type-42: The type of the LSA. Each LSA type has a separate advertisement format. The LSA
types defined in RFC-2328 are as follows LSA Type Description 1 Router-LSAs 2 Network-LSAs 3 Summary-LSAs (IP network) 4 Summary-LSAs (ASBR) 5 AS-external-LSAs = As mentioned previously, Type-3 LSAs are originated by ABRs 8 in respect of routes internal to the autonomous system 2, while Type-5 LSAs are originated by the ASBR 12 in respect of routes external to the autonomous system 2.
= Link State ID 44: This field identifies the portion of the internet environment that is being described by the LSA. The contents of this field depend on the LSAs LS type. For example, in network-LSAs the Link State ID is set to the IP
interface address of the network's Designated Router (from which the network's IP address can be derived).
= Advertising Router 46: The Router ID of the router that originated the LSA. For example, in network-LSAs this field is equal to the Router ID of the network's Designated Router.
= Options 40: The optional capabilities supported by the described portion of the routing domain.
= LS Type-42: The type of the LSA. Each LSA type has a separate advertisement format. The LSA
types defined in RFC-2328 are as follows LSA Type Description 1 Router-LSAs 2 Network-LSAs 3 Summary-LSAs (IP network) 4 Summary-LSAs (ASBR) 5 AS-external-LSAs = As mentioned previously, Type-3 LSAs are originated by ABRs 8 in respect of routes internal to the autonomous system 2, while Type-5 LSAs are originated by the ASBR 12 in respect of routes external to the autonomous system 2.
= Link State ID 44: This field identifies the portion of the internet environment that is being described by the LSA. The contents of this field depend on the LSAs LS type. For example, in network-LSAs the Link State ID is set to the IP
interface address of the network's Designated Router (from which the network's IP address can be derived).
= Advertising Router 46: The Router ID of the router that originated the LSA. For example, in network-LSAs this field is equal to the Router ID of the network's Designated Router.
- 15 -= LS sequence number 48: Detects old or duplicate LSAs. Successive instances of an LSA are given successive LS sequence numbers.
= LS checksum 50: The Fletcher checksum of the complete contents of the LSA, including the LSA
header but excluding the LS age field.
= Length 52: The length, in bytes, of the LSA, including the LSA header.
In general, policies can be defined using match criteria corresponding to any one or more attributes of an LSA. These attributes may include predetermined contents of any one or more of the fields 38-52 of the LSA
header 36. Policies can also be defined using match criteria corresponding to other attributes related to the route, but not forming part of the LSA. Exemplary attributes of this type include the source protocol, and BGP-AS. Thus, for example, a "Discard" policy may be defined for ABR(B) 8b having a match criteria corresponding to the address of ABR(A) 8a as the contents of the advertising router field 46, such that LSAs originating from ABR(A) 8a are discarded. Implementation of such a policy in ABR(B) 8b would mean that information concerning address and routes within Sreas 0Ø0.1 4a and 0Ø0.2 4b would not be propagated into Area 0Ø0.3 4c, thereby ensuring that Areas 0Ø0.1 and 0Ø0.2 4a,4b cannot be accessed from Area 0Ø0.3 4c.
Additionally, policies can be defined using match criteria corresponding to the contents of any one or more fields specific to each type of LSA. For example, as shown in FIGs. 3b and 3c, Type-5 LSAs 54 include Network Mask 56, Forwarding Address 58 and External Route Tag 60 fields, while Type-3 LSAs 62 contain a Network Mask field 64, the
= LS checksum 50: The Fletcher checksum of the complete contents of the LSA, including the LSA
header but excluding the LS age field.
= Length 52: The length, in bytes, of the LSA, including the LSA header.
In general, policies can be defined using match criteria corresponding to any one or more attributes of an LSA. These attributes may include predetermined contents of any one or more of the fields 38-52 of the LSA
header 36. Policies can also be defined using match criteria corresponding to other attributes related to the route, but not forming part of the LSA. Exemplary attributes of this type include the source protocol, and BGP-AS. Thus, for example, a "Discard" policy may be defined for ABR(B) 8b having a match criteria corresponding to the address of ABR(A) 8a as the contents of the advertising router field 46, such that LSAs originating from ABR(A) 8a are discarded. Implementation of such a policy in ABR(B) 8b would mean that information concerning address and routes within Sreas 0Ø0.1 4a and 0Ø0.2 4b would not be propagated into Area 0Ø0.3 4c, thereby ensuring that Areas 0Ø0.1 and 0Ø0.2 4a,4b cannot be accessed from Area 0Ø0.3 4c.
Additionally, policies can be defined using match criteria corresponding to the contents of any one or more fields specific to each type of LSA. For example, as shown in FIGs. 3b and 3c, Type-5 LSAs 54 include Network Mask 56, Forwarding Address 58 and External Route Tag 60 fields, while Type-3 LSAs 62 contain a Network Mask field 64, the
- 16 -contents of any one or more of which may be used as match criteria for forwarding policies in the manner described above.
In accordance with an embodiment of the invention, an advertising router (e.g. ASBR 12 or an ABR 8) operates (e.g. under software control) to define a route' tag in respect of each LSA originating from the router. The route tag is attached to each LSA, and is used as a match criteria for policy-based forwarding of the LSA through at least the ASBR 12, ABR(A) 8a and ABR(B) 8b.
For Type-5 LSAs 54 (FIG. 3b), which convey information concerning external routes, the ASBR 12 can conveniently insert the route tag into the External Route Tag field 60 of the LSA 54. Policies defined for each of ABR(A) 8a and ABR(B) 8b, and having match criteria corresponding to the contents of the External Route Tag field 60 of Type-5 LSAs 54, can then be used to control the advertisement of external routes into each of the areas 4a-4c of the autonomous system 2.
In order to accommodate the route tag in Type-3 LSAs 62, a suitable internal route tag field must be added, for example, following the TOS Metric Field 66 (see FIG. 3), to thereby create a "modified" Type-3 LSA. Accordingly, a route tag defined by ABR(A) 8a, for example, can be inserted (as an internal route tag) into the internal route tag field of the modified Type-3 LSA 62. Policies defined for the ASBR 12 and ABR(B) 8b, and having match criteria corresponding to the contents of the internal route tag field of modified Type-3 LSAs 62, can then be used to control the advertisement of internal routes (in this example, within Areas 0Ø0.1 and 0Ø0.2 4a and 4b) into the external communications network 10 and Area 0Ø0.3 4c, respectively.
