Multiple VIPs in Different Subnets

Unanswered Question

Is there any way to setup the CSS with VIPs in different subnets. If we were using an inline configuration, I don't see how this would be possible.

Let's assume three subnets A, B, and C. We would like to have a VIP in subnet A pointing to all the web servers in subnet A. Same for subnets B and C.

I guess we could configure a trunk port with a CIRCUIT interface in each of the subnets A, B, and C. This would allow clients to route to the VIP in each subnet. My concern is the return traffic. With only one default route in the CSS, all return traffic would traverse one CIRCUIT interface. Am I correct, or am I misunderstanding something?



I have this problem too.
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I think I answered my own question. Here is how I envision setting it up.

1. Create a routing subnet for the upstream connection.

2. Create individual subnets A, B, and C for the downstream (server) connections.

3. Create VIPs and content rules for each downstream subnet (A, B, C).

4. My upstream router needs to have routes for each downstream subnet.

Not sure how I missed this before, but is anyone able to validate this for me?



cajalat Fri, 05/18/2007 - 07:14

I believe you are correct. We have practically the same scenario working here. I have a /29 allocated to the front-end of the CSS and the upstream HSRP routers (call that vlan 10). Then I have multiple subnets for backend servers behind the CSS setup as an 802.1q trunk vlans (call them VLAN 100, 101, 102, etc). I route for those subnets belonging to VLANs 101, 102, etc on the upstream routers to point to the VRRP address of the CSS (the VRRP address of the CSS in VLAN 10). I also route whatever IP used as a virtual to the CSS VRRP address as well. So my upstream routes will have routes to the VIPs and the backend VLANs all pointing to the CSS's VRRP address.


Gilles Dufour Mon, 05/21/2007 - 04:56


you then configure 3 default routes.

One for each subnet.

The CSS when given the choice will select the gateway that matches the incoming traffic.



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