• Status: Solved
  • Priority: Medium
  • Security: Public
  • Views: 450
  • Last Modified:

REF: BRIDGE CRITERIA AND MANUAL ENTRY OF PORT PRIORITY MULTIPLES OF 16

RERERING TO ELECTION CRITERIA BUT SPECIFIC TO 'LOWEST SENDER PORT ID'

If there is a design of switches in the form of a tree or whatever, for example and the 'Root Bridge/Switch' is at the TOP and a company wished to add a 'Manual entry' ie to prioritize each of their department switches.

I have read it can be done as although the default priority is 128, this can be changed specifically for individual vlans in multiples of 16 ie:

Lowest Sender Port ID
- consists of Port priority
- And port ID (port number)
- Port priority can be configured
- config-if)#spanning-tree vlan 10 port-priority 16, or 32 or 48 etc etc

If this is true does that mean if a company does NOT have the relevant IOS features to use 'SAY'  'RSTP+ OR MST', which have the feature, 1 instance per vlan, is the above an 'OLD' feature which was replace by 'RSTP+ OR MST' for example?
0
mikey250
Asked:
mikey250
1 Solution
 
Don JohnstonInstructorCommented:
>I have read it can be done as although the default priority is 128

A default priority of 128 is in the DEC spanning-tree spec. The default priority in IEEE 802.1d spanning-tree is 32768.

>this can be changed specifically for individual vlans in multiples of 16 ie:

You can only change the priority on a per-VLAN basis if you're running Per-VLAN spanning-tree.

The original STP (DEC) and the industry implementation of 802.1d uses Common (or Mono) Spanning-Tree. That is a single instance of spanning-tree regardless of VLANs. Cisco's implementation is to have a separate instance for each VLAN.
0

Featured Post

New feature and membership benefit!

New feature! Upgrade and increase expert visibility of your issues with Priority Questions.

Tackle projects and never again get stuck behind a technical roadblock.
Join Now