WO2018010614A1 - Établissement de connexion de session bfd - Google Patents

Établissement de connexion de session bfd Download PDF

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Publication number
WO2018010614A1
WO2018010614A1 PCT/CN2017/092337 CN2017092337W WO2018010614A1 WO 2018010614 A1 WO2018010614 A1 WO 2018010614A1 CN 2017092337 W CN2017092337 W CN 2017092337W WO 2018010614 A1 WO2018010614 A1 WO 2018010614A1
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state
bfd
bfd session
session
peer device
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PCT/CN2017/092337
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English (en)
Chinese (zh)
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吴文
汪亮
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新华三技术有限公司
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Publication of WO2018010614A1 publication Critical patent/WO2018010614A1/fr

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  • BFD Bidirectional Forwarding Detection
  • BFD establishes sessions on two devices to monitor bidirectional forwarding between the two devices.
  • Path which serves the upper layer protocol.
  • the BFD protocol specifies three states for establishing a BFD session connection: DOWN (not ready), INIT (ready), and UP (established).
  • FIG. 1 is a state transition diagram of a BFD session connection establishment according to an exemplary embodiment of the present disclosure
  • FIG. 2 is a flowchart showing a method of determining that a preset condition is satisfied, according to an exemplary embodiment of the present disclosure
  • FIG. 3 is a schematic diagram of message interaction of a BFD session connection establishment process according to an exemplary embodiment of the present disclosure
  • FIG. 4 is a schematic diagram of a hardware structure of a network device to which a BFD session connection establishing apparatus is applied according to an exemplary embodiment of the present disclosure
  • FIG. 5 is a schematic structural diagram of the network device according to an exemplary embodiment of the present disclosure.
  • FIG. 6 is another schematic structural diagram of the network device according to an exemplary embodiment of the present disclosure.
  • BFD can be associated with other upper-layer protocols.
  • a typical application is to detect whether the PW is normal through BFD-linked PW (Pseudowire). Assume that there are two PEs (Provider Edges, service provider network edge) devices PE1 and PE2, and a PW is established on the physical link between PE1 and PE2. The PW is bound to a BFD session, and the BFD is on PE1 and PE2. The initial state of the session is DOWN.
  • a BFD session connection can be established between PE1 and PE2 through the following processing.
  • PE1 can send a BFD packet indicating that the BFD session is in the DOWN state to PE2.
  • the PE2 switches the BFD session to the INIT state, and then sends the BFD packet indicating that the BFD session is in the INIT state to the PE1.
  • the PE1 After receiving the BFD packet indicating the INIT state, the PE1 switches the BFD session to the UP state, and then sends the BFD packet indicating that the BFD session is in the Up state to PE2. After receiving the BFD packet indicating the UP state, the PE2 switches the BFD session to the UP state.
  • the BFD packets exchanged between PE1 and PE2 need to be sent to the CPU (Central Processing Unit) for judgment and processing.
  • the CPU Central Processing Unit
  • the CPU processing performance of any of the devices deteriorates, for example, when PE2 has a large processing workload, resulting in a decrease in processing performance, the following may occur.
  • the PE2 After receiving the BFD packet in the UP state, the PE2 sends the BFD packet to the CPU. The CPU fails to process the BFD packet and is discarded. After the detection time is reached, the BFD session on PE2 is switched from the INIT state to the DOWN state. The state of PE1 is also switched from the UP state to the DOWN state after the detection time is reached. Afterwards, PE1 and PE2 will try to initiate a BFD session connection again. The CPU of PE2 may still discard BFD packets. Therefore, after the oscillating process, the BFD session on PE1 and PE2 will eventually reach the UP state. In this process, the state of the BFD session is oscillated due to the degraded CPU processing performance of the PE2. As a result, the upper-layer protocol that is associated with the BFD session is also flapped. For example, the neighbor relationship of the upper-layer routing protocol flaps.