In accordance with an embodiment of the invention, an advertising router (e.g. ASBR 12 or an ABR 8) operates (e.g. under software control) to define a route' tag in respect of each LSA originating from the router. The route tag is attached to each LSA, and is used as a match criteria for policy-based forwarding of the LSA through at least the ASBR 12, ABR(A) 8a and ABR(B) 8b.
For Type-5 LSAs 54 (FIG. 3b), which convey information concerning external routes, the ASBR 12 can conveniently insert the route tag into the External Route Tag field 60 of the LSA 54. Policies defined for each of ABR(A) 8a and ABR(B) 8b, and having match criteria corresponding to the contents of the External Route Tag field 60 of Type-5 LSAs 54, can then be used to control the advertisement of external routes into each of the areas 4a-4c of the autonomous system 2.
In order to accommodate the route tag in Type-3 LSAs 62, a suitable internal route tag field must be added, for example, following the TOS Metric Field 66 (see FIG. 3), to thereby create a "modified" Type-3 LSA. Accordingly, a route tag defined by ABR(A) 8a, for example, can be inserted (as an internal route tag) into the internal route tag field of the modified Type-3 LSA 62. Policies defined for the ASBR 12 and ABR(B) 8b, and having match criteria corresponding to the contents of the internal route tag field of modified Type-3 LSAs 62, can then be used to control the advertisement of internal routes (in this example, within Areas 0Ø0.1 and 0Ø0.2 4a and 4b) into the external communications network 10 and Area 0Ø0.3 4c, respectively.
- 17 -In general, the actions performed by a forwarding policy may be arbitrary, and thus may be selected as desired for each particular implementation. Policies may also differ on a per-router basis. Exemplary actions include:
= Pass, in which the LSA is forwarded to a downstream link; and = Discard, in which the LSA is discarded without forwarding.
In addition to the above exemplary policy actions, the forwarding table may be updated with route information contained in the LSA. This route information may identify a route as either an inclusion route or an exclusion route, as desired. Updating the database 34 may also be based on a policy decision, using any suitable desired attribute (or combination of attributes) of the LSA, as discussed above, such as, for example, the contents of the advertising router field 46 and/or the route tag (i.e. the contents of the external route tag field 60 of Type-5 LSAs 54 or the internal route tag field 66 of Type-3 LSAs 62).
Alternatively, an exclusion route flag may be defined and inserted into the LSA by the advertising router. The exclusion route flag may, for example, include a binary "0"
or "1", inserted into an unused portion of the options field 40 of the LSA header 36 (see FIG. 2a). As a result, the route identified in the LSA can be marked (e.g. in the forwarding table) as an inclusion or an exclusion route, as appropriate, based on the value of the exclusion route flag. Once the route has been marked as an exclusion route, a router cannot re-set the route, or otherwise override a route policy decision to discard LSA destined for the exclusion route.
= Pass, in which the LSA is forwarded to a downstream link; and = Discard, in which the LSA is discarded without forwarding.
In addition to the above exemplary policy actions, the forwarding table may be updated with route information contained in the LSA. This route information may identify a route as either an inclusion route or an exclusion route, as desired. Updating the database 34 may also be based on a policy decision, using any suitable desired attribute (or combination of attributes) of the LSA, as discussed above, such as, for example, the contents of the advertising router field 46 and/or the route tag (i.e. the contents of the external route tag field 60 of Type-5 LSAs 54 or the internal route tag field 66 of Type-3 LSAs 62).
Alternatively, an exclusion route flag may be defined and inserted into the LSA by the advertising router. The exclusion route flag may, for example, include a binary "0"
or "1", inserted into an unused portion of the options field 40 of the LSA header 36 (see FIG. 2a). As a result, the route identified in the LSA can be marked (e.g. in the forwarding table) as an inclusion or an exclusion route, as appropriate, based on the value of the exclusion route flag. Once the route has been marked as an exclusion route, a router cannot re-set the route, or otherwise override a route policy decision to discard LSA destined for the exclusion route.
- 18 -Thus it will be seen that the present invention provides a method and apparatus for policy-based control of traffic forwarding within an autonomous system 2, by implementing policy-based propagation of LSAs through the AS 2. This does not require altering the conventional OSPF
protocol, but rather can be accomplished by extending the functionality of ASBR5 12 and ABRs 8 to implement policies based on the contents of Type-3 and Type-5 LSAs. Thus the functionality of ASBRs 12 can be extended to implement forwarding policies based on the contents of an internal route tag field 66 of modified Type-3 LSAs 62 advertised by an ABR 8. Similarly, the functionality of ABRs 8 can be extended to: define and insert an internal route tag into modified Type-3 LSAs 62; and to implement forwarding policies based on the contents of the external route tag field 60 of Type-5 LSAs 54, and the internal route tag field 66 of modified Type-3 LSAs 62 advertised by other ABRs 8. Accordingly the present invention can be readily deployed within new autonomous systems, and/or as a software up-grade of legacy routers in existing autonomous systems.
The embodiment(s) of the invention described above is(are) intended to be exemplary only. The scope of the invention is therefore intended to be limited solely by the scope of the appended claims.
protocol, but rather can be accomplished by extending the functionality of ASBR5 12 and ABRs 8 to implement policies based on the contents of Type-3 and Type-5 LSAs. Thus the functionality of ASBRs 12 can be extended to implement forwarding policies based on the contents of an internal route tag field 66 of modified Type-3 LSAs 62 advertised by an ABR 8. Similarly, the functionality of ABRs 8 can be extended to: define and insert an internal route tag into modified Type-3 LSAs 62; and to implement forwarding policies based on the contents of the external route tag field 60 of Type-5 LSAs 54, and the internal route tag field 66 of modified Type-3 LSAs 62 advertised by other ABRs 8. Accordingly the present invention can be readily deployed within new autonomous systems, and/or as a software up-grade of legacy routers in existing autonomous systems.
The embodiment(s) of the invention described above is(are) intended to be exemplary only. The scope of the invention is therefore intended to be limited solely by the scope of the appended claims.
Claims (28)
1. A method of enabling policy-based traffic forwarding in a data network having at least two area border routers (ABRs), the method comprising steps of:
generating a link state advertisement (LSA) message, and defining a route tag in respect of the generated LSA message; and at each ABR receiving the LSA message, controlling propagation of the received LSA, into an area of the data network hosted by the ABR, using a respective forwarding policy having match criteria corresponding to the defined route tag;
wherein the respective forwarding policy of a first ABR differs from that of a second ABR, such that the received LSA message is flooded into the area hosted by the first ABR, and not flooded into the respective area hosted by the second ABR.
generating a link state advertisement (LSA) message, and defining a route tag in respect of the generated LSA message; and at each ABR receiving the LSA message, controlling propagation of the received LSA, into an area of the data network hosted by the ABR, using a respective forwarding policy having match criteria corresponding to the defined route tag;
wherein the respective forwarding policy of a first ABR differs from that of a second ABR, such that the received LSA message is flooded into the area hosted by the first ABR, and not flooded into the respective area hosted by the second ABR.
