Nortel Networks 2300 manual Configuring a Snoop Filter

590Appendix A: Troubleshooting a WS Switch

Configuring a Snoop Filter

To configure a snoop filter, use the following command:

set snoop filter-name [condition-list] [observer ip-addr][snmp-lengthnum]

The filter-namecan be up to 32 alphanumeric characters.

The condition-listspecifies the match criteria for packets. Conditions in the list are ANDed. Therefore, to be copied and sent to an observer, a packet must match all criteria in the condition-list. You can specify up to eight of the following conditions in a filter, in any order or combination:

frame-type {eq neq} {beacon control data management probe} channel {eq neq} channel

bssid {eq neq} bssid src-mac {eq neq} mac-addrdest-mac {eq neq} mac-addrhost-mac {eq neq} mac-addrmac-pair mac-addr1mac-addr2

To match on packets to or from a specific MAC address, use the dest-macor src-macoption. To match on both send and receive traffic for a host address, use the host-macoption. To match on a traffic flow (source and destination MAC addresses), use the mac-pairoption. This option matches for either direction of a flow, and either MAC address can be the source or destination address.

If you omit a condition, all packets match that condition. For example, if you omit frame-type, all frame types match the filter.

For most conditions, you can use eq (equal) to match only on traffic that matches the condition value. Use neq (not equal) to match only on traffic that is not equal to the condition value.

The observer ip-addroption specifies the IP address of the station where the protocol analyzer is located. If you do not specify an observer, the AP radio still counts the packets that match the filter. (See “Displaying Remote Traffic Moni- toring Statistics” on page 594.)

The snap-lengthnum option specifies the maximum number of bytes to capture. If you do not specify a length, the entire packet is copied and sent to the observer. Nortel recommends specifying an snap length of 100 bytes or less.

The following command configures a snoop filter named snoop1 that matches on all traffic, and copies the traffic to the device that has IP address 10.10.30.2:

23x0# set snoop snoop1 observer 10.10.30.2 snap-length 100

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