s vermill wrote: > > Group: > > One Cisco Press book says this about VTP pruning: > > "...This means that it restricts broadcasts, mulicasts, and > flooded unicast traffic from switches that do not have ports > assigned to that VLAN..." > > Anyone one know what, if any, implications this has for OSPF > adjacencies? Specifically, I'm dealing with a proposed > topology where all of the access switches will have MSFCs. > OSPF will be used to support a multicast application. All > inter-switch links will be trunked due to a requirement that > any user be able to plug into any wall jack and log into > his/her VLAN (this will be accomplished via User Registration > Tool). So will every MSFC form an adjacency with every other > MSFC on every subnet/VLAN via the trunks? Or will a switch > without any active users in a given VLAN be pruned out and thus > no adjacency? > > I'm guessing the adjacencies will form. This is good in the > context of not needing to form a new adjacency at such time a > new VLAN user plugs in. It's bad in the context of how many > adjacencies will need to be maintained. > > I realize that not every access switch necessarily needs an > MSFC to support multicast. This isn't my design. Just my > potential problem to deal with... > > Thanks all, > > Scott > >
Well, I finally got to experiment with this topology. Not surprisingly, OSPF adjacencies form in spite of the broad claim that VTP pruning restricts multicast. I'm still a little green with respect to large networks consisting entirely of these blurred layer 2 / layer 3 boxes. I'm accustomed to a couple of distribution or core devices having L3 capability, but not every single switch in the network (some folks have deep pockets). So my concern that adjacencies would unnecessarily form over every single VLAN (via the dot1q trunks) was unfounded. On the access switches, simply configuring only those VLAN interfaces that are absolutely necessary on the MSFCs limits adjacencies to what is desired. Furthermore, there is always the option to omit network statements in the OSPF config. I wish I had this kind of lab at my disposal all of the time. Unfortunately, I suspect that the users are about to stampede. Scott Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=58761&t=58577 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
