Vspan Guidelines And Restrictions - Cisco WS-SUP32-GE-3B - Supervisor Engine 32 Software Configuration Manual

Local SPAN, RSPAN, and ERSPAN Configuration Guidelines and Restrictions
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VSPAN Guidelines and Restrictions

Local SPAN, RSPAN, and ERSPAN all support VSPAN.
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These are VSPAN guidelines and restrictions:
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Catalyst Supervisor Engine 32 PISA Cisco IOS Software Configuration Guide, Release 12.2ZY
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You can configure both Layer 2 LAN ports (LAN ports configured with the switchport command)
and Layer 3 LAN ports (LAN ports not configured with the switchport command) as sources or
destinations.
You cannot mix individual source ports and source VLANs within a single session.
If you specify multiple ingress source ports, the ports can belong to different VLANs.
You cannot mix source VLANs and filter VLANs within a session. You can have source VLANs or
filter VLANs, but not both at the same time.
When enabled, local SPAN, RSPAN, and ERSPAN use any previously entered configuration.
When you specify sources and do not specify a traffic direction (ingress, egress, or both), "both" is
used by default.
SPAN copies Layer 2 Ethernet frames, but SPAN does not copy source trunk port ISL or 802.1Q
tags. You can configure destination ports as trunks to send locally tagged traffic to the traffic
analyzer.
A destination port configured as a trunk tags traffic from a Layer 3 LAN source port with
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the internal VLAN used by the Layer 3 LAN port.
Local SPAN sessions, RSPAN source sessions, and ERSPAN source sessions do not copy locally
sourced RSPAN VLAN traffic from source trunk ports that carry RSPAN VLANs.
Local SPAN sessions, RSPAN source sessions, and ERSPAN source sessions do not copy locally
sourced ERSPAN GRE-encapsulated traffic from source ports.
A port specified as a destination port in one SPAN session cannot be a destination port for another
SPAN session.
A port configured as a destination port cannot be configured as a source port.
Destination ports never participate in any spanning tree instance. Local SPAN includes BPDUs in
the monitored traffic, so any BPDUs seen on the destination port are from the source port. RSPAN
does not support BPDU monitoring.
All packets sent through the switch for transmission from a port configured as an egress source are
copied to the destination port, including packets that do not exit the switch through the port because
STP has put the port into the blocking state, or on a trunk port because STP has put the VLAN into
the blocking state on the trunk port.
For VSPAN sessions with both ingress and egress configured, two packets are forwarded from the
destination port if the packets get switched on the same VLAN (one as ingress traffic from the
ingress port and one as egress traffic from the egress port).
VSPAN only monitors traffic that leaves or enters Layer 2 ports in the VLAN.
Chapter 48 Configuring Local SPAN, RSPAN, and ERSPAN
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