WO2014026571A1

WO2014026571A1 - Method and device for sending generic routing encapsulation tunnel message

Info

Publication number: WO2014026571A1
Application number: PCT/CN2013/081236
Authority: WO
Inventors: 邱军; 焦欣文; 刘必振; 姜超
Original assignee: 中兴通讯股份有限公司
Priority date: 2012-08-14
Filing date: 2013-08-09
Publication date: 2014-02-20
Also published as: CN102868613A

Abstract

Provided are a method and device for sending a generic routing encapsulation tunnel message. The method includes: determining a partitioned value of a generic routing encapsulation tunnel message; according to the message partitioned value, judging whether a message to be sent needs to be partitioned; if needed, partitioning the message to be sent; and sending the partitioned message to be sent or the message to be sent which need not be partitioned, after encapsulating same using a generic routing encapsulation protocol. The present invention can reduce the partitioning probability of a message after being encapsulated, thereby reducing the occupancy of the decapsulation node resources due to restructuring, and improving the network transmission capability.

Description

General route encapsulation tunnel message sending method and device

The present invention relates to the field of communications, and in particular, to a method and apparatus for transmitting a general route encapsulation tunnel message. Background technique

The Generic Routing Encapsulation (GRE) protocol is a tunnel encapsulation protocol that encapsulates packets of a certain network layer protocol, such as IP, IPv6, and MPLS, into another network layer protocol, such as IP. The mechanism in IPv6 packets enables packets to be transmitted on heterogeneous networks. In some cases, the system needs to transmit a payload packet, which needs to be encapsulated and sent to a destination. The payload packet uses a different protocol than the protocol supported by the network. In this case, the payload needs to be carried out. The GRE is encapsulated, and then the GRE packet is encapsulated in another protocol for forwarding. The outer protocol is an encapsulation protocol, which is a protocol used on the network.

Referring to FIG. 1, when the user network is transformed into an IPv6 network, and the backbone network is still an IPv4 network, when the IPv6 user of the user network needs to access the remote IPv6 service, the GRE provides a tunnel encapsulation technology to enable the user's IPv6. Packets can traverse the IPv4 backbone network. Encapsulation and decapsulation are performed on the IPv4 network edge device. When the original IPv6 packet of the IPv6 user reaches the IPv4 network edge device R1 for forwarding, the forwarding routing table is searched and the IPv6 packet is imported into the GRE tunnel for GRE encapsulation: Encapsulating the GRE header And the outer IPv4 header, the encapsulated IPv4 packet traverses the IPv4 network and reaches the edge device R2 of the IPv4 network, decapsulates the R2 device, strips the outer packaged IPv4 header and the GRE header, and restores the original IPv6 packet. The text is forwarded by IPv6 to the IPv6 destination. When the encapsulated IPv4 packet length is greater than the maximum transmission unit (MTU) of the outbound interface of the GRE tunnel or the MTU of the intermediate forwarding device, the encapsulated IPv4 packet will be fragmented. GRE decapsulation node must first After reorganization, decapsulation can be performed and forwarding will continue.

When the MTU of the GRE tunnel is unreasonable, the encapsulated GRE packets are fragmented on the GRE tunnel outbound interface or the intermediate forwarding device. The fragmented GRE packets are reassembled on the GRE decapsulation node before they can be forwarded. The recombination processing burden of the GRE tunnel decapsulation node is increased. When a large number of users access the GRE tunnel and there are a large number of fragments, the processing capability of the decapsulation node becomes a bottleneck of network transmission. In addition, reorganization requires a large amount of reassembly pool resources. If the reassembly server has limited reassembly resources, a large number of fragments arrive at the decapsulation node, which may result in partial fragmentation not requiring reassembly pool resources and packet loss. Summary of the invention

The main technical problem to be solved by the embodiments of the present invention is to provide a method and a device for sending a general-purpose route encapsulation tunnel packet, which can reduce the probability of fragmentation of the packet after encapsulation, and reduce the occupation of the decapsulated node resource by reorganization. , improve network transmission capabilities.

