OT: WAAS Central Manager deployment - separate subnets

Hi all,

Sorry for the OT, but the collective brain power available is too hard
to resist!

Has anyone who has deployed WAAS, deployed a primary and standby
Central Manager WAEs across separate subnets?

The document entitled "Enterprise Data Center Wide Area Application
Services (WAAS) Design Guide" states:

"Cisco recommends installing two CMs for WAAS deployment: a primary
and a standby. It is preferable to deploy the two CMs in different
subnets and different geographical locations if possible."

This raises some questions in my mind. I know that the process of
bringing the standby CM up as the primary requires manual
intervention, but assuming the primary dies and the standby comes up,
how do the WAE deployed throughout the network in
"application-accelerator" mode know how to communicate with the
standby (now primary) CM? Its IP address is not the same as the dead
primary.

The only feasible scenario I can think of is that once the standby CM
comes up as the primary, it actively communicates with the deployed
WAEs and informs them of the change in CM IP address. The problem is,
I can't find any Cisco documentation that verifies this. There doesn't
seem to be a way to configure the deployed WAEs with the IP address of
the standby CM -- just a single "central-manager address x.x.x.x"
command, which under normal conditions points at the primary CM IP
address.

The alternative is that, in the event of a primary CM failure, each
WAE needs to be manually reconfigured to point at the standby (now
primary) CM IP address. If that's the case -- yuck!

Can anyone clear this up?

cheers,
Dale

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Received on Tue Jun 02 2009 - 16:31:09 ART