CN100574235C

CN100574235C - The method and apparatus that is used for Border Gateway Protocol based on contextual prefix updates

Info

Publication number: CN100574235C
Application number: CNB200680001816XA
Authority: CN
Inventors: 马丁·迪杰纳斯; 戴维·D·沃德
Original assignee: Cisco Technology Inc
Current assignee: Cisco Technology Inc
Priority date: 2005-01-27
Filing date: 2006-01-20
Publication date: 2009-12-23
Anticipated expiration: 2026-01-20
Also published as: CN101099342A

Abstract

A kind of equipment that is used for providing at Border Gateway Protocol (BGP) main frame the routing table renewal is disclosed.Represent one or more contexts of different routing table in the BGP main frame, to be defined.As setting up the part of bgp session with bgp peer, the specific context in described one or more contexts is announced to bgp peer.In response to receive the routing update message that comprises the information that identifies this specific context from bgp peer, at the routing table of BGP main frame place renewal by this specific context representative.

Description

The method and apparatus that is used for Border Gateway Protocol based on contextual prefix updates

Technical field

Relate generally to network Route Selection of the present invention.More specifically, the present invention relates in Border Gateway Protocol (BGP), provide based on contextual prefix updates.

Background technology

The method of describing in this part can be implemented, but the method that has not necessarily before envisioned or realized.Therefore, unless indicate in addition here, the method for describing in this part is not the prior art of the application's claim, and not because be included in just admit it is prior art in this part.

Border Gateway Protocol (BGP) is the path vector routing protocol that is used for Route Selection between autonomous system.The function that is endowed the network element (BGP main frame or peer-to-peer) of BGP ability is the network element switching network reachability information that is endowed the BGP ability with other.The bgp version of normal realization is BGP-4, and it defines in RFC1771 (delivered by internet engineering task group (IETF) March nineteen ninety-five).

In order to exchange routing information, two BGP main frames are at first set up peering session by exchange BGP OPEN (BGP is open) message.The BGP main frame exchanges its whole routing tables subsequently.After this initial exchange, each BGP main frame only sends to its one or more bgp peers with the incremental update of new, modified and unavailable or the route of recalling in one or more BGP UPDATE (bgp update) message.Route is defined as information unit that network destination and attribute to the network path of this destination are matched mutually.The attribute of network path comprises along the network address of the computer system in this path and (is also referred to as address prefix or just is called prefix), or the like.In the BGP main frame, route is stored in the routing information storehouse (RIB).The specific software implementation that depends on BGP, RIB can be represented by one or more routing tables.When a more than routing table was represented RIB, routing table can be the logical subsets that is stored in the information in the same amount of physical memory, and perhaps routing table can be stored in the physically separated memory space.

According to the definition among the RFC1771, the structure of BGP UPDATE message only adapts to the renewal to internet protocol version four (IPv4) singlecast router.X.25 and frame relay the multi-protocols exaptation of the BGP of definition is to the renewal of the routing information that is used for a plurality of network layer protocols among the RFC2858 (delivered by IETF in June, 2000), and described a plurality of network layer protocols for example are IPv 6 (IPv6), the Internet packet exchange (IPX), Appletalk, Banyan Vines, ATM(Asynchronous Transfer Mode).RFC2558 has introduced the change that two monodrome parameters adapt to the BGPUPDATE message structure: Address-Family Identifier symbol (AFI) and subsequent address family identifier (SAFI).

The AFI parameter is being carried the identity of the network layer protocol that is associated with the ensuing network address in the path of going to the destination.The SAFI parameter provides the extraneous information about the type of the Network layer reachability information that comprises in the BGP UPDATE message, and for the value of this parameter-definition indicate usually communication forwarding mechanism type, for example unicast or multicast.Though some in AFI and the SAFI value is reserved for private, common spendable AFI of the public and SAFI value must be distributed by internet number assignment mechanism (IANA).AFI/SAFI makes up the type that is realized being used to refer to the BGP prefix updates by the software of BGP, and what form prefix updates has, and how to explain the route that comprises in the BGP UPDATE message.

But the AFI/SAFI hierarchical structure is a kind of can not the modification at an easy rate to adapt to the strict structure of variation.Do not follow the novel address of the current hierarchical structure of master's house family address and follow-up family address if desired, then there is not any good method that renewal is conveyed to the route that comprises the address of following this novel address, because only use AFI and/or SAFI value may not describe this novel address fully.

For example, along with the diffusion of the networks of different type flow such as stream-type video and ip voice, in network, may there be the dissimilar address that belongs to same address family.Network may transmit audio frequency, video and routine data flow in the IPv4 address network.In this case, wish to be different types of traffic storage networking route in different routing tables, to realize routing update faster.But, because different routes are to represent that by same address family (for example indicating the AFI/SAFI combination of IPv4 clean culture) therefore current BGP implementation can't be distinguished these routes, thereby will have to they are placed in the same routing table.Thereby with regard to distinguishing the route that transmits the networks of different type flow, the AFI/SAFI combination has been proved to be inefficient at least.

The method that adapts to a kind of past of new address family in the BGP implementation is the new SAFI value that branch is used in sign VPN(Virtual Private Network) address.In the method, the implementation of BGP also is modified, to handle particularly by BGP UPDATE message being used for of transmitting prefix to the renewal of the route that comprises the VPN address.

But this method has some shortcomings.A problem is when receiving BGP UPDATE message, must extract whole route earlier from message, could determine to upgrade to go to which routing table then.Another problem of utilizing this method to adapt to new address family is whenever by distributing new AFI and/or SAFI value to limit new address family, just need realize and the BGPUPDATE message structure be made formal change the software of BGP.

Another problem of utilizing the AFI/SAFI hierarchical structure to upgrade route in BGP is that present BGP is not supported in the NEXT_HOP PATH attribute that the BGP UPDATE message that is used for the IPv4 route comprises and sends the IPv6 address prefix.At present, BGP acquiescence NEXT_HOP property value be BGPUPDATE message at same address family.Its reason is that 16 byte IPv6 addresses can't be stored in the 4 byte IPv4 address spaces, and therefore, it is that the IPv4 route of the address in " pure " IPv6 network provides routing update that BGP can't be utilized for next jumping in the route wherein.

Based on afore-mentioned, clearly need be in BGP for comprising that the route from the address of the address style of redetermination or address family provides routing table to upgrade, and does not require the technology that any modification is made in the software realization of BGP itself simultaneously.In addition, clearly need be in BGP the jumping of next in route be that the IPv4 route of the address in the IPv6 network provides renewal.