To solve the above technical problem, the technical solution adopted by the embodiment of the present invention is as follows:

A method for sending a general-purpose route encapsulation tunnel packet, the method comprising the following steps: determining a packet fragmentation value of a general route encapsulation tunnel packet;

And determining, according to the packet fragmentation value, whether the packet to be sent needs to be fragmented; if necessary, performing fragmentation on the to-be-sent packet;

The packet to be sent after the fragmentation or the to-be-sent packet that does not need to be fragmented is encapsulated and sent using the general routing encapsulation protocol.

Preferably, the packet fragmentation value is a preset fixed value.

Preferably, the method for obtaining the packet fragmentation value is: sending a probe packet, and calculating, according to the fed back packet information, a maximum transmission unit value of the universal routing encapsulation tunnel, and setting the maximum transmission unit value to the Message fragmentation value.

Preferably, the setting, by using the detection packet, the packet fragmentation value of the universal routing encapsulation tunnel includes: Obtaining a first maximum transmission unit value of the universal routing encapsulation tunnel, and setting the first maximum transmission unit value to an initial packet fragmentation value;

And configuring, according to the first maximum transmission unit value, a probe packet, and transmitting the probe packet, where the probe packet is a non-fragmentable packet;

If the received response packet is a response packet that discards the probe packet, the second largest transmission unit value of the universal routing encapsulation tunnel is calculated according to the response packet, and the second maximum transmission is used. The unit value updates the initial packet fragment value;

The second maximum transmission unit value is updated to the message fragment value.

Preferably, the obtaining the first maximum transmission unit value of the universal routing encapsulation tunnel comprises: obtaining a maximum transmission unit value of the outbound interface of the universal routing encapsulation tunnel, and subtracting the encapsulation header length from the maximum transmission unit value to obtain a general routing encapsulation tunnel The first maximum transmission unit value; the encapsulation header length includes: an outer IP header length and an outer common routing encapsulation header length.

Preferably, the method further includes: repeatedly sending the probe message periodically or irregularly. The embodiment of the present invention further provides a device for sending a general-purpose route encapsulation tunnel packet, which includes a fragmentation value obtaining unit, a packet fragmentation unit, a message encapsulation unit, and a message sending unit.

The fragmentation value obtaining unit is configured to determine a fragmentation value of the general routing encapsulation tunnel packet, and the packet fragmentation unit is configured to determine, according to the packet fragmentation value, whether fragmentation is to be sent. If necessary, the packet to be sent is fragmented;

The packet encapsulating unit is configured to encapsulate the to-be-sent packet to be sent or the to-be-sent packet to be sent according to a general routing encapsulation protocol;

The packet sending unit is configured to send the to-be-sent packet that is encapsulated by the packet encapsulating unit.

Preferably, the fragment value obtaining unit is further configured to preset the packet fragment value to be a fixed value.

Preferably, the fragmentation value obtaining unit further includes a probe message module and a slice value setting module; The probe packet module is configured to generate a probe packet that detects a maximum transmission unit value of the universal route encapsulation tunnel; and send the probe packet to a packet encapsulation unit;

The fragment value setting module is configured to calculate a maximum transmission unit value of the universal routing encapsulation tunnel according to the fed back message information, and set the maximum transmission unit value to the packet fragmentation value.

Preferably, the fragment value setting module is further configured to obtain a first maximum transmission unit value of the universal routing encapsulation tunnel, and set the maximum transmission unit value to an initial packet fragmentation value;

The probe packet module is further configured to: according to the first maximum transmission unit value obtained by the fragment value setting module, construct a probe packet, and send the constructed probe packet to the packet encapsulation Unit

The fragment value setting module is further configured to: determine whether the received response message is a response message for discarding the detection message, and if yes, calculate the real-purpose routing encapsulation tunnel according to the response message. And a second maximum transmission unit value, and updating the initial message fragment value by using the second maximum transmission unit value, and updating the second maximum transmission unit value to a packet fragmentation value.

