CN101174970A - Implementation method of anycast service, method of sending anycast request, anycast router - Google Patents

Abstract

The embodiment of the present invention discloses a method for implementing an anycast service. The method includes: receiving a packet P, and the packet P is an anycast request packet; searching for a unicast address of an anycast server according to the destination address of the packet P; converting the destination address of the packet P into the unicast address of the anycast server to form a second packet P; and sending the second packet P to the anycast server. The embodiment of the invention also discloses a method for sending an anycast request, a method for processing an anycast request, a method for processing and responding to an anycast request, an anycast router, an anycast server, and a system for realizing anycast service. Since the embodiment of the present invention adopts technologies such as encapsulation, address conversion, and decapsulation, the anycast packet P has the advantages of unicast, and at the same time realizes efficient selection of optimal group members in all ASs.

Description

Implementation method of anycast service, method of sending anycast request, anycast router

technical field

The invention relates to the communication field, in particular to a method for realizing anycast service, a method for sending anycast request, and an anycast router.

Background technique

Currently, the most widely used IP service modes on the Internet are unicast and multicast services. In unicast communication, the sender and receiver have a definite one-to-one relationship; in multicast communication, one sender corresponds to multiple receivers. With the development of network communication, people propose an anycast (anycast) service mode, which allows a sender to communicate with any member of a group of receivers with the same anycast address. And IPv6 officially regards anycast service as one of the modes of IP services, which is defined as: use an anycast address to identify a group of hosts that provide a certain service, and packets sent to the anycast address will be transmitted to any host in this group one. See Figure 1, which shows the basic concept of anycast service. Member1 and Member2 form an anycast group, assuming that the group is Group A. Member1 and Member2 provide the same service, have the same anycast address, and call it anycast server. Service requesters Sender1 and Sender2 send IP packets whose destination address is the address of the anycast group to obtain services, that is to say, obtain services from Member1 or Member2. Through the anycast mechanism, Sender1 obtains services from Member1, which is closer to itself, and Sender2 obtains services from Member2.

In many practical applications, the use efficiency and service quality of the network can be improved by using the anycast service mode. The specific realization goals of anycast can be simply stated as:

1) The number of anycast groups can be expanded.

It is hoped that anycast can handle anycast servers distributed around the world rather than being limited to autonomous domains. An autonomous domain refers to a collection of one or more networks under the management and control of a single entity. Each autonomous domain corresponds to an autonomous domain number that is uniformly assigned by the Internet Assigned Numbers Authority (IANA). Restricting anycast within the autonomous domain can gain many advantages: for example, there is a unified management policy, the use of the interior gateway protocol for routing, the scale of the network is relatively small, the network topology is known, and so on. At present, many methods can be used to implement anycast in an autonomous domain.

2) The number of group members can be expanded. It should be possible to improve the quality of service by increasing the number of group members. For example, the number of global DNS servers is huge, and the anycast service mechanism should be able to support anycast groups with unlimited members.

3) Efficient selection of optimal group members. In any case, the anycast service should select the optimal or nearly optimal communication node. This requires routers to learn more about anycast groups and their members. Clearly this is a conflicting goal with scalability.

4) Transparent to other protocols of the network and transparent to application layer software.

The importance of goal 4) lies in the fact that huge costs have been invested in the development of the Internet so far, and any changes to existing protocols will require huge costs. Similarly, if the application layer software needs to be modified to use the anycast service, the vitality of anycast will be greatly reduced.

The earliest anycast service was implemented in the network layer by directly dividing anycast addresses in the IPv4 address space, but doing so would expand the routing table without limit; thus causing a sharp drop in network performance. Global anycast service will be difficult to implement when each router needs to maintain separate routing information for each anycast group and group members.

At present, the more popular method of implementing IP-anycast service is GIA (Globle IP Anycast, Global IP Anycast). GIA requires that each router be able to distinguish anycast addresses from unicast addresses. The sender identifies the anycast packet by adding anycast prefix to the unicast address. When the router receives the packet, it can quickly find the home domain by changing the anycast prefix (GIA assumes that each anycast service will have an initial service provider, it must have an exact location, and the domain where this location is located should be the anycast server of the home domain of the anycast service.

See Figure 2, which depicts GIA's mapping of addresses:

When the server receives a packet whose destination address has an anycast prefix, it first removes the prefix, then adds 0 at the end of the address, and finally utilizes the mapped address through the access frequency of the pre-divided anycast group.

GIA distinguishes anycast addresses into internal ones (for routers, if the home domain of the anycast address is the same as the autonomous domain in which it is located, this address is called an internal address), commonly used and uncommonly used. Routing to internal addresses is simple, going directly to servers in the home domain. For the internal anycast address, since the optimal server is located in the network identified by the unicast address prefix of the home domain, and is exactly the same as the unicast route, the optimal server can be found directly through the group ID. For frequently accessed anycast addresses, the router conducts a diffuse search within a certain range, and selectively caches the found results, so that subsequent anycast packets of this type can be quickly forwarded. And for the anycast address that is visited infrequently, the packet is routed directly to the anycast server located in the home domain. Since there is no need to maintain infrequently used anycast address information, the problem of swelling the routing table is solved to a certain extent.

The potential problem of GIA is that all infrequently accessed anycast requests are routed to the main anycast domain regardless of whether there are better servers around the requester. It is difficult to find the optimal server for these anycast requests, so the optimal server cannot be efficiently implemented Efficient selection of group members; at the same time, due to the distinction between anycast address and unicast address, it cannot be applied in the existing network address structure, which is not conducive to global use and reduces the vitality of IP-anycast service.

