topic Spanning Tree failover time in Switches, Hubs, and Modems

Spanning Tree failover time

AlertForce — Thu, 12 Jun 2008 08:29:03 GMT

Hi,

May I know what is the failover time if 1 enable spanning tree protocol on 2 ProCurve 6200? How much time is needed for the path to switch over from the root to the backup?

Any documentation from the HP web site that have black and white to state on the failover time?

Thanks.

Regards,
Patrick Law

Re: Spanning Tree failover time

cenk sasmaztin — Thu, 12 Jun 2008 10:14:14 GMT

hi Patrick

stp fail over time change asper network topology most switch in topogogy most fail over time few switch in topology few fail over time.Because each switch send other switch bpdu packet when don't take switches bpdu packet after change topology.

you can make two switch stp or rstp config
you can loos maximum one ping packet namely 1ms

bytes=32 time=1ms
cenk

Re: Spanning Tree failover time

Matt Hobbs — Thu, 12 Jun 2008 11:07:25 GMT

It depends a lot on your network design and what type of failure you're simulating. In a best case scenario it's usually under a second. Since it is a standard protocol it should be fairly similar between all vendors.

From http://www.cisco.com/en/US/tech/tk389/tk621/technologies_white_paper09186a0080094cfc.shtml

"The IEEE recently decided to incorporate most of these concepts into two standards: 802.1w (RSTP) and 802.1s (MST). With the implementation of these new protocols, convergence times in the low hundreds of milliseconds can be expected while scaling to thousands of VLANs."

Re: Spanning Tree failover time

AlertForce — Thu, 12 Jun 2008 22:21:30 GMT

Hi,

I am using 02 x 6200 as the core switches (connect to each other with stacking cable), and 2824 as edge switches. Each of the 2824 will connect to both of the 6200 via fiber.

STP will be configured at the 6200 (one as root, the other as backup), no configuration will be done at the 2824, correct me if my setup/setting is wrong.

My objective is to make sure devices connected to the edge switches can communicate to each other.

I would like to know what is the failover time if:
- The root malfunction, and the path is switch to the backup.
- The fiber link between the edge switch and the root broke, and the edge switch will use the link between it and the backup.

Thank.

Regards,
Patrick Law

Re: Spanning Tree failover time

Matt Hobbs — Fri, 13 Jun 2008 00:34:27 GMT

I would say around the one second mark, but you really just need to test it yourself. These things can change slightly between firmware revisions and configuration settings.

For your fiber links I'd recommend you use the UDLD feature. Also, you should enable STP on the edge switches.

Re: Spanning Tree failover time

AlertForce — Tue, 17 Jun 2008 02:02:08 GMT

Hi,

So any point of failing, be it the core switch, or any of the fiber link, the recovery time is less then 1 second?

Thanks.

Regards,
Patrick Law

Re: Spanning Tree failover time

Mohieddin Kharnoub — Tue, 17 Jun 2008 17:56:49 GMT

Hi

From my experience, i would say in a full mesh MSTP topology with correct configuration the fail over won't take more than 300ms because you have an Active-Active kind of topology in this case and we are talking about L2 redundancy.

With L3 redundancy like VRRP, you have to count a couple of seconds, and Nortel claims with their proprietary protocol - SMLT (or Routed SMLT)- that they've reduced to a second.

Good Luck !!!