Preferably, the fragment value setting module obtains the maximum transmission unit value of the outbound interface of the universal routing encapsulation tunnel, and subtracts the encapsulation header length from the maximum transmission unit value to obtain the first maximum transmission unit value of the universal routing encapsulation tunnel. The length of the encapsulation header includes: an outer IP header length and an outer universal routing encapsulation header length.

Preferably, the probe message module is further configured to repeatedly send the probe message periodically or irregularly.

The beneficial effects of the embodiment of the present invention are as follows: By setting a packet fragmentation value, the packet to be sent is compared with the value to determine whether to perform fragmentation, so that a larger packet is fragmented before being encapsulated, and subtracted. The probability of fragmentation after packet encapsulation is reduced, which further reduces the occupation of decapsulating node resources by reorganization and improves network transmission capability.

In addition, the method and device for sending a general route encapsulation tunnel message in the embodiment of the present invention are also The MTU value of the general route encapsulation tunnel is dynamically detected by using the probe packet, and the packet fragmentation value is dynamically set by the value, so that the fragmentation of the packet is more effective and accurate. The MTU value is fragmented for the packets to be sent or forwarded by the GRE tunnel, further reducing the probability of fragmentation of the encapsulated GRE packets, and decentralizing the reassembly nodes to reduce the burden of reassembly of the GRE tunnel decapsulation nodes, and reducing the reorganization Decapsulate the occupation of node resources and improve network transmission capacity. DRAWINGS

1 is a network topology diagram of a general route encapsulation tunnel transmission in the prior art;

2 is a flowchart of a method for transmitting a packet of a general routing encapsulation tunnel according to an embodiment of the present invention; and FIG. 3 is a schematic structural diagram of a device for sending a packet of a general routing encapsulation tunnel according to an embodiment of the present invention. detailed description

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

Referring to FIG. 2, an embodiment of the present invention provides a method for sending a general-purpose route encapsulation tunnel message, which mainly includes the following steps:

Step S201: Obtain a packet fragmentation value of the GRE tunnel.

In this step, the packet fragment value of the GRE tunnel is obtained, and the value is used as the reference value of the fragment to be sent. There are many ways to obtain the fragment value of the packet. Preferably, in this embodiment, there are two ways of obtaining: One is to define a general transmission capacity of the GRE tunnel, and set a suitable one. The fragmentation value, which is an optimal fixed value. When the packet exceeds the fragment value, the fragmentation operation is performed.

In addition, there is another way to obtain the following: The dynamic real-time control of the packet fragmentation value makes the packet transmission more effective and accurate. The specific method is as follows: Sending a probe packet, according to the feedback The packet information is calculated to obtain the maximum transmission unit value of the universal routing encapsulation tunnel, and the value is used as the packet fragmentation value.

The specific process of setting the packet fragmentation value by using the probe packet may be divided into the following steps: Step S2011: Obtain the first maximum transmission unit value of the general route encapsulation tunnel, and set the fragmentation value of the initial packet;

In this step, the maximum transmission unit value of the GRE tunnel can be obtained by direct acquisition or probe acquisition. In this embodiment, a preferred acquisition mode is provided: first, the route is searched according to the destination address configured by the GRE tunnel, and the outbound interface of the GRE tunnel is obtained from the route entry, and the MTU value of the outbound interface is obtained; Option configuration, calculate the length of the GRE header, plus the length of the outer IP header is recorded as the length of the encapsulation header. The GRE original header length is 4 bytes. The GRE can be configured with the Checksum option, the Key option, and the Sequence Number option. For each additional option, the header length is increased by 4 bytes, and the Check option is 2 bytes long. The padding field of the byte is also 4 bytes, and the resulting GRE header length is 4-16 bytes. The GRE outer IP header is 20 bytes long, and the outer IP header cannot contain options. Then, the length of the encapsulation header is subtracted from the MTU value of the outbound interface, and the result is used as the first MTU value of the GRE tunnel, and the value is set as the initial packet fragmentation value.