Contents of the invention

The technical problem to be solved by the embodiment of the present invention is to provide a globally scalable IP-anycast service scalable method. In order to solve the above technical problem, the embodiment of the present invention provides a method for implementing anycast service. The method includes:

Receiving a packet P, the packet P is an anycast request packet;

Find the unicast address of anycast server according to the destination address of the packet P;

converting the destination address of the packet P into the unicast address of the anycast server to form a second packet P;

Sending the second packet P to the anycast server.

The present invention also provides an anycast router, and the anycast server includes:

The first receiving unit is configured to receive a packet P, and the packet P is an anycast request packet;

A first processing unit, configured to search for the unicast address of the anycast server according to the address of the packet P;

converting the destination address of the packet P into the unicast address of the anycast server to form a second packet P;

A first sending unit, configured to send the second packet P to the anycast server.

The present invention also provides a method for sending an anycast request, the method comprising:

Receiving a packet P, the packet P is an anycast request packet;

Search anycast routing table according to the destination address of the packet P to select anycast server;

Encapsulating the packet P into a first packet P, the destination address of the first packet P is the address of anycast router corresponding to the anycast server, and the payload of the first packet P is the packet P;

The first packet P is sent.

The present invention also provides an anycast router, which includes:

The second receiving unit is configured to receive a packet P, and the packet P is an anycast request packet;

The second processing unit is configured to search an anycast routing table according to the destination address of the packet P to select an anycast server; encapsulate the packet P into a first packet P, and the destination address of the first packet P is the anycast server. The address of the anycast router corresponding to the broadcast server, the payload of the first packet P is the packet P;

The second sending unit is configured to send the first packet P.

The present invention also provides a method for processing anycast requests, the method comprising:

receiving a first packet P, decapsulating the first packet P into a packet P, the packet P being the payload of the first packet P;

Find the unicast address of the anycast server according to the destination address of the packet P;

converting the destination address of the packet P into the unicast address of the anycast server to form a second packet P;

Sending the second packet P to the anycast server.

The present invention also provides an anycast router, which includes:

a third receiving unit, configured to receive the first packet P;

The third processing unit is configured to decapsulate the first packet P into a packet P, and the packet P is the payload of the first packet P; search for the anycast according to the destination address of the packet P The unicast address of the server; converting the destination address of the packet P into the unicast address of the anycast server to form a second packet P;

A third sending unit, configured to send the second packet P to the anycast server.

The present invention also provides a method for processing anycast requests, the method comprising:

receiving a first packet P;

It is determined that the destination address of the first packet P is not its own anycast address, and the first packet P is forwarded according to a unicast route by searching a local routing table.

The present invention also provides an anycast router, which includes:

a fourth receiving unit, configured to receive the first packet P;

A fourth processing unit, configured to determine that the destination address of the first packet P is not its own anycast address;

The fourth sending unit is configured to forward the first packet P according to a unicast route by searching a local routing table.

The present invention also provides a method for processing and responding to anycast requests, the method comprising:

receiving a response packet of the second packet P;

Transforming the source address of the response packet of the second packet P into the anycast address of the anycast server sending the second packet P to form a third packet P;

Said third packet P is sent.

The present invention also provides an anycast router, and the anycast server includes:

A fifth receiving unit, configured to receive a response packet of the second packet P;

A fifth processing unit, configured to transform the source address of the second packet P into the anycast address of the anycast server sending the second packet P, to form a third packet P;

The fifth sending unit is configured to send the third packet P.

The present invention also provides a method for processing and responding to anycast requests, the method comprising:

receiving a second packet P;

After processing the second packet P, a response packet of the second packet P is formed, the source address of the response packet is the unicast address of the anycast server, and the destination address is the anycast address of the anycast router sending the packet P;

A response packet of the second packet P is sent.

The present invention also provides an anycast server, which includes:

a sixth receiving unit, configured to receive the second packet P;

The sixth processing unit is configured to form a response packet of the second packet P after processing the second packet P, the source address of the response packet is the unicast address of the anycast server, and the destination address is the address of the anycast router sending the packet P anycast address;

A sixth sending unit, configured to send a response packet of the second packet P.

The present invention also provides a system for realizing anycast service, the system includes:

The first anycast router is used to receive a packet P, and the packet P is an anycast request packet; according to the destination address of the packet P, the anycast routing table is searched to select an anycast server; and the packet P is encapsulated into a first Packet P, the destination address of the first packet P is the address of the anycast router corresponding to the anycast server, and the payload of the first packet P is the packet P; sending the first packet P;

The second anycast router is configured to receive the first packet P; decapsulate the first packet P into a packet P, that is to say restore the payload into a packet P; search for the anycast according to the address of the packet P The unicast address of the server; converting the destination address of the packet P into the unicast address of the anycast server to form a second packet P; sending the second packet P to the anycast server.

The anycast server is configured to receive the second packet P, and provide corresponding anycast service according to the content of the second packet P.

It can be seen from the above technical solutions that, because the embodiment of the present invention adopts technologies such as encapsulation, address conversion, and decapsulation, the anycast packet P has the advantages of unicast, and at the same time realizes the efficient realization of optimal group members in all ASs choose.

