CSS11501 Single-armed redundancy configuration issue

[jvanderbijl]

Hi,

I am trying to get a pair of CSS11501 to work in a single-armed configuration. The basic configuration as pointed out in

http://www.cisco.com/en/US/partner/products/hw/contnetw/ps792/products_configuration_example09186a00802206a3.shtml

is clear to me: the CSS listens at the virtual IP address as specified in the service definition and replaces the virtual IP destination address in the original packet with the IP address of a real server (NAT).

In order to make this NAT work, the response packets of the server must be routed back to the CSS.

My problem is: which IP address do I have to use as a gateway address on the servers? If I use the circuit IP address of the primary CSS, all works fine, but that wouldn't work in case of failure of the primary CSS. I would guess I would have to set up another virtual router configuration for return traffic, but apparently virtual routers can only be used for IP addresses assigned to content rules.

Thanks in advance,

Jacco van der Bijl

[seilsz · Accepted solution]

You would configure the servers to point at a virtual interface configured with the following:

ip redundant-interface vrid ip_address

You can find more detailed information here:

http://www.cisco.com/en/US/products/hw/contnetw/ps792/products_configuration_guide_chapter09186a008029b1da.html#wp1063393

~Zach

[jvanderbijl]

Zach,

Ah, that seems to do the trick. Thanks for the pointer.

Regards, Jacco.

[jfoerster]

Hi Jacco,

another possibility than the one described by Zach would be to use source groups replacing the src-address of the connetion with the one of the CSS (or a redundant one). This would cause the routing to be fine as the return flow is directed to the CSS.

Kind Regards,

Joerg

[jvanderbijl]

Hi Joerg,

Hmm, interesting suggestion. In this case, Zach's method was easier to implement, but I will keep this in mind for future projects.

Thanks for your response,

Regards, Jacco.