CSS redundancy on one-armed configuration

[wong.kenneth]

Can we configure box-to-box redundancy on a one-armed configuration or do we have to use the 'Active-active stateful failover ASR' ?

We are using CSS 11500.

[Gilles Dufour]

you can use box-to-box.

However, the vip/interface redundancy is much more interesting.

With the combination of ASR you have stateful redundancy that you do not have with box-to-box.

Also, box-to-box redundancy as a single point of failure since you can have only 1 cable for the redundancy protocol between the 2 CSS.

If this connection fails, both CSS will become active and you get into lot of troubles.

Regards,

Gilles.

[wong.kenneth]

We had this exact question posed to us on the single point of failure scenario!

Now, for active-active ASR, you have 'isc-port'. Is that used for stateful failover flow of information? Therefore, any failures on this port would not pose a problem other that loss of statefulness?

Is it possible to have more than 2 CSS for this active-active scenario?

thanks!

[Gilles Dufour]

the isc-port is indeed only being used to exchange flow information and the lost of it is not so much a problem. Be aware you can configure 2 isc-port.

One is active and the other one is backup.

With VIP/Interface redundancy I have tested 3 CSS and it worked [no isc port being used].

However this is not officially supported so I would not recommend such a solution.

Gilles.