WO2009043239A1

WO2009043239A1 - A stream forwarding method and device

Info

Publication number: WO2009043239A1
Application number: PCT/CN2008/071279
Authority: WO
Inventors: Wei Li
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2007-09-29
Filing date: 2008-06-12
Publication date: 2009-04-09
Also published as: CN101136851A

Abstract

A stream forwarding method, includes the steps of: when the IPv6 message to be forwarded arrives, searching the IPv6 index table in the session table, with the IPv6 message to be forwarded, for the V6 index value matching the message; if the search succeeds, constructing the Key value of the session table according to the V6 index value; searching the session table, with the IPv6 message to be forwarded, for the corresponding message forwarding information, according to the Key value of the session table, to process latter message forwarding; if the search fails, setting up a V6 value matching the IPv6 message to be forwarded in the IPv6 index table. At the same time, the embodiment of the present invention discloses a stream forwarding device. The embodiment of the present invention keeps the original stream forwarding mode of IPv4 message, and solves the problem of the address conversion between IPv6 networks by adding IPv6 index tables to realize IPv6 message stream forwarding; meanwhile, IPv6 network stream forwarding and IPv4 network stream forwarding is unified, and the inter- communication between IPv4 network and Ipv6 network is realized.

Description

Flow forwarding method and device

The present invention relates to the field of communications technologies, and in particular, to a stream forwarding method and device. Background technique

With the development of communication technologies, technologies such as Next Generation Network (NGN, Next Generation Network) and network security have been widely used. People have targeted pinhole firewalls, media proxy devices, and network address translation devices (NAT, Network Address Translation). The performance requirements of devices based on stream forwarding are also increasing. Compared with the traditional packet forwarding device, the stream forwarding device has the advantages of high speed and good security. In the current Internet Protocol version 4 (IPv4) network, a large number of stream forwarding devices play an important role in solving network address translation, network security, and topology hiding.

Faced with the growing Internet development and decreasing address space, Internet Protocol version 6 (IPv6) has become a major development direction in the Internet Protocol (IP) technology. Compared with IPv4, IPv6 has great short-term and long-term value in network-based applications. But the question is how to quickly realize the transition from IPv4 to IPv6. If the IPv4 network is forcibly replaced with an IPv6 network, it will affect a large number of existing network devices, so IPv4 and IPv6 will coexist for a long time.

Referring to Figure 1, Figure 1 shows the structure of the source IP address and destination IP address of IPv6. IPv6 increases the address space from IPv4 32bits to 128bits. SIP1 is the first 32bits of the source IP address, SIP2. The second 32 bits of the source IP address, and so on, DIP1 is the first 32 bits of the destination IP address, and DIP4 is the last 32 bits of the destination IP address.

How to ensure the interworking between IPv4 and IPv6 networks, compatibility between IPv4 and IPv6 networks, and IPv6 network address translation, network security, and topology hiding have become issues that need to be solved.

One of the biggest features of the stream forwarding device is the uniqueness of the round-trip path required for the forwarded message. The message is mainly forwarded by looking up the session table. The lookup key value of the Session table is a quintuple: source IP address (SIP, Source IP Address), destination IP address (DIP, Destination IP Address), source port (Source Port), destination port (Destination Port), and protocol (Protocol). ), Forward the message by looking up the quintuple.

In the IPv6 domain, the IP address is changed from the original 32 bits to 128 bits. The existing stream forwarding technology generally increases the length of the Key value, that is, the length of the original 32-bit IPv4 address becomes 128 bits, and the length of the IPv6 address is used as the key value to search for the session.

The prior art solution model works as follows:

When a message arrives at a stream forwarding device, there are four possible possibilities:

IPv4 -> IPv4;

IPv4 -> IPv6;

IPv6 -> IPv4;

IPv6 -> IPv6.

According to the above four combinations, the Key values are assembled separately, and the session table is searched according to four different situations.