Step S2012: Construct a probe packet according to the first maximum transmission unit value, and encapsulate and send the probe packet.

In this embodiment, the detection packet may be in the form of a GRE keepalive packet. The length of the inner IP packet is the first MTU of the GRE tunnel. The GRE Keepalive packet is a two-layer GRE encapsulation. When the inner GRE header is encapsulated, the options for the GRE tunnel option are only added to the Key option. The Checksum option and the Sequence Number option are not added. The outer GRE header is configured according to the GRE tunnel option. The encapsulation is performed. The non-fragmentable DF flag bit in the outer IP header of the GRE keepalive packet is set to 1, and the keepalive packet is sent. GRE Keepalive packets are transmitted in the network if the MTU of a node in the GRE network is less than The length of the GRE Keepalive packet. Because the non-fragmented DF flag is set in the outer IP header, the node sends the Internet Control Message Protocol (ICMP) Datagram to the source node while discarding the Keepalive packet. Too Big will spoof the text, and fill in the MTU value of the node in the next hop MTU field of the ICMP message header. The ICMP Datagram Too Big message belongs to the ICMP Destination Unreachable message. The type field is 3, that is, type 3, and the code field is 4, that is, code 4. The ICMP header carries the original IP header that generates the ICMP message. 8-byte data portion.

Step S2013: If the received response message is a response packet for discarding the probe packet, the second largest transmission unit value of the real-time universal route encapsulation tunnel is calculated according to the response packet, and the second maximum transmission unit value is used. Update the initial packet fragment value;

In this embodiment, if an ICMP Datagram Too Big message is received in the network, the MTU of a node in the network is smaller than the length of the Keepalive message, and the received ICMP Datagram Too Big message is parsed from the ICMP Datagram Too Big. The source IP address, the destination address, and the protocol number are removed from the original IP address carried in the packet. If the protocol number is 47, it indicates that the GRE packet is encapsulated. The GRE tunnel is found according to the source and destination IP addresses, and the ICMP packet is used. The next hop MTU field value is subtracted from the encapsulation header length to obtain a second maximum transmission unit value, and the initial packet fragment value is updated with the second maximum transmission unit value.

If the MTU value of each node in the GRE network is greater than or equal to the keepalive packet length, the MTU of the GRE tunnel is kept unchanged and the packet fragmentation value is not updated.

After obtaining the packet fragment value by the above method, go to the following steps:

Step S202: determining, according to the packet fragmentation value, whether the packet to be sent needs to be fragmented; if fragmentation is required, proceeding to step S203; otherwise, executing step S204;

In this embodiment, the updated packet fragmentation value is sent to the forwarding plane, and is used as a basis for determining whether to perform early fragmentation when the forwarding plane forwards the packet through the GRE tunnel; When the GRE tunnel is encapsulated, the fragment value is also used as a basis for judging whether or not to slice in advance. If the length of the packet to be forwarded or sent is greater than the packet fragment value, the process goes to step S203. If the length of the packet to be forwarded or sent is less than or equal to the packet fragment value, the process proceeds directly to step S204.

Step S203: Perform a fragmentation process on the packet that needs to be fragmented.

In this step, the packet that is determined to be fragmented in step S202 is mainly subjected to fragmentation processing according to the corresponding fragmentation mode.

Step S204: Perform GRE encapsulation on the processed packet.

In this step, the processed fragmented packet or the packet that does not need to be fragmented is GRE-encapsulated, and the process proceeds to step S205.

Step S205: Send the encapsulated message.

