Dell EMC SmartFabric OS10 User Guide Release 10.5.0

Flow-based mirroring

Flow-based mirroring is a mirroring session in which traffic matches specified policies that mirrors to a destination port. Port-based mirroring maintains a database that contains all monitoring sessions, including port monitor sessions. The database has information regarding the sessions that are enabled or not enabled for flow-based monitoring. Flow-based mirroring is also known as policy-based mirroring.

To enable flow-based mirroring, use the flow-based enable command. Traffic with particular flows that traverse through the ingress interfaces are examined. Appropriate ACL rules apply in the ingress direction. By default, flow-based mirroring is not enabled.

To enable evaluation and replication of traffic traversing to the destination port, configure the monitor option using the permit, deny, or seq commands for ACLs assigned to the source or the monitored port (MD). Enter the keywords capture session session-id with the seq, permit, or deny command for the ACL rules to allow or drop IPv4, IPv6, ARP, UDP, EtherType, ICMP, and TCP packets.

IPV4-ACL mode

seq sequence-number {deny | permit} {source [mask] | any | host ip-address} [count [byte]] [fragments] [threshold-in-msgs count] [capture session session-id]

If you configure the flow-based enable command and do not apply an ACL on the source port or the monitored port, both flow-based monitoring and port mirroring do not function. Flow-based monitoring is supported only for ingress traffic.

The show monitor session session-id command displays output that indicates if a particular session is enabled for flow-monitoring.

View flow-based monitoring

OS10# show monitor session 1
S.Id  Source        Destination    Dir  SrcIP  DstIP  DSCP  TTL  State Reason
----------------------------------------------------------------------------
1    ethernet1/1/1  ethernet1/1/4  both  N/A   N/A    N/A  N/A  true   Is UP

Traffic matching ACL rule

OS10# show ip access-lists in
Ingress IP access-list testflow
 Active on interfaces :
  ethernet1/1/1
 seq 5 permit icmp any any capture session 1 count (0 packets)
 seq 10 permit ip 102.1.1.0/24 any capture session 1 count bytes (0 bytes)
 seq 15 deny udp any any capture session 2 count bytes (0 bytes)
 seq 20 deny tcp any any capture session 3 count bytes (0 bytes)