Local Span, Rspan, And Erspan Guidelines And Restrictions - Cisco 7604 Configuration Manual

Local SPAN, RSPAN, and ERSPAN Configuration Guidelines and Restrictions

Local SPAN, RSPAN, and ERSPAN Guidelines and Restrictions

These guidelines and restrictions apply to local SPAN, RSPAN, and ERSPAN:
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Cisco 7600 Series Router Cisco IOS Software Configuration Guide, Release 12.2SX
52-10
A SPAN destination port that is copying traffic from a single egress SPAN source port sends only
egress traffic to the network analyzer. However, in Release 12.2(18)SXE and later releases, if you
configure more than one egress SPAN source port, the traffic that is sent to the network analyzer
also includes these types of ingress traffic that were received from the egress SPAN source ports:
Any unicast traffic that is flooded on the VLAN
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Broadcast and multicast traffic
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This situation occurs because an egress SPAN source port receives these types of traffic from the
VLAN but then recognizes itself as the source of the traffic and drops it instead of sending it back
to the source from which it was received. Before the traffic is dropped, SPAN copies the traffic and
sends it to the SPAN destination port. (CSCds22021)
Entering additional monitor session commands does not clear previously configured SPAN
parameters. You must enter the no monitor session command to clear configured SPAN parameters.
Connect a network analyzer to the SPAN destination ports.
All the SPAN destination ports receive all of the traffic from all the SPAN sources.
With Release 12.2(18)SXD and later releases, you can configure destination trunk port
Note
VLAN filtering using allowed VLAN lists (see the
VLAN Filtering" section on page
With Release 12.2(18)SXE and later releases, for local SPAN and RSPAN, you can
configure Source VLAN Filtering (see the
SPAN and RSPAN" section on page
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.
Note A destination port configured as a trunk tags traffic from a Layer 3 LAN source port with
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.
Chapter 52 Configuring Local SPAN, RSPAN, and ERSPAN
"Configuring Destination Trunk Port
52-25).
"Configuring Source VLAN Filtering for Local
52-24).
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