Cisco Cisco Expressway
Prerequisites
Before setting up a cluster of X8.1.1 Expressway peers or adding an X8.1.1 Expressway to a cluster, ensure
that:
that:
n
All clusters peers are running the same version of code. The only occasion where different peers are
allowed to run different versions of code is for the short period of time while a cluster is being upgraded from
one version of code to another, during which time the cluster will operate in a partitioned fashion.
allowed to run different versions of code is for the short period of time while a cluster is being upgraded from
one version of code to another, during which time the cluster will operate in a partitioned fashion.
n
A DNS SRV record is available for the cluster which contains A or AAAA records for each peer of the
cluster.
cluster.
n
Each peer has a different LAN configuration (a different IPv4 address and a different IPv6 address, where
enabled).
enabled).
n
Each peer in a cluster is within a 15ms hop (30ms round trip delay) of each and every other Expressway in
or to be added to the cluster.
or to be added to the cluster.
n
Each peer in a cluster is directly routable to each and every other Expressway in or to be added to the
cluster. (There must be no NAT between cluster peers – if there is a firewall ensure that the required ports
are opened.)
cluster. (There must be no NAT between cluster peers – if there is a firewall ensure that the required ports
are opened.)
n
Each peer is running on a hardware platform with equivalent capabilities; for example, you cannot cluster a
peer running on a 2 core Medium VM with peers running on 8 core Large VMs.
peer running on a 2 core Medium VM with peers running on 8 core Large VMs.
n
All peers have the same set of option keys installed:
l
The number of call license keys may be different on different peers; all other license keys must be
identical on each peer.
identical on each peer.
l
The Expressway must be restarted after installing some option keys in order to fully activate them.
n
Each peer has a different system name.
n
H.323 mode is enabled on each peer (
Configuration > Protocols > H.323
, and for H.323 mode select
On); even if all endpoints in the cluster are SIP only, H.323 signaling is used for endpoint location searching
and sharing bandwidth usage information with other peers in the cluster.
and sharing bandwidth usage information with other peers in the cluster.
n
The Expressway cluster has a DNS SRV record that defines all cluster peers.
n
The DNS servers used by the Expressway peers must support both forward and reverse DNS lookups of
all Expressway peer addresses; the DNS servers must also provide address lookup for any other DNS
functionality required, such as:
all Expressway peer addresses; the DNS servers must also provide address lookup for any other DNS
functionality required, such as:
l
NTP servers or the external manager if they configured using DNS names
l
Microsoft Lync Server FQDN lookup
l
LDAP server forward and reverse lookup (reverse lookups are frequently provided through PTR records).
Note that DNS server configuration is specific to each peer.
Cisco Expressway Cluster Creation and Maintenance Deployment Guide (X8.1.1)
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Prerequisites