CSS 11501 multiple IPs

Unanswered Question
Aug 27th, 2009
User Badges:


We have a CSS setup with only one ethernet port(eth1) ,one arm configuration.

This port is ingress aswell as egress for loadbalancing traffic.

It takes in client request from various sources and load balances to services on the same network.

For E.g is VIP and it load balances to servers located at and

Due to high network traffic we are looking to increase the ehternet links capacity.

I understand we cannot do etherchanneling with css.

So is it possible to connect another ethernet link (eth2) on the same vlan and recieve

client traffic on it for a new VIP for e.g as well as keeping on eth1

Or STP will block this port eth2 thinking its a loop?

Any solution?

Many Thanks


  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 0 (0 ratings)
Gilles Dufour Thu, 08/27/2009 - 07:00
User Badges:
  • Cisco Employee,

That won't work.

You need to either replace your fastethernet with a Gig link if you're not already using gig interface.

You can then keep your design.

Or you need to split ingress and egress traffic and therefore get rid of one-armed design.


fareed_farooqui Wed, 09/02/2009 - 01:03
User Badges:

Hi Giles

Thanks for answering ..

About the split ingress and egress design..

Do I just need to configure another eth interface and assign the same vlan to it. Will that split the ingress and egress traffic. or Do i need to do something else.

Much Appreciated.

interface e1

bridge vlan 2

interface e2

bridge vlan 2

Gilles Dufour Wed, 09/02/2009 - 03:26
User Badges:
  • Cisco Employee,

That can be enough if on the switch side, the interfaces are not connected to the same vlan.

So, if you have cat6k======CSS with both link in vlan 2 on css and both link in vlan 2 on cat6k, spanning tree will block one of the link and you did not solve anything.

If you can put the clients in vlan X on the cat6k and the servers in vlan 2, you can then keep the css interfaces (both of them) in vlan 2.

The css will bridge vlan x and vlan 2.

This is ok.


fareed_farooqui Wed, 09/02/2009 - 05:20
User Badges:

Thanks Gilles.

I will do just that.. i.e put clients in differnt vlan and servers in differnt vlan..




This Discussion