Dell N3200-ON Networking N-Series Switches CLI Reference Guide version 6.8.0 - Page 716

Port Monitor Commands Dell Networking N1108EP-ON/N1500/N2200-ON/N3200-ON Series Switches Dell Networking switches allow the user to monitor traffic with an external network analyzer. The external network analyzer can use any of the Ethernet ports as a probe port. The probe port transmits a mirror copy of the traffic being probed. SPAN and RSPAN encapsulation is supported. Network traffic transmission is always disrupted whenever a configuration change is made for port monitoring. Therefore, whenever port monitoring is enabled, the probe port does not always forward traffic as a normal port. When diagnosing problems, an operator should always check the status of port monitoring. The port monitoring feature allows the user to configure a session. A session consists of one destination or probe port and one or multiple source ports. When a session is enabled, any traffic entering or leaving the source ports of that session is copied (mirrored) onto the corresponding destination port. A network traffic analyzer can be attached to destination ports to analyze the traffic patterns of source ports. A session is operationally active only if both a destination port and at least one source port are configured. If neither is true, the session is inactive. A port configured as a destination port acts as a mirroring port when the session is operationally active. If it is not, the port acts as a normal port and participates in all normal operation with respect to transmitting traffic. The port mirroring logic stage occurs after the after the VLAN tag processing stage on ingress and before the VLAN tag processing stage on egress. When mirroring packets associated with DVLAN/QinQ SP or CE ports, the outer VLAN tag may or may not appear in the frame. Due to the internal processing of QinQ tagging, the TPID of ingress frames mirrored from the SP port will always be 0x8100. In addition, packets forwarded internally across a stacking link may have different tags applied than packets forwarded on a local egress port. This is due to the processing required for forwarding across a stack. Any Ethernet port may be configured as a source port. Caveats: • Platforms may behave unpredictably if an attempt is made to mirror a port of greater speed than the probe port. Layer 2 Switching Commands 716