Real-Time Monitoring Link/Protocol Neighbor State

Abstract

Various protocols are deployed in today's networks, such as BGP / ISIS / OSPF etc. Link neighbor state changes and protocol neighbor state changes are the most important network events that need to be processed with the highest priority. In particular, the SDN controller needs to quickly sense the link neighbor and protocol neighbor state change information in the network. Thus, the various policies applied by the SDN controller to the network can quickly match the current state of the network. This document discusses some possible scenarios and the relevant requirements.¶

1. Introduction

Various protocols are deployed in today's networks, such as BGP / ISIS / OSPF / LDP / BFD etc. When managing a network, one of the most important things to monitor is changes to the various protocols' neighbor states. Many times a protocol neighbor state change is indicative of a problem on the network, and it is an important basis for the SND controller to deploy the traffic steering policies. There are several ways to monitor these state changes, e.g. we can use command-line interface (CLI) to get them from the devices, but typically it's done with either SNMP based polling and/or SNMP traps. For BGP, we can use BMP (BGP Monitoring Protocol) [RFC7854] to collect BGP neighbor state change information.¶

Link neighbor state changes and protocol neighbor state changes are the most important network events that need to be processed with the highest priority. In particular, the SDN controller needs to quickly sense the link neighbor and protocol neighbor state change information in the network. Thus, the various policies applied by the SDN controller to the network can quickly match the current state of the network.¶

The problem of the current real-time data collection method: Collecting protocol neighbor state will also collect many other large amounts of information data associated with it and have a significant impact on the reception/processing of high priority protocol neighbor state data. E.g., the processing of the BMP Peer Up/Down message is not real-time, and is affected by the receiving and processing of other BMP messages, especially a large number of route monitoring messages.¶

At present, the SDN controller uses a single channel to receive real-time data from the network, and then classifies the data and processes it in order, which causes the delay of the neighbor state information processing to grow; and the neighbor information data structure of different protocols are different; these cases will increase the delay in which the SDN controller processes neighbor state data.¶

2. Requirements and Options

Summary of requirements are as follows:¶

Requirement 1: Network event prioritization, Set Link neighbor state changes and protocol neighbor state changes as the most important network events.¶

Requirement 2: The structure of the link neighbor and protocol neighbor state change information needs to use a normalized format, such as a unified TLV.¶

Requirement 3: Link Neighbor and Protocol Neighbor State Change Information requires a separate transport channel to be separated from other low priority data.¶

Requirement 4: SDN controller implements the convergence mechanism of the existing network protocol in milliseconds/second.¶

Some options to be discussed:¶

1) A new Neighbor State Monitoring Protocol.¶

2) Consider processing all neighbor states into LS information, flooding them through IGP, and collecting them on the controller through BGP-LS.¶

3) Consider processing all neighbor states into LS information, imorting them to the BGP-LS Local-RIB, and collecting them on the controller through BMP.¶

4) gRPC + YANG Model.¶

5) To be added...¶

3. Neighbor State Information Format

At present, the neighbor information data structure of different protocols are different. In order to speed up processing in controller or collector, this document proposes to use a normalized format as following:¶

+---------------------------------------+
|      Protocol Type                    |
+---------------------------------------+
|      Node-IP Address                  |
+---------------------------------------+
|      Local-IP Address                 |
+---------------------------------------+
|      Peer-IP Address                  |
+---------------------------------------+
|      Neighbor State                   |
+---------------------------------------+
|      Timestamp                        |
+---------------------------------------+
Figure 1 Link Neighbor/Protocol Neighbor State Information Format

Where:¶

Protocol Type: 1: ISIS / 2: OSPF / 3: BGP / 4: LDP / 5: BFD etc.¶

Node-IP Address: The IP Address of the monitored node, usually the router ID.¶

Local-IP Address: Local-IP Address of the Neighbor¶

Peer-IP Address: Peer-IP Address of the Neighbor¶

Neighbor State: The state of the Neighbor¶

Timestamp: The timestamp of the moment of the event¶

4. Acknowledgements

The authors would like to thank Robin Li, Zhongjia Wang for their contributions to this work.¶

5. Contributors

Mach Chen mach.chen@huawei.com¶

Yunan Gu guyunan@huawei.com¶

8. Normative References

[RFC2119]

Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, <https://www.rfc-editor.org/info/rfc2119>.

[RFC4271]

Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A Border Gateway Protocol 4 (BGP-4)", RFC 4271, DOI 10.17487/RFC4271, January 2006, <https://www.rfc-editor.org/info/rfc4271>.

[RFC5492]

Scudder, J. and R. Chandra, "Capabilities Advertisement with BGP-4", RFC 5492, DOI 10.17487/RFC5492, February 2009, <https://www.rfc-editor.org/info/rfc5492>.

[RFC7854]

Scudder, J., Ed., Fernando, R., and S. Stuart, "BGP Monitoring Protocol (BMP)", RFC 7854, DOI 10.17487/RFC7854, June 2016, <https://www.rfc-editor.org/info/rfc7854>.