Mutli-site VTP design

[william.culver]

I have 6 sites connected in a dark fiber ring.  The two sites have 6500 series switches connected by 10Gb redundant fiber paths.  All servers will be hosted at one of the sites, with a second site having failover capabilities for the virtual server environment (VMware SRM).  Originally all sites were set up as a single flat network with one subnet.  I am in the process of establishing subnets for each location to isolate data traffic as well as voice, security, wireless, video, etc.  I will have redundant connections to all sites, yet provide for each site to operate in isolation.  I will need to have the local vlans defined on the local layer 3 switches, but from a VTP design standpoint, should all sites be part of a single VTP domain as they are currently, or separate domains with traffic routed between sites?

Any thoughts would be greatly appreciated.

[Reza Sharifi]

William,

This is just my opinion.  If you don't have a lager number of switches and you only have one or 2 VLANs/Subnets per location, don't use VTP at all.

Put all the switches in transparent mode and configure the vlans manully per site. This way you don't have to worry each time you insert a new switch in your network you do not bring down the entire network.

There are some disadvantages to the use of VTP. You must balance the ease of VTP administration against the inherent risk of a large STP domain and the potential instability and risks of STP. The greatest risk is an STP loop through the entire campus. When you use VTP, there are two things to which you must pay close attention:

• Remember the configuration revision and how to reset it each time that you insert a new switch in your network so that you do not bring down the entire network.

• Avoid as much as possible to have a VLAN that spans the entire network.

http://www.cisco.com/en/US/tech/tk389/tk689/technologies_tech_note09186a0080094c52.shtml

HTH

Reza

[lgijssel]

I have been using VTP for years now and it has never posed me any problems. When used properly, the risk of anything going wrong are remote.

For critical cases, you may create a text file with the vlans in it. If need should be, you can always paste the file into cli and you would have your vlans back.

Then about your actual question: I would prefer to split the vtp domains in such way that each location has his own.

This will be easier to administer and it reduces the risk of human error.

regards,

Leo

[william.culver]

Okay, thanks.  I want to set up separate VTP domains at each location.  What happens when I set one of the existing L3 switches from client to server with a new domain.  Obviously I need to consider any routing implications, etc, but will there be any end user impact?  Will there be any outage?