cisco 6509 commands

[lecarbajal]

Hello,

Is there a command to reset the HSRP group in a cisco 6509?
My problem is : I have 2 swcore 6509 configured with HSRP + PVST some groups are active in one switch and the others are active in the secondary switch.

After a maintenance we had a problem with some border sw connected to these 2 swcore.

I want to manually reset the active and secondary root for each vlan , without change the priority in the hsrp pvst configuration.
Regards,

 

[dgrizzard]

If you set preemption on HSRP the primary will fail back over after it comes up again. However realistically, say if you had 4 networks connecting to this core, you would want 2 networks to use Sw1 as their primary and the 2 other ones to use Sw2. This way you are utilizing your switches efficiently.

 

[VinceWhirlwind]

Interesting point, dgrizzard.

For example, I have set up networks so that "even" VLANs are routed by CORE1 and "odd" VLANs are routed by CORE2. Or "North" vs. "South".

However, other times you might think it will be far simpler for ongoing support if one core is doing all the routing with the second one as backup for all the VLANs.

I think as far as the original poster is concerned, his issue isn't whether HSRP is pre-empting or not, his real issue is that the redundancy hasn't been setup properly for some of his border switches. He should address the actual issue and ensure that in a failover situation ALL his border switches maintain connectivity to the backup CORE.

 

[Quadratic]

I don't really understand what is being asked here. What is meant by "reset the active and secondary root for each vlan, without change the priority in the hsrp pvst configuration"?

While they should always be in sync (your STP root bridges should map to your HSRP Active gateways), techincally STP and HSRP are mutually-exclusive processes. To trigger HSRP changes, adjust priorities with preemption set. To trigger STP bridge changes, adjust STP priorities. Not mapping HSRP actives to STP root bridges is a bad idea, though.

Does that answer the question? If not, I don't think I really understand what you're asking for here.

CCNP, CCDP, CCIP
Core Network Planner, ISP

 

[VinceWhirlwind]

Agree - your STP priority should match your HSRP priority.

 

[dgrizzard]

Agree, I don't understand the bottom part, I was just answering his first question. HSRP and PVST are two different things.

Vince, regarding splitting up your networks between two cores I would say.. 1) you can have higher bursts of traffic throughout a period, and some/most might not need this so it may not be too big of a deal 2) only half of your networks need to converge, not all of them.

For me #2 would be a bigger deal, especially if you're running VoIP. I would rather the network converge and no one notice anything (even a delayed/dropped voice call). A 50/50 shot though since either way your voice might be running on the core that drops.

 

[Quadratic]

I don't think there is a right answer for active/standby versus active/active. There are tradeoffs, and I think really it depends on the sitaution.

CCNP, CCDP, CCIP
Core Network Planner, ISP

 

[VinceWhirlwind]

True.

As far as dgrizzard's point 1) goes, I would say that if you have bursts of traffic that exceed one core switch's ability to pass traffic, then you are under-provisioned in the first place. This might be acceptable if cost is a limiting factor, otherwise your boss is going to have to buy you more toys

 

[dgrizzard]

Agree, unfortunately sometimes you work for people that are not so forward thinking