Redundancy SW

[Toss Leey]

Hi

I have two access switch 48 ports connect to distribution Switch 6500, Do I need to add another distribution Switch for redundancy and configure both distribution switch for HSRP, or what is the advice to make Network HA..

Thank you

[Jon Marshall · Accepted solution]

If you want redundancy at the distribution layer then you have two options with what you have -

1) purchase another supervisor for your existing 6500 and make sure you have redundant power supplies connected to separate power circuits.

This would give you redundancy up to the chassis but not including that.

2) purchase another 6500. You could then run these as separate interconnected switches and run HSRP as you say or if the supervisors supported it you could run VSS on the 6500s which means you only need to configure one of the switches ie. no need for HSRP and other replication of config.

Jon

[Toss Leey]

if i run VSS on both 6500s, is that means traffic for user in access switch will Loadbalance between both 6500s? Aand do i need stackwise cable between both?

Thank you

[Jon Marshall]

Yes, with VSS your etherchannel from the access switch would be spread between both 6500 switches and all links in the etherchannel would be used.

VSS is not stacking so no stacking cables.

You need certain supervisors and/or modules for VSS support and you configure a VSL (Virtual Switch Link) between the two switches.

So you may find your current 6500 does not have the right supervisor for VSS.

You could still have two 6500s but then you would need to run HSRP for example and your access switches would have a link or etherchannel per 6500 and one would block per vlan due to STP.

It really depends on what you already have.

Jon

[Jon Marshall]

Just to add with two separate 6500s you don't necessarily need to block one of the uplinks per access switch.

You could interconnect your 6500s with a L3 connection which might allow both uplinks from the access switches to forward traffic.

I say might because it depends on your vlans in the access layer and how they are spread across the switches.

Really need more information to say for sure.

Jon

[Joseph W. Doherty · Accepted solution]

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Posting

BTW, for Jon's #1 solution, "This would give you redundancy up to the chassis but not including that." also implies your access switches don't terminate both their uplinks on the same line card, otherwise the line card also becomes a potential single point of failure.

Also BTW, with two uplinks to the same chassis, or logical chassis (i.e. VSS), you might be able to Etherchannel the two links also allowing both to be used without STP blocking one.

Lastly, if you go with a 2nd distribution L3 switch, non-VSS (6500), depending on your needs, you don't have to use another 6500, or even a chassis device.