IDSM Support on Cisco 6500 with VSS

Unanswered Question
Jan 13th, 2010

I have a setup where there are 2 x Cisco

6509E Switches with FWSM and IDSM.

I am trying to Loab Balance traffic to the 2 x IDSM using Etherchannel and can only do this when both IDSMs are in a single chassis, I check some Cisco sites which highlighted that this can only be done like this. however I need this to run accross the chassis and take advantage of the VSS and have box level redundancy as well. Can you please advice if this fetaure will be released soon and or if there is any information available on this.

The IOS version on the Sup is 12.2(33)SXI1

The IOS version on the IDSM is 6.0.3

The information that got was from the following website:



I have this problem too.
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Farrukh Haroon Sun, 02/07/2010 - 10:25

By just making  inline vlan pairs and bridging all traffic through the IDSM(s) before reaching the default gateway (FWSM or MSFC), you should get this to work. There is no stateful replication in the IDSM anyway. So both modules act independently in any case.


User VLAN 101 >>  IDSM Pair 101 >> 701 >> SVI ON FWSM 701

But the documentation is not very clear, your link suggests what you want to do should be doable, But this other link reads:

"EtherChannel load balancing (ECLB) is notsupported between an IDSM-2 in the active chassis and an IDSM-2 in thestandby chassis."



masgerali Sun, 02/07/2010 - 23:55

Hi Farukkh,

First of all I appreciate your reply on my case. I know that ECLB is not supported with one IDSM on the Active Chassis and one IDSM on the Standby in a VSS setup. What I want to know if Cisco is working on a solution to this as it only makes sense to fully utilise the VSS capability then to have 2 IDSM one chassis and doing ECLB on that.

I need to know which IOS will support this in future and when is the release date.



Farrukh Haroon Mon, 02/08/2010 - 00:01

Thanks for the clarification.

I would recommend to accelerate this issue with your local Cisco Account Team. The more customers that request this feature, the more likely it is to be introducted in a future release.



masgerali Mon, 02/08/2010 - 00:19

Dear Farukkh,

Thanks for the support. I have done the escalation within Cisco but am just getting the response as "The scenario we are looking for is not going to be supported in the near future".

I was hoping someone (especially from Cisco) might have an answer on this forum. As it is only logical to take the full advantage of VSS by having the 2 IDSM on each chassis and being able to do ECLB on them.




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