2. A method as claimed in claim 1, wherein the data network is an Open Shortest Path first (OSPF) network.
3. A method as claimed in claim 1, wherein the route tag comprises one of:
an internal route tag associated with an address located within an autonomous system of the data network; and an external route tag associated with an address located outside the autonomous system.
an internal route tag associated with an address located within an autonomous system of the data network; and an external route tag associated with an address located outside the autonomous system.
4. A method as claimed in claim 1, wherein the step of defining the route tag comprises steps of:
setting a route tag value respecting the generated LSA; and inserting the route tag value into a predetermined field of the generated LSA.
setting a route tag value respecting the generated LSA; and inserting the route tag value into a predetermined field of the generated LSA.
5. A method as claimed in claim 4, wherein the route tag value is set by a policy having match criteria corresponding to a predetermined attribute of the generated LSA.
6. A method as claimed in claim 5, wherein the predetermined attribute comprises any one or more of:
a source address; a source area; a destination address; and a destination area.
a source address; a source area; a destination address; and a destination area.
7. A method as claimed in claim 4, wherein the generated LSA is a Type-5 LSA, and the step of inserting the route tag comprises a step of inserting the route tag value into an external route tag field of the generated LSA.
8. A method as claimed in claim 4, wherein the step of inserting the route tag comprises a step of inserting the route tag value into an internal route tag field of a modified Type-3 LSA.
9. A method as claimed in claim 1, wherein the forwarding policy corresponds to one of:
a pass decision, in which the received LSA is forwarded to a downstream link; and a discard decision, in which the received LSA is discarded without forwarding.
a pass decision, in which the received LSA is forwarded to a downstream link; and a discard decision, in which the received LSA is discarded without forwarding.
10. A method as claimed in claim 9, wherein implementation of the forwarding policy further comprises a step of updating a forwarding table using information contained in the received LSA as either one of: an inclusion route; and an exclusion route.
11. A router for enabling policy-based traffic forwarding in a data network having at least two routers, the router comprising means for controlling propagation of a received link state advertisement (LSA) message, into an area of the data network hosted by the router, using a respective forwarding policy having match criteria corresponding to a route tag defined in respect of the LSA, wherein the forwarding policy of the router differs from that of a second router, such that the received LSA message is flooded into the area hosted by the router, and not flooded into a respective second area hosted by the second router.
12. A router as claimed in claim 11, wherein the data network comprises an Open Shortest Path first (OSPF) network.
13. A router as claimed in claim 12, wherein the router comprises any one of an autonomous system border router, and an area border router.
14. A router as claimed in claim 11, wherein the route tag comprises one of:
an internal route tag associated with an address located within an autonomous system of the data network; and an external route tag associated with an address located outside the autonomous system.
an internal route tag associated with an address located within an autonomous system of the data network; and an external route tag associated with an address located outside the autonomous system.
15. A router as claimed in claim 11, wherein the forwarding policy corresponds to one of:
a pass decision, in which the LSA is forwarded to a downstream link; and a discard decision, in which the LSA is discarded without forwarding.
a pass decision, in which the LSA is forwarded to a downstream link; and a discard decision, in which the LSA is discarded without forwarding.
16. A router as claimed in claim 15, wherein the means for implementing the forwarding policy further comprises means for updating a forwarding table using information contained in the LSA as either one of an inclusion route and an exclusion route.
17. A router as claimed in claim 11, further comprising means for defining the route tag in respect of the LSA.
18. A router as claimed in claim 17, wherein the means for defining the route tag comprises:
means for setting a route tag value respecting the LSA; and means for inserting the route tag into a predetermined field of the LSA.
means for setting a route tag value respecting the LSA; and means for inserting the route tag into a predetermined field of the LSA.
19. A router as claimed in claim 18, wherein the means for setting the route tag value comprises a policy having match criteria corresponding to one or more predetermined attributes of the LSA.
20. A router as claimed in claim 19, wherein the one or more predetermined attributes comprise any one or more of: a source address; a source area; a destination address; and a destination area.
21. A router as claimed in claim 18, wherein the router is an ABR, and the means for inserting the route tag is adapted to insert the route tag value into an external route tag field of a Type-5 LSA.
22. A router as claimed in claim 18, wherein the router is an ABR, and the means for inserting the route tag is adapted to insert the route tag value into an internal route tag field of a modified Type-3 LSA.
23. A computer readable medium storing a software program for controlling a router to enable policy-based traffic forwarding in a data network having at least two routers, each router hosting an area of the data network, the software program comprising program code executable by the router and adapted to control propagation of a received link state advertisement (LSA) message, into a respective area of the data network hosted by the router, using a respective forwarding policy having a match criteria corresponding to a route tag defined in respect of the LSA, wherein the respective forwarding policy of a first router differs from that of a second router, such that the received LSA message is flooded into the area hosted by the first router, and not flooded into a respective second area hosted by the second router.
24. A computer readable medium as claimed in claim 23, wherein the program code adapted to implement the forwarding policy further comprises program code adapted to control the router to update a forwarding table using information contained in the LSA as either one of: an inclusion route and an exclusion route.
25. A computer readable medium as claimed in claim 23, further comprising program code adapted to control the router to define the route tag in respect of the LSA.
26. A computer readable medium as claimed in claim 25, wherein the program code adapted to control the router to define the route tag comprises:
program code adapted to control the router to set a route tag value respecting the LSA; and program code adapted to control the router to insert the route tag into a predetermined field of the LSA.
program code adapted to control the router to set a route tag value respecting the LSA; and program code adapted to control the router to insert the route tag into a predetermined field of the LSA.
27. A computer readable medium as claimed in claim 26, wherein the router is an ASBR, and the program code adapted to control the router to insert the route tag is adapted to control the router to insert the route tag value into an external route tag field of a Type-LSA.
28. A computer readable medium as claimed in claim 26, wherein the router is an ABR, and the program code adapted to control the router to insert the route tag is adapted to control the router to insert the route tag value into an internal route tag field of a modified Type-3 LSA.
