Jeff, If you are going to (must) use VLANs, they should never extend beyond the distribution layer. That is, a VLAN may exist in the access layer (possibly across more than one A/L switch) but should terminate at the D/L. Beyond the D/L into the core, the network is to be purely routed/switched with no VLAN activity (there are exceptions to this with a switched core in which you may want to set up VLANs - routed core is often preferred. Even in this exception case, these "core VLANs are different VLANs than in the A/L).
Whether any trunking is needed is probably a more important question: It sounds (from your wording) that this is a fresh design - if you do not have to trunk VLANs (with "have to=must" being the operative words), then the best design going these days is to put one VLAN per A/L switch; each VLAN corresponds directly to a separate subnet. On the D/L switches, there are multiple routed interfaces (subinterfaces) each performing routing for the individual subnets corresponding to the A/L switches. In this manner, your entire network is essentially routed (hosts connecting down to their D/L switch are switched, yes, but they are only in their own subnet) and you don't have to worry about anything to do with VTP or STP. So, here is a one line summary: If you don't absolutely need to use VLANs, don't: route. Cheers, Arjen -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Jeffrey Reed Sent: March 22, 2002 5:26 AM To: [EMAIL PROTECTED] Subject: More VTP Questions [7:39131] Thanks to everyone who helped clarify the VTP Domain process and I have more questions. I am working on a textbook Cisco network design. We have two 6509s in the core, four 6509s in the distribution layer and about 30 6509s at the access layer. We also have two Server Farm 6509s hanging off the core switches. The core and distribution will route and well switch to the server farm and the access layers. Well have about 4-5 VLANs in each access layer, so well over 100 VLANs total. Hence my strong interest in VTP. Reading through the VTP stuff today, I saw where the VTP communication occurs through VLAN1. The reseller who sold the design said we would have multi-path layer3 connectivity between core and distribution and layer 2 out to access 6509s. Assuming we only had routed links between the core and distribution layers, then how would the VTP updates get through to the distribution layer from the core? Can we effectively have both a routed link and a bridged VLAN1 link throughout the network? Does that make sense? Any suggestions on how this is accomplished with one VTP domain or a better way would be appreciated. Jeff Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=39152&t=39131 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