  • the BFD session connection establishment method is provided in the following embodiment, and the BFD session connection establishment method is provided in the following embodiment, and the method can be applied to the BFD session connection.
  • Method of network equipment Method of network equipment.
  • a new state PRE-UP is introduced on the basis of three states DOWN (not ready), INIT (ready), and UP (established) established by the BFD session. (quasi-UP), PER-UP represents an unsteady state that has not been fully UP and may change.
  • the BFD session connection establishment method is described with a PE device as an example of a network device, but
  • the application of the method is not limited to the PE device, and may be other network devices that can run the BFD protocol.
  • the BFD session on the PE device is in the DOWN state, if the PE device receives the BFD packet sent by the peer device to indicate the DOWN state, the BFD session is switched to the INIT state.
  • the BFD session is in the INIT state, if the PE device receives the BFD packet sent by the peer device and indicates the status of the INIT or the UP, the BFD session is switched to the PRE-UP state.
  • the BFD session is in the PRE-UP state, if the PE device receives the BFD packet sent by the peer device and indicates the INIT or the UP state, the BFD session is maintained in the PRE-UP state.
  • the PE device switches the BFD session to the UP state when it determines that the preset condition is met.
  • the foregoing preset condition is: the N (N is a positive integer) BFD packets sent from the peer device, and the two adjacent BFD packets in the N BFD packets are continuously received.
  • the interval between receptions is within a preset time range.
  • the preset time range may be expressed as [T-t1, T+t2], where T represents a transmission time interval of the BFD message, and t1 and t2 represent preset time interval errors.
  • t1 and t2 may be the same or different. For example, both t1 and t2 may be preset to 20%T.
  • the received BFD packet indicating the UP state may be counted by a counter, and the initial value of the counter value i of the counter is 0.
  • the method for determining whether the foregoing preset condition is met may be as shown in FIG. 2, and includes the following steps.
  • step S201 the PE device determines whether the BFD packet of the BFD session is to be established. If yes, the process proceeds to step S202. Otherwise, the process returns to step S201.
  • step S202 the PE device determines whether the BFD packet indicates the UP state. If yes, step S203 is performed. Otherwise, step S209 is performed.
  • step S204 the PE device determines whether the counter value of the counter is greater than 1, that is, determines whether i is greater than 1, and if so, proceeds to step S205, otherwise, returns to step S201.
  • step S205 the PE device calculates a difference A between the time when the BFD packet indicating the UP state is received and the time when the BFD packet indicating the UP state is received, and then the step S206 is performed.
  • step S206 the PE device determines whether A is within the preset time range [T-t1, T+t2]. If yes, step S207 is performed; otherwise, step S209 is performed.
  • Step S207 the PE device determines whether the counter value of the counter is equal to N, that is, determines whether i is equal to N, and if so, proceeds to step S208, otherwise, returns to step S201.
  • the PE device receives the BFD packet sent by the peer device, and does not receive the BFD packet from the peer device.
  • the BFD session is switched to the DOWN state.
  • the PE device switches the BFD session to the PRE-UP state if it receives the BFD packet sent by the peer device and indicates the INIT state.
  • the PE device receives the BFD packet indicating the DOWN state sent by the peer device, or does not receive the BFD indicating the UP state sent by the peer device within the detection time. If the packet is received, the BFD session is switched to the DOWN state.
  • the PE device When the BFD session is in the DOWN state, the PE device maintains the BFD session in the DOWN state if it receives the BFD packet from the peer device.
  • the PE device When the BFD session is in the INIT state, the PE device maintains the BFD session in the INIT state if it receives the BFD packet in the DOWN state sent by the peer device.
  • the PE device If the BFD session is in the UP state, the PE device maintains the BFD session in the UP state if it receives the BFD packet in the INIT or the UP state.
  • the PE device When the BFD session is in the INIT state, the PE device does not receive the peer device during the detection time. The BFD session is switched to the DOWN state.
  • the PE device When the BFD session is in the DOWN state, the PE device sends a BFD packet indicating the DOWN state to the peer device.