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Families Citing this family (190)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6751191B1 (en) | 1999-06-29 | 2004-06-15 | Cisco Technology, Inc. | Load sharing and redundancy scheme |
US7349979B1 (en) * | 1999-12-02 | 2008-03-25 | Cisco Technology, Inc. | Method and apparatus for redirecting network traffic |
US6839829B1 (en) | 2000-01-18 | 2005-01-04 | Cisco Technology, Inc. | Routing protocol based redundancy design for shared-access networks |
US7058007B1 (en) | 2000-01-18 | 2006-06-06 | Cisco Technology, Inc. | Method for a cable modem to rapidly switch to a backup CMTS |
US7881208B1 (en) | 2001-06-18 | 2011-02-01 | Cisco Technology, Inc. | Gateway load balancing protocol |
AU2002320191A1 (en) * | 2001-06-27 | 2003-03-03 | Arbor Networks | Method and system for monitoring control signal traffic over a computer network |
US7042888B2 (en) * | 2001-09-24 | 2006-05-09 | Ericsson Inc. | System and method for processing packets |
US20030084219A1 (en) * | 2001-10-26 | 2003-05-01 | Maxxan Systems, Inc. | System, apparatus and method for address forwarding for a computer network |
US20030088620A1 (en) * | 2001-11-05 | 2003-05-08 | Microsoft Corporation | Scaleable message dissemination system and method |
US6968393B1 (en) * | 2001-11-19 | 2005-11-22 | Redback Networks, Inc. | Method and apparatus for an attribute oriented routing update |
US7085846B2 (en) * | 2001-12-31 | 2006-08-01 | Maxxan Systems, Incorporated | Buffer to buffer credit flow control for computer network |
US7233593B2 (en) * | 2002-03-05 | 2007-06-19 | Nortel Networks Limited | System, device, and method for routing information in a communication network using policy extrapolation |
US7295561B1 (en) | 2002-04-05 | 2007-11-13 | Ciphermax, Inc. | Fibre channel implementation using network processors |
US20030195956A1 (en) * | 2002-04-15 | 2003-10-16 | Maxxan Systems, Inc. | System and method for allocating unique zone membership |
US20030200330A1 (en) * | 2002-04-22 | 2003-10-23 | Maxxan Systems, Inc. | System and method for load-sharing computer network switch |
US20030202510A1 (en) * | 2002-04-26 | 2003-10-30 | Maxxan Systems, Inc. | System and method for scalable switch fabric for computer network |
US20030202520A1 (en) * | 2002-04-26 | 2003-10-30 | Maxxan Systems, Inc. | Scalable switch fabric system and apparatus for computer networks |
US7362744B2 (en) * | 2002-08-15 | 2008-04-22 | International Business Machines Corporation | Database management system and method of using it to transmit packets |
US7436855B2 (en) * | 2003-02-21 | 2008-10-14 | Alcatel Lucent | Prohibit or avoid route mechanism for path setup |
US8078758B1 (en) * | 2003-06-05 | 2011-12-13 | Juniper Networks, Inc. | Automatic configuration of source address filters within a network device |
US8386272B2 (en) * | 2003-08-06 | 2013-02-26 | International Business Machines Corporation | Autonomic assistance for policy generation |
US20050047412A1 (en) * | 2003-08-25 | 2005-03-03 | Susan Hares | Establishment and enforcement of policies in packet-switched networks |
US7391730B1 (en) * | 2004-07-21 | 2008-06-24 | Cisco Technology | System and method for synchronizing link state databases in a network environment |
US7519009B2 (en) * | 2004-09-29 | 2009-04-14 | The Boeing Company | Virtual exterior gateway protocol and related methods |
US7742431B2 (en) * | 2004-12-22 | 2010-06-22 | Cisco Technology, Inc. | Selectively sending link state messages in a network link state protocol based on interest of network nodes |
WO2007051490A1 (en) * | 2005-10-31 | 2007-05-10 | Hewlett-Packard Development Company, L.P. | Distributing routing information in autonomous systems |
US8531953B2 (en) * | 2006-02-21 | 2013-09-10 | Barclays Capital Inc. | System and method for network traffic splitting |
US8589573B2 (en) | 2006-03-08 | 2013-11-19 | Cisco Technology, Inc. | Technique for preventing routing loops by disseminating BGP attribute information in an OSPF-configured network |
US20070258447A1 (en) * | 2006-05-04 | 2007-11-08 | Robert Raszuk | Inter-area summarization of edge-device addresses using RFC3107 |
US20080288919A1 (en) * | 2007-05-14 | 2008-11-20 | Microsoft Corporation | Encoding of Symbol Table in an Executable |
US7995500B2 (en) * | 2006-11-30 | 2011-08-09 | Cisco Technology, Inc. | Managing an amount of tunnels in a computer network |
US8175099B2 (en) * | 2007-05-14 | 2012-05-08 | Microsoft Corporation | Embedded system development platform |
US7672253B2 (en) * | 2007-08-06 | 2010-03-02 | Cisco Technology, Inc. | Border router with selective filtering of link state advertisements |
US8238338B2 (en) | 2007-09-14 | 2012-08-07 | Cisco Technology, Inc. | Interior gateway protocol summarization preserving internet protocol reachability information |
US7860027B2 (en) * | 2007-11-21 | 2010-12-28 | Cisco Technology, Inc. | Extending an IP everywhere network over a plurality of flooding domains |
US7876700B2 (en) * | 2007-12-14 | 2011-01-25 | Verizon Patent And Licensing Inc. | Method and system for providing default route advertisement protection |
US9456054B2 (en) | 2008-05-16 | 2016-09-27 | Palo Alto Research Center Incorporated | Controlling the spread of interests and content in a content centric network |
CN101753424B (en) * | 2008-11-28 | 2012-07-04 | 华为技术有限公司 | Data communication system, router, data sending and mobility management method |
US8923293B2 (en) | 2009-10-21 | 2014-12-30 | Palo Alto Research Center Incorporated | Adaptive multi-interface use for content networking |
US8959201B2 (en) * | 2009-12-16 | 2015-02-17 | Juniper Networks, Inc. | Limiting control traffic in a redundant gateway architecture |
CN101820395B (en) * | 2010-05-19 | 2012-11-28 | 杭州华三通信技术有限公司 | Routing information configuration and private network label addition method and device based on MPLS (Multiple Protocol Label Switching) |
US8478917B2 (en) | 2010-09-22 | 2013-07-02 | Microsoft Corporation | Automatic addressing protocol for a shared bus |
KR20120071118A (en) * | 2010-12-22 | 2012-07-02 | 한국전자통신연구원 | Path computation apparatus and path computation apparatus method for the same |