Description of drawings

By accompanying drawing by way of example and non-limited way explanation the present invention, in the accompanying drawing similarly label be meant similar elements, wherein:

Fig. 1 is the block diagram that illustrates the overview of the network element that can realize an embodiment on it;

Fig. 2 is the block diagram of diagram according to the example of the relation of an embodiment between the bgp context that defines on two bgp peers;

Fig. 3 A is the block diagram of diagram according to the form of the BGP UPDATE message of an embodiment;

Fig. 3 B is a diagram according to the block diagram based on the form of contextual capability value field of BGP CAPABILITIES (BGP ability) parameter of an embodiment;

Fig. 3 C is a diagram according to the block diagram based on the form of the context description field of contextual capability value field of an embodiment;

Fig. 3 D is the block diagram of diagram according to the form of the contextual PATH of the indication of an embodiment (path) attribute value field;

Fig. 4 is the flow chart of overview that diagram is used for providing at BGP an embodiment of routing table method for updating;

Fig. 5 illustrates the block diagram that can realize the computer system of an embodiment on it; And

Fig. 6 is the block diagram of the form of diagram BGP CONTEXT (bgp context) capability value field.

Embodiment

Described and be used for providing routing table method for updating and equipment in Border Gateway Protocol (BGP).In the following description, for purpose of explanation, a large amount of details have been provided so that understand the present invention fully.But it will be apparent to one skilled in the art that does not have these details can implement the present invention yet.In other examples, known structure and equipment illustrate with the block diagram form, to avoid unnecessarily fuzzy the present invention.

Here according to following outline embodiment is described:

1.0 general introduction

2.0 26S Proteasome Structure and Function general introduction

3.0 the architectural feature of an embodiment

3.1 context and context identifier

3.2BGP the form based on contextual UPDATE message

3.3BGP context description format

3.4BGP with the PATH attribute format of context-sensitive

4.0 the routing table method for updating is provided in BGP

4.1 process based on contextual prefix updates

4.2 process based on contextual next jumping Route Selection

5.0 be used for announcement and upgrade contextual CONTEXT capability approach

6.0 realize mechanism-ardware overview

7.0 expansion and replacement

1.0 general introduction

The demand that the aforementioned background art part is pointed and other demands and the target that will display from the following description are achieved in the present invention, and the present invention comprises a kind of equipment that is used for providing at Border Gateway Protocol (BGP) main frame the routing table renewal in one aspect.Represent one or more contexts of different routing table in the BGP main frame, to be defined.As setting up the part of bgp session with bgp peer, the BGP main frame is announced specific context in the described context to bgp peer.In response to receive the routing update message that comprises the information that identifies this specific context from bgp peer, the BGP main frame upgrades the routing table by this specific context representative.

In a feature aspect this, the storage of each different routing table has one group of route of the address prefix that belongs to same address family.In another feature aspect this, the storage of each different routing table has one group of route of the address prefix that belongs to different address family.

In a feature aspect this, in each different routing table, store one group of route, every group of route is used for the packets of information that route is carried particular type.In this feature, the information of particular type can be at least a in video, audio frequency or the data message.

In a feature aspect this, each in described one or more contexts is associated with unique context identifier and unique context-descriptive.As the part of announcement specific context, the context identifier and the context-descriptive that are associated with this specific context are sent to bgp peer.Comprise the context identifier that is associated with this specific context in the information that bgp peer sends subsequently in the routing update message of going to the BGP main frame.

In a feature aspect this, context identifier that is associated with specific context and context-descriptive are to give bgp peer sending to as a part of setting up bgp session in the BGP CAPABILITIES parameter that comprises in the BGPOPEN message of bgp peer by announcement.

In a feature aspect this, the routing update message that receives from bgp peer is a BGPUPDATE message.

In a feature aspect this, routing update message comprises context property, and wherein context property is a BGP PATH attribute.The value of first context property associates certain the contextual context identifier in the 2nd BGP PATH attribute and the BGP main frame, and wherein this context is different from the context of indicating in routing update message.In one embodiment, the 2nd BGP PATH attribute is a NEXT_HOP PATH attribute.

In a feature aspect this, the step of upgrading routing table at BGP main frame place comprises the value that extracts context identifier from routing update message.Only when any context identifier of certain context dependent connection in the value of context identifier coupling and the BGP main frame, all the other information in the routing update message just are extracted.

In a feature aspect this, with the context-descriptive of context dependent connection based on the Address-Family Identifier symbol (AFI) of the type of marked network address or based on the communicate by letter subsequent address family identifier (SAFI) of type of forwarding mechanism of sign.In another feature aspect this, context-descriptive is based on AFI and SAFI.

In a feature aspect this, when closing the bgp session of wherein announcing context identifier, the association between one or more contexts and their the corresponding context identifiers is destroyed.In another feature, the association between one or more contexts and their the corresponding context identifiers is striden different B GP and is kept conversationally.

In a feature aspect this, bgp peer sends to the BGP main frame and is used for only upgrading by as a part of setting up bgp session and by the routing update message of the routing table of the context representative of BGP main frame announcement.

In one aspect of the method, the present invention includes the computer equipment that is configured to carry out above-mentioned steps.In a feature aspect this, this computer equipment is a router.In one aspect of the method, the present invention includes the computer-readable medium that is configured to carry out above-mentioned steps.

2.0 26S Proteasome Structure and Function general introduction

In one embodiment, according to the form assembling BGP UPDATE message that any address family's information (for example AFI and/or SAFI) is not provided.As replacement, BGP UPDATE message comprises the context identifier of the specific context of being announced and consulting by bgp peer during being identified at bgp session sets up.Thereby, AFI/SAFI hierarchical structure and BGP UPDATE message are removed coupling, replace, between bgp peer, setting up the BGP OPEN message of bgp session, defined contextual any address family's hierarchical structure or the description of representing specific routing table in the included BGP CAPABILITIES parameter.Follow-up BGP UPDATE message includes only contextual identifier and to the renewal of the address prefix that is stored in the route in the specific routing table.

In operation, support the BGP main frame of above-mentioned BGP UPDATE message format to wish that to it each routing table of switching network reachability information distributes a unique context identifier for it.During setting up bgp session with bgp peer, the context-descriptive that BGP host notification peer-to-peer is associated with routing table and the value of context identifier.When the BGP main frame received the BGP UPDATE message that is marked with particular context identifier, the BGP main frame can be based on the definite routing table that must be updated of this particular context identifier.

Fig. 4 is the flow chart of overview that diagram is used for providing at BGP an embodiment of routing table method for updating.In step 402, different routing table represented in the one or more contexts of BGP host definition.In step 404,, make a context ID (or context identifier) associated for each context.In addition, can execution in step 406, in this step, make a context-descriptive associated for each context.

