Span And Rspan Session Limits; Default Span And Rspan Configuration; Configuring Span - Cisco 4500M Software Manual

Configuring SPAN

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SPAN Traffic
You can use local SPAN to monitor all network traffic, including multicast and bridge protocol data unit
(BPDU) packets, Cisco Discovery Protocol (CDP), VLAN Trunk Protocol (VTP), Dynamic Trunking
Protocol (DTP), Spanning Tree Protocol (STP), and Port Aggregation Protocol (PAgP) packets. You
cannot use RSPAN to monitor Layer 2 protocols. (See the
on page 39-16
In some SPAN configurations, multiple copies of the same source packet are sent to the SPAN
destination port. For example, a bidirectional (both Rx and Tx) SPAN session is configured for the
sources a1 Rx monitor and the a2 Rx and Tx monitor to destination port d1. If a packet enters the switch
through a1 and is switched to a2, both incoming and outgoing packets are sent to destination port d1.
Both packets are the same (unless a Layer-3 rewrite occurs, in which case the packets are different
because of the added Layer 3 information).

SPAN and RSPAN Session Limits

You can configure up to two simultaneous SPAN sessions containing ingress sources and up to four
simultaneous SPAN sessions containing egress sources. Bidirectional sources count as both ingress and
egress. RSPAN destination sessions count as a session containing an ingress source.

Default SPAN and RSPAN Configuration

Table 39-1
Table 39-1 Default SPAN and RSPAN Configuration
Feature
SPAN state
Source port traffic to monitor
Filters
Encapsulation type (destination port)
Ingress forwarding (destination port)
Host learning (destination port)
Configuring SPAN
The following sections describe how to configure SPAN:
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Software Configuration Guide—Release 12.2(25)EW
39-6
You cannot use filter VLANs in the same session with VLAN sources.
You can monitor only Ethernet VLANs.
for more information.)
shows the default SPAN and RSPAN configuration.
SPAN Configuration Guidelines and Restrictions, page 39-7
Configuring SPAN Sources, page 39-8
Configuring SPAN Destinations, page 39-9
Monitoring Source VLANs on a Trunk Interface, page 39-9
Chapter 39
"RSPAN Configuration Guidelines" section
Default Setting
Disabled.
Both received and sent traffic (both).
All VLANs, all packet types, all address types.
Native form (no encapsulation type header).
Disabled.
Disabled.
Configuring SPAN and RSPAN
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