Description of drawings

Figure 1 is a schematic diagram of anycast service;

Fig. 2 is a schematic diagram of the address mapping process of GIA;

Fig. 3 is the flow chart of the method of Embodiment 1 of the present invention;

Figure 4 is an example of anycast forwarding;

Fig. 5 is a structural diagram of Embodiment 2 of the present invention;

Fig. 6 is a structural diagram of Embodiment 3 of the present invention;

Fig. 7 is a structural diagram of Embodiment 4 of the present invention;

Fig. 8 is a structural diagram of Embodiment 5 of the present invention;

Fig. 9 is a structural diagram of Embodiment 6 of the present invention;

Fig. 10 is a structural diagram of Embodiment 7 of the present invention;

FIG. 11 is a diagram of optimal path selection efficiency according to an embodiment of the present invention.

Detailed ways

The present invention does not need to change the existing address structure of the network, deploying anycast servers on a global scale, and providing corresponding anycast services according to different anycast group addresses is the basic condition for realizing globally scalable IP-anycast services. The present invention requires that when deploying a new anycast service, it is first necessary to deploy the HAS (Home Anycast Server, local anycast server, AS _Aid =AS _Uid AS) of the anycast service, and deploy a FAR (First hop Anycast Router) at the HAS front end , the first hop router, and the AR closest to the AS) enables the HAS to access the network through the FAR. During initial operation, HAS will actively register with its FAR. When the new anycast service, HAS and FAR are deployed, and when a new AS (Anycast Server, anycast server) is added for the anycast service, a FAR is deployed at the front end of each AS, and the AS accesses the network through its FAR.

For an anycast service, AS can be properly deployed in different locations on the global Internet according to actual needs. AR (Anycast Router, Anycast router, IR that supports tunnel-based IP-anycast) can be deployed according to the following rules:

(1) Try to deploy AR at the border of the autonomous domain with a large number of connections;

(2) When there is no AS corresponding to the anycast service in an autonomous domain, and requests for the anycast service in the autonomous domain occur frequently, AR should be deployed on the border of the autonomous domain;

AR should be deployed from a global perspective, and AR should be evenly distributed in the global Internet as far as possible. The purpose of this deployment is to enable more anycast requests to obtain better anycast server information than HAS on AMP.

In order to realize the global anycast service, certain information will be recorded in each AR’s ART (Anycast Routing Table, Anycast routing table, the routing table that records AS information in the AR), such as the anycast address ASAid of the AS (ASAid, anycast address, anycast address), unicast address ASUid (ASUid, unicast address, unicast address), the FARUid corresponding to the AS, the hop count L from the FAR to the current AR (L takes a positive integer), and the selection evaluation value of the AS V (V takes a positive integer) wait. V may be the actual distance from the AR to the AS, the busyness of the AS or the processing capability of the AS; in the present invention, it is assumed that V is the number of hops from the AR to the AS. And because different ASs have different ASAids, in ART, each record represents an AS.

In the present invention, the number of hops L from the FAR to the current AR can be controlled (L takes a positive integer) and V is taken as the number of hops from the AR to the AS. The present invention generally requires each AR to master the AS information in its V-hop autonomous domain; Control V within 4 or 5, so that each AR knows certain information, then all ARs can be connected to provide global anycast service. And by controlling this record information, the storage capacity of the ART routing table information is reduced to a certain extent at the same time, thereby improving the scalability of the number of anycast groups.

The method for implementing anycast service after the global anycast service network structure is provided will be specifically introduced below through an embodiment.

Embodiment 1, each packet on the IP network will inevitably carry a source address and a destination address when it is sent out, and the source address and the destination address of the network layer packet P (Internet protocol packet) are respectively src and dest. If the packet P is an anycast packet, then dest is the Aid (Aid, anycast address, anycast address) of the anycast service. Referring to Fig. 3, the specific process of this embodiment is as follows:

Block diagram 101: AR receives a packet P; the source address and destination address of the packet P are src and dest respectively;

Block diagram 102: judge whether grouping P is TP (Tunnel Packet anycast tunnel grouping); If grouping P is TP, then execution block diagram 103, if grouping P is not TP then execution block diagram 107;

The tunnel packet refers to an encapsulated IP packet, which may also be referred to as a first packet P. The so-called encapsulation refers to the IP tunnel technology that uses the packet P as the payload of a new IP packet. The process of AR encapsulating packet P is as follows: (1) select the optimal AS according to the V value recorded by AR in ART; (2) use packet P as the payload of the encapsulated packet, that is, as the IP data packet after encapsulation Data part; after encapsulation, the source address and destination address of the packet P are src and the FARAid of the optimal AS respectively. (3) mark this grouping P as anycast tunnel grouping, so that FAR recognizes; Can mark tunnel grouping by defining new Next Header in IPV6, can use certain reserved bit position to mark anycast tunnel grouping in IPV4.

Since the packet P is marked by the above method, in the block diagram 102, whether it is TP can be judged by Next Header or a certain reserved bit.

After an AR performs the encapsulation process on the packet P, it actually knows the destination address of the anycast service, that is to say, the encapsulation process changes the forwarding path of the packet P in the original IR environment. This is also the anycast tunneling technology newly defined in the present invention. More precisely, the anycast tunneling technology refers to: the two sides of the communication are connected with a logical tunnel, and an optimal path is found through the anycast technology, and the path that should be transmitted in the original IR Threads are hidden.

Block Diagram 103: If the packet P is TP, it means that the packet P is encapsulated, and the dest it carries is the AR corresponding to the AS, and the corresponding AR can be the FAR of the destination AS, so the AR uses the ART information stored in it Determine whether the dest of the packet P is its own ARuid; if it is because the destination address of the packet P is the FARAid of the optimal AS, it means that the AR is the FAR of the destination AS of the packet P, then execute block 104; otherwise execute block 106 ;

Block Diagram 104: Since the packet P involved in Block Diagram 103 is encapsulated, that is, the packet P is TP, and has undergone address translation and other processes, the packet P is decapsulated, and the address translation process is performed to form a second packet P.

