Bridged-LAN Environments in the 7600 Card
11-11
Management Bridge
Parameters
The following bridge parameters can be set by management. The
parameters listed in Table 11-3, are port-independent while the
parameters in Table 11-4 are set for individual bridge ports.
Bridged-LAN
Environment
s in the
7600 Card
The 7600 Card provides a flexible, user-defined bridging capability
designed to support local bridged-LAN environment
s
of different sizes.
Table 11-3
Port-independent Bridge Parameters
Parameter
Description
Bridge-priority
A 2-octet value that allows the network manager to influence the choice of root bridge and
the designated bridge. It is appended as the most significant portion of a bridge ID. It can
also detect the case where two or more ports on the same bridge are attached to the same
LAN, i.e. are in direct communication through a path of bridged LAN components, none of
which operate the STP.
Bridge-hello-time
The time that elapses between generation of CBPDUs by a bridge that assumes itself to be
the root bridge. It is also the time interval between transmissions of Topology Change
Notification BPDUs to the root bridge when the bridge is trying to communicate a topology
change to the designated bridge on the LAN to which its Root Port is attached. The
recommended time is 2 secs.
Bridge-max-age
The message age value at which a stored CBPDU is discarded. The value recommended in
802.1d is 20 secs.
Bridge-forward-delay A parameter that prevents a bridge from forwarding data packets until the changes in the
spanning tree have been completed throughout the network. It is the time spent in the
Listening State and the Learning State. It is also used for the aging time of dynamic entries in
the Filtering Database while the Topology Change flag is set in protocol messages received
from the root. The value recommended in 802.1d is 15 secs.
Bridge-aging-time
Dynamic station addresses are discarded from the FDB when no data is received from the
station for bridge-aging-time. Static addresses with a delete-on-timeout status are also
discarded after Bridge-aging-time. Recommended default: 5 min.
Table 11-4
Port-dependent bridge parameters
Parameter
Description
Bridge-port-priority
A 1-octet value that allows the network manager to influence the choice of port when a
bridge has two ports connected in a loop. It is appended as the most significant portion of
the port ID.
Bridge-path-cost
The cost to be added to the root path cost field to determine the cost of the path to the root
through this port. The larger the value for the path-cost, the less through traffic the LAN
reached through the port will carry.
abtthgde.book Page 11 Tuesday, June 23, 1998 10:29 AM
