Vspan Guidelines And Restrictions; Rspan Guidelines And Restrictions - Cisco 7604 Configuration Manual

Chapter 52 Configuring Local SPAN, RSPAN, and ERSPAN
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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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RSPAN Guidelines and Restrictions

These are RSPAN guidelines and restrictions:
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OL-4266-08
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 router for transmission from a port configured as an egress source are
copied to the destination port, including packets that do not exit the router 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.
If you configure a VLAN as an ingress source and traffic gets routed into the monitored VLAN,
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the routed traffic is not monitored because it never appears as ingress traffic entering a Layer 2
port in the VLAN.
– If you configure a VLAN as an egress source and traffic gets routed out of the monitored VLAN,
the routed traffic is not monitored because it never appears as egress traffic leaving a Layer 2
port in the VLAN.
Supervisor Engine 2 does not support RSPAN if you configure an egress SPAN source for a local
SPAN session.
Supervisor Engine 2 does not support egress SPAN sources for local SPAN if you configure RSPAN.
All participating routers must be trunk-connected at Layer 2.
Any network device that supports RSPAN VLANs can be an RSPAN intermediate device.
Networks impose no limit on the number of RSPAN VLANs that the networks carry.
Intermediate network devices might impose limits on the number of RSPAN VLANs that they can
support.
Cisco 7600 Series Router Cisco IOS Software Configuration Guide, Release 12.2SX
Local SPAN, RSPAN, and ERSPAN Configuration Guidelines and Restrictions
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