Cisco 4506-E Software Guide - Page 395

SPAN Configuration Guidelines

Page 395 highlights

Chapter 26 Configuring SPAN and RSPAN Figure 26-1 Example SPAN Configuration Port 5 traffic mirrored on Port 10 1 2 3 4 5 6 7 8 9 10 11 12 Configuring SPAN E6 E7 E5 E8 E11 E4 E9 E12 E3 E10 E2 E1 44389 SwitchProbe For SPAN configuration, the source ports and the destination port must be on the same switch. SPAN does not affect the switching of network traffic on source ports; copies of the packets that are received or transmitted by the source ports are sent to the destination port. SPAN Configuration Guidelines This section describes the configuration guideslines for configuring SPAN: • Incoming traffic on the SPAN destination port is disabled by default. You can enable it using the inpkts enable keywords. However, while the port receives traffic for its assigned VLAN, it does not participate in spanning tree for that VLAN. To avoid creating spanning tree loops with incoming traffic enabled, assign the SPAN destination port to an unused VLAN. • In software release 5.2 and later releases, with the inpkts option enabled, you can prevent the switch from learning source MAC addresses from traffic that is received on the SPAN destination port using the learning disable keywords. If you want the switch to learn source MAC addresses from traffic that is received on the SPAN destination port, enter the learning enable keywords. By default, the switch learns source MAC addresses from incoming traffic (learning enable) if the inpkts option is enabled. The source MAC address learning options only affect traffic that is received from a device that is attached to the SPAN destination port itself, not from traffic that is mirrored from the SPAN source. • When monitoring a VLAN on a switch, you must monitor both transmit and receive traffic (both). You cannot monitor only transmit (Tx) or only receive (Rx) traffic. • If you specify a set of VLANs with the filter option, the traffic that is spanned by the session is limited to the VLANs specified. • You cannot configure SPAN on sc0. • Any traffic between two network nodes that are attached to a switch port that is configured as a SPAN source port is not mirrored to the SPAN destination port. You can span local traffic that passes through the switch. • You can have up to five SPAN sessions running at the same time with any combination of ingress and egress sessions. 78-15486-01 Catalyst 4500 Series, Catalyst 2948G, Catalyst 2980G Switches Software Configuration Guide-Release 8.1 26-5

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26-5
Catalyst 4500 Series, Catalyst 2948G, Catalyst 2980G Switches Software Configuration Guide
Release 8.1
78-15486-01
Chapter 26
Configuring SPAN and RSPAN
Configuring SPAN
Figure 26-1
Example SPAN Configuration
For SPAN configuration, the source ports and the destination port must be on the same switch.
SPAN does not affect the switching of network traffic on source ports; copies of the packets that are
received or transmitted by the source ports are sent to the destination port.
SPAN Configuration Guidelines
This section describes the configuration guideslines for configuring SPAN:
Incoming traffic on the SPAN destination port is disabled by default. You can enable it using the
inpkts enable
keywords. However, while the port receives traffic for its assigned VLAN, it does not
participate in spanning tree for that VLAN. To avoid creating spanning tree loops with incoming
traffic enabled, assign the SPAN destination port to an unused VLAN.
In software release
5.2 and later releases, with the
inpkts
option enabled, you can prevent the switch
from learning source MAC addresses from traffic that is received on the SPAN destination port using
the
learning disable
keywords. If you want the switch to learn source MAC addresses from traffic
that is received on the SPAN destination port, enter the
learning enable
keywords. By default, the
switch learns source MAC addresses from incoming traffic (
learning enable
) if the
inpkts
option
is enabled. The source MAC address learning options only affect traffic that is received from a
device that is attached to the SPAN destination port itself, not from traffic that is mirrored from the
SPAN source.
When monitoring a VLAN on a switch, you must monitor both transmit and receive traffic (
both
).
You cannot monitor only transmit (
Tx
) or only receive (
Rx
) traffic.
If you specify a set of VLANs with the
filter
option, the traffic that is spanned by the session is
limited to the VLANs specified.
You cannot configure SPAN on sc0.
Any traffic between two network nodes that are attached to a switch port that is configured as a
SPAN source port is not mirrored to the SPAN destination port. You can span local traffic that passes
through the switch.
You can have up to five SPAN sessions running at the same time with any combination of ingress
and egress sessions.
1
2
3
4
5
6
7
8
9
10
11 12
Port 5 traffic mirrored
on Port 10
E3
E2
E1
E4
E5
E6 E7
E8
E9
E11
E12
E10
SwitchProbe
44389