In step 408, the BGP main frame is initiated the bgp session with bgp peer.As a part of setting up session, in step 410, the BGP main frame announces the context of all definition to peer-to-peer.BGP can carry out this step by comprise each contextual context identifier and context-descriptive in the CAPABILITIES parameter of BGP OPEN message, perhaps can carry out this step by present any other BGP communication technology known or that develop later on.

In step 412, the BGP main frame receives routing update message from bgp peer, and this routing update message comprises the context ID of the previous announcement of BGP main frame to this peer-to-peer.In one embodiment, routing update message is a BGPUPDATE message of following the form that comprises the field that is used to store context ID.In step 414, the BGP main frame extracts context ID from message, and in step 416, determine the context ID that extracts whether with the BGP main frame and the context ID context dependent connection in any one be complementary.

Effective context ID of BGP main frame if the context ID that extracts does not match, then in step 418, the BGP main frame abandons this message.In another different embodiment, the bgp process that operates on the main frame can be a backward compatibility, and can support traditional being used to upgrade the BGP method of route.In this embodiment, in step 418, the bgp process on the main frame does not abandon message, but handles this message in a conventional manner.

Be complementary if in step 416, determine the context ID that extracts and effective context ID of BGP main frame,, then this message is unpacked in step 412.Next, in step 422, the routing update that comprises in the message is applied to the route in the routing table that is associated with the context ID that extracts from message.

3.0 the architectural feature of an embodiment

3.1 context and context identifier

In one embodiment, context identifier is defined as the value of a nybble, and joins with the context dependent of representing different routing table.In this embodiment, context identifier distributes in order from " 1 " beginning, and the value of context identifier only to them for it and the bgp session of definition is meaningful.In another different embodiment, even after bgp session is closed, the BGP main frame also can keep the context identifier of distributing to specific context.Like this, the association between context identifier and the context continues to get off, and the BGP main frame can with one or more different bgp session that identical or different bgp peer is set up in use identical context identifier to identify identical context.

In different embodiment, context identifier can be to identify any size of different routing table and the value of data type uniquely.In addition, because context identifier is to consult between the bgp peer that participates in particular B GP session, so context identifier can be that its type and size are only to the significant value of participant of particular B GP session.In addition, the BGP main frame can be selected by any way context identifier to be distributed to context, as long as the routing table that BGP main frame and its peer-to-peer can be discerned context uniquely and be associated by context identifier.

The context representative is stored in one group of route in the routing table.Thereby context can be defined as representing and can be stored in may be the routing table of logical subsets of the information among the RIB or any group of routes in the physically separated table.The address family of any number can be represented in context, include but not limited to IPv4, IPv6, Appletalk, Banyan Vines, IPX, Decnet IV, exchange multi-megabit data, services (SMDS), frame relay, ATM, High-Level Data Link Control (HDLC), Network Service Access point (NSAP), domain name service (DNS), autonomous system (AS) number, based on the rapid transport protocol (XTP) of IPv4, based on the XTP of IPv6 and pattern XTP originally.In addition, such routing table can be represented in context, and this routing table is being stored the prefix with identical address family but is being used to the route of the grouping of the particular type route such as audio frequency, video and the packet.For example, can define different contexts and represent the IPv4 singlecast router that is used for route stream-type video, voice IP and routine data grouping.

In addition, as mentioned above, BGP UPDATE message no longer comprises and is used to identify the type of its address prefix that carries and/or any information of address family, but comprises type and/or address family with the address prefix of the context dependent connection of consulting as setting up the part of bgp session.

For example, in the context of VPN Route Selection, the BGP main frame is not to utilize the VPN label to come the address prefix of mark route, but defining context and context identifier are represented one group of VPN route, and these routes are shared same VPN label and are stored in the specific routing table.The BGP main frame is announced the VPN context identifier to bgp peer during bgp session is set up subsequently.When receiving the BGP UPDATE message that comprises the VPN context identifier, the BGP main frame will know that it need upgrade this specific routing table, upgrades and do not need to extract all address prefixs from message so that judge to use to which routing table.

3.2BGP the form based on contextual UPDATE message

In one embodiment, BGP UPDATE message is defined and is used in the bgp process.Fig. 3 A is the block diagram of the example format of this message of diagram, and this message is marked as BGP C-UPDATE message 300 in the figure.As shown in Figure 3A, this form comprises the context identifier field 302 of value of context identifier that is used to preserve and represents the context dependent connection of routing table.

All the other fields shown in Fig. 3 A, promptly infeasible route length 304, to recall among route 306, total path attribute length 308, path attribute 310 and Network layer reachability information 312 and the RFC1771 field for BGP UPDATE message definition identical.That is the length of having recalled route field 306 in the infeasible routes length field 304 storage particular messages.Recalled the IP prefix list of the route that route 306 storage recalls from service, wherein each address prefix is encoded as＜length, prefix〉two tuples of form.The length of path attributes field 310 in total path attribute length field 308 storing messages.Path attributes field 310 is at variable-length tlv triple＜attribute type, attribute length, property value〉several predetermined PATH attributes of middle storage.Network layer reachability information field 312 storages are by the tabulation of one or more address prefixs of the route of this particular B GP UPDATE message announcement.Information in the tabulation is stored as＜length, prefix〉two tuples, wherein＜length be in two tuples ensuing address prefix be the length of unit with the position.

3.3BGP context description format

In one embodiment, defined based on contextual CAPABILITIES parameter value and can carry out based on contextual renewal so that bgp process can be announced it.The CAPABILITIES parameter value is that RFC3392 was delivered by IETF in November, 2002 according to the standard definition of setting forth among the RFC3392.RFC3392 has defined the CAPABILITIES parameter, so that by not requiring the capability advertisement that appropriateness is provided under the situation that the BGP equity is terminated, helps introduce new ability in BGP.CAPABILITIES parameter with one or more abilities of BGP main frame is sent out in BGP OPEN message, so that the ability that this BGP main frame of notice bgp peer is supported.

According to the definition among the RFC3392, the CAPABILITIES parameter comprises one or more tlv triple＜capability code, capability length, ability value 〉, wherein capability code is a byte field that clearly identifies individual capabilities, capability length is that what to comprise capability value field is a byte field of the length of unit with the byte, and ability value is the variable length of explaining according to the value of capability code field.

Fig. 3 B is a diagram according to the block diagram based on the form of contextual C-UPDATE capability value field 320 of the BGP CAPABILITIES parameter of an embodiment.In Fig. 3 B, C-UPDATE capability value field 320 is arrays of type-length-value (TLV) element, and wherein each element is a tlv triple＜context identifier, length, context-descriptive 〉.In each element, the aforesaid context identifier value of context identifier field 322 storages, context-descriptive length field 3214 is the length of context description field 326.