  • the device When the BFD session is in the INIT state, the device sends a BFD packet indicating the INIT state to the peer device.
  • the BFD packet indicating the UP state is sent to the peer device.
  • the BFD packet indicating the UP state is sent to the peer device.
  • a new BFD session connection establishment state PRE-UP is introduced. If the BFD session is in the DOWN state, the network device, such as the PE device, does not directly switch the BFD session to the UP state but switches to the BFD session. PRE-UP status. When the BFD session is in the INIT state, the network device does not directly switch the BFD session to the UP state but switches to the PRE-UP if it receives the BFD packet from the peer device indicating the INIT or the UP state. After the BFD session enters the PRE-UP state, the device sends a BFD packet indicating the UP state to the peer device, and receives the BFD packet from the peer device.
  • the BFD session is switched to the UP state when the condition is met.
  • the preset condition is that the receiving time intervals between the N BFD packets indicating the UP state and the BFD packets indicating the UP state are consecutively within a preset time range.
  • the description of whether the PW is normal or not is detected by the BFD linkage PW.
  • a PW is established on the physical link between the two PEs, PE1 and PE2.
  • the PW is bound to a BFD session.
  • the CPU of PE2 has a large processing workload, so the processing performance is poor.
  • the initial state of the BFD session on both PE1 and PE2 is DOWN.
  • the BFD session connection establishment process between PE1 and PE2 includes the following steps.
  • step S301 the PE1 sends a BFD packet indicating the DOWN state to the PE2.
  • Step S302 After receiving the BFD packet indicating the DOWN state, the PE2 switches the BFD session to the INIT state, and then sends the BFD packet indicating the INIT state to the PE1.
  • Step S303 After receiving the BFD packet indicating the INIT state, the PE1 switches the BFD session to the PRE-UP state, and then sends the BFD packet indicating the UP state to the PE2.
  • Step S304 after receiving the BFD packet indicating the UP state, the PE2 switches the BFD session to the PRE-UP. Status, and then send a BFD packet indicating the UP status to PE1.
  • PE1 and PE2 When the BFD session is in the PRE-UP state, PE1 and PE2 send BFD packets indicating the UP state to the peer according to the interval.
  • step S305 the PE1 switches the BFD session to the UP state when it determines that the preset condition is met.
  • step S306 the PE2 switches the BFD session to the UP state when it determines that the preset condition is met.
  • the present disclosure also provides an embodiment of a network device.
  • network device 40 can include a processor 10, a machine readable storage medium 20 that stores machine executable instructions.
  • Processor 10 and machine readable storage medium 20 are communicable via system bus 30. And, by reading and executing the machine executable instructions in the machine readable storage medium 20 corresponding to the BFD session establishment control logic, the processor 10 can perform the BFD session connection establishment method described above.
  • the machine-readable storage medium 20 referred to herein can be any electronic, magnetic, optical, or other physical storage device that can contain or store information such as executable instructions, data, and the like.
  • the machine-readable storage medium may be: RAM (Radom Access Memory), volatile memory, non-volatile memory, flash memory, storage drive (such as a hard disk drive), solid state drive, any type of storage disk. (such as a disc, dvd, etc.), or a similar storage medium, or a combination thereof.
  • the BFD session connection establishment control logic may include: a receiving module 501, a first switching module 502, a second switching module 503, a sending module 504, and a third switching module 505, where:
  • the receiving module 501 is configured to receive a BFD packet sent by the peer device of the BFD session.
  • the first switching module 502 is configured to: when the BFD session is in the DOWN state, if the receiving module 501 receives the BFD packet sent by the peer device and indicates the INIT state, the BFD session is switched to the PRE-UP state;
  • the second switching module 503 is configured to: when the BFD session is in the INIT state, if the receiving module 501 receives the BFD packet sent by the peer device and indicates the INIT or the UP state, the BFD session is switched to the PRE-UP state. ;
  • the sending module 504 is configured to: when the BFD session is in the PRE-UP state, send a BFD packet indicating the UP state to the peer device;
  • the third switching module 505 is configured to switch the BFD session to the UP state when the BFD session is in the PRE-UP state, if the preset condition is met, the preset condition is that the N BFDs indicating the UP state are continuously received.
