maximum 29XX switches on a 6500 series

[a.pijpaert]

Hello,

is there a recommended maximum of user ports i can connect directly to a 6500 series core switch?

So I have a situation with about 80 24-ports switches (in stacks of 2 or 3) connected with fiber to the core switch. Now one of the network managers states we need a distribution layer cause performance in the 6500 will drop. Reason for this is that the 29XX series switches do not support layer 3.

Is this correct? And does the added layer 3 functionality in a (extra) distribution layer increase performance in the core? Even though almost all traffic is user - server traffic and servers are connected to core?

Anyone know? THanks!

[amit-singh]

Hi Friend,

Which sup engine do you have and is there any switch fabric module you are running. Cat6500' are cross-fabric chassis which gives 32GBPS backplane switch capacity bedefualt. If you have SFM (switch fabric module) installed then it will give 256 GBPS of backplane capacity.

If you are running Sup720, you have 720 GBPS backplane capacity and you will see a greater performance by cat65K.

If you dont have SFM or sup 720, then yes with direct access switches uplink to Core might slow down the performance of the core switch.

If that's the case I would suggest to got for hierarchical design and add another layer of the architecture i.e distribution layer.Now what you can do with this additional layer, is that you can uplink your access layer to it, have your inter-vlan routing done on thius layer, have to access control policy deployed at this layer.

This addtion layer and the above functionalities will off load the processing of traffic at core and core will be efficient enough to process the traffic as fast as it can. This is a abosultely correct approach.

Please, write back for any qurstions.

HTH, Please rate if it does.

-amit singh

[a.pijpaert]

Hello,

thank you for the fast response.

I don't know what supervisor module they have. I will check.

BUT, if inter VLAN is handled by the distribution layer, doesn't the data traffic still have to pass the core (as it's traffic between server, connceted to core and user, connected to access switch)?

[amit-singh]

Yes, the traffic will still pass from the core but keep in mind that you are offloading the extra processes from the core, like inter-vlan routing, access control policies and any other security process.

It also depends on the kind of network topolgy you have, the applications you are running, the users of the application and also few other fatcors. You also have to take all these things into consideration. Depending on your network setup, you can also go for another layer or be on the same set up as you are now. i would suggest the proper palling with proper information collection before taking the final step.

HTH, please rate if it does.

-amit singh

[cisco]

Hi Amit,

Could you please explain more abt Cross-fabric chassis and SFM . Is this SFM works on 6500 switches only or any other switches too ??one more question modules which are installed in switch arent fabric-enabled modules ??

regards

Neo

[amit-singh]

Neo,

Cross-bar fabric basicall y provides you the ability to have different switching capacity without any performace impact. cat6500 gives you 40 GBPS full duplex throughput per slot with no performace impact.

SFM only works with Cat6500, it doesnot work with any other switch.Not even with cat6000.

HTH, Please rate if it does.

-amit singh

[cisco]

one more question modules which are installed in switch arent fabric-enabled modules ??

regards

Neo

[amit-singh]

If the modules are not fabric enabled, the will be classic line cards and will work only on 32GBPS switching fabric.

HTH, Please rate if it does.

-amit singh

[cisco]

Hey Amit,

This Fabric enabled thing is new for me .So i am getting curious as to is there any physical difference too between classic line cards and Fabric enabled cards ?

regards

Neo

[cisco]

any ideas

regards

Neo

[amit-singh]

Yes, There is a diffrence the way febric enabled line cards connects to the back plane. They have extra connections to connect to the back plane and scale upto 256GBPS.

Classic cards doesnot have those connectors and can be used only for 32GBS.

HTH, Please rate if it does.

-amit singh