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Packet Filter Applications
893-01006-C
6-3
The Centillion 50/100 and Model 5000BH switches are designed for large
multiprotocol internetworks. These switches offer a comprehensive set of traffic
management capabilities, including broadcast explorer suppression, a source route
broadcast explorer proxy, a NetBIOS name proxy, and a NetBIOS name filter.
All operate in conjunction with switch-wide virtual ring and network-wide VLAN
capabilities, as well as network-wide VLANs under ATM LANE.
Introduction to Packet Filtering
Centillion packet filtering is designed to allow a high level of flexibility to give
users better control when directing frames. Most production networks have
broadcast-intensive protocols that consume bandwidth; however, with packet
filtering, SpeedView gives network managers control over how broadcast frames
are forwarded. Applying packet filtering can prevent wasted bandwidth and boost
overall network throughput.
Packet filters on the Centillion 50/100 and Model 5000BH switches enable you to
offset a specified number of bytes into a frame to locate the bytes to match.
Actions are then carried out based on the matching conditions.
Token ring frames (Figure 6-1
) have two offsets. The first is a MAC offset that
starts at the access control (AC) field of a token ring frame. The second is an LLC
offset that starts at the destination service access point (DSAP) field.
Figure 6-1. Token Ring Packet Filter Offsets
7034
MAC filter
begins here
if offset is 0
Bytes:
SD
AC FC
Source
address
LLC or MAC frame
information
Frame
check
Ending
delimeter
Frame
status
66
Route
information
0-30 variable bytes 4 1 1
Destination
address
111
LLC filter
begins here
if offset is 0