The ACL agent module saves monitoring details in its local database and also in the CAM region to monitor packets that match thespecified criterion. The ACL agent maintains data on the source port, the destination port, and the endpoint to which the packet must beforwarded when a match occurs with the ACL entry.If you configure the flow-based enable command and do not apply an ACL on the source port or the monitored port, both flow-basedmonitoring and port mirroring do not function. Flow-based monitoring is supported only for ingress traffic and not for egress packets.The port mirroring application maintains a database that contains all monitoring sessions (including port monitor sessions). It hasinformation regarding the sessions that are enabled for flow-based monitoring and those sessions that are not enabled for flow-basedmonitoring. It downloads monitoring configuration to the ACL agent whenever the ACL agent is registered with the port mirroringapplication or when flow-based monitoring is enabled.The show monitor session session-id command has been enhanced to display the Type field in the output, which indicateswhether a particular session is enabled for flow-monitoring.Example Output of the show CommandDell# show monitor session 1SessID Source Destination Dir Mode Source IP Dest IP DSCPTTL Drop Rate Gre-Protocol FcMonitor------ ------ ----------- --- ---- --------- -------- ------- ---- ---- ----------- ---------1 Te 1/2 remote-ip rx Port 0.0.0.0 0.0.0.0 00 No N/A N/A yesDell#The show config command has been modified to display monitoring configuration in a particular session.Example Output of the show Command(conf-mon-sess-11)#show config!monitor session 11flow-based enablesource TenGigabitEthernet 1/1 destination TenGigabitEthernet 1/1 direction bothThe show ip | mac | ipv6 accounting commands have been enhanced to display whether monitoring is enabled for traffic thatmatches with the rules of the specific ACL.Example Output of the show CommandDell# show ip accounting access-list!Extended Ingress IP access list kar on TenGigabitEthernet 1/1Total cam count 1seq 5 permit ip 192.168.20.0/24 173.168.20.0/24 monitorDell#show ipv6 accounting access-list!Ingress IPv6 access list kar on TenGigabitEthernet 1/1Total cam count 1seq 5 permit ipv6 22::/24 33::/24 monitorEnabling Flow-Based MonitoringFlow-based monitoring is supported on the platform.Flow-based monitoring conserves bandwidth by monitoring only specified traffic instead of all traffic on the interface. This feature isparticularly useful when looking for malicious traffic. It is available for Layer 2 and Layer 3 ingress and egress traffic. You can specify trafficusing standard or extended access-lists.1 Enable flow-based monitoring for a monitoring session.138 Access Control Lists (ACLs)