The decapsulation process mentioned in this block diagram 104 is the process of recovering the original packet P from the encapsulated packet, that is to say, the header information is removed and the payload is restored to the original packet P; then address conversion is performed to encapsulate the packet P The subsequent address dest is transformed into the ASUid obtained by querying its ART.

Block Diagram 105: Send the second packet P to the network layer of the AR, and the network layer sends the packet P to the destination according to the unicast service rule.

Block Diagram 106: It shows that the AR is only a passing AR during the anycast packet transmission process, and should continue to be forwarded through the AR along its unicast service rules.

Block Diagram 107: Since AR judges that the packet P is not a TP, that is to say, the packet P does not yet know its optimal destination AS address; then AR continues to inquire whether there is an IP address identical to the dest of the packet P through the information stored in ART. ASAid; if found, execute block diagram 108, if not find, then execute block diagram 111 or block diagram 111A;

Block Diagram 108: If the AR finds the same ASAid as the dest of the packet P, it means that the corresponding AR of the optimal AS of the packet P is within the K hop range of the AR, and the corresponding AR can be the FAR of the destination AS; then continue to judge Whether the ARuid of the AR is equal to the FARuid of the selected optimal AS; if so, execute block 109; otherwise, execute block 110; the optimal AS mentioned in this block may be the closest AS to the AR sending the packet P.

Block Diagram 109: Execute the address conversion process, transform the destination address dest of the packet P into the ASuid obtained by querying the ART of the AR, and form the second packet P; execute the block diagram 105;

At the same time, if the ARuid of the AR is equal to the FARuid of the selected optimal AS, it means that the selected optimal AS is the HAS of the anycast service group;

Block diagram 110: because the packet P received by the AR is not a TP, but there is an optimal AS within the K-hop range of the AR, then the encapsulation process is performed on the packet P to form a second packet P, and block diagram 105 is executed;

Performing the encapsulation process is the above mentioned for the packet P: (1) select the optimal AS according to the V value of the ART record of the AR; (2) use the packet P as the payload of the packet after encapsulation, that is, refer to As the data part of the IP data packet after encapsulation; the source address and destination address of the packet P after encapsulation are src and the FARAid of the optimal AS respectively. (3) Mark the packet P as an anycast tunnel packet for identification by FAR and AR; in IPV6, a tunnel packet can be marked by defining new header information, and in IPV4, a reserved bit position of packet P can be used to mark anycast Tunnel grouping.

Block Diagram 111: When the packet P received by the AR is neither a TP nor the same ASAid as dest in the packet P can not be found, the group P that may be received is a unicast packet or the AS of the anycast group requested by the packet P is not the AR. Yes, it means that the AR is just a passing AR during the anycas packet transmission process, and the packet P should continue to be forwarded through the AR along its unicast service rules.

When the initiator of anycast communication successfully sends the first IP packet to the optimal anycast server, subsequent data packets are also transmitted along this path. When the anycast server needs to send a data packet to the communication initiator, it is set as the response process of the AS, which means that the AS sends a response packet to the AR that first sent the packet P. Since the anycast packet P is forwarded to the FAR of the optimal AS, the address translation process is performed, so the destination address of the packet P received by the optimal AS is ASuid, and the original address of the packet it responds to must be ASuid, and the beginning of the response process is to use ASAid Communication, so FAR must change ASUid to ASAid, this process only needs to be done once. When there is a response packet, in order to distinguish this situation, the forwarding of the response packet by the anycast server will be further judged when the packet P received by the AR is not a TP and the ASAid that is the same as dest in the packet P cannot be found; then the block diagram 111 It can be replaced by the following block diagram;

Block Diagram 111A: Determine whether the ASAid corresponding to the src of the packet P can be found in the ART of the AR; if it cannot be found, it means that the AR is an AR passing through anycast packet transmission or is not an anycast request packet at all, and no processing is required to execute block diagram 106; If the query is found, block diagram 112 is executed;

Block diagram 112: further judge whether the AR is the FAR of the AS represented by src in the packet P; if not, execute block diagram 113, and if so, execute block diagram 114;

Block Diagram 113: It shows that although the packet P is a response packet from an AS, but the AS has not registered the current AR as a FAR, the address inversion process of the packet should be performed by the FAR, so it is only necessary to forward the packet P according to the unicast mechanism ;

Block Diagram 114: At this time, it is the process of AS responding to anycast request. Since anycast packet P is forwarded to the FAR of the optimal AS, the address conversion process is performed, so the destination address of the packet received by the optimal AS is ASuid, and the original address of the packet it responds to is ASuid. The address must be ASuid, and the initial response process uses ASAid for communication, so FAR must change ASUid into ASAid, that is, perform an address inverse conversion process to form the third packet P. The address inverse conversion process mentioned here means that the AR changes the source address src of the packet P into the ASAid that sends the response, while the destination address remains unchanged.

In order to make the method of Embodiment 1 of the present invention clearer, an example is given below for auxiliary explanation: Refer to FIG. 4 , which is a network topology diagram of an example of anycast forwarding. HAS and AS2 form an anycast group whose address is ASAid. . AR1-AR5 are deployed to process anycast requests, and other IRs forward packets according to Internet standards. AR1 and AR4 are FAR of AS2 and HAS respectively. AC1-AC3 are anycast service requesters, and the optimal server corresponding to each requester depends on the value of V. Assume that HAS is the optimal AS of AC2 and AC3, AS2 is the optimal AS of AC1, and assume k=3.