In this embodiment, the route or the outbound interface of the destination address of the GRE tunnel may be changed. To maintain the real-time and validity of the packet fragmentation value, the probe packet may be sent periodically or irregularly. The MTU value of the latest GRE tunnel is obtained, and the optimal packet fragment value is updated.

Referring to FIG. 3, in the embodiment of the present invention, a general route encapsulation tunnel packet sending apparatus is further provided, which mainly includes a fragment value obtaining unit 301, a packet fragmentation unit 302, a packet encapsulating unit 303, and a packet sending. Unit 304;

The fragment value obtaining unit 301 is configured to obtain a packet value of a general route encapsulation tunnel message.

To achieve a better packet fragmentation value of the GRE tunnel, the fragmentation value obtaining unit 301 further includes: a probe packet module 3011 and a fragmentation value setting module 3012;

The probe packet module 3011 can be configured to customize a packet fragment value so that the GRE tunnel can fragment the packet. The probe packet 3011 can also be configured to generate a probe report for detecting the maximum transmission unit value of the general route encapsulation tunnel. And sending the probe packet to the packet encapsulation unit After the 303 is encapsulated, the packet sending unit 304 performs transmission, and the packet fragmentation value is efficiently obtained by using the method.

The fragmentation value setting module 3012 is configured to calculate a maximum transmission unit value of the universal routing encapsulation tunnel according to the fed back message information, and set the value to a packet fragmentation value.

Further, the probe packet module 3011 is further configured to construct a probe packet according to the first maximum transmission unit value acquired by the fragment value setting module 3012, and send the constructed probe packet to the packet encapsulation unit. After the 303 is encapsulated, the packet is sent by the packet sending unit 304; the probe packet is a non-fragmentable packet;

The fragmentation value setting module 3012 is further configured to determine whether the feedback packet is a response packet for discarding the probe packet, and if yes, calculate, according to the response packet, a second maximum of the universal routing encapsulation tunnel in real time. Transmit the unit value and set the second maximum transmission unit value update to the latest message fragment value.

In this embodiment, the specific process of obtaining the packet fragmentation value by the fragmentation value acquisition unit 301 has already performed detailed parameters in the above-mentioned general route encapsulation tunnel packet transmission method, and details are not described herein.

The message fragmentation unit 302 is configured to determine, according to the packet fragmentation value, whether the packet to be sent needs to be fragmented; if necessary, fragment the to-be-sent packet;

The packet encapsulating unit 303 is configured to perform GRE encapsulation according to the to-be-sent packet to be sent or the to-be-sent packet that does not need to be fragmented.

The packet sending unit 304 is configured to send the to-be-sent packet encapsulated by the packet encapsulating unit 303.

The above is a further detailed description of the present invention in connection with the specific embodiments, and the specific embodiments of the present invention are not limited to the description. It is to be understood by those skilled in the art that the present invention may be practiced without departing from the spirit and scope of the invention.

Claims

claims

1. A method for sending universal routing encapsulated tunnel messages. The method includes:

Determine the general routing encapsulation tunnel message fragmentation value;

According to the message fragmentation value, determine whether the message to be sent needs to be fragmented; if necessary, fragment the message to be sent;

For fragmented messages to be sent, or messages to be sent that do not need to be fragmented, use the universal routing encapsulation protocol to encapsulate and send them.

2. The universal routing encapsulation tunnel message sending method as claimed in claim 1, wherein the message fragmentation value is a preset fixed value.

3. The universal routing encapsulation tunnel message sending method according to claim 1, wherein the method of obtaining the message fragmentation value includes: sending a detection message, and calculating the universal routing encapsulation based on the feedback message information. The maximum transmission unit value of the tunnel is set as the packet fragmentation value.

