Monday, March 12, 2007

CCIE VTP

As you probably know already the Switching part in the lab exam is now taking a grater part in the lab score ~20 points so it is definitely a major subject. VTP (VLAN Trunk Protocol) key points for the lab: In the lab you will have 2x3550 and 2x3560 making configuration of VLAN and VTP slight more interesting and very interesting for spanning tree but this is for another post. vtp default mode is server on server mode you can create modify delete vlan assign password for higher security. vtp check revision numbers the switch with the higher revision number win and update all. mean that if you insert into a new setup a switch that was in production or was handled to show a higher revision number will mess up all your setup so it is most recommended to delete flash:vlan.dat ! all the vlans info is kept in that file ! set / check the vtp mode to server vtp mode server ! set a new vtp domain vtp domain newCCIE ! set a password other then cisco notice that the password is case sensitive vtp password otherthencisco ! and only then install it into your topology !for the lab i would check the vtp status show vtp st ! if status or revision or configuration of vlan is not suitable to my needs ! i would change the domain name to a different domain and re change it to the needed ! domain this would make the revision number to 0 Version of the vtp is not so much concern unless specifically asked as the difference mainly between ver 1 to 2 is the support of token ring on ver 2 VTP pruning is a nice feature that allow the switches to save some traffic by pruning unnecessary vlan traffic. vtp modes : Server as was mentioned before this mode is to allow to create modify and delete vlan Client is not allowed to create delete or modify vlan information Transparent is allowed to create modify delete vlan only on the local switch. VTP is used to transfer multiple vlan information and due to that it can only travel between trunks, so if you have problem with vtp information propagation check your trunk, also one of the switches must be server and other clients for the information to be transferred properly. also ver1 and v2 are not compatible so make sure all switches use the same vtp version. Another key difference between ver 1 and 2 In Transparent mode vtp advertisement that travel trough the switch are drop if not on the same domain, but on ver 2 it is propagated and not dropped. Hope this was some informative review on vtp, note that there is much more to vtp then what I have specified here but I think I have summarized some key features that I use in my practice and real life.
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