Context description field 326 is arrays of TLV element.Fig. 3 C is the block diagram based on the form of C-UPDATE context description field 326 in contextual capability value field 320 of diagram according to an embodiment.In Fig. 3 C, C-UPDATE context description field 326 comprises context description type field 332, context-descriptive type length field 334 and context-descriptive types value field 336.

The contextual type of context description type field 332 storages.For example, in one embodiment, context description type field 332 storages are used to identify effective AFI value of particular address family, perhaps can store the effective SAFI value that is used to identify follow-up address family.In addition, in another different embodiment, context description type field 332 can be stored the value by any address same clan type of IANA definition, perhaps can be only to be any value that meaning that the bgp peer in the bgp session is understood is consulted in advance, for example above-mentioned context identifier.

The length of context-descriptive type length field 334 storage context-descriptive types value fields 336.The value that 336 storages of context-descriptive types value field are associated with the context-descriptive type of sign in the context description type field 332.

3.4BGP the contextual PATH attribute format of indication

In one embodiment, the specific PATH attribute in the BGP UPDATE message may be used on the different context of the context that context identifier identified stored in the context identifier field with this message.The example of this attribute is a NEXT_HOP PATH attribute, and its indication BGP main frame receives the address prefix of next jumping in the route of BGP UPDATE message for it.In other words, BGP message can comprise that to next jumping in the route be the renewal of supporting from the route of the address prefix in the network of the address of another different address family.

In order to support said circumstances, in one embodiment, introduced CONTEXT PATH (context path) attribute.CONTEXT PATH attribute is a special P ATH attribute, and it is used as the container of storing other PATH attributes.

According to the definition among the RFC177I, the PATH attribute is the variable-length list of element, and wherein each element is a tlv triple＜attribute type, attribute length, property value 〉.According to an embodiment, CONTEXT PATH attribute is the PATH attribute according to above-mentioned formal definition, the attribute codes of attribute type field stores CONTEXT PATH attribute wherein, the length of attribute length field memory attribute value field.

Fig. 3 D is the block diagram of diagram according to the form of the CONTEXT PATH attribute value field of this embodiment.The variable-length list of CONTEXT PATH attribute value field 340 storage elements, wherein each element is one two tuple＜other path attribute type, other path attribute context identifiers 〉.In specific BGP UPDATE message, the attribute type of another PATH attribute that comprises in other path attribute type field 342 these message of storage, other path attribute context identifier field 344 storages contextual context identifier relevant with these other path attributes.

For example, suppose that NEXT_HOP PATH attribute has attribute type value " 3 ", and CONTEXT PATH attribute has attribute type value " 61 ".Suppose that in addition the BGP main frame receives the BGP UPDATE message with the context identifier field that comprises value " 1 " (prefix updates that comprises in the Indication message is with relevant by the route in the routing table of context " 1 " representative), and this message also comprise with and the value of the context-sensitive NEXT_HOP PATH attribute that is associated of context identifier " 5 ".In this case, BGP UPDATE message will comprise and comprises value＜61,2,3:5〉CONTEXT PATH attribute, wherein " 61 " are the attribute types of CONTEXTPATH attribute, " 2 " be CONTEXT PATH property value be the length of unit with the byte, the PATH attribute of the type " 3 " that comprises in " 3:5 " indication BGP UPDATE message and the context dependent that the context identifier " 5 " in the BGP main frame is identified.

4.0 the routing table method for updating is provided in BGP

4.1 process based on contextual prefix updates

Fig. 1 is the block diagram that illustrates the overview of the network element that can realize an embodiment on it.Network element 102A, the 102B, 102C and the 102D that have been endowed the BGP ability can be connected to network 100 communicatedly.Though Fig. 1 only illustrates four network elements, other embodiment can be realized by the network element of any number that is connected to network.

In Fig. 1, network element 102A comprises operating system 104A and the bgp process 106A that carries out on operating system.Bgp process 106A safeguards one group of routing table, and the example of these routing tables is routing table 108A, 108B and 108C.As shown in Figure 1, routing table 108A storage is described to the route of " context A ", and is assigned with context ID " 1 ".Similarly, routing table 108B storage is described to the route of " context B ", and is assigned with context ID " 2 ", and routing table 108C storage is described to the route of " context C ", and is assigned with context ID " 3 ".

Network element 102B also realizes this embodiment, and comprises operating system 104B and the bgp process 106B that carries out on operating system.Bgp process 106B safeguards one group of routing table, and the example of these routing tables is routing table 108D, 108E and 108F.As shown in Figure 1, routing table 108D storage is described to the route of " context B ", and is assigned with context ID " 1 ".Similarly, routing table 108E storage is described to the route of " context C ", and is assigned with context ID " 2 ", and routing table 108F storage is described to the route of " context D ", and is assigned with context ID " 3 ".The context-descriptive of the routing table among Fig. 1 among description and marked network element 102A and the 102B and the value of context identifier only are used for the example purpose, also can use the value of any class value or any kind.

During the initial setup of the bgp session between them, network element 102A and 102B announce its context-descriptive and context identifier separately, and consult them and can be which routing table exchange route.As shown in Figure 1, network element 102A can exchange the route from its routing table 108B with the routing table 108D among the network element 102B, because the context-descriptive of the context-descriptive of routing table 108B and routing table 108D is complementary.Similarly, network element 102A can exchange the route from its routing table 108C with the routing table 108E among the network element 102B, because the context-descriptive of the context-descriptive of routing table 108C and routing table 108E is complementary.Can not be exchanged during bgp session from the route of the routing table 108A among the network element 102A with from the route of the routing table 108F among the network element 102B, because network element 102A does not have to safeguard the route that is described to " context D ", and network element 102B does not have to safeguard the route that is described to " context A ".

In case network element 102A and 102B have consulted them and can be the routing table of its exchange route, they just can exchange and upgrade route by the BGP UPDATE message of assembling and send the context identifier mark that utilizes required routing table.

Fig. 2 is the block diagram of diagram according to the relation of an embodiment between the bgp context that defines on network element 102A and the 102B.The commutative BGP UPDATE of network element 102A and 102B message is to upgrade the route by the context representative of definition and announcement.

As shown in Figure 2, bgp context concerns that 202A illustrates the relation of setting up between the route that is described to " context B " that defines on network element 102A and the 102B.When network element 102A wishes that network element 102B is arrived in the routing update of transmission " context B ", its the assembling BGPUPDATE message and utilize context identifier " 1 " come mark it, because concern as shown in the 202A as bgp context, network element 102B has announced its context ID " 1 " and has represented the route that is described to " context B ".When receiving BGP UPDATE message, network element 102B extracts context identifier from message, and because context identifier is " 1 ", so network element 102B knows that the routing update in the message must be applied to the routing table 108D that is storing the route that is described to " context B ".