First introduce the request process of AC1: AC1 sends anycast request packet P, whose destination address is ASAid. P first passes through IR3. Since IR3 has not been modified, it cannot recognize that packet P is an anycast packet, so P is forwarded as a normal unicast packet. When P arrives at AR3, according to the forwarding mechanism, AR3 performs an encapsulation process on P to generate an anycast tunnel packet TP whose source address and destination address are AC1Uid and AR1Uid respectively, and forwards it, and finally the TP reaches AR1. Since AR1's ART records that the FARUid corresponding to AS2 is itself, AR1 is the FAR of AS2 according to AR1's ART. The decapsulation process is therefore performed to recover the packet P from the TP. Then execute the address conversion process, replace P's destination address with AS2Uid and send it to AS2. AS2 returns a response packet RP (Response packet) whose source address is AS2Uid and destination address is AC1Uid. Since AR1 is the FAR of AS2, AR1 performs the inverse address translation process, replaces the source address of RP with ASAid and sends it out. All the IRs and ARs passing through will directly forward the packet without special processing. Finally, the RP reaches AC1 and completes the entire anycast communication process. The processing of P and RP in the above forwarding process is transparent to AS and AC.

In the embodiment of the present invention, the encapsulation of anycast packet P is performed only once during the transmission process. This is because the destination address of the packet after encapsulation becomes a FAR unicast address, so it is not any ASAid, so it cannot be encapsulated again.

Through Figure 4, the following table 1 can be given: anycast forwarding instance table

request node Packet main path AMP (referring to the packet path when the AR in Figure 4 is regarded as a general IR) Anycast packet path AP (referring to the frontal path after AR and IR transmission) Tunnel path ATP (that is, the path from encapsulation to decapsulation of packet P) AS AC ₁ IR ₃ -AR ₃ -IR ₅ -IR ₄ -AR ₄ -HAS IR ₃ -AR ₃ -IR ₂ -AR ₁ -AS ₂ AR ₃ -IR ₂ -AR ₁ AS ₂ AC ₂ IR ₆ -IR ₅ -IR ₄ -AR ₄ -HAS IR ₆ -IR ₅ -IR ₄ -AR ₄ -HAS - HAS AC ₃ IR ₁ -AR ₅ -AR ₂ -IR ₄ -AR ₄ -HAS IR ₁ -AR ₅ -AR ₂ -IR ₄ -AR ₄ -HAS AR ₅ -AR ₂ -IR ₄ -AR ₄ HAS

From the comparison of the tunnel path in Table 1 with the main path of the packet, we can further understand the concept of tunnel technology: the two sides of the communication are connected by a logical tunnel, and an optimal path is found through anycast technology, and the original IR The transmission route thread is hidden.

Embodiment 2, the embodiment of the present invention also provides an anycast router; referring to FIG. 5, the anycast router includes:

The first receiving unit 201 is configured to receive a packet P, where the packet P is an anycast request packet;

The first processing unit 202 is configured to search for the unicast address of the anycast server according to the address of the packet P; transform the destination address of the packet P into the unicast address of the anycast server to form a second packet P;

The first sending unit 203 is configured to send the second packet P to the anycast server.

The anycast server may further include a first judging unit 204, configured to judge that the packet P is not a tunnel packet TP before searching for the unicast address of the anycast server according to the address of the packet P.

The representation method of the tunnel group is as follows: defining new header information for the group P or using a certain reserved bit position of the group P as an identifier to represent the tunnel group TP, and correspondingly judging that the group P is not a tunnel The grouping specifically includes: when the packet P does not contain the identifier, judging that the packet P is not a tunnel packet.

Embodiment 3, the present invention also provides an anycast router, see Figure 6, the anycast router includes:

The second receiving unit 301 is configured to receive a packet P, where the packet P is an anycast request packet;

The second processing unit 302 is configured to search an anycast routing table according to the destination address of the packet P to select an anycast server; encapsulate the packet P into a first packet P, and the destination address of the first packet P is the an address of an anycast router corresponding to the anycast server, and the payload of the first packet P is the packet P;

The second sending unit 303 is configured to send the first packet P.

After receiving the packet P, the second processing unit 302 further judges that the packet P is not a tunnel packet; the representation method of the tunnel packet is: define new header information for the packet P or convert the packet A certain reserved bit position of P is used as an identifier to represent the tunnel packet TP, and correspondingly, judging that the packet P is not a tunnel packet specifically includes: when the packet P does not contain the identifier, then judging that the packet P is not a tunnel grouping.

The second processing unit 302 searches the anycast routing table according to the destination address of the packet P to select an anycast server, specifically, searches the anycast routing table according to the destination address of the packet P and selects an anycast server closest to itself.

The anycast router selected by the second processing unit 302 may be the first-hop router of the anycast server.

Embodiment 4, the present invention also provides an anycast anycast router, see Figure 7, the anycast router includes:

A third receiving unit 401, configured to receive the first packet P;

The third processing unit 402 is configured to decapsulate the first packet P into a packet P, and the packet P is the payload of the first packet P; search for the any packet according to the destination address of the packet P the unicast address of the anycast server; converting the destination address of the packet P into the unicast address of the anycast server to form a second packet P;

The third sending unit 403 is configured to send the second packet P to the anycast server. Embodiment 5, the present invention also provides an anycast anycast router, see Figure 8, the anycast router includes:

a fourth receiving unit 501, configured to receive the first packet P;

The fourth processing unit 502 is configured to determine that the destination address of the first packet P is not its own anycast address;

The fourth sending unit 503 is configured to forward the first packet P according to a unicast route by searching a local routing table.

