27-10
Cisco Catalyst Blade Switch 3020 for HP Software Configuration Guide
OL-8915-03
Chapter 27 Configuring SPAN and RSPAN
Configuring SPAN and RSPAN
Configuring Local SPAN
These sections contain this configuration information:
•
SPAN Configuration Guidelines, page 27-10
•
Creating a Local SPAN Session, page 27-11
•
Creating a Local SPAN Session and Configuring Incoming Traffic, page 27-13
•
Specifying VLANs to Filter, page 27-14
SPAN Configuration Guidelines
Follow these guidelines when configuring SPAN:
•
For SPAN sources, you can monitor traffic for a single port or VLAN or a series or range of ports
or VLANs for each session. You cannot mix source ports and source VLANs within a single SPAN
session.
•
The destination port cannot be a source port; a source port cannot be a destination port.
•
You cannot have two SPAN sessions using the same destination port.
•
When you configure a switch port as a SPAN destination port, it is no longer a normal switch port;
only monitored traffic passes through the SPAN destination port.
•
Entering SPAN configuration commands does not remove previously configured SPAN parameters.
You must enter the
no monitor session
{
session_number
|
all
|
local
|
remote
} global configuration
command to delete configured SPAN parameters.
•
For local SPAN, outgoing packets through the SPAN destination port carry the original
encapsulation headers—untagged, ISL, or IEEE 802.1Q—if the
encapsulation replicate
keywords
are specified. If the keywords are not specified, the packets are sent in native form. For RSPAN
destination ports, outgoing packets are not tagged.
•
You can configure a disabled port to be a source or destination port, but the SPAN function does not
start until the destination port and at least one source port or source VLAN are enabled.
•
You can limit SPAN traffic to specific VLANs by using the
filter vlan
keyword. If a trunk port is
being monitored, only traffic on the VLANs specified with this keyword is monitored. By default,
all VLANs are monitored on a trunk port.
•
You cannot mix source VLANs and filter VLANs within a single SPAN session.
•
Egress SPAN routed packets (both unicast and multicast) show the incorrect source MAC address.
For local SPAN packets with native encapsulation on the destination port, the packet shows the MAC
address of VLAN 1. This problem does not appear with local SPAN when the encapsulation replicate
option is used. This limitation does not apply to bridged packets. The workaround is to use the
encapsulate replicate
keywords in the
monitor session
global configuration command.
VLAN filtering
On a trunk interface used as a source port, all VLANs are
monitored.
RSPAN VLANs
None configured.
Table 27-1
Default SPAN and RSPAN Configuration (continued)
Feature
Default Setting