Similarly, when network element 102B wishes that network element 102A is arrived in the routing update of transmission " context B ", its the assembling BGP UPDATE message and utilize context identifier " 2 " come mark it, because bgp context concerns shown in the 202A that network element 102A has announced its context ID " 2 " and represented the route that is described to " context B ".When receiving BGPUPDATE message, network element 102A extracts context identifier from message, and because context identifier is " 2 ", so network element 102A knows that the routing update in the message must be applied to the routing table 108B that is storing the route that is described to " context B ".

Bgp context concerns that 202B illustrates the relation of setting up between the route that is described to " context C " that defines on network element 102A and the 102B.The route that is described to " context B " with exchange is similar, to be described to " context C " in order exchanging and to concern the route of announcing shown in the 202B as bgp context, network element 102A utilizes context identifier " 2 " mark to go to the BGP UPDATE message of network element 102B, and network element 102B utilizes context identifier " 3 " mark to go to the BGP UPDATE message of network element 102A.

4.2 process based on contextual next jumping Route Selection

In one embodiment, BGP UPDATE message is used to upgrade such route, and for this route, next jumping in the path is the address of only supporting in the network of the network address of another different address family.In this embodiment, the BGP main frame receive be used to upgrade particular way by BGP UPDATE message, wherein this message comprises NEXT_HOP PATH attribute.The value of NEXT_HOP attribute comprises the address prefix that is stored in such routing table, this routing table by be different from message at the contextual second context representative.BGP UPDATE message also comprises the CONTEXTPATH attribute, and its value associates the different contextual context identifiers with this of NEXT_HOP PATH attribute.The BGP main frame is subsequently according to the information updating route in the BGP UPDATE message, and will be stored in from the address prefix of NEXT_HOP attribute in the routing table by the representative of second context.Then, when the BGP main frame receives must be according to the grouping of this particular way origin route the time, the BGP main frame is the positioning address prefix in by the routing table of second context representative, and correspondingly route should grouping.

For example, the BGP main frame is stored in its IPv4 in the different routing tables with the IPv6 route, and wherein each routing table is by a different context representative.The BGP main frame receive be used to upgrade particular way with IPv4 unicast address prefixes by BGP UPDATE message.But the NEXT_HOP attribute that comprises in the message is but being stored the IPv6 address prefix, thereby next jumping in the indication route is the IPv6 network.BGP UPDATE message also comprises the CONTEXT attribute, and its value is got up NEXT_HOP attribute and IPv6 context relation.The BGP main frame is according to the information updating route in the BGP UPDATE message.In addition, based on the information in the CONTEXT attribute, the BGP main frame knows that it need be stored in the IPv6 address in the NEXT_HOP attribute in the routing table of being represented by the IPv6 context.Then, in case receive need be along this particular way by the grouping that is routed for the BGP main frame, the BGP main frame is the address prefix of next jumping of location in by the routing table of IPv6 context representative just.Thereby this embodiment of the present invention makes it possible to grouping is routed to the IPv6 network of not supporting the IPv4 addressing from the IPv4 network.

Above-mentioned to use the NEXT_HOP attribute should be regarded as with the example of routing packets in conjunction with the CONTEXT attribute exemplary, rather than restrictive.Above-mentioned technology can realize by the BGP main frame, comes the route grouping to be stored in by any route in the routing table of different contexts representatives along address prefix wherein.Except IPv4 and IPv6, this route can comprise the VPN route, and address prefix belongs to the route (for example being used for transmitting in the IPv4 unicast networks route of video, audio frequency and data) of information that is used for transmitting particular type of same address family.

5.0 be used for announcement and upgrade contextual CONTEXT capability approach

At present, bgp protocol can utilize the multi-protocols that define among the IETF RFC2858 to expand to a plurality of address families and prefix information carries in subsequent address family, but this method is limited to the purpose face of land that meets the AFI/SAFI hierarchical structure.It all must be the method that is exchanged prefix information by the specific context of AFI and/or SAFI definition with regard to the mode that can use as specific context with each context that needn't guarantee to be announced that the method for this part provides a kind of.Method formerly fails to provide solution for QoS Route Selection between how topological Route Selection (MTR), territory or any other service that is not represented as AFI and/or SAFI.

Discuss in the internet-draft of IETF document " ietf-idr-bgp4 " series on the purpose face of land of bgp update.An example of this document is " draft-ietf-idr-bgp4-26.txt ", and it was delivered by IETF in October, 2004.At first, bgp update method at be global I Pv4 unicast table.Occurred the BGP multi-protocols expansion of RFC2858 then, its allows to come the different address family of addressing based on known address family with subsequent address family identifier.Utilize this method, can be transmitted to network router by BGP such as the such information of IPv4 multicast reversing paths information.The design of multi-protocols expansions is used for the mode of these tables of addressing based on a kind of basis to making of special objective table, separates and expands protonotion but only stayed table that little space can be used for utilizing other types.

The method has here defined the context communication capability that can be used to replace multi-protocols extended addressing scheme or use in conjunction with this scheme.This method has been described the CONTEXT ability, and wherein each destination context is that use pattern code and value are described, and is associated with a context identifier.When two BGP spokesman have exchanged its context-descriptive, utilize special CONTEXT AFI and utilize context identifier to replace the SAFI value, the prefix exchange just can take place.

Utilize this method, can utilize existing updating message form again, its additional benefits is can defining context, but needn't force contextual definition to enter two-stage AFI/SAFI hierarchical structure.The backwards compatibility that this method also allows and the existing BGP such as route refresh (defining in the IETF RFC2918 that delivers in September, 2000) expands.

In the method, the bgp peer in the bgp session is announced its ability for individual contexts exchange reachability information by utilizing CAPABILITIES parameter (defining among the RFC3392 that deliver in November, 2002).The CAPABILITIES parameter is associated with the CONTEXT ability, and comprises capability code, capability length and capability value field.Capability code clearly identifies certain capabilities.Capability length comprises the length of capability value field.Capability value field is a variable length, and it is carrying the information of the ability that defines in the capability code field.

Here in the method for Miao Shuing, the ability that exchanges reachability information for individual contexts is associated with CONTEXT address family, and is identified by CONTEXT AFI value.In one embodiment, CONTEXT AFI value is by IANA definition and maintenance.In different embodiment, CONTEXTAFI does not provide or defines to use for the public but be used for the value of special-purpose autonomous system by bgp peer.When announcement CONTEXT ability, the BGP main frame comprises CONTEXT AFI value in the capability code field of CAPABILITIES parameter, support contextual reachability information to inform this BGP main frame of its bgp peer.The BGP main frame comprises the information of describing one or more specific contexts subsequently in the capability value field of CAPABILITIES parameter.