The prior art has the following disadvantages:

1. Many stream forwarding devices use hardware to find the session table. When the IPv4 address becomes an IPv6 address, that is, the address length changes from 32 bits to 128 bits, the key value of the session table is increased by a total of 192 bits. This length is greater than the maximum length of many hardware finderes, which makes the finder unable to work, resulting in stream forwarding. The device is not working properly;

2. When the IPv4 address becomes an IPv6 address, the length of the address increases, which is incompatible with the original IPv4 version. As a result, the development of new functions for joining IPv6 is huge, and there are too many code branches, so the risk is large. Summary of the invention

The technical problem to be solved by the present invention is to provide a flow forwarding method and device, which can improve the IPv6 network flow forwarding function and realize the interworking between the IPv4 network and the IPv6 network.

In order to solve the above technical problem, the embodiment of the present invention provides a flow forwarding method, including: when the IPv6 packet to be forwarded arrives, the IPv6 index to be forwarded is searched and matched in the IPv6 index table of the session table. V6 index value;

If the search is successful, the key value of the session table is constructed according to the V6 index value; and the IPv6 packet to be forwarded is searched for the corresponding packet forwarding information in the session table according to the key value of the session table. , for subsequent message forwarding;

If the search fails, a V6 index value matching the to-be-forwarded packet is created in the IPv6 index table. Correspondingly, an embodiment of the present invention further provides a flow forwarding device, including:

a storage unit, configured to store a session table, where the session table further includes an IPv6 index table;

The locating unit searches for the matching V6 index value in the IPv6 index table in the session table stored in the storage unit according to the IPv6 packet to be forwarded;

a processing unit, when the search unit finds a V6 index value that matches the to-be-forwarded packet in the IPv6 index table, constructs a Key value of the session table according to the V6 index value; and searches for the V6 in the searching unit. When the index value fails, the session table of the packet to be forwarded and the corresponding IPv6 index table are created. The table searches for packet forwarding information and performs subsequent packet forwarding.

The implementation of the present invention has the following beneficial effects:

In the embodiment of the present invention, the original IPv4 packet forwarding mode is maintained, and the IPv6 packet forwarding is implemented by adding an IPv6 index table, thereby solving the problem of address translation between IPv6 networks; and simultaneously enabling IPv6 network flow forwarding and IPv4 network circulation. The two are unified to realize the interworking between the IPv4 network and the IPv6 network. DRAWINGS

Figure 1 is a schematic diagram showing the composition of a source IP address and a destination IP address of an IPv6 packet;

2 is a schematic diagram of generating a V6 index value by using a source and a destination IP address of a packet;

3 is a schematic diagram of adding a V6 index value shown in FIG. 2 to an original quintuple to form a new Key value; FIG. 4 is a schematic flowchart of a flow forwarding method according to an embodiment of the present invention;

FIG. 5 is a schematic diagram of the composition of a stream forwarding device according to an embodiment of the present invention. detailed description

In order to make the objects, the technical solutions and the advantages of the embodiments of the present invention more clearly, the embodiments of the present invention are further described in detail below with reference to the accompanying drawings.

In the embodiment of the present invention, the IPv6 index table is added to replace the new part of the IPv6 address, and the index value that is much smaller than the IPv6 index length is used as the Key value to perform the lookup of the Session table.

Referring to Figure 2, Figure 2 is a schematic diagram of generating the V6 index value of the source and destination IP addresses of the packet, that is, the source IP address of the packet and the first 96 bits of the destination IP address, and a total of 192 bits are composed of V6 index values.

The specific implementation is as follows: When the IPv6 packet to be forwarded arrives, 32 bits are obtained after the IPv6 address is fetched. The value is placed in the original IPv4 address as the Key value in the original IPv4 session lookup. A new IPv6 index value, that is, a V6 index value, is created for the first 96 bits of the new source and destination IPv6 addresses (for the IPv4 address, the default value of the first 96 bits is 0), which is the IPv6 index. The value is used as a Key value for session lookup.

Referring to FIG. 3, FIG. 3 is a schematic diagram of adding the V6 index value to the original quintuple to form a new Key value. It should be noted that the range of the V6 index value may be based on the Session entry in the flow forwarding device. Count it. Assuming that there is a 1M Session table in the flow forwarding device, we assume that the V6 index values of all sessions are different. The number of IPv6 index entries also needs to be 1M, that is, the V6 index value ranges from 0 to 0xFFFFF.

