Re: Root port

Also let me just say you are right about port cost...I am not saying it ONLY influences your switch because obviously the cost is sent down stream to other switches.

However, the outbound interface cost is not taken into consideration. In this case with only 2 switches the port cost set on R means absolutely nothing to D. The port priority set locally on D means absolutely nothing when D calculates the root port.

The received port priority D gets in the BPDU from R is what will matter if you do not alter port cost on D

Again, a simple lab test will confirm this for you

Sent from my Verizon Wireless BlackBerry

Regards,

 Joe Astorino - CCIE #24347
Sr. Technical Instructor - IPexpert
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-----Original Message-----
From: Carlos G Mendioroz <tron_at_huapi.ba.ar>
Date: Wed, 21 Apr 2010 09:50:15
To: Joe Astorino<jastorino_at_ipexpert.com>
Cc: just kennie<justkennie_at_gmail.com>; CCIE Groupstudy<ccielab_at_groupstudy.com>
Subject: Re: Root port

Joe,
Either I'm confused or...

Port priority is a local thing, and port cost is what STP adds up to
inform the rest of the connected network the path cost to the root,
so hardly a local thing.

-Carlos

Joe Astorino @ 21/4/2010 8:34 -0300 dixit:
> What you read is simply not true. STP cost is a local thing. If you want to influence the root port of B by changing something on A you need to use port priority
>
>
> Sent from my Verizon Wireless BlackBerry
>
> Regards,
>
> Joe Astorino - CCIE #24347
> Sr. Technical Instructor - IPexpert
> Mailto: jastorino_at_ipexpert.com
> Telephone: +1.810.326.1444
> Live Assistance, Please visit: www.ipexpert.com/chat
> eFax: +1.810.454.0130
>
> IPexpert is a premier provider of Self-Study Workbooks, Video on Demand, Audio Tools, Online Hardware Rental and Classroom Training for the Cisco CCIE (R&S, Voice, Security & Service Provider) certification(s) with training locations throughout the United States, Europe, South Asia and Australia. Be sure to visit our online communities at www.ipexpert.com/communities and our public website at www.ipexpert.com
>
> -----Original Message-----
> From: just kennie <justkennie_at_gmail.com>
> Date: Wed, 21 Apr 2010 12:09:51
> To: Cisco certification<ccielab_at_groupstudy.com>
> Subject: Root port
>
> I have two switches A and B connected together through two trunks A1 ----
> B1, and A2 ---- B2. present the root bridge is A, and all the ports are
> forwarding. As for B, the root port is B1, and B2 in blocking. My question
> is how do I make B2 forwaing on B. On my lab I reduced the cost of B2 on B
> from 19 to 10, and it works. Bu on cisco site, I was told you will reduce
> the cost of A2 on A for B2 to be the root port on B. Please assist.
>
>
>
> Idowu Kehinde
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-- 
Carlos G Mendioroz  <tron_at_huapi.ba.ar>  LW7 EQI  Argentina
Blogs and organic groups at http://www.ccie.net