Management and Configuration Guide K/KA/KB.15.15

packet is forwarded. Therefore, the destination MAC address that you want to mirror will not
appear in routed packet headers.
This restriction also applies to the destination MAC address of a host that is directly connected
to a routing switch. (Normally, a host is connected to an edge switch, which is directly
connected to the router.)
To mirror routed traffic, we recommend that you use classifier-based policies to select IPv4 or
IPv6 traffic for mirroring, as described in “About selecting inbound traffic using advanced
classifier-based mirroring” (page 354).
• On a switch, you can use a MAC address only once as a source MAC address and only once
as a destination MAC address to filter mirrored traffic.
For example, after you enter the following commands:
monitor mac 111111-222222 src mirror 1
monitor mac 111111-222222 dest mirror 2
The following commands are not supported:
monitor mac 111111-222222 src mirror 3
monitor mac 111111-222222 dest mirror 4
In addition, if you enter the monitor mac 111111-222222 both mirror 1 command,
you cannot use the MAC address 111111-222222 in any other monitor mac mirror
configuration commands on the switch.
• To re-use a MAC address that has already been configured as a source and/or destination
address for traffic selection in a mirror session, you must first remove the configuration by
entering the no form of the command and then re-enter the MAC address in a new monitor
mac mirror command.
For example, if you have already configured MAC address 111111-222222 to filter inbound
and outbound mirrored traffic, and you decide to use it to filter only inbound traffic in a mirror
session, you could enter the following commands:
monitor mac 111111-222222 both mirror 1
no monitor mac 111111-222222 both mirror 1
monitor mac 111111-222222 src mirror 1
• A mirroring session in which you configure MAC-based mirroring is not supported on a port,
trunk, mesh, or VLAN interface on which a mirroring session with a classifier-based mirroring
policy is configured.
About selecting inbound traffic using advanced classifier-based mirroring
In software release K.14.01 or greater, in addition to the traffic selection options described in
“Configure the monitored traffic in a mirror session” (page 350), traffic mirroring supports the use
of advanced classifier-based functions that provide:
• A finer granularity for selecting the inbound IP traffic that you want to mirror on an individual
port or VLAN interface (instead of mirroring all inbound traffic on the interface)
• Support for mirroring both IPv4 and IPv6 traffic
• The ability to re-use the same traffic classes in different software-feature configurations; for
example, you can apply both a QoS rate-limiting and mirroring policy on the same class of
traffic.
Deprecation of ACL-based traffic selection
In software release K.14.01 or greater, advanced classifier-based policies replace ACL-based
traffic selection in mirroring configurations.
354 Monitoring and Analyzing Switch Operation