4. The universal routing encapsulation tunnel message sending method as claimed in claim 3, wherein the use of detection messages to set the message fragmentation value of the universal routing encapsulation tunnel includes:

Obtain the first maximum transmission unit value of the universal routing encapsulation tunnel, and set the first maximum transmission unit value as the initial message fragmentation value;

Construct a detection message according to the first maximum transmission unit value, encapsulate and send the detection message; wherein, the detection message is a non-fragmentable message;

If the received response message is a response message that discards the detection message, the real-time second maximum transmission unit value of the universal routing encapsulation tunnel is calculated based on the response message, and the second maximum transmission unit value is used The unit value updates the initial message fragmentation value;

The second maximum transmission unit value is updated to the message fragmentation value.

5. The universal routing encapsulation tunnel message sending method according to claim 4, wherein said obtaining the first maximum transmission unit value of the universal routing encapsulation tunnel includes: Obtain the maximum transmission unit value of the outbound interface of the universal routing encapsulation tunnel, and subtract the encapsulation header length from the maximum transmission unit value to obtain the first maximum transmission unit value of the universal routing encapsulation tunnel; wherein, the encapsulation header length includes: The length of the layer IP header and the length of the outer general routing encapsulation header.

6. The universal routing encapsulation tunnel message sending method according to any one of claims 3 to 5, wherein the method further includes: repeatedly sending the detection message regularly or irregularly.

7. A universal routing encapsulation tunnel message sending device, which includes: a fragmentation value acquisition unit, a message fragmentation unit, a message encapsulation unit and a message sending unit; wherein,

The fragmentation value acquisition unit is configured to determine the universal routing encapsulation tunnel message fragmentation value; the message fragmentation unit is configured to determine whether the message to be sent needs to be fragmented based on the message fragmentation value; If necessary, fragment the message to be sent;

The message encapsulation unit is configured to encapsulate the fragmented message to be sent, or the message to be sent that does not require fragmentation, according to a universal routing encapsulation protocol;

The message sending unit is configured to send the message to be sent that has been encapsulated by the message encapsulating unit.

8. The universal routing encapsulation tunnel message sending device according to claim 7, wherein the fragmentation value acquisition unit is further configured to preset the message fragmentation value to a fixed value.

9. The universal routing encapsulation tunnel message sending device as claimed in claim 7, wherein the fragmentation value acquisition unit further includes: a detection message module and a fragmentation value setting module; wherein,

The detection message module is configured to generate a detection message that detects the maximum transmission unit value of the universal routing encapsulation tunnel, and send the detection message to the message encapsulation unit;

The fragmentation value setting module is configured to calculate the maximum transmission unit value of the universal routing encapsulation tunnel based on the feedback message information, and set the maximum transmission unit value as the message fragmentation value.

10. The universal routing encapsulated tunnel message sending device as claimed in claim 9, wherein: The fragmentation value setting module is further configured to obtain the first maximum transmission unit value of the universal routing encapsulation tunnel, and set the first maximum transmission unit value as the initial message fragmentation value;

The detection message module is also configured to construct a detection message based on the first maximum transmission unit value obtained by the fragmentation value setting module, and send the detection message to the message encapsulation unit; wherein , the detection message is a non-fragmentable message;

The fragmentation value setting module is also configured to determine whether the received response message is a response message that discards the detection message. If so, calculate the real-time universal routing encapsulation tunnel based on the response message. the second maximum transmission unit value, and use the second maximum transmission unit value to update the initial message fragmentation value, and update the second maximum transmission unit value to the message fragmentation value.

11. The universal routing encapsulated tunnel message sending device according to claim 10, wherein the fragmentation value setting module is configured to obtain the maximum transmission unit value of the universal routing encapsulated tunnel outbound interface and use the maximum transmission unit Subtract the encapsulation header length from the value to obtain the first maximum transmission unit value of the universal routing encapsulation tunnel;

Wherein, the encapsulation header length includes: the outer IP header length and the outer general routing encapsulation header length.

12. The universal routing encapsulation tunnel message sending device according to any one of claims 9-11, wherein the detection message module is further configured to repeatedly send the detection message regularly or irregularly.