The anycast router may further include a second judging unit 504, configured to judge the anycast server corresponding to the source address of the first packet P before searching the local routing table and forwarding the first packet P. The anycast address is not in the local anycast routing table.

Embodiment 6, the present invention also provides an anycast anycast router, see Figure 9, the anycast router includes:

A fifth receiving unit 601, configured to receive a response packet of the second packet P;

The fifth processing unit 602 is configured to transform the source address of the second packet P into the anycast address of the anycast server sending the second packet P, to form a third packet P;

The fifth sending unit 603 is configured to send the third packet P.

The fifth processing unit 602 transforms the source address of the response packet of the second packet P into the anycast address of the anycast server sending the second packet P, and before forming the third packet P, it may be further determined that the The destination address of the first packet P is not its own anycast address, and it is determined that the anycast address of the anycast server corresponding to the source address of the first packet P is in the local anycast routing table.

Embodiment 7. The present invention also provides an anycast anycast server. Referring to FIG. 10, the anycast server includes:

A sixth receiving unit 701, configured to receive the second packet P;

The sixth processing unit 702 is configured to form a response packet of the second packet P after processing the second packet P, the source address of the response packet is the unicast address of the anycast server, and the destination address is the anycast router sending the packet P the anycast address of

The sixth sending unit 703 is configured to send a response packet of the second packet P.

Embodiment 8, the present invention also provides a system for realizing anycast service, the system includes:

The first anycast router is used to receive a packet P, and the packet P is an anycast request packet; according to the destination address of the packet P, the anycast routing table is searched to select an anycast server; and the packet P is encapsulated into a first Packet P, the destination address of the first packet P is the address of the anycast router corresponding to the anycast server, and the payload of the first packet P is the packet P; sending the first packet P;

The second anycast router is used to receive the first packet P; decapsulate the first packet P into a packet P, that is to say restore the payload into a packet P; search for the anycast according to the address of the packet P The unicast address of the server; converting the destination address of the packet P into the unicast address of the anycast server to form a second packet P; sending the second packet P to the anycast server.

The anycast server is configured to receive the packet P, and provide corresponding anycast service according to the contents of the packet P.

After the first anycast router sets the payload of the first packet P as the packet P, it marks the packet P as a tunnel packet; the representation method of the tunnel packet is: define The new header information may use a certain reserved bit position of the packet P as an identifier to represent the tunnel packet TP.

When the first anycast router performs encapsulation, the anycast router corresponding to the anycast server is the first-hop router of the anycast server.

The system may further include a third anycast router, configured to receive the first packet P; if it is determined that the destination address of the first packet P is not its own anycast address, the first packet P is sent by searching the local routing table Forward according to unicast routing.

The system may further include a fourth anycast server, configured to receive a packet P, and the packet P is an anycast request packet; search for the unicast address of the anycast server according to the address of the packet P; The destination address of P is transformed into the unicast address of the anycast server to form a second packet P; and the second packet P is sent to the anycast server.

The anycast server can be further used to form a response packet of the second packet P after providing the corresponding anycast service according to the content of the second packet P, and the source address of the response packet is the unicast address of the anycast server , the destination address is the anycast address of the anycast router sending the packet P; sending the response packet of the second packet P; the corresponding system may further include a fifth anycast router for receiving the response packet of the second packet P Transforming the source address of the response packet of the second packet P into the anycast address of the anycast server sending the second packet P to form a third packet P; sending the third packet P.

It can be seen from the above technical solutions that because the present invention adopts technologies such as encapsulation, address translation, and decapsulation, the anycast group P has the advantages of unicast, and at the same time realizes efficient selection of optimal group members in all ASs. And through the encapsulation process, as long as each AR masters the AS information in its V-hop autonomous domain; V can be controlled within 4 or 5, so that each AR knows certain information, then all ARs can be connected to provide global anycast Serve. And by controlling this record information, the storage capacity of ART routing table information is reduced to a certain extent at the same time, thereby improving the scalability of the number of anycast groups;

Further, since it is difficult to deploy the network environment of the present invention on a large scale in the actual environment of the Internet at the current stage, the applicant has verified the efficiency of the present invention through simulation tests.

The simulated topology is taken from the real Internet topology obtained by the Route Overview project of the University of Oregon. This project collects BGP tables of backbone routers in more than 50 regions around the world and updates them every day, thus reflecting the most realistic Internet topology. According to the division of autonomous domains by IANA, the connection information of 5939 autonomous domains is extracted for simulation.

Firstly, the shortest path between any two autonomous domains is obtained from the adjacency relationship of autonomous domains. The routing strategy between autonomous domains, such as cost and distance, is not considered here, and only the minimum number of hops is used as the basis for routing selection. The shortest path obtained The average path is 4.03, and the longest path is 9, which is in line with the small world nature of the Internet. Then 100 anycast groups are assigned to the entire network, and the number of group members is evenly distributed between [1, 1000]. For each anycast group We randomly select HAS in the network and assume that other group members are also randomly distributed.

