Span Configuration - Cisco Catalyst 2000 Configuration Handbook

206 Cisco LAN Switching Configuration Handbook
(global) access-list 6 permit host 172.30.5.91
(global) access-list 6 permit host 172.30.5.95
(global) interface gig 3/1
(interface) no snmp trap link-status
Displaying Information About SNMP
Table 12-3 lists some switch commands that you can use to display helpful information
about SNMP.
Table 12-3 Switch Commands to Display SNMP Information
Display Function
SNMP configuration
RMON collections
12-3: Switched Port Analyzer
Switched Port Analyzer (SPAN) mirrors traffic from one or more source switch
■
ports or a source VLAN to a destination port. This allows a monitoring device such as
a network analyzer to be attached to the destination port for capturing traffic.
SPAN source and destination ports must reside on the same physical switch.
■
Multiple SPAN sessions can be configured to provide several simultaneous monitors.
■
■ Remote SPAN (RSPAN) provides traffic mirroring from a source on one switch to a
destination on one or more remote switches.
RSPAN is carried from source to destination over a special RSPAN VLAN.
■
Note What happens if a speed mismatch occurs between the SPAN source and destination
ports? During a SPAN session, a switch merely copies the packets from the source and places
them into the output queue of the destination port. If the destination port becomes congest-
ed, the SPAN packets are dropped from the queue and are not seen at the destination. Traffic
from the SPAN source then is not affected by any congestion at the SPAN destination.

SPAN Configuration

Create a SPAN session.
1.
Command
(exec) show snmp
(exec) show rmon [alarms | events | history | statistics]
(Catalyst 2900/3500 only) Select the source and destination:
■
(global) interface dest-interface
(interface) port monitor [src-interface | vlan src-vlan]