US11178244B2 (en) * | 2011-08-09 | 2021-11-16 | Comcast Cable Communications, Llc | Content delivery network routing using border gateway protocol |
WO2013052893A1 (en) * | 2011-10-07 | 2013-04-11 | Huawei Technologies Co., Ltd. | Simple topology transparent zoning in network communications |
US9280546B2 (en) | 2012-10-31 | 2016-03-08 | Palo Alto Research Center Incorporated | System and method for accessing digital content using a location-independent name |
US9400800B2 (en) | 2012-11-19 | 2016-07-26 | Palo Alto Research Center Incorporated | Data transport by named content synchronization |
US9325561B2 (en) * | 2012-12-05 | 2016-04-26 | At&T Intellectual Property I, L.P. | Inter-provider network architecture |
US10430839B2 (en) | 2012-12-12 | 2019-10-01 | Cisco Technology, Inc. | Distributed advertisement insertion in content-centric networks |
US9978025B2 (en) | 2013-03-20 | 2018-05-22 | Cisco Technology, Inc. | Ordered-element naming for name-based packet forwarding |
US9935791B2 (en) | 2013-05-20 | 2018-04-03 | Cisco Technology, Inc. | Method and system for name resolution across heterogeneous architectures |
US9185120B2 (en) | 2013-05-23 | 2015-11-10 | Palo Alto Research Center Incorporated | Method and system for mitigating interest flooding attacks in content-centric networks |
US9444722B2 (en) | 2013-08-01 | 2016-09-13 | Palo Alto Research Center Incorporated | Method and apparatus for configuring routing paths in a custodian-based routing architecture |
US9258210B2 (en) | 2013-10-01 | 2016-02-09 | Juniper Networks, Inc. | Dynamic area filtering for link-state routing protocols |
US9407549B2 (en) | 2013-10-29 | 2016-08-02 | Palo Alto Research Center Incorporated | System and method for hash-based forwarding of packets with hierarchically structured variable-length identifiers |
US9276840B2 (en) | 2013-10-30 | 2016-03-01 | Palo Alto Research Center Incorporated | Interest messages with a payload for a named data network |
US9282050B2 (en) | 2013-10-30 | 2016-03-08 | Palo Alto Research Center Incorporated | System and method for minimum path MTU discovery in content centric networks |
US9401864B2 (en) | 2013-10-31 | 2016-07-26 | Palo Alto Research Center Incorporated | Express header for packets with hierarchically structured variable-length identifiers |
US10101801B2 (en) | 2013-11-13 | 2018-10-16 | Cisco Technology, Inc. | Method and apparatus for prefetching content in a data stream |
US9311377B2 (en) | 2013-11-13 | 2016-04-12 | Palo Alto Research Center Incorporated | Method and apparatus for performing server handoff in a name-based content distribution system |
US10129365B2 (en) | 2013-11-13 | 2018-11-13 | Cisco Technology, Inc. | Method and apparatus for pre-fetching remote content based on static and dynamic recommendations |
US10089655B2 (en) | 2013-11-27 | 2018-10-02 | Cisco Technology, Inc. | Method and apparatus for scalable data broadcasting |
US9503358B2 (en) * | 2013-12-05 | 2016-11-22 | Palo Alto Research Center Incorporated | Distance-based routing in an information-centric network |
US9379979B2 (en) | 2014-01-14 | 2016-06-28 | Palo Alto Research Center Incorporated | Method and apparatus for establishing a virtual interface for a set of mutual-listener devices |
US10172068B2 (en) | 2014-01-22 | 2019-01-01 | Cisco Technology, Inc. | Service-oriented routing in software-defined MANETs |
US10098051B2 (en) | 2014-01-22 | 2018-10-09 | Cisco Technology, Inc. | Gateways and routing in software-defined manets |
US9374304B2 (en) | 2014-01-24 | 2016-06-21 | Palo Alto Research Center Incorporated | End-to end route tracing over a named-data network |
US9954678B2 (en) | 2014-02-06 | 2018-04-24 | Cisco Technology, Inc. | Content-based transport security |
US9531679B2 (en) | 2014-02-06 | 2016-12-27 | Palo Alto Research Center Incorporated | Content-based transport security for distributed producers |
US9678998B2 (en) | 2014-02-28 | 2017-06-13 | Cisco Technology, Inc. | Content name resolution for information centric networking |
US10089651B2 (en) | 2014-03-03 | 2018-10-02 | Cisco Technology, Inc. | Method and apparatus for streaming advertisements in a scalable data broadcasting system |
US9836540B2 (en) | 2014-03-04 | 2017-12-05 | Cisco Technology, Inc. | System and method for direct storage access in a content-centric network |
US9473405B2 (en) | 2014-03-10 | 2016-10-18 | Palo Alto Research Center Incorporated | Concurrent hashes and sub-hashes on data streams |
US9391896B2 (en) | 2014-03-10 | 2016-07-12 | Palo Alto Research Center Incorporated | System and method for packet forwarding using a conjunctive normal form strategy in a content-centric network |
US9626413B2 (en) | 2014-03-10 | 2017-04-18 | Cisco Systems, Inc. | System and method for ranking content popularity in a content-centric network |
US9407432B2 (en) | 2014-03-19 | 2016-08-02 | Palo Alto Research Center Incorporated | System and method for efficient and secure distribution of digital content |
US9916601B2 (en) | 2014-03-21 | 2018-03-13 | Cisco Technology, Inc. | Marketplace for presenting advertisements in a scalable data broadcasting system |
US9363179B2 (en) | 2014-03-26 | 2016-06-07 | Palo Alto Research Center Incorporated | Multi-publisher routing protocol for named data networks |
US9363086B2 (en) | 2014-03-31 | 2016-06-07 | Palo Alto Research Center Incorporated | Aggregate signing of data in content centric networking |
US9716622B2 (en) | 2014-04-01 | 2017-07-25 | Cisco Technology, Inc. | System and method for dynamic name configuration in content-centric networks |
US9390289B2 (en) | 2014-04-07 | 2016-07-12 | Palo Alto Research Center Incorporated | Secure collection synchronization using matched network names |
US10075521B2 (en) | 2014-04-07 | 2018-09-11 | Cisco Technology, Inc. | Collection synchronization using equality matched network names |
US9473576B2 (en) | 2014-04-07 | 2016-10-18 | Palo Alto Research Center Incorporated | Service discovery using collection synchronization with exact names |
US9451032B2 (en) | 2014-04-10 | 2016-09-20 | Palo Alto Research Center Incorporated | System and method for simple service discovery in content-centric networks |