The embodiment of the present invention does not guarantee that all anycast requests are routed to the globally optimal AS. Define P as the actual path length from AC to AS, and P ^* as the shortest path length from AC to all members of anycast group, and define the optimal service Discovery efficiency φ=P/P ^* . Refer to Figure 11 to illustrate that as the number of ARs in the network increases, the discovery efficiency of optimal services continues to increase. When ARs account for 45% of the total number of IRs and above, anycast grouping can basically find the optimal service Path. Compared with GIA, due to the partial anycast grouping, regardless of whether there are members of the group around the requester, GIA directly routes the anycast grouping to the home domain. Therefore, the efficiency of GIA is in a straight line, depending on the infrequent anycast group mentioned above. The access frequency of the address. It can be seen that the efficiency of the present invention has been significantly improved in most cases.

The implementation method of the anycast service provided by the present invention and the anycast router have been introduced in detail above. In this paper, specific examples are used to illustrate the principle and implementation of the present invention. The descriptions of the above embodiments are only used to help understand the present invention. The method of the invention and its core idea; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation and scope of application. In summary, the content of this specification should not be understood To limit the present invention.

Claims (32)

1. A method for implementing anycast service, characterized in that the method comprises: Receiving a packet P, the packet P is an anycast request packet; Find the unicast address of anycast server according to the destination address of the packet P; converting the destination address of the packet P into the unicast address of the anycast server to form a second packet P; Sending the second packet P to the anycast server. 2. The method according to claim 1, wherein before searching for the unicast address of the anycast server according to the address of the packet P, further comprising: judging that the packet P is not a tunnel packet TP. 3. The method for implementing anycast service according to claim 2, characterized in that, the representation method of the tunnel group is: defining new header information for the group P or setting a certain reserved bit of the group P The position is used as an identifier to represent the tunnel packet TP, and correspondingly, judging that the packet P is not a tunnel packet specifically includes: when the packet P does not contain the identifier, judging that the packet P is not a tunnel packet. 4. An anycast router, characterized in that the anycast server includes: The first receiving unit is configured to receive a packet P, and the packet P is an anycast request packet; A first processing unit, configured to search for the unicast address of the anycast server according to the address of the packet P; converting the destination address of the packet P into the unicast address of the anycast server to form a second packet P; A first sending unit, configured to send the second packet P to the anycast server. 5. The anycast server according to claim 4, wherein the anycast server further comprises a first judging unit, configured to search for the unicast address of the anycast server according to the address of the packet P, It is first determined that the packet P is not a tunnel packet TP. 6. The anycast server according to claim 5, characterized in that, The representation method of the tunnel group is as follows: defining new header information for the group P or using a certain reserved bit position of the group P as an identifier to represent the tunnel group TP, and correspondingly judging that the group P is not a tunnel The grouping specifically includes: when the packet P does not contain the identifier, judging that the packet P is not a tunnel packet. 7. A method for sending an anycast request, characterized in that the method comprises: Receiving a packet P, the packet P is an anycast request packet; Search anycast routing table according to the destination address of the packet P to select anycast server; Encapsulating the packet P into a first packet P, the destination address of the first packet P is the address of anycast router corresponding to the anycast server, and the payload of the first packet P is the packet P; The first packet P is sent. 8. The method for sending an anycast request according to claim 7, characterized in that, after receiving the packet P, it is further judged that the packet P is not a tunnel packet; the representation method of the tunnel packet is: P defines new header information or uses a certain reserved bit position of the packet P as an identifier to represent the tunnel packet TP. Correspondingly, judging that the packet P is not a tunnel packet specifically includes: when the packet P does not contain any When the above identifier is found, it is judged that the packet P is not a tunnel packet. 9. The method for sending an anycast request according to claim 7, wherein the searching anycast routing table according to the destination address of the packet P to select an anycast server is specifically searching for an anycast server according to the destination address of the packet P The anycast routing table selects the nearest anycast server. 10. The method for sending an anycast request according to any one of claims 7 to 9, characterized in that, The anycast router corresponding to the anycast server is the first-hop router of the anycast server. 11. An anycast router, characterized in that the anycast router comprises: The second receiving unit is configured to receive a packet P, and the packet P is an anycast request packet; The second processing unit is configured to search an anycast routing table according to the destination address of the packet P to select an anycast server; encapsulate the packet P into a first packet P, and the destination address of the first packet P is the anycast server. The address of the anycast router corresponding to the broadcast server, the payload of the first packet P is the packet P; The second sending unit is configured to send the first packet P. 12. The anycast router according to claim 11, wherein after receiving the packet P, the second processing unit further judges that the packet P is not a tunnel packet; the representation method of the tunnel packet is: Defining new header information for the packet P or using a certain reserved bit position of the packet P as an identifier to represent the tunnel packet TP, correspondingly, judging that the packet P is not a tunnel packet specifically includes: when the packet P If does not contain the identifier, it is determined that the packet P is not a tunnel packet. 13. The anycast router according to claim 11, characterized in that, The second processing unit searches the anycast routing table according to the destination address of the packet P to select an anycast server, specifically, searches the anycast routing table according to the destination address of the packet P and selects an anycast server closest to itself. 14. The anycast router according to any one of claims 11 to 13, characterized in that, The anycast router selected by the second processing unit is the first-hop router of the anycast server. 15. A method for processing anycast requests, characterized in that the method comprises: receiving a first packet P, decapsulating the first packet P into a packet P, the packet P being the payload of the first packet P; Find the unicast address of the anycast server according to the destination address of the packet P; converting the destination address of the packet P into the unicast address of the anycast server to form a second packet P; Sending the second packet P to the anycast server. 