Cabletron Systems CSX1000 - Manual (Page 236)

USER’S GUIDE
236 CyberSWITCH
K NOWN C ONNECT L IST C ONFIGURATION E LEMENTS
D EVICE N AME
The name of a bridge device that has been preconfigured in the On-node Device Database section of
the Configuring Device Level Databases chapter. This is a device to which you want the system to
connect and forward bridged unicast packets.
K NOWN C ONNECT L IST B ACKGROUND I NFORMATION
In Unrestricted Mode, standard bridge processing attempts to forward frames with unknown or
broadcast MAC addresses through all available interfaces. This can cause a problem with the
limited bandwidth and high cost of dial-up WAN links. The CyberSWITCH’s Known Connect List
feature, and its support of bridge filters, gives you flexible options in controlling the risk of bridge
flooding over WAN links.
When operating as a bridge or in IP Host Mode, in the course of processing the MAC frames, the
CyberSWITCH builds its bridge table and associates each MAC address it sees with an interface.
When a remote bridge establishes a connection and begins sending traffic to the CyberSWITCH,
the CyberSWITCH adds these remote addresses to its bridge table and associates the remote bridge
with them. Later, if the connection is dropped, and if the CyberSWITCH receives a packet destined
for one of the remote addresses, it will re-establish the connection with the remote bridge only if the
remote bridge is specified on the Known Connect List, or if a forwarding filter is configured.
Furthermore, if the Known Connect List option is used, the CyberSWITCH can only re-establish the
connection while the remote bridge is still “known”; that is, if the system receives the new,
outbound packet before the Spanning Tree Bridge Age Time timer ages-out the destination MAC
address from the bridge table. If a connect filter is used, the CyberSWITCH can re-establish the
connection regardless of how long it’s been since the last connection. The default Bridge Age Time
is 5 minutes. Refer to
page 220 to change the default value.