Referring to FIG. 4, FIG. 4 is a schematic flowchart diagram of a flow forwarding method according to an embodiment of the present invention.

5101. Construct a V6 index value of the IPv6 index table. The specific implementation is: when the packet to be forwarded arrives, if the packet contains an IPv6 address, the IPv6 address is extracted, and the newly added source and destination IPv6 addresses are 96. A total of 192 bits (for IPv4 addresses, the default value of the first 96 bits is 0) creates a new V6 index value, which is stored in the IPv6 index table;

5102: The IPv6 index to be forwarded is used to search for the corresponding V6 index value in the IPv6 index table. First, the first 96 bits of the source and destination IP addresses of the IPv6 packet are extracted. Set to 0), the total of 192 bits is taken as the Key value, and the corresponding V6 index value is searched in the IPv6 index table; and it is determined whether the search is successful, and if so, S103 is executed, and if the search fails, S106 is executed. ;

5103. Construct a key value of the session table. When the V6 index value corresponding to the IPv6 packet to be forwarded is successfully found in the IPv6 index table, fill the V6 index value corresponding to the IPv6 packet in the IPv6 index table. Enter the position of the V6 index value in the search key value in the Session table. Then fill in the last 32 bits of the packet source and destination IP address (the last 32 bits of the IPv4 packet is the v4 address itself) and fill in the search in the Session table. The source and destination IP addresses in the Key value, and the source, destination port, protocol number, and V6 index value constitute a new Key value of the Session table;

5104: Searching for the corresponding packet forwarding information in the session table by using the key value of the packet to be forwarded; searching for the corresponding packet forwarding information in the session table according to the Key value in the session table; If the information about the packet forwarding of the IPv6 packet is successfully found in the table, the S110 is performed, and the packet is forwarded according to the original IPv4 flow forwarding process. If the search fails, the S105 is executed, and the IPv6 packet is re-created. The corresponding Session table; 5106: The V6 index value is generated according to the to-be-forwarded packet, and the first 96 bits of the source and destination IP addresses of the to-be-forwarded packet are used as the key value, and the V6 corresponding to the IPv6 packet to be forwarded cannot be found in the IPv6 index table. When the index value is used, an IPv6 index table needs to be created. Specifically, the first 96 bits of the source and destination IP addresses are used to generate a V6 index value of a certain length according to a certain algorithm.

5107, constructing a Key value of the session table; using a five-tuple (source IP, destination IP, source port Sport, destination port Dport, and protocol number Protocol) plus a V6 index value to form a new Key value;

S108: Construct a session table according to the Key value of the session table.

5109: Create an IPv6 index table according to the V6 index value. After the session table is successfully created, create an IPv6 index table by using the first 96 bits of the source and destination IP addresses.

5110: The original IPv4 flow forwarding packet is forwarded. After the IPv6 index table is created, the IPv6 packet to be forwarded is forwarded according to the original IPv4 flow forwarding mode.

Referring to FIG. 5, FIG. 5 is a schematic diagram of a composition of a flow forwarding device according to an embodiment of the present invention;

The storage unit 1 is configured to store a session table, where the session table further includes an IPv6 index table. The session table is created by using the source and destination IP addresses of the packets to be forwarded. 96 bits generate a certain length of V6 index value according to a certain algorithm; use the quintuple (source IP, destination IP, source port, destination port and protocol number) and V6 index value to form a new Key value of the Session table; The key value is used to create a Session table. After the session table is successfully created, an IPv6 index table is created by using the first 96 bits of the source and destination IP addresses.

The searching unit 2 searches for the corresponding V6 index value in the IPv6 index table in the session table stored in the storage unit 1 according to the IPv6 packet to be forwarded;

The processing unit 3, when the search unit 2 finds a V6 index value that matches the to-be-forwarded packet in the IPv6 index table, constructs a Key value of the session table according to the IPv6 index table; When the V6 index value fails to be found, a session table corresponding to the to-be-forwarded packet and an IPv6 index table are created.

The forwarding unit 4 is configured to search for the corresponding packet forwarding information in the session table according to the key value of the session table according to the Key value of the session table, and perform subsequent packet forwarding according to the original IPv4 flow forwarding mode.

