Spanning Tree Port Priority

Archived from groups: comp.dcom.lans.ethernet (More info?)

In my configuration report of my HP 4000m Procurve switch there lists a
section for Spanning Tree Operation, then a listing of ports and a
priority number. I just barely understand this end of IT, but realize
a lower number represents higher priority. However, if my config
report states Spanning tree is not enabled, do these priority numbers
matter? All but one are set at 128, and one is at 64. (Follow up
questions to come if this matters despite STP being disabled)

Any good online referrences to explain this stuff to me better? The HP
management and config guide doesn't help me much.

Thanks-
Brian

Archived from groups: comp.dcom.lans.ethernet (More info?)

bpanders71@hotmail.com wrote:
> In my configuration report of my HP 4000m Procurve switch there lists a
> section for Spanning Tree Operation, then a listing of ports and a
> priority number. I just barely understand this end of IT, but realize
> a lower number represents higher priority. However, if my config
> report states Spanning tree is not enabled, do these priority numbers
> matter? All but one are set at 128, and one is at 64. (Follow up
> questions to come if this matters despite STP being disabled)
>
> Any good online referrences to explain this stuff to me better? The HP
> management and config guide doesn't help me much.

You can go to the IEEE web site and download 802.1D. Find the getieee
button to do this.

In IEEE 802.1D, Clause 17 discusses the Rapid Spanning Tree Protocol,
and refers back to Clause 9 for a discussion of the priority bits.
These priority bits are part of the overall Switch ID (64 bits) and
Port ID (16 bits). By configuring the priority bits, a network
administrator can encourage the RSTP to use certain switches and data
paths preferentially.

However, I don't know where HP finds enough bits for 128 levels. The
IEEE standard mentions 3 or 4 bits assigned specifically to priority,
not 7 bits.

Anyway, I would think that if RSTP is disabled, then how these bits are
set should not matter.

Bert

128 is the default port priority on cisco switches. i m not sure wit the others. but if u have a good idea of spanning tree protocol (STP) . then setting the lowest priority on that particular port makes it (most eligible) for choosing the designated port or Root port. if we want to set up the port as root port or designated port manually .


Regards,
VD