Routed Access Layer question

clamz

Hello,

I'm currently in the planning and designing phase of migrating a 3-story building from a strictly L2 access layer (directly to core) to a routed layer design.

Quick layout:

I have a /24 data and voice subnet allocated to each IDF. The first floor IDF (IDF1) is the distribution layer. I'm doing eigrp stubs connected for IDF2 and IDF3 (2nd / 3rd floors). I will have two equal cost links on both switches to each core switch.

My only concern is that I have a vlan interface 777 (see code below). That currently lives on the core switches (HSRP between cores) and it L2 trunked to this 3-story building. This Vlan needs to be spanned across all three IDF's in this building. There is one caveat, this network does not need to live over in the Datacenter since no devices need to be on that subnet in that physical location, so I can move it to IDF1.

Has anybody addressed these issues when moving over to another design like routed access layer? What is the best solution that you have worked out for your environments? I'm hesistant to Re-IP the cameras but if i have to put them on the Data VLAN that is native to each closet, then I will have to do it. Thanks for your help.

[b] 6509 Core 1 [/b]

interface Vlan777
 description SSB Camera VLAN
 ip address 10.1.7.2 255.255.255.0
 ip wccp 0 redirect in
 ip wccp 70 redirect in
 ip pim sparse-mode
 ip rip advertise 15
 ip cgmp
 standby preempt
 standby 106 priority 110
 standby 206 ip 10.1.7.1
 standby 206 priority 110

[b] 6509 Core 2 [/b]

interface Vlan777
 description SSB Camera VLAN
 ip address 10.1.7.3 255.255.255.0
 ip wccp 0 redirect in
 ip wccp 70 redirect in
 ip pim sparse-mode
 ip rip advertise 15
 ip cgmp
 standby 206 ip 10.1.7.1

clamz

I've been brainstorming and I think I know the answer to my own question:

The key limitation to L3 routed access layer design is that you cannot extend a vlan across access-layer switches.
However if this subnet is hosted by the core switch, would this design work? On the access-layer switches, could I create vlan 777 and by means of a gateway of last resort, would it reach the 10.1.7.0/24 subnet native to the Core switches?

I want to know the limitations to this design, otherwise ill probably go with the standard L2 access layer. However, if the only limitation is that all your subnets have to be unique to that access layer and not spanned to other areas, then I feel I could make that work.

Thanks,
clamz

networker050184

VPLS if you have the gear to support it!

Most likely not, so you can go with an SVI routed approach over trunks. Only allow the routed VLAN and any special case VLAN that needs to span more than one switch.