16. An anycast router, characterized in that the anycast router comprises: a third receiving unit, configured to receive the first packet P; The third processing unit is configured to decapsulate the first packet P into a packet P, and the packet P is the payload of the first packet P; search for the anycast according to the destination address of the packet P The unicast address of the server; converting the destination address of the packet P into the unicast address of the anycast server to form a second packet P; A third sending unit, configured to send the second packet P to the anycast server. 17. A method for processing anycast requests, characterized in that the method comprises: receiving a first packet P; It is determined that the destination address of the first packet P is not its own anycast address, and the first packet P is forwarded according to a unicast route by searching a local routing table. 18. The method for processing an anycast request according to claim 17, characterized in that before the searching the local routing table and forwarding the first packet P further comprises: judging that the source address of the first packet P corresponds to The anycast address of the anycast server is not in the local anycast routing table. 19. An anycast router, characterized in that the anycast router comprises: a fourth receiving unit, configured to receive the first packet P; A fourth processing unit, configured to determine that the destination address of the first packet P is not its own anycast address; The fourth sending unit is configured to forward the first packet P according to a unicast route by searching a local routing table. 20. The anycast router according to claim 19, characterized in that, the anycast router further comprises a second judging unit, which is used to judge the The anycast address of the anycast server corresponding to the source address of the first packet P is not in the local anycast routing table. 21. A method for processing and responding to anycast requests, characterized in that the method comprises: receiving a response packet of the second packet P; Transforming the source address of the response packet of the second packet P into the anycast address of the anycast server sending the second packet P to form a third packet P; Said third packet P is sent. 22. The method of claim 21, wherein, The transforming the source address of the response packet of the second packet P into the anycast address of the anycast server sending the second packet P, before forming the third packet P, also includes: judging the purpose of the first packet P The address is not its own anycast address, and it is determined that the anycast address of the anycast server corresponding to the source address of the first packet P is in the local anycast routing table. 23. An anycast router, characterized in that the anycast server includes: A fifth receiving unit, configured to receive a response packet of the second packet P; A fifth processing unit, configured to transform the source address of the second packet P into the anycast address of the anycast server sending the second packet P, to form a third packet P; The fifth sending unit is configured to send the third packet P. 24. The anycast router according to claim 23, wherein: The fifth processing unit transforms the source address of the response packet of the second packet P into the anycast address of the anycast server that sends the second packet P, and before forming the third packet P, first judges that the first The destination address of the packet P is not its own anycast address, and it is determined that the anycast address of the anycast server corresponding to the source address of the first packet P is in the local anycast routing table. 25. A method for processing and responding to anycast requests, characterized in that the method comprises: receiving a second packet P; After processing the second packet P, a response packet of the second packet P is formed, the source address of the response packet is the unicast address of the anycast server, and the destination address is the anycast address of the anycast router sending the packet P; A response packet of the second packet P is sent. 26. An anycast server, characterized in that the anycast server comprises: a sixth receiving unit, configured to receive the second packet P; The sixth processing unit is configured to form a response packet of the second packet P after processing the second packet P, the source address of the response packet is the unicast address of the anycast server, and the destination address is the address of the anycast router sending the packet P anycast address; A sixth sending unit, configured to send a response packet of the second packet P. 27. A system for realizing anycast service, characterized in that the system comprises: The first anycast router is used to receive a packet P, and the packet P is an anycast request packet; according to the destination address of the packet P, the anycast routing table is searched to select an anycast server; and the packet P is encapsulated into a first Packet P, the destination address of the first packet P is the address of the anycast router corresponding to the anycast server, and the payload of the first packet P is the packet P; sending the first packet P; The second anycast router is configured to receive the first packet P; decapsulate the first packet P into a packet P, that is to say restore the payload into a packet P; search for the anycast according to the address of the packet P The unicast address of the server; converting the destination address of the packet P into the unicast address of the anycast server to form a second packet P; sending the second packet P to the anycast server. The anycast server is configured to receive the second packet P, and provide corresponding anycast service according to the content of the second packet P. 28. The system for realizing anycast service according to claim 27, characterized in that, after said first anycast router converts the payload of said first packet P into said packet P, said packet P Marked as a tunnel packet; the representation method of the tunnel packet is: defining new header information for the packet P or using a reserved bit position of the packet P as an identifier to represent the tunnel packet TP. 29. The system implemented by anycast service according to claim 27, characterized in that, When the first anycast router performs encapsulation, the anycast router corresponding to the anycast server is the first-hop router of the anycast server. 30. The system for implementing anycast service according to claim 27, characterized in that, the system further comprises a third anycast router, configured to receive the first packet P; determine the purpose of the first packet P The address is not its own anycast address, and the first packet P is forwarded according to a unicast route by searching a local routing table. 31. The system for implementing anycast service according to claim 27, characterized in that, the system further comprises a fourth anycast server, configured to receive a packet P, and the packet P is an anycast request packet; according to The address of the group P is searched for the unicast address of the anycast server; the destination address of the group P is transformed into the unicast address of the anycast server to form a second group P; the second group P sent to the anycast server. 32. The system for realizing anycast service according to claim 27, characterized in that, the anycast server is further configured to form the second group P after providing the corresponding anycast service according to the content of the second group P Response packet, the source address of the response packet is the unicast address of the anycast server, and the destination address is the anycast address of the anycast router sending the packet P; the response packet of the second packet P is sent; The system further includes a fifth anycast router, configured to receive the response packet of the second packet P; transform the source address of the response packet of the second packet P into the address of the anycast server sending the second packet P anycast address, forming a third packet P; sending said third packet P.

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