Cabletron Systems NB30 manual Bridge Port Level Parameters

Models: NB30

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NB-30 Bridging

Bridge Port Level Parameters

The following Þelds are applicable to each bridge port on the NB-30.

Priority

If two or more ports on the same bridge are connected to the same LAN segment, they will receive the same Root ID/Root Cost/Bridge ID information in ConÞguration BPDUs received at each port. In this case, the BPDUÕs Port ID information Ñ the transmitting portÕs identiÞer and its manageable Priority component Ñ is used to determine which is the Designated Port for that segment.

A lower assigned value gives the port a higher Priority when BPDUs are compared. The allowable range is 0-FF hexadecimal (0-255 decimal); the default is 80 hexadecimal.

Path Cost

Displays the cost that this port will contribute to the calculation of the overall Root path cost in a ConÞguration BPDU transmitted by this bridge port. You can lower a portÕs Path Cost to make the port more competitive in the selection of the Designated Port Ñ for example, you may want to assign a lower path cost to a port on a higher performance bridge. The allowable range is 1 to 65535.

Designated Cost

Displays the cost of the path to the Root Bridge of the Designated Port on the LAN to which this port is attached. This cost is added to the Path Cost to test the value of the Root Path Cost parameter received in ConÞguration BPDUs.

Designated Root

Displays the unique bridge identiÞer of the bridge that is assumed to be the Root Bridge.

Designated Bridge

Displays the network address portion of the Bridge ID (MAC address/priority component) for the bridge that is believed to be the Designated Bridge for the LAN associated with this port.

The Designated Bridge ID, along with the Designated Port and Port IdentiÞer parameters for the port, is used to determine whether this port should be the Designated Port for the LAN to which it is attached. The Designated Bridge ID is also used to test the value of the Bridge IdentiÞer parameter in received BPDUs.

Designated Port

Displays the network address portion of the Port ID (which includes a manageable priority component) of the port believed to be the Designated Port for the LAN associated with this port.

The Designated Port ID, along with the Designated Bridge and Port IdentiÞer parameters for the port, is used to determine whether this port should be the Designated Port for the LAN to which it is attached. Management also uses it to determine the Bridged LAN topology.

Bridge Spanning Tree

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Page 47
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Cabletron Systems NB30 manual Bridge Port Level Parameters