US9203885B2 (en) | 2014-04-28 | 2015-12-01 | Palo Alto Research Center Incorporated | Method and apparatus for exchanging bidirectional streams over a content centric network |
US9992281B2 (en) | 2014-05-01 | 2018-06-05 | Cisco Technology, Inc. | Accountable content stores for information centric networks |
US9609014B2 (en) | 2014-05-22 | 2017-03-28 | Cisco Systems, Inc. | Method and apparatus for preventing insertion of malicious content at a named data network router |
US9455835B2 (en) | 2014-05-23 | 2016-09-27 | Palo Alto Research Center Incorporated | System and method for circular link resolution with hash-based names in content-centric networks |
US9276751B2 (en) | 2014-05-28 | 2016-03-01 | Palo Alto Research Center Incorporated | System and method for circular link resolution with computable hash-based names in content-centric networks |
US9467377B2 (en) | 2014-06-19 | 2016-10-11 | Palo Alto Research Center Incorporated | Associating consumer states with interests in a content-centric network |
US9537719B2 (en) | 2014-06-19 | 2017-01-03 | Palo Alto Research Center Incorporated | Method and apparatus for deploying a minimal-cost CCN topology |
US9516144B2 (en) | 2014-06-19 | 2016-12-06 | Palo Alto Research Center Incorporated | Cut-through forwarding of CCNx message fragments with IP encapsulation |
US9426113B2 (en) | 2014-06-30 | 2016-08-23 | Palo Alto Research Center Incorporated | System and method for managing devices over a content centric network |
EP3164962B1 (en) * | 2014-07-03 | 2020-08-26 | Fiber Mountain, Inc. | Data center path switch with improved path interconnection architecture |
US9699198B2 (en) | 2014-07-07 | 2017-07-04 | Cisco Technology, Inc. | System and method for parallel secure content bootstrapping in content-centric networks |
US9621354B2 (en) | 2014-07-17 | 2017-04-11 | Cisco Systems, Inc. | Reconstructable content objects |
US9959156B2 (en) | 2014-07-17 | 2018-05-01 | Cisco Technology, Inc. | Interest return control message |
US9729616B2 (en) | 2014-07-18 | 2017-08-08 | Cisco Technology, Inc. | Reputation-based strategy for forwarding and responding to interests over a content centric network |
US9590887B2 (en) | 2014-07-18 | 2017-03-07 | Cisco Systems, Inc. | Method and system for keeping interest alive in a content centric network |
US9535968B2 (en) | 2014-07-21 | 2017-01-03 | Palo Alto Research Center Incorporated | System for distributing nameless objects using self-certifying names |
US9882964B2 (en) | 2014-08-08 | 2018-01-30 | Cisco Technology, Inc. | Explicit strategy feedback in name-based forwarding |
US9729662B2 (en) | 2014-08-11 | 2017-08-08 | Cisco Technology, Inc. | Probabilistic lazy-forwarding technique without validation in a content centric network |
US9503365B2 (en) | 2014-08-11 | 2016-11-22 | Palo Alto Research Center Incorporated | Reputation-based instruction processing over an information centric network |
US9391777B2 (en) | 2014-08-15 | 2016-07-12 | Palo Alto Research Center Incorporated | System and method for performing key resolution over a content centric network |
US9800637B2 (en) | 2014-08-19 | 2017-10-24 | Cisco Technology, Inc. | System and method for all-in-one content stream in content-centric networks |
US9467492B2 (en) | 2014-08-19 | 2016-10-11 | Palo Alto Research Center Incorporated | System and method for reconstructable all-in-one content stream |
US9497282B2 (en) | 2014-08-27 | 2016-11-15 | Palo Alto Research Center Incorporated | Network coding for content-centric network |
US20160065503A1 (en) * | 2014-08-29 | 2016-03-03 | Extreme Networks, Inc. | Methods, systems, and computer readable media for virtual fabric routing |
US10204013B2 (en) | 2014-09-03 | 2019-02-12 | Cisco Technology, Inc. | System and method for maintaining a distributed and fault-tolerant state over an information centric network |
US9553812B2 (en) | 2014-09-09 | 2017-01-24 | Palo Alto Research Center Incorporated | Interest keep alives at intermediate routers in a CCN |
US10069933B2 (en) | 2014-10-23 | 2018-09-04 | Cisco Technology, Inc. | System and method for creating virtual interfaces based on network characteristics |
US9590948B2 (en) | 2014-12-15 | 2017-03-07 | Cisco Systems, Inc. | CCN routing using hardware-assisted hash tables |
US9536059B2 (en) | 2014-12-15 | 2017-01-03 | Palo Alto Research Center Incorporated | Method and system for verifying renamed content using manifests in a content centric network |
US10237189B2 (en) | 2014-12-16 | 2019-03-19 | Cisco Technology, Inc. | System and method for distance-based interest forwarding |
US9846881B2 (en) | 2014-12-19 | 2017-12-19 | Palo Alto Research Center Incorporated | Frugal user engagement help systems |
US9473475B2 (en) | 2014-12-22 | 2016-10-18 | Palo Alto Research Center Incorporated | Low-cost authenticated signing delegation in content centric networking |
US10003520B2 (en) | 2014-12-22 | 2018-06-19 | Cisco Technology, Inc. | System and method for efficient name-based content routing using link-state information in information-centric networks |
US9660825B2 (en) | 2014-12-24 | 2017-05-23 | Cisco Technology, Inc. | System and method for multi-source multicasting in content-centric networks |
US9832291B2 (en) | 2015-01-12 | 2017-11-28 | Cisco Technology, Inc. | Auto-configurable transport stack |
US9954795B2 (en) | 2015-01-12 | 2018-04-24 | Cisco Technology, Inc. | Resource allocation using CCN manifests |
US9916457B2 (en) | 2015-01-12 | 2018-03-13 | Cisco Technology, Inc. | Decoupled name security binding for CCN objects |
US9946743B2 (en) | 2015-01-12 | 2018-04-17 | Cisco Technology, Inc. | Order encoded manifests in a content centric network |
US9602596B2 (en) | 2015-01-12 | 2017-03-21 | Cisco Systems, Inc. | Peer-to-peer sharing in a content centric network |
US9462006B2 (en) | 2015-01-21 | 2016-10-04 | Palo Alto Research Center Incorporated | Network-layer application-specific trust model |
US9552493B2 (en) | 2015-02-03 | 2017-01-24 | Palo Alto Research Center Incorporated | Access control framework for information centric networking |
US10333840B2 (en) | 2015-02-06 | 2019-06-25 | Cisco Technology, Inc. | System and method for on-demand content exchange with adaptive naming in information-centric networks |