In the method, context identifier and the context-descriptive that context and the information in the capability value field of CAPABILITIES parameter of being included in comprise that each specific context of being announced with quilt is associated described.For example, Fig. 6 is the block diagram of the form of diagram BGP CONTEXT capability value field.

In Fig. 6, bgp context capability value field 600 comprises context identifier 602, describes length 604 and context-descriptive 326.Context identifier 602 is associated with the specific context of the BGP main frame of the CAPABILITIES parameter that sends announcement context ability, and identifies the specific context of this BGP main frame uniquely.The length that length 604 comprises context description field is described.

In one embodiment, the form of context description field 326 is according to illustrated form among Fig. 3 C.Value in the context description field 326 is described the context that is associated with context identifier.Context-descriptive comprises one or more tlv triple＜types, length, the value〉tabulation, wherein each tlv triple is described a specific context.In each tlv triple, type field indication recipient is the interpreted value field how.When all tlv triple that and if only if are all mated, think that just context mates.

According to an embodiment, in the tlv triple that comprises in context description field, the size of type field is a byte, length field be a byte and designated value field be the length of unit with the byte, value field has variable-length.The value that the recipient is depended on type field is the content of processing costs field by different way.In one embodiment, any in the train value under the type field portability:

" 0 ": reserve.Other reserved value that can have any number, for example " 255 ", or the like;

" 1 ": Address-Family Identifier symbol (AFI).If type field is " 1 ", then value field must comprise the effective AFI value that claims the space according to the address Praenomen of being safeguarded by IANA;

" 2 ": subsequent address family identifier (SAFI).If type field is " 2 ", then value field must comprise the effective SAFI value according to the address family space of being safeguarded by IANA;

" 3 ": QoS identifier (qosid).If type field is " 3 ", then value field must comprise two bytes (16) QoS identifier, and BGP spokesman utilizes this identifier to identify to be used for this other particular table of QoS level;

" 4 ": topological identifier (topoid).If type field is " 4 ", then value field must comprise the topological identifier value of two bytes (16) that is used for identifying topology table by BGP spokesman.Thereby specific type field value makes this method for example can use with MTR.

Other context-descriptive types values for example can and be safeguarded by the IANA definition.

In operation, when the BGP main frame was wished for the context swap route outside the AFI/SAFI hierarchical structure, it can be to its peer-to-peer announcement CONTEXT ability in comprising the CAPABILITIES parameter of the description of one or more specific contexts.If two bgp peers have all been announced same context, then can be specific context exchange routing information.Type/value in and if only if the context-descriptive thinks that just two bgp peers have announced same context when all identical.The context identifier of being accused by each square tube is unessential at this in relatively.The BGP main frame is stored each context identifier that receives so that it can identify context in the data that processing receives.

When the CONTEXT ability has been exchanged and the context supported is consulted, and when two bgp peers are wished for specific context exchange reachability information, bgp peer uses CONTEXT AFI to identify extended context and is used, and provides the context identifier that is associated with this specific context as the SAFI value.

For example, in one embodiment, the BGP main frame can be announced address prefix by the specific context representative by sending the BGP UPDATE message of formulating form according to the multi-protocols expansion of BGP.Particularly, bgp peer comprises a MP_REACH_NLRI path attribute in this message, comprises CONTEXT AFI and comprise the context identifier of this specific context in the AFI of this attribute field in the SAFI of this attribute field.When the bgp peer of BGP main frame received CONTEXTAFI in BGP UPDATE message and the identification MP_REACH_NLRI attribute, bgp peer used the SAFI value to discern the specific context of previous announcement.

Similarly, when the BGP main frame wished to recall the route of being represented by this specific context, the BGP main frame sent the BGPUPDATE message that comprises the MP_UNREACH_NLRI attribute to its bgp peer.The MP_UNREACH_NLRI attribute comprises CONTEXT AFI in its AFI field, and comprises the context identifier of this specific context in its SAFI field.When bgp peer received this message, it discerned CONTEXT AFI, and used and discern this specific context from the context identifier of SAFI field.In case it has discerned this specific context, bgp peer is just recalled the address prefix that comprises in the NLRI field of MP_UNREACH_NLRI attribute.

This being used for utilized current multi-protocols extended format again with the method that available contexts expands to outside the current AFI/SAFI context, therefore do not need to change BGP UPDATE message format.The existing AFI/SAFI of depending on value specifies given contextual expansion to need not protocol modification just to use CONTEXT AFI and context identifier (as the SAFI value) to specify new context.

The method here can be used for any network equipment operating system, other network softwares or provides or hold in the combination of this software and hardware of the realization that the place bgp protocol.

6.0 realize mechanism-ardware overview

Fig. 5 illustrates the block diagram that can realize the computer system 500 of one embodiment of the present of invention on it.Preferred embodiment is to utilize the one or more computer programs operate in such as on the such network element of router device to realize.Thereby in this embodiment, computer system 500 is routers.

Computer system 500 comprises the bus 502 that is used to the information of transmitting or other communication agencies and the processor 504 that is coupled and is used for process information with bus 502.Computer system 500 also comprises the main storage 506 such as random-access memory (ram), flash memory or other dynamic memories, and it is coupled to bus 502, is used for the instruction that stored information and processor 504 will be carried out.Main storage 506 also can be used for being stored in temporary variable or other average informations during processor 504 executes instruction.Computer system 500 also comprises read-only memory (ROM) 508 or other static storage devices, and it is coupled to bus 502, is used to store the instruction of static information and processor 504.Memory device 510 such as disk, flash memory or CD is provided, and it is coupled to bus 502, is used for stored information and instruction.

Communication interface 518 can be coupled to bus 502, to be used for that information and command selection are transferred to processor 504.Interface 518 is conventional serial interface, for example RS-232 or RS-422 interface.Exterior terminal 512 or other computer systems are connected to computer system 500, and utilize interface 514 to provide order to it.Operate in that firmware in the computer system 500 or software provide terminal interface or based on the command interface of character, so that external command can be provided for computer system.

Switching system 516 is coupled to bus 502, and has input interface 514 and output interface 519 to one or more external network elements.External network element can comprise the local network 522 that is coupled to one or more main frames 524, perhaps such as the such global network with one or more servers 530 in internet 528.Switching system 516 exchanges to output interface 519 according to the information flow-rate that known predetermined protocol and convention will arrive input interface 514.For example, switching system 516 and processor 504 cooperations can be determined to arrive the destination of the packet of input interface 514, and utilize output interface 519 to send it to correct destination.The destination can comprise main frame 524, server 530, other end stations, perhaps other Route Selection and the switching equipment in local network 522 or the internet 528.

