Migrating from STP to MSTP

[osiristrading]

Hi all

We would like to migrate our LAN to MSTP to gain the benefits of RSTP. What is the best approach to minimise downtime?

We have two Catalyst 4006 switches trunked together via Etherchannel, along with 12 2950 switches, which each have a connection to each 4006 for redundancy.

Any input would be greatly appreciated.

Thanks

[cisco_lad2004]

How many VLANs ?

[osiristrading]

We have 12 VLANs.

[cisco_lad2004]

Then you might get away with using PVRST instead of MST, this way you can do one VLAN at the time without affecting the other ones and still benefit from RSTP.

You will have a short glitch when you migrate a VLAN to PVRST.

If you plan to increase the VLAN database, then MST is the way to go. and in this case you need good planning.

HTH

Sam

[leekleybm]

I agree with ciscolad, rapid-PVST+ is the way to go. Here is a 6500 migration document that may help.

http://www.cisco.com/en/US/products/hw/switches/ps708/products_configuration_example09186a00807b0670.shtml

[osiristrading]

Thanks guys, rpvst+ looks like the best bet and should be easy to configure.

I understand that while the network reconverges, there will be some downtime. Approximately how long will this downtime be?

[cisco_lad2004]

I recall not more than 10-15 sec.