Kevin O'Gilvie wrote: > > Dear All, > > I have a Cat5k and about 15 Cat29xx . > All 29xx are connected to the Cat 5, the Cat 5 cpnnects to the > Pix, Pix > Connects to the router. > There are no Vlans in place. > I would like to enable VTP Domain but I would like to know the > best way to > go about thist. > Some of our 29xx are old some are new, I heard horror stories > of VTP taking > down the network. I would like to make the Cat5k my vtp Server > and all the > 29xx 's vtp clients.
I'm more of an expert on real LANs than virtual LANs ;-), so somebody will correct me if I say anything wrong, but I think your plan sounds fine. You may want to have one other switch act as a VTP server as a backup. The other switches should be clients, as you have planned. You should enter VLAN information on the primary server switch normally and only enter information on the other switch acting as a VTP server if you know for sure that the primary server is going to be down for a while. Or, just keep it simple, and have just one VTP server switch, as you have planned. Cisco requires VTP, by the way, so you will have to use it once you start implementing VLANs. You will probably want to put all the switches in the same VTP domain since your network is small, which you can easily do by simply supplying the same domain name for all of the switches. Be very careful with the spelling so that the domain name is exactly the same on all the switches. The name is case-sensitive, by the way. Most problems with VTP are due to non-systematic updating of VLAN data by novice network engineers. As mentioned, you should have no more than one or two switches acting as a server, and you should only make changes on one of those switches, unless the other one is down and will be down for a while. A switch looks at the configuration revision number (CRN) of a VTP advertisement. If a VTP server or client receives an advertisement where the received CFN is higher then the current CFN, the switch sends a request to the originating server for a subset advertisement. The switch then replaces its VLAN configuration with the contents of the subset advertisement. The switch floods the original summary advertisement out all trunk ports. A switch in transparent mode ignores the advertisement and floods it out all trunk ports. Note that when a server or client receives a VTP subset advertisement, the switch erases its old VLAN configuration and replaces it with the new information from the advertising server. This behavior can result in problems. Consider the case where you have configured a switch off-line before connecting it to a network. Now suppose you have configured the switch to be a VTP server and that you made many changes as you were working, resulting in a switch with a higher CFN than exists in the running network. When you connect the new switch to the network, its VLAN configuration replaces that of all the switches in the network. VTP does not add to existing configurations; it replaces them. So, you may have just wiped out numerous VLANs that already existed. Any ports that were in the deleted VLANs are now disabled. The network becomes unusable at this point! VTP is a powerful tool, but it must be used with care. To avoid problems, be sure to document the VLAN names and IDs that are in use, using network management software or an Excel spreadsheet. And that's probably way more verbiage than you needed! ;-) But I hope it is helpful. _______________________________ Priscilla Oppenheimer www.troubleshootingnetworks.com www.priscilla.com > > Your Advice is Greatly appreciated, > > Kevin > > Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=56038&t=55943 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
