How to avoid Dual Active VSS switches in the network...

[vishal agavane]

Hi Team,

We have 2 nos of VSS switches in the network those are connected with 2 nos 10 Gbps uplink, all access switches are connected to both VSS chassis with dual uplinks, When we removed VSL link between these two vss switches both became active. We have completely Layer-2 network, is that any feature which we can use and avoid dual active scenario in VSS and make any one of the switch in standby mode and all Layer link on that switch will be available in case of VSL link goes down.

I have 3750X series switches are connected to both VSS Core switch It's world be much appreciated if some one provide well document on this and their suggestion.

Your reply will be much appreciated.

Thanks,

Vishal

[Reza Sharifi]

Hi,

There are 2 solutions for dual active detection:

1-Deploy fast-hello.  With fast-hello, you usually connect a direct 1Gig link between the 2 VSS switches and configure the port as fast-hello

2-Deploy ePAGP.  For this solution, you configure ePAGP to use one of the Portchannels that connect access switches to VSS.

for more information refer to this link:

http://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst6500/ios/12-2SX/configuration/guide/book/vss.html#wp1063718

HTH 

[vishal agavane]

Thanks for the reply Reza,

Please let me know if we go with Epagp then when VSL link goes down then what would be the result?

1st My there won't be any effect in the network, standby chassis remain in Standby Mode and active in Active Mode?

2nd Active chassis will reboot and became standby and my standby chassis will be Active?

3rd Standby chassis will be shutdown all port except VSL? and only Active chassis will work?

4th Active chassis will restart and shutdown all port except VSL? and standby chassis will be active?

5th ???

Reza it would be much helpful if you please guide how to configured EPagp on 6500 and 3750X switch with "c3750e-universalk9-mz.122-55.SE8.bin (ipservices)" image.

Thanks,

Vishal

[Reza Sharifi]

Hi,

The maximum number of chassis you can use for VSS is 2.  So, there is no 3rd and 4th chassis.

here is the confign guide for configuring pagp

http://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst3750x_3560x/software/release/12-2_53_se/configuration/guide/3750xscg/swethchl.html#wp1378883

HTH

[vishal agavane]

Your correct Reza,

We have 2 nos of VSS chassis (6500) and many 3750x switches are connected to both VSS chassis over optical links (Complete Layer 2 Network).

Can we deploy your second solution in our topology (Deploy ePAGP) ?

If i am going with ePAGP deployment what will happen with Two VSS chassis (Active & Standby) when VLS link goes down?