Data Center Dual Connections with HSRP

Unanswered Question
Aug 16th, 2010

My new data center is providing me two GigE Fiber connections which use HSRP. My current switches are two WS-C2960-24TC-S. Can these be setup to utilize the dual HSRP feed?

Thanks!

-Ted

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Jon Marshall Mon, 08/16/2010 - 17:24

tedtucker wrote:

My new data center is providing me two GigE Fiber connections which use HSRP. My current switches are two WS-C2960-24TC-S. Can these be setup to utilize the dual HSRP feed?

Thanks!

-Ted

Ted

It's not clear exactly what you mean by fiber connections using HSRP but in answer to your question no it won't work properly with 2960 switches because these are L2 switches and so you can only have one L3 SVI active at any one time and these switches are not capable of routing between vlans.

For that you need to consider 3560/3750/4500/6500 switches.

Jon

tedtucker Mon, 08/16/2010 - 19:12

Jon thanks for the reply.

They said they provide me with two diverse paths to my cabinet. Terminating at the top of my rack, yielding two GigE fiber ports. They said they use HSRP.

I assume this would require me to purchase two say "WS-C3560X-24T-S" and and create a virtual IP with a static route to their gateway?

Does this sound right or am I way off?

Thanks,

Ted

Jon Marshall Tue, 08/17/2010 - 04:39

tedtucker wrote:

Jon thanks for the reply.

They said they provide me with two diverse paths to my cabinet. Terminating at the top of my rack, yielding two GigE fiber ports. They said they use HSRP.

I assume this would require me to purchase two say "WS-C3560X-24T-S" and and create a virtual IP with a static route to their gateway?

Does this sound right or am I way off?

Thanks,

Ted

Ted

No you are not way off

Any L3 switch would do the job and yes you would need 2 of them so 3560's would be fine for what you need.

What do the 2960's connect back to ie. you must have other switches/routers in your DC. Bear in mind that if the 2960s connect back to L3 switches then you could still terminate the fibers on the 2960s and then run HSRP on the L3 switches you alreaday have. That's why i asked about the setup in your DC.

Jon

Atif Awan Tue, 08/17/2010 - 22:40

I think we need to understand this better before you run off to buy two switches :- ). From the explanation provided it appears to me that this is a hosted DC environment and you have two Layer-2 switches for attaching the servers in your cabinet. The DC guys have provisioned two fiber uplinks for his cabinet and run HSRP on their end.

If they have provided you with a list of IP Addresses for your servers as well as the default gateway (probably the HSRP) from the same IP pool then all you have to do is to use the fiber uplinks to interconnect your switches to the DC switches. Had your switches been stackables it would have been cleaner to achieve this. In your case you can cascade the two switches and terminate one uplink on each switch. Ideally the switch to switch cascade connection should be an etherchannel provided you have the spare ports.

Again my response is based on my understanding of your situation so please provide additional information if the above is not correct.

tedtucker Tue, 08/17/2010 - 23:41

Atawan you are absolutely correct:

I have a:

- Hosted DC environment

- The DC guys have provisioned two fiber uplinks for my cabinet and run HSRP on their end and provide me with "blended tier 1 bandwidth"

- They provided me with a gateway and pool of IP's

- Currently in my disposal I have two Layer 2 Switches WS-C2960-24TC-S

If I am correct I could use one Fiber GigE SFP on each switch for my Switch <--> DC connection and the other as my Switch <--> Switch connection.

     Using this setup I would be able to use NIC bonding/teaming on my servers between the switches for High Availability?

So what would two Layer 3 (WS-C3560X-24T-S) yeild me in reference to HSRP and High Availability?

    

     I assume using this setup I would creat a new gateway which was a virtual IP that floated between units and created a static route to my gateway provided from my DC. This would also have the same Switch <--> DC connection and Switch <--> Switch connection I assume. I would also use NIC bonding/teaming on my servers between the switches for High Availability?

Thanks for taking the time.

-Ted

Atif Awan Wed, 08/18/2010 - 00:06

In your case I would stick with your current switches but you do need to ensure that you do not run into a split-brain scenario when your switch to switch cascade connection goes down. That is why I suggested that this be an etherchannel if possible but with the current switches you have I do not think you have a spare uplink for etherchannel. An option would be to use one of the uplinks for switch-switch connection as you stated and have a backup etherchannel of 2 or more ports but you have to weigh the risk of inadvertently introducing a loop in this scenario. Also please go through switching best practices on the cisco website to make sure you configure your switches with the required features to prevent running into such problems. I would also suggest you discuss your design with the DC team to ensure that they are in sync and will support this without any issue.

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