US10075401B2 (en) | 2015-03-18 | 2018-09-11 | Cisco Technology, Inc. | Pending interest table behavior |
US10116605B2 (en) | 2015-06-22 | 2018-10-30 | Cisco Technology, Inc. | Transport stack name scheme and identity management |
US10075402B2 (en) | 2015-06-24 | 2018-09-11 | Cisco Technology, Inc. | Flexible command and control in content centric networks |
US10701038B2 (en) | 2015-07-27 | 2020-06-30 | Cisco Technology, Inc. | Content negotiation in a content centric network |
US9986034B2 (en) | 2015-08-03 | 2018-05-29 | Cisco Technology, Inc. | Transferring state in content centric network stacks |
US10610144B2 (en) | 2015-08-19 | 2020-04-07 | Palo Alto Research Center Incorporated | Interactive remote patient monitoring and condition management intervention system |
US9832123B2 (en) | 2015-09-11 | 2017-11-28 | Cisco Technology, Inc. | Network named fragments in a content centric network |
US10355999B2 (en) | 2015-09-23 | 2019-07-16 | Cisco Technology, Inc. | Flow control with network named fragments |
US9977809B2 (en) | 2015-09-24 | 2018-05-22 | Cisco Technology, Inc. | Information and data framework in a content centric network |
US10313227B2 (en) | 2015-09-24 | 2019-06-04 | Cisco Technology, Inc. | System and method for eliminating undetected interest looping in information-centric networks |
US10454820B2 (en) | 2015-09-29 | 2019-10-22 | Cisco Technology, Inc. | System and method for stateless information-centric networking |
US10263965B2 (en) | 2015-10-16 | 2019-04-16 | Cisco Technology, Inc. | Encrypted CCNx |
US9794238B2 (en) | 2015-10-29 | 2017-10-17 | Cisco Technology, Inc. | System for key exchange in a content centric network |
US9807205B2 (en) | 2015-11-02 | 2017-10-31 | Cisco Technology, Inc. | Header compression for CCN messages using dictionary |
US10009446B2 (en) | 2015-11-02 | 2018-06-26 | Cisco Technology, Inc. | Header compression for CCN messages using dictionary learning |
US10021222B2 (en) | 2015-11-04 | 2018-07-10 | Cisco Technology, Inc. | Bit-aligned header compression for CCN messages using dictionary |
US10097521B2 (en) | 2015-11-20 | 2018-10-09 | Cisco Technology, Inc. | Transparent encryption in a content centric network |
US9912776B2 (en) | 2015-12-02 | 2018-03-06 | Cisco Technology, Inc. | Explicit content deletion commands in a content centric network |
US10097346B2 (en) | 2015-12-09 | 2018-10-09 | Cisco Technology, Inc. | Key catalogs in a content centric network |
US10078062B2 (en) | 2015-12-15 | 2018-09-18 | Palo Alto Research Center Incorporated | Device health estimation by combining contextual information with sensor data |
US10257271B2 (en) | 2016-01-11 | 2019-04-09 | Cisco Technology, Inc. | Chandra-Toueg consensus in a content centric network |
US9949301B2 (en) | 2016-01-20 | 2018-04-17 | Palo Alto Research Center Incorporated | Methods for fast, secure and privacy-friendly internet connection discovery in wireless networks |
US10305864B2 (en) | 2016-01-25 | 2019-05-28 | Cisco Technology, Inc. | Method and system for interest encryption in a content centric network |
US10043016B2 (en) | 2016-02-29 | 2018-08-07 | Cisco Technology, Inc. | Method and system for name encryption agreement in a content centric network |
US10742596B2 (en) | 2016-03-04 | 2020-08-11 | Cisco Technology, Inc. | Method and system for reducing a collision probability of hash-based names using a publisher identifier |
US10003507B2 (en) | 2016-03-04 | 2018-06-19 | Cisco Technology, Inc. | Transport session state protocol |
US10051071B2 (en) | 2016-03-04 | 2018-08-14 | Cisco Technology, Inc. | Method and system for collecting historical network information in a content centric network |
US10038633B2 (en) | 2016-03-04 | 2018-07-31 | Cisco Technology, Inc. | Protocol to query for historical network information in a content centric network |
US9832116B2 (en) | 2016-03-14 | 2017-11-28 | Cisco Technology, Inc. | Adjusting entries in a forwarding information base in a content centric network |
US10212196B2 (en) | 2016-03-16 | 2019-02-19 | Cisco Technology, Inc. | Interface discovery and authentication in a name-based network |
US11436656B2 (en) | 2016-03-18 | 2022-09-06 | Palo Alto Research Center Incorporated | System and method for a real-time egocentric collaborative filter on large datasets |
US10067948B2 (en) | 2016-03-18 | 2018-09-04 | Cisco Technology, Inc. | Data deduping in content centric networking manifests |
US10091330B2 (en) | 2016-03-23 | 2018-10-02 | Cisco Technology, Inc. | Interest scheduling by an information and data framework in a content centric network |
US10033639B2 (en) | 2016-03-25 | 2018-07-24 | Cisco Technology, Inc. | System and method for routing packets in a content centric network using anonymous datagrams |
US10320760B2 (en) | 2016-04-01 | 2019-06-11 | Cisco Technology, Inc. | Method and system for mutating and caching content in a content centric network |
US9930146B2 (en) | 2016-04-04 | 2018-03-27 | Cisco Technology, Inc. | System and method for compressing content centric networking messages |
US10425503B2 (en) | 2016-04-07 | 2019-09-24 | Cisco Technology, Inc. | Shared pending interest table in a content centric network |
US10027578B2 (en) | 2016-04-11 | 2018-07-17 | Cisco Technology, Inc. | Method and system for routable prefix queries in a content centric network |
US10404450B2 (en) | 2016-05-02 | 2019-09-03 | Cisco Technology, Inc. | Schematized access control in a content centric network |
US10320675B2 (en) | 2016-05-04 | 2019-06-11 | Cisco Technology, Inc. | System and method for routing packets in a stateless content centric network |
US10547589B2 (en) | 2016-05-09 | 2020-01-28 | Cisco Technology, Inc. | System for implementing a small computer systems interface protocol over a content centric network |
US10063414B2 (en) | 2016-05-13 | 2018-08-28 | Cisco Technology, Inc. | Updating a transport stack in a content centric network |
US10084764B2 (en) | 2016-05-13 | 2018-09-25 | Cisco Technology, Inc. | System for a secure encryption proxy in a content centric network |
US10103989B2 (en) | 2016-06-13 | 2018-10-16 | Cisco Technology, Inc. | Content object return messages in a content centric network |