  • the receiving time interval between the two adjacent BFD packets in the BFD packet indicating the UP state is within a preset time range, where N is a positive integer.
  • the BFD session connection establishment control logic further includes: a maintenance module 506, configured to: when the BFD session is in the PRE-UP state, if the receiving module 501 receives the UP status sent by the peer device The BFD session is maintained in the PRE-UP state if the BFD packet is not met.
  • the maintenance module 506 is further configured to: when the BFD session is in the PRE-UP state, if the receiving module 501 receives the BFD packet sent by the peer device and indicates the INIT state, the BFD session is maintained as the PRE-UP. status.
  • the BFD session connection establishment control logic further includes: a fourth switching module 507, configured to: when the BFD session is in the PRE-UP state, if the receiving module 501 receives the peer device, the DOWN indicates that the DOWN is sent. If the receiving module 501 does not receive the BFD packet sent by the peer device within the detection time, the BFD session is switched to the DOWN state.
  • a fourth switching module 507 configured to: when the BFD session is in the PRE-UP state, if the receiving module 501 receives the peer device, the DOWN indicates that the DOWN is sent. If the receiving module 501 does not receive the BFD packet sent by the peer device within the detection time, the BFD session is switched to the DOWN state.
  • the preset time range is [T-t1, T+t2], where T represents the transmission time interval of the BFD message, and t1 and t2 represent the preset time interval error.
  • the processor 10 is caused to execute by executing machine executable instructions in the machine readable storage medium 20 corresponding to the BFD session connection establishment control logic described above:
  • the BFD session on the network device When the BFD session on the network device is in the inactive DOWN state and the BFD packet sent by the peer device indicating that the INIT state is ready is received, the BFD session is switched to the established PRE-UP state.
  • the BFD session After the BFD session is in the INIT state and receives the BFD packet sent by the peer device to indicate the INIT state or the UP state, the BFD session is switched to the PRE-UP state;
  • the BFD session is switched from the PRE-UP state to the UP state.
  • the preset condition is that the two BFD packets indicating the UP state are continuously received from the peer device, and the two adjacent BFD packets in the BFD packet indicating the UP state are consecutively received.
  • the receiving time interval is within a preset time range, wherein the N is a positive integer.
  • the processor 10 is further caused by the machine executable instruction to: when the BFD session is in the PRE-UP state, if a BFD packet indicating the UP state sent by the peer device is received, and the method is not satisfied
  • the preset condition is to maintain the BFD session in the PRE-UP state.
  • the processor 10 is further caused by the machine executable instruction to: when the BFD session is in the PRE-UP state, if the BFD packet sent by the peer device indicating the INIT state is received, The BFD session is maintained in the PRE-UP state.
  • the processor 10 is further caused by the machine executable instruction to: when the BFD session is in the PRE-UP state, if the BFD packet indicating the DOWN state sent by the peer device is received, The BFD session is switched to the DOWN state.
  • the processor 10 is further caused by the machine executable instruction to: when the BFD session is in the PRE-UP state, if the BFD packet sent by the peer device is not received within the detection time, The BFD session is switched to the DOWN state.
  • the preset time range is [T-t1, T+t2], where T represents the transmission time interval of the BFD message, and t1 and t2 represent the preset time interval error.
  • machine readable storage medium comprising machine executable instructions, such as machine readable storage medium 20 of FIG. 4, which may be processor 10 in network device 40 Executed to implement the BFD session connection establishment method described above.
  • the processor 10 can perform the following operations:
  • the BFD session When the BFD session is in the DOWN state and the BFD packet is sent to the peer device, the BFD session is switched to the PRE-UP state.