The present invention relates to the system of using a computer 500 provides in bgp process based on contextual routing table renewal.According to one embodiment of present invention, upgrading by computer system 500 based on contextual routing table in the bgp process provides in response to one or more sequences that processor 504 execution are included in the instruction of one or more in the main storage 506.This instruction can be read the main storage 506 from another computer-readable medium (as memory device 510).The execution that is included in the command sequence in the main storage 506 makes processor 504 carry out process steps described herein.One or more processors in the multiprocessing configuration also can be used to carry out the command sequence that is included in the main storage 506.In alternative embodiment, can use hardware circuitry to come instead of software instruction or combine to realize the present invention with software instruction.Thereby embodiments of the invention are not limited to any particular combinations of hardware circuit and software.

Terminology used here " computer-readable medium " refers to participate in provide instruction for any medium of carrying out to processor 504.This medium can be taked many forms, includes but not limited to: non-volatile media, Volatile media and transmission medium.Non-volatile media for example comprises CD or disk, as memory device 510.Volatile media comprises dynamic memory, as main storage 506.Transmission medium comprises coaxial cable, copper cash and optical fiber, comprises the circuit that contains bus 502.Transmission medium also can be taked the form of sound wave or light wave, for example sound wave that generates or light wave during radio wave and infrared data communication.

The common form of computer-readable medium for example comprises floppy disk, flexible disk, hard disk, tape or any other magnetizing mediums, CD-ROM, any other light medium, punched card, paper tape, any other has the physical medium of sectional hole patterns, RAM, PROM and EPROM, FLASH-EPROM, any other memory chip or chuck, the carrier wave of Miao Shuing hereinafter, perhaps computer any other medium that can read.

The various forms of computer-readable medium can be used for one or more sequences of one or more instruction are sent to processor 504 for execution.For example, instruction can at first be carried on the disk of remote computer.Remote computer can be with instruction load in its dynamic memory, and utilizes modulator-demodulator to send instruction via telephone wire.The modulator-demodulator of computer system 500 this locality can receive the data on the telephone wire, and uses infrared transmitter that data are converted to infrared signal.The infrared detector that is coupled to bus 502 may be received in the data of carrying in the infrared signal, and data are placed on the bus 502.Bus 502 is sent to main storage 506 with data, and processor 504 gets instruction and executes instruction from main storage 506.The instruction that main storage 506 receives can be stored on the memory device 510 before or after processor 504 is carried out alternatively.

Communication interface 518 also is provided to the bidirectional data communication coupling of the network link 520 that is connected to local network 522.For example, communication interface 518 can be integrated services digital network (ISDN) card or modulator-demodulator, connects with the digital communication that is provided to the respective type telephone wire.Again for example, communication interface 518 can be the Local Area Network card, connects with the data communication that is provided to compatible LAN.Also can realize Radio Link.In any this implementation, communication interface 518 sends and receives electricity, electromagnetism or light signal, and these signals have carried the digital data stream of representing various types of information.

The network link 520 general data communication that are provided to other data equipments through one or more networks.For example, network link 520 can be provided to host computer 524 or by the connection of the data equipment of Internet service provider (ISP) 526 operation through local network 522.ISP 526 and then pass through worldwide packet data communication network (being commonly referred to " internet " 528 now) again data communication services is provided.Local network 522 and internet 528 all use electricity, electromagnetism or the light signal that carries digital data stream.Through the signal of diverse network with on network link 520 and through the signal of communication interface 518 (these signals carry go to and from the numerical data of computer system 500) is the exemplary form of the carrier wave of transmission information.

Computer system 500 can be passed through network, network link 520 and communication interface 518 and be sent message and receive data, comprises program code.In the Internet example, server 530 can be through the request code of internet 528, ISP 526, local network 522 and communication interface 518 transfer application.According to the present invention, the application program of a this download provides upgrading based on contextual routing table in the BGP main frame as described herein.

The code that receives can be carried out by processor 504 when receiving, and/or is stored in memory device 510 or other non-volatile memory mediums for follow-up execution.By this way, computer system 500 can obtain the application code of carrier format.

7.0 expansion and replacement

In aforementioned specification, with reference to specific embodiment the present invention has been described.But, should be understood that, under the prerequisite that does not break away from the broader spirit and scope of the present invention, can carry out various modifications and change.Therefore, specification and accompanying drawing all will be understood that it is illustrative, and not restrictive.

Claims

1. one kind is used for providing the routing table method for updating at the Border Gateway Protocol main frame, comprises by computer implemented following steps:

The one or more contexts of definition in the computer storage of described Border Gateway Protocol main frame, wherein a different routing table represented in each context;

As a part of between described Border Gateway Protocol main frame and Border Gateway Protocol peer-to-peer, setting up the Border Gateway Protocol session, announce specific context in described one or more context to described Border Gateway Protocol peer-to-peer; And

In response to receiving the routing update message that comprises the information that identifies described specific context, at the specific routing table of described Border Gateway Protocol main frame place renewal by described specific context representative from described Border Gateway Protocol peer-to-peer.

2. the method for claim 1, wherein:

Defining one or more contextual steps comprises each context in described one or more contexts and unique context identifier and unique context-descriptive is associated;

The step of announcing described specific context comprises context identifier that is associated with described specific context to described Border Gateway Protocol peer-to-peer transmission and the context-descriptive that is associated with described specific context; And

The described information that is included in the described routing update message comprises the described context identifier that is associated with described specific context.

3. method as claimed in claim 2, wherein:

Described specific context is first context;

The described context identifier that is associated with described specific context is first context identifier; And

Described routing update message comprises context property, wherein:

Described context property is the first Border Gateway Protocol path attribute, and

The value of described context property associates the second Border Gateway Protocol path attribute and second context identifier, is different from described first contextual second context dependent connection in described second context identifier and the described one or more context.

4. method as claimed in claim 3, the wherein said second Border Gateway Protocol path attribute is the NEXT_HOP attribute.

5. method as claimed in claim 4, wherein:

Described specific routing table by the described first context representative comprises internet protocol version four (IPv4) address prefix;

The value of described NEXT_HOP attribute comprises because of holding fidonetFido version 6 (IPv6) address; And

Described second context representative comprises another different routing table of IPv6 address prefix.

6. method as claimed in claim 5, wherein:

The step of upgrading described specific routing table comprises the described IPv6 of storage address; And

Described method is further comprising the steps of: network packet is routed to the IPv6 network from the IPv4 network, and wherein said route step is included in described IPv6 address, location in described another different routing table.

7. method as claimed in claim 2, the step of wherein announcing described specific context are included in the Border Gateway Protocol ability parameter that comprises in the Border Gateway Protocol open message and send described context identifier that is associated with described specific context and the described context-descriptive that is associated with described specific context to described Border Gateway Protocol peer-to-peer.

