Automating Network Optimization, Part 2

In Part 1 of this series, Stephane introduced two temporary network optimization scenarios requiring the deployment of tunnels: a troubleshooting issue and a customer request for increased bandwidth between two sites. In this post, he shows how the troubleshooting situation can be handled using automation.

Here’s how the troubleshooting scenario I discussed in Part 1 is handled using a prototype. The first piece is to have an online network analysis tool that is aware of the routing (including the existing traffic engineering tunnels), the performance metrics, and the traffic matrix of the network in real time. With this, there is no more need to import the last set of data that may come from multiple sources. Simulations may still be performed manually with the network analysis tool to try to find the best solution. However, thanks to the power of machine learning techniques and algorithms as well as historical data about all the analytics, the tool may be able to propose some solutions that the operator can simulate. The last thing that may be automated is the implementation of the solution: Most routers today support the PCEP protocol that allows traffic engineering tunnels to be instantiated by a PCE to the router.

Prototyping the Network Optimization Use Case:

This automated network optimization use case is not science fiction and can be done today.

Packet Design’s Explorer Suite of online products (Route Explorer, Traffic Explorer, and Performance Explorer) collects and stores analytics from the network (routing, performance, traffic matrix, traffic engineering tunnels, etc.) in real time and is used in many networks. It also provides an analytics and automation platform for delivering SDN applications. The Explorer SDN-TE app, built on this SDN Platform, provides a first level of analysis of the network compared to a particular objective given as an input. The SDN-TE app can provide some solutions to ensure this objective is continually met and can interact with a PCE to provision the tunnels in the network.

One solution to be used as a PCE is Cisco XTC, which is a simple PCE server feature embedded in IOS XR 6.1 and later versions (so it is managed as a regular network node). It can be activated on any existing router running XR, and it can run as a virtual machine anywhere thanks to IOS XRv.

The prototype works as follows:

• An alarm is raised to the NMS from a network component or from Explorer product alerts.
• The operator is informed of the issue.
• The operator can view the issue using the Explorer products.
• The operator can use the Explorer SDN-TE app to see a global view of the situation and to retrieve TE tunnel recommendations to address the issue, or
• Simulate some network changes using Explorer’s planning feature.
• When the operator agrees on a solution, it can use either the SDN-TE app (if its recommendations are approved) or the tunnel provision app (to set up any other tunnel).
• The SDN-TE app then uses the XTC API to request a tunnel setup in the network on the right head end. It can provision either an RSVP-TE tunnel or a Segment Routing TE tunnel depending on the network design choice.
• XTC issues a PCEP PCInitiate message to the router to set up the tunnel. A particular PCEP extension (draft-ietf-pce-association-policy) is used to request the router to steer the traffic into the tunnel.
• The head end is programmed with the tunnel and the steering policy, and the problem is solved.
• Since Route Explorer keeps track of all the tunnels in the network, when the initial problem has been solved the operator can decide to remove the tunnels that have been provisioned. The SDN-TE app and XTC API will again be used for this.

In Part 3, I will discuss how a customer request for a temporary increase in bandwidth between two sites can be managed.