Re: Clarification on VTP



On Oct 29, 7:15 am, CraftWorks <craftworks.network...@xxxxxxxxx>
wrote:
Hi,
Greetings and a Good day to you. I need a clarification.
Say there are 5 Switches on a LAN (With Static VLANs).
Let's call them
1)SWT - A
2)SWT - B
3)SWT - C
4)SWT - D
5)SWT - E

Let's say each on these Switches are interconnect to at least Two of
the above mentioned switches. Let's Say two of these Switches i.e. SWT
- A and SWT - B are also connected to a Router.

All of these Switches are on a Single VTP Domain. We do not know how
many of these switches are Servers but there obviously is one Switch
which acts as a VTP Server Switch. Now one has access to Let us say
"SWT - C" which is a VTP client Switch. When I say access I imply on
the console with a rollover cable.

Clarification One
-----------------

Now how do we know from the information on "SWT - C" that which
Switches are acting as or deployed as a Server of the VTP Domain.

Clarification Two
-----------------

Suppose One "VTP Server Switch" is disconnected from the domain for 20
minutes and then reconnect again back, in the 20 minute period what
happens to the VLANS on the Domain as a whole.

Some links to Authoritative information would also be helpful.
Thanks,
CraftWorks.

I don't know of a way to show which switches are servers without
physically going to them and doing a show vtp or show config. You can
verify how many vlans they know about, and the domain they are in, but
doing a show vtp domain or show vtp status depending on IOS or CAT.

As for a disconnection, it all depends on your architecture. Simply
taking away a vtp domain inherently should do nothing, but if that
switch also has layer 3 in it (via msfc or l3 switch), then you will
be down. If all other switches have connections to the layer 3 owner
of the vlans, or redundant connections, then switches will continue to
work. All VTP does is distribute a list of vlans along with names,
configurations, and numbers to other switches to ensure vlans are
synched up across layer 2 switches. If the master goes away, the rest
continue to know about the vlans, and will continue to forward traffic
as necessary. Provided they can still forward frames that will reach
the router (gateway), things should be fine. If however the master is
also the router or has the only uplink to the router (since most
people make the vtp server the 'core' switch or switches which should
be closely aligned with the l3 interfaces), then your network will
have impact.

Here is Cisco's documentation:

http://www.cisco.com/warp/public/473/21.html

http://www.javvin.com/protocolVTP.html

.



Relevant Pages

  • Re: Example of Layer 2 VLAN
    ... If you have multiple switches in a network and need certain vlans contained to a group of switches, ... VTP would be configured in Transparent mode, and the switches local vlan database would only contain the vlans defined on that switch. ... two vlans that I don't want to propagate or broadcast to other ...
    (comp.dcom.sys.cisco)
  • Re: Help on VLAN configuration: Catalyst 3750
    ... If you use VTP, make sure you use a dedicated domain ... for this series of switches. ... > (DB and File Server) should not be available to WLAN users. ... > should have both internet access and access to the server. ...
    (comp.dcom.sys.cisco)
  • VTP client mode with 64+ VLANs on 2950-24
    ... The vtp domain consists of two switches that are vtp server, vtp pruning is enabled and v2 is used. ... Most of the other switches are running in vtp client mode, but we have also got some older 2950s that are only capable of running a maximum of 64 VLANs. ...
    (comp.dcom.sys.cisco)
  • Re: VTP client mode with 64+ VLANs on 2950-24
    ... > we have about 70 VLANs in our network. ... > switches that are vtp server, vtp pruning is enabled and v2 is used. ... > Most of the other switches are running in vtp client mode, ...
    (comp.dcom.sys.cisco)
  • VTP password Server/client
    ... I want to put a password on all of my switches here at work (VTP ... We have a single core 4500 with dual sup's. ... I am thinking that I am going to lose telnet access to all of my ...
    (comp.dcom.sys.cisco)