Expressway C&E clustering

[JacobMunson]

Hello all,

I am trying to understand the best practice configuration for Expressway clustering. The "Cisco Expressway Cluster Creation and Maintenance" guide seems to talk about the process to cluster 2 expressway servers i.e. Creating a cluster of 2 Expressway E servers. It also talks about the DNS needed on the external side of an expressway E cluster however there is nothing on the internal side. The following configuration is what I am trying to understand.

A cluster of Expressway E servers both configured in dual Nic mode.

A cluster of Expressway E servers

connected to a 1 Pub 2 Sub CUCM cluster with 2 IMP servers.

My questions are how does the Unified Communications Traversal and B2B neighbor zones need to be configured?

Do both C's have peers to both E's creating a mesh? If so how is the traffic managed or are they equal cost paths?

When Adding the CM, Unity & IM&P servers to the Expressway C's how is that traffic managed or is it also equal cost paths

Thank you for the info in advance.

[Patrick Sparkman · Accepted solution]

Refer to the Expressway and CUCM via SIP Trunk Deployment Guide for setting up B2B calling, which will take you through the process of setting up the required zones, search rules etc.

Refer to the "Neighboring Between Expressway Clusters" section of the Expressway Admin Guide on pg 118 to get an additional idea of how clustering works as well as how calls are routed via the cluster.

[JacobMunson]

I found following in the Expressway admin guide which was really answered the root of my question

In this case, when a call is received on your local Expressway and is passed via the relevant zone to the remote cluster, it will be routed to whichever peer in that neighboring cluster has the lowest resource usage.

This tells me it's a bad idea to cluster expressway servers that are geographically in different locations. Thank you