cisco design question

[afsharki2]

Let's say I have the following:

routed refers to routed interface

we want to ping between computer1 and computer2

Current design:

(computer1)----Sw1----routed----Sw2---routed---Sw3---routed----Sw4-----(computer2)

Future design:

(computer1)---Sw1----routed-----Sw2-----trunk----Sw3-----routed-----Sw4-----(computer2)

As you can see, a trunk is now attempting to be implemented between Sw2 and Sw3.  What configuration changes need to be done to make this happen? so the packets can get from comp1 to comp2.  Do we have to create a new vlan definition (svi), so that it knows to route it up to the next inerface?

I have a feeling I'm missing something really important.  Please let me know if this is not clear enough. 

[Jon Marshall]

Sorry, one other question.

Are you proposing to have the L3 interfaces for the voice gateways ie. their default gateway on the VSS pair ie. you are not going to put them on DS2 ?

Jon

[afsharki2]

correct, and I actually didn't even think about that till you brought it up, I'm really glad you brought that up.  The thing with DS1/2/3 is that they have a lot of access switches under them that have a lot of IP phones.  Now the phone calls have to traverse an additional hop to go inbound/outbound.  As far as the stuff under access vlan 50 at the bottom of the diagram, those are just v224 and v350 for analog.  There aren't much analog phones making in/out bound phone calls just to let you know.

[afsharki2]

Also, is there a speed difference between having all routed interfaces the whole path compared to having a trunk in between?

[Jon Marshall]

You won't notice any difference.

Jon

[Jon Marshall]

You will need to peer across the trunk link using SVIs at either side. If you have multiple SVIs on sw2 and sw3 and you are running a routing protocol you should make most of them passive otherwise you end up with a lot of extra peerings.

So you can either use one of more of your existing SVI to peer across the trunk link or you can create new dedicated vlan(s) just for the peerings and make all your existing data vlans passive.

 I have used dedicated vlans ie. no end clients in those vlans just to keep things clean but either would work and it is entirely up to you.

The above assumes you are running a routing protocol, if not just a case of using static routes. I am also assuming you have existing vlans and SVI on sw2 and sw3 otherwise why use a trunk.

Jon

[afsharki2]

yes I do have SVIs for other vlans defined, but only on SW2 which is our distribution switch. sw3 is the core