  • the BFD session is switched to the PRE-UP state, when the BFD session is in the INIT state and the BFD packet is sent to the peer device to indicate the INIT state or the UP state.
  • the BFD session is switched from the PRE-UP state to the UP state.
  • the preset condition is that the two BFD packets indicating the UP state are continuously received from the peer device, and the two adjacent BFD packets in the BFD packet indicating the UP state are consecutively received.
  • the receiving time interval is within a preset time range, wherein the N is a positive integer.
  • the machine executable instruction further causes the processor 10 to: if the BFD session is in the PRE-UP state, if a BFD packet indicating the UP state sent by the peer device is received, and the method is not satisfied
  • the preset condition maintains the BFD session in the PRE-UP state.
  • the machine executable instructions further cause the processor 10 to: when the BFD session is in the PRE-UP state, After receiving the BFD packet sent by the peer device and indicating the INIT state, the BFD session is maintained in the PRE-UP state.
  • the machine executable instruction further causes the processor 10 to: when the BFD session is in the PRE-UP state, if a BFD packet indicating the DOWN state sent by the peer device is received, or If the BFD session sent by the peer device is not received, the BFD session is switched to the DOWN state.
  • the preset time range is [T-t1, T+t2], where T represents the transmission time interval of the BFD message, and t1 and t2 represent the preset time interval error.
  • first, second, third, etc. may be used in the present disclosure to describe various information, such information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other.
  • first information may also be referred to as second information without departing from the scope of the present disclosure.
  • second information may also be referred to as first information.
  • word "if” as used herein may be interpreted as "when” or “when” or “in response to a determination.”
  • the device embodiment since it basically corresponds to the method embodiment, reference may be made to the partial description of the method embodiment.
  • the device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separate, and the components displayed as units may or may not be physical units, ie may be located A place, or it can be distributed to multiple network units. Some or all of the modules may be selected according to actual needs to achieve the objectives of the present disclosure. Those of ordinary skill in the art can understand and implement without any creative effort.

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Abstract

La présente invention concerne un procédé d'établissement de connexion de session BFD et un dispositif de réseau. Le procédé comprend les étapes suivantes : lorsqu'une session BFD est dans un état DOWN, si un paquet BFD qui est envoyé par un dispositif d'extrémité pair et qui indique un état INIT est reçu, un dispositif de réseau commute la session BFD vers un état PRE-UP; si la session BFD est dans l'état INIT, si un paquet BFD qui est envoyé par le dispositif d'extrémité pair et qui indique que l'état INIT ou un état UP est reçu, le dispositif de réseau commute encore la session BFD vers l'état PRE-UP; lorsque la session BFD est dans l'état PRE-UP, le dispositif de réseau envoie, au dispositif d'extrémité pair, un paquet indiquant l'état UP; et si une condition prédéfinie est satisfaite, le dispositif de réseau commute en outre la session BFD vers l'état UP, la condition prédéfinie étant une condition dans laquelle N paquets BFD indiquant l'état UP sont reçus en continu à partir du dispositif d'extrémité pair, et l'intervalle de temps de réception entre deux paquets BFD adjacents se situant dans une plage de temps prédéfinie.
PCT/CN2017/092337 2016-07-15 2017-07-10 Établissement de connexion de session bfd WO2018010614A1 (fr)

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CN111478851A (zh) * 2020-02-29 2020-07-31 新华三信息安全技术有限公司 一种报文处理方法和装置
WO2022022366A1 (fr) * 2020-07-30 2022-02-03 中兴通讯股份有限公司 Procédé et dispositif d'établissement de session bfd de tunnel

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CN111478851A (zh) * 2020-02-29 2020-07-31 新华三信息安全技术有限公司 一种报文处理方法和装置
CN111478851B (zh) * 2020-02-29 2022-05-27 新华三信息安全技术有限公司 一种报文处理方法和装置
WO2022022366A1 (fr) * 2020-07-30 2022-02-03 中兴通讯股份有限公司 Procédé et dispositif d'établissement de session bfd de tunnel

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