RE: STP Root Port Election..

Hi,

Root port:

Lowest cost to root
Lowest sender bridge ID ( priorty+mac)
Lowest sender port ID (priority+portnumber)

IN 802.1D
A designated port is any port that isn't a root port, blocking port or
disabled port.

In the situation where two switches are connected to the same segment that
isn't the segment with the root port then the above is again used to
determine which port is blocking and which is the Designated.

The root bridge has all ports designated.

cheers

-----Original Message-----
From: nobody_at_groupstudy.com [mailto:nobody_at_groupstudy.com] On Behalf Of
Jitendra Anbu
Sent: Monday, June 15, 2009 12:23 AM
To: CCIE R/S, Groupstudy
Subject: STP Root Port Election..

Hi all,

When electing the root port, what criteria does a switch look at before
making
its decision?

My understanding is (in order);

1. Lowest Cost to the root bridge
2.Lowert port address (port priority : port number) --> Is this of the
sender
or the receiving root bridge?
3.Lowest bridge ID

Is my understanding correct?

Also, how does a switch decide on its DESIGNATED port? Is this the lowest
bridge ID?

thanks,

Jit

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Received on Mon Jun 15 2009 - 00:40:52 ART