8. method as claimed in claim 7, the step of wherein announcing described specific context comprise that also sending the described Border Gateway Protocol main frame of indication supports the context address family identifier value by the processing of the route of context representative.

9. method as claimed in claim 8, wherein said routing update message also comprise described context address family identifier value.

10. method as claimed in claim 2, wherein said routing update message are the Border Gateway Protocol updating message that comprises the field that is used to store the described context identifier that is associated with described specific context.

11. method as claimed in claim 2, the step of wherein upgrading described specific routing table comprises:

From described routing update message, extract the value of the described context identifier that is associated with described specific context; And

Only when the value of any context identifier of any context dependent connection in the value of the described context identifier that is associated with described specific context coupling and the described Border Gateway Protocol main frame, just extract all the other information that comprise in the described routing update message.

12. method as claimed in claim 2, wherein the described context-descriptive that is associated with described specific context comprises one of following: the communicate by letter subsequent address family identifier of type of forwarding mechanism of the Address-Family Identifier symbol of the type of marked network address and sign.

13. method as claimed in claim 2 is further comprising the steps of: when closing described Border Gateway Protocol session, destroy the association between described one or more context and their the corresponding context identifiers.

14. method as claimed in claim 2 is further comprising the steps of: stride the different boundary gateway protocol and keep association between described one or more context and their the corresponding context identifiers conversationally.

15. the method for claim 1 is further comprising the steps of:

At described Border Gateway Protocol main frame place, receive and to be used for only upgrading by as a part of setting up described Border Gateway Protocol session and by one or more routing update messages of the routing table of the context representative of described Border Gateway Protocol main frame announcement; And

The wherein said routing update message that is used to upgrade described specific routing table is the member of described one or more routing update messages.

16. the method for claim 1, wherein the storage of each different routing table has one group of route of the address prefix that belongs to same address family.

17. the method for claim 1, wherein the storage of each different routing table has one group of route of the address prefix that belongs to different address family.

18. the method for claim 1 wherein stores one group of route in each different routing table, every group of route is used for the packets of information that route is carried particular type.

19. method as claimed in claim 18, the information of wherein said particular type comprise at least a in video information, audio-frequency information and the data message.

20. the method for claim 1, wherein this method is carried out by router.

21. an equipment that is used for providing at the Border Gateway Protocol main frame routing table renewal comprises:

Be used for the one or more contextual devices of computer storage definition at described Border Gateway Protocol main frame, wherein a different routing table represented in each context;

Be used for announcing to the Border Gateway Protocol peer-to-peer device of the specific context of described one or more contexts, wherein said specific context is announced as a part of setting up the Border Gateway Protocol session between described Border Gateway Protocol main frame and described Border Gateway Protocol peer-to-peer; And

Be used for upgrading at described Border Gateway Protocol main frame place the device by the specific routing table of described specific context representative, wherein said routing table is in response to and receives the routing update message that comprises the information that identifies described specific context from described Border Gateway Protocol peer-to-peer and be updated.

22. equipment as claimed in claim 21, wherein:

Describedly be used for defining one or more contextual devices and comprise and be used for device that each contexts of described one or more contexts and unique context identifier and unique context-descriptive are associated;

The described device that is used to announce described specific context comprises the device that is used for sending to described Border Gateway Protocol peer-to-peer context identifier that is associated with described specific context and the context-descriptive that is associated with described specific context; And

23. equipment as claimed in claim 22, wherein:

Described specific context is first context;

Described routing update message comprises context property, wherein:

24. equipment as claimed in claim 23, the wherein said second Border Gateway Protocol path attribute is the NEXT_HOP attribute.

25. equipment as claimed in claim 24, wherein:

26. equipment as claimed in claim 25, wherein:

The described device that is used to upgrade described specific routing table comprises the device that is used to store described IPv6 address; And

Described equipment comprises also and is used for network packet is routed to the device of IPv6 network from the IPv4 network that the wherein said device that is used for route comprises the device that is used in described another described IPv6 address, different routing tables location.

27. equipment as claimed in claim 22, the wherein said device that is used for announcing described specific context comprise that the Border Gateway Protocol ability parameter that is used for comprising in the Border Gateway Protocol open message sends the device of described context identifier that is associated with described specific context and the described context-descriptive that is associated with described specific context to described Border Gateway Protocol peer-to-peer.

28. equipment as claimed in claim 27, the wherein said device that is used to announce described specific context comprise that also being used to send the described Border Gateway Protocol main frame of indication supports the device by the context address family identifier value of the processing of the route of context representative.

29. equipment as claimed in claim 28, wherein said routing update message also comprise described context address family identifier value.

30. equipment as claimed in claim 22, wherein said routing update message are the Border Gateway Protocol updating message that comprises the field that is used to store the described context identifier that is associated with described specific context.

31. equipment as claimed in claim 22, the wherein said device that is used to upgrade described specific routing table comprises:

Be used for extracting the device of the value of the described context identifier that is associated with described specific context from described routing update message; And

When only being used for the value when the value coupling of the described context identifier that is associated with described specific context and any context identifier of any context dependent connection of described Border Gateway Protocol main frame, just extract the device of all the other information that comprise in the described routing update message.

32. equipment as claimed in claim 22, wherein the described context-descriptive that is associated with described specific context comprises one of following: the communicate by letter subsequent address family identifier of type of forwarding mechanism of the Address-Family Identifier symbol of the type of marked network address and sign.

33. equipment as claimed in claim 22 also comprises being used for destroying the device of the association between described one or more context and their the corresponding context identifiers when closing described Border Gateway Protocol session.

34. equipment as claimed in claim 22 also comprises being used to stride the device that the different boundary gateway protocol keeps the association between described one or more context and their the corresponding context identifiers conversationally.

35. equipment as claimed in claim 21 also comprises:

Be used at described Border Gateway Protocol main frame place, receive and to be used for only upgrading by as a part of setting up described Border Gateway Protocol session and by the device of one or more routing update messages of the routing table of the context representative of described Border Gateway Protocol main frame announcement; And

36. equipment as claimed in claim 21, wherein the storage of each different routing table has one group of route of the address prefix that belongs to same address family.

37. equipment as claimed in claim 21, wherein the storage of each different routing table has one group of route of the address prefix that belongs to different address family.

38. equipment as claimed in claim 21 wherein stores one group of route in each different routing table, every group of route is used for the packets of information that route is carried particular type.

39. equipment as claimed in claim 38, the information of wherein said particular type comprise at least a in video information, audio-frequency information and the data message.

40. equipment as claimed in claim 21, wherein said equipment is router.