These additional parameters are only displayed for the CLI:
• Admin status – Sho ws if this interfac e is enabled .
• External path cost – The path cost for the IST. This parameter is used by the
STA to determine the best path between devices. T herefore, lower valu es should
be assigned to ports attached to faster media, and higher values assigned to ports
with slower media. (Path cost takes precedence over port priority.)
• Internal path cost – The path cost for the MST. See the prec eding item .
• Priority – Defines the priority used for this p ort in the S pan ning Tree A lg ori thm . If
the path cost for all ports on a switch is the same, the po rt wit h th e h ighe st pri ori ty
(i.e., lowest value) will be configured as an activ e link in the Spanni ng Tree. This
makes a port with higher priority less lik ely to be blocke d if the Spann ing Tree
Algorithm is detecting network loops. Where more than one port is assigned the
highest priority, the port with the lowest numeric identifier will be enab led.
• Designated root – The priority and MA C address of t he device in the Spanning
Tree that this switch has accepted as th e root dev ice.
• Fast forwarding – This field provid es the same inform ation a s Adm in Ed ge por t,
and is only included for backward compatibility with earlier products.
•
Admin Edge Port
– You can enable this option if an interface is attached to a LAN
segment that is at the end of a bridged LAN or to an end node. Sin ce end nodes
cannot
cause forwarding loops, they can pass directly through to the spanning tree
forwarding state. Specifying Edge Ports provides quicker convergence for devices
such as workstations or servers, retains the current forwarding database to reduce
the amount of frame flooding required to rebuild address t ables duri ng
reconfiguration events, does not cause the spanning tree to reconfigur e when the
interface changes state, and also overcomes other STA-related timeout problems.
However, remember that Edge Port should only be ena bled fo r po rts c onn ec ted to
an end-node device.
• Admin Link Type – The link type attached to this inte rface.
- Point-to-Point – A connection to exactly one other brid ge.
- Shared – A connection to two or more bridges.
- Auto – The switch automatically determines if the in terface is attached t o a
point-to-point link or to shared media.
Web
– Click Spanning Tree, STA, Port Information or STA Trunk Information.
Figure 10-3 STA Port Information
10-12
Spanning Tree Algorithm
10