HP 2650 - Load Balancing?

[Mark Simmonds_2]

Hi there,

We have 2 data rooms each with a 5308XL with GBIC and 1000Base T modules in both rooms. They have a 4 GB trunk between them.

Would it be possible to Load balance a HP 2650 to each 5308XL's so that we have Two 1 gig connections to each data room? from the 2650?. (We have the capacity on the 5308's to do this).

I have looked at LACP, but it seems that you can only do this to only a single switch. Is this correct? or can you load balance? with a more complex configuration?

[Stuart Teo]

If I read your question correctly, MESH technology would be the answer to your question.


5308----5308
| \/ |
| /\ |
2605----2605

[Ralph Bean]

Hello Mark -

You are either asking:

1. Can I run a 2-port Gig trunk from the 2650 to the 1st 5308 and a 2nd 2-port Gig
trunk from the 2650 to the 2nd 5308
or
2. Can I create a 'triangle' or 3-sided trunk that includes the 2650 and the two
5308s?

The answer to Q1 is Yes. The answer to Q2 is No, because our trunks are point-to-point (that is, switch-to-switch).

If you are asking Q2, then if you replace the 2650 with a Series 5300 or 4000M Switch, then you can configure the 'triangle' as a mesh and it will load-balance.

There may be other possible solutions, although I would need to know what your design goals are.

Regards,
Ralph

[Mark Simmonds_2]

Basically all we want to do is to give 100MB to each desktop PC at our site. We have over 600 users all on 10MB at the moment.

We decided on the 5308's at the core level with a 4gig trunk between them, and all 2650's out to the user area's so its all HP.

Basically I was worried that with using the 2 gig trunk to a single 5308, that the 4Gig backbone would be very over utilized if users (some CAD) would need to access servers in the other computer room, and use the 4GIG backbone. (Hence the load balacing question).
The trianglulation would be ideal, but now I am thinking that we may not need the 4 Gig backbone between the computer rooms. Could we use the 2650's (one connection to each room)as the backbones between the 5308's?. If this is to work, then we could connect all 18 of the 2650's to each dataroom providing a 18Gig connection between each computer room? (Am I correct?)

Thanks

[Mark Simmonds_2]

Basically we would love to do the attached:

[Ralph Bean · Accepted solution]

Hello Mark -

These network design questions do not always lend themselves well to a simple question-answer exchange.

Your diagram is clear in terms of what you want to accomplish, but it doesn't show all design elements, particular routing vs switching intent. So, I will give you two answers, one if you intend to switch all of your traffic and another in case you intend to route it.

Option 1. For your topology to work for switched traffic AND STILL LOAD-BALANCE you need a protocol that will do 3+-point load-balancing. Note that trunking only load balances between two points (switches). Meshing will load balance among 3 or more switches, but the 2650 does not have meshing. So, one solution is to replace the 2650 with a 530X, turn meshing on in the three 530Xs, and use your 2650 somewhere that you don't need 3-point connectivity.

Option 2. You can make your 3-point topology work with routing, at the possible expense of changing your IP administration. That is, if you configure the links between the 2650 and the 5308s as three separate subnets, the computer rooms as two (yet) different subnets, and your clients attached to the 2650 as a 6th (or more) subnet(s) and configure the 5308s and 2650 for routing, then your 'triangle' topology will work and the traffic will travel the shortest route necessary. It will not technically load-balance, but it will satisfy your goal of avoiding a lot of traffic from the 2650 to one 5308 then to the other 5308. You should also turn on STP or RSTP in all three switches so that any non-routable traffic does not create a so-called broadcast storm and bring your network down. Any switched (non-routed) traffic will not be routed across an optimum path, of course.

Regards,
Ralph