Bridging 57
T0008-16F Release 5.2M
Bridge Filtering
Bridge Filtering
What is It? Bridge filtering prevents extraneous traffic from traversing the WAN and stops the
unintentional proliferation of traffic onto other remote LAN segments.
In Ethernet Transparent Bridging, the broadcast feat ure lets statio ns determi ne rou tes
to other end stations. Broadcasting to the entire network can unnecessarily degrade
performance because of broadcasts traversing LAN segments that are not in any part
of the network where the target station resides.
Therefore, you can use bridge filtering methods such as MAC Address Filtering,
Protocol Filtering, and NetBIOS Name Filtering to control broadcast traffic and
reduce overhead.
How Filtering is
Used Filtering is used to:
•Reduce
unnecessary traffic affecting the performance of LAN segments.
Filtering broadcasts can help to reduce this overhead.
• Control the unnecessary proliferation of application level broadcasting used
on Novell and NetBIOS applications.
• Restrict access to certain LAN segments for security reasons.
• Prevent unnecessary traffic from proliferating onto the WAN where
bandwidth is limited. This can help to reduce congestion and minimize delay
for traffic that must cross the WAN.
• Prevent stations using a certain protocol from operating outside their intended
scope. Protocol formats that are filtered include DSAP and SNAP.
You can filter the MAC address contained in a frame or a protocol. The system
applies MAC address filtering first and then follows with protocol filtering if
appropriate.
MAC Address filtering can be performed on either the source address or destination
address.