The flow forwarding device further includes:

The timer 5 is used to set the aging time of the session table and the IPv6 index table, and trigger the meeting periodically. The table of words and the IPv6 index table are updated.

It should be noted that all Session entries have a certain aging time, and this time is fixed. There is also a timestamp, and this timestamp is constantly rising. When the timestamp of the session entry is greater than the aging time, the session entry should be deleted. However, whenever a packet hits the Session table of the stream forwarding device, the timestamp in the Session table is refreshed once (timestamp is cleared). After the IPv6 index table is added, whenever the timestamp in the Session table is refreshed once, the timestamp in the IPv6 index table is also refreshed once.

In a stream forwarding device, there is usually an operation to actively delete the Session table. After the IPv6 index table is added, if you delete the session again, you need to delete the IPv6 index table.

Since the IPv6 index table and the session table are not a simple one-to-one relationship, there may be one-to-many (that is, the first 96 bits of the source and destination IP addresses of the two messages are equal), so the IPv6 index table cannot be simple. delete. The approach that can be taken is to accelerate aging. That is, the timestamp of the IPv6 index table can be modified, and the IPv6 index table can be aged after ten seconds by adjusting the timer 5 (this time can be determined according to the actual situation). If a message can hit the Session within ten seconds, the IPv6 index table will naturally be refreshed, otherwise it will age.

In the embodiment of the present invention, the original IPv4 packet forwarding mode is maintained, and the IPv6 packet forwarding is implemented by adding an IPv6 index table, thereby solving the problem of address translation between IPv6 networks; and simultaneously enabling IPv6 network flow forwarding and IPv4 network circulation. The two are unified to realize the interworking between the IPv4 network and the IPv6 network.

The above is only a preferred embodiment of the present invention, and the scope of the present invention is not limited thereto, and thus equivalent changes made in the claims of the present invention are still within the scope of the present invention.

Claims

Rights request

A flow forwarding method, comprising:

When the IPv6 packet to be forwarded arrives, the IPv6 index to be forwarded is searched for the matching V6 index value in the IPv6 index table of the session table.

If the search is successful, the Key value of the session table is constructed according to the V6 index value; and the to-be-transferred message is forwarded for subsequent packets;

If the search fails, a V6 index value matching the to-be-forwarded packet is created in the IPv6 index table.

2. The flow forwarding method according to claim 1, wherein the V6 index value that matches the to-be-forwarded packet is created in the IPv6 index table, and includes:

The V6 index value is generated in the first 96 bits of the source and destination IP addresses of the IPv6 packet; the V6 index value is added to the original quintuple Key value of the session table to form a new Key value and a new session table;

Add the V6 index value to the IPv6 index table as an IPv6 index entry.

The flow forwarding method according to claim 2, wherein the searching for the V6 index value in the IPv6 index table of the session table by using the IPv6 packet to be forwarded includes:

When the IPv6 packet to be forwarded arrives, the 192 bits of the first 96 bits of the source and destination IP addresses of the IPv6 packet are used as the Key value to search the IPv6 index table.

The stream forwarding method according to claim 3, wherein the constructing the Key value of the session table according to the V6 index value comprises:

Filling the V6 index value into the V6 index value of the Key value part of the session table; filling the source and destination IP address 32-bit addresses of the IPv6 file to be forwarded into the source and destination IP addresses of the session table key value, The key value of the new session table is formed along with the source, destination port, protocol number, and the V6 index value.

The flow forwarding method according to any one of claims 1 to 4, wherein the IPv6 packet to be forwarded is searched for in the session table according to a key value of the session table. Packet forwarding information, for subsequent packet forwarding, including:

If the corresponding packet forwarding information is found in the session table, the packet is forwarded according to the original IPv4 process;

If no corresponding packet forwarding information is found in the session table, a session table corresponding to the packet and an IPv6 index table are created.

The stream forwarding method according to claim 5, wherein the aging time of the IPv6 index table is consistent with the session table.

7. The stream forwarding method according to claim 6, wherein the time stamp of the IPv6 index table is modified to extend the aging time.

A flow forwarding device, the device comprising:

The stream forwarding device of claim 8, wherein the device further comprises: a timer, configured to set an aging time of the session table and the IPv6 index table, and periodically trigger the session table to update.