US10305865B2 (en) | 2016-06-21 | 2019-05-28 | Cisco Technology, Inc. | Permutation-based content encryption with manifests in a content centric network |
US10148572B2 (en) | 2016-06-27 | 2018-12-04 | Cisco Technology, Inc. | Method and system for interest groups in a content centric network |
US10009266B2 (en) | 2016-07-05 | 2018-06-26 | Cisco Technology, Inc. | Method and system for reference counted pending interest tables in a content centric network |
US9992097B2 (en) | 2016-07-11 | 2018-06-05 | Cisco Technology, Inc. | System and method for piggybacking routing information in interests in a content centric network |
US10122624B2 (en) | 2016-07-25 | 2018-11-06 | Cisco Technology, Inc. | System and method for ephemeral entries in a forwarding information base in a content centric network |
US10069729B2 (en) | 2016-08-08 | 2018-09-04 | Cisco Technology, Inc. | System and method for throttling traffic based on a forwarding information base in a content centric network |
US10956412B2 (en) | 2016-08-09 | 2021-03-23 | Cisco Technology, Inc. | Method and system for conjunctive normal form attribute matching in a content centric network |
US10225628B2 (en) | 2016-09-14 | 2019-03-05 | Fiber Mountain, Inc. | Intelligent fiber port management |
US10033642B2 (en) | 2016-09-19 | 2018-07-24 | Cisco Technology, Inc. | System and method for making optimal routing decisions based on device-specific parameters in a content centric network |
US10212248B2 (en) | 2016-10-03 | 2019-02-19 | Cisco Technology, Inc. | Cache management on high availability routers in a content centric network |
US10447805B2 (en) | 2016-10-10 | 2019-10-15 | Cisco Technology, Inc. | Distributed consensus in a content centric network |
US10135948B2 (en) | 2016-10-31 | 2018-11-20 | Cisco Technology, Inc. | System and method for process migration in a content centric network |
US10243851B2 (en) | 2016-11-21 | 2019-03-26 | Cisco Technology, Inc. | System and method for forwarder connection information in a content centric network |
CN111837368B (en) | 2018-02-23 | 2022-01-14 | 华为技术有限公司 | Advertising and programming of preferred path routing using interior gateway protocols |
WO2019190699A1 (en) * | 2018-03-28 | 2019-10-03 | Futurewei Technologies, Inc. | Method and apparatus for preferred path route information distribution and maintenance |
CN112055954B (en) | 2018-04-26 | 2022-08-26 | 华为技术有限公司 | Resource reservation and maintenance of preferred path routes in a network |
WO2019212678A1 (en) | 2018-05-04 | 2019-11-07 | Futurewei Technologies, Inc. | Explicit backups and fast re-route mechanisms for preferred path routes in a network |
WO2019236221A1 (en) | 2018-06-04 | 2019-12-12 | Futurewei Technologies, Inc. | Preferred path route graphs in a network |
US10887216B2 (en) * | 2019-02-12 | 2021-01-05 | Hewlett Packard Enterprise Development Lp | Managing default route advertisements by an area border router in an open shortest path first network |
CN113179212B (en) * | 2021-03-11 | 2022-05-27 | 新华三信息安全技术有限公司 | Message processing method and device |
Family Cites Families (16)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5265092A (en) * | 1992-03-18 | 1993-11-23 | Digital Equipment Corporation | Synchronization mechanism for link state packet routing |
US5684800A (en) * | 1995-11-15 | 1997-11-04 | Cabletron Systems, Inc. | Method for establishing restricted broadcast groups in a switched network |
US5917820A (en) * | 1996-06-10 | 1999-06-29 | Cisco Technology, Inc. | Efficient packet forwarding arrangement for routing packets in an internetwork |
US6275492B1 (en) * | 1996-12-03 | 2001-08-14 | Nortel Networks Limited | Method and apparatus for routing data using router identification information |
US5964841A (en) * | 1997-03-03 | 1999-10-12 | Cisco Technology, Inc. | Technique for handling forwarding transients with link state routing protocol |
US6473421B1 (en) * | 1999-03-29 | 2002-10-29 | Cisco Technology, Inc. | Hierarchical label switching across multiple OSPF areas |
EP1063814A1 (en) * | 1999-06-24 | 2000-12-27 | Alcatel | A method to forward a multicast packet |
SE521516C2 (en) * | 1999-09-14 | 2003-11-11 | Ericsson Telefon Ab L M | Routing monitoring and handling device for communication network, using control device with copy of link condition database for its associated routing regions |
US6606325B1 (en) * | 1999-12-10 | 2003-08-12 | Nortel Networks Limited | Fast path forwarding of link state advertisements using multicast addressing |
US6871235B1 (en) * | 1999-12-10 | 2005-03-22 | Nortel Networks Limited | Fast path forwarding of link state advertisements using reverse path forwarding |
US6928483B1 (en) * | 1999-12-10 | 2005-08-09 | Nortel Networks Limited | Fast path forwarding of link state advertisements |
US6650626B1 (en) * | 1999-12-10 | 2003-11-18 | Nortel Networks Limited | Fast path forwarding of link state advertisements using a minimum spanning tree |
JP3501093B2 (en) * | 2000-04-18 | 2004-02-23 | 日本電気株式会社 | QoS path calculator |
DE60130844T2 (en) * | 2000-08-29 | 2008-07-17 | International Business Machines Corp. | Autonomous OSPF system with a main network separated into two sections |
US7234001B2 (en) * | 2000-12-20 | 2007-06-19 | Nortel Networks Limited | Dormant backup link for OSPF network protection |
US7082473B2 (en) * | 2001-02-01 | 2006-07-25 | Lucent Technologies Inc. | System and method for optimizing open shortest path first aggregates and autonomous network domain incorporating the same |
-
2001
- 2001-07-06 US US09/899,265 patent/US7831733B2/en active Active
- 2001-12-20 WO PCT/CA2001/001827 patent/WO2003005649A1/en active IP Right Grant
- 2001-12-20 CA CA2433891A patent/CA2433891C/en not_active Expired - Fee Related
- 2001-12-20 EP EP01994574A patent/EP1405468B1/en not_active Expired - Lifetime
- 2001-12-20 DE DE60128733T patent/DE60128733T2/en not_active Expired - Lifetime
Also Published As
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EP1405468B1 (en) | 2007-05-30 |
US7831733B2 (en) | 2010-11-09 |
DE60128733T2 (en) | 2008-01-31 |
EP1405468A1 (en) | 2004-04-07 |
US20030014540A1 (en) | 2003-01-16 |
DE60128733D1 (en) | 2007-07-12 |
CA2433891A1 (en) | 2003-01-16 |
WO2003005649A1 (en) | 2003-01-16 |
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