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Cisco SCE 8000 10GBE Software Configuration Guide
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Chapter 14 Value-Added Services (VAS) Traffic Forwarding
Intelligent Traffic Mirroring
The mapping of traffic portions to VAS server groups is done through the standard SCA BB GUI, this
definition is given per package.
Mirroring Termination
Mirroring of a flow can continue until the flow is terminated, or be limited to a certain volume passed
over the flow. This enables a huge data reduction on the server side, as well as performance saving in the
Cisco SCE platform.
An RST packet is sent to the server when the mirroring is stopped due to a stop condition. This is done
in order to signal the server that the mirroring has stopped.
The RST packet is sent in the direction of intiator to initatee with the additional VLAN tag.
Mirroring Exceptions
Since the decision to mirror is based on service classification, which can be done on the first payload or
after first few packets, the entire TCP handshake is not mirrored.
To save in performance on both sides, zero payload packets are also not mirrored. (note that this type of
packets have no real value for offline analysis).
If the VLAN traffic is mirrored, Cisco SCE devices replace the VLAN information from the incoming
traffic with the VAS-configured VLAN information before mirroring the traffic on the VAS port.
Mirroring the TCP-Segmented HTTP GET Packets
From Cisco SCE Release 3.7.5, traffic mirroring can be enabled for all the TCP-segmented HTTP GET
packets if the HTTP port is 80, 8080, or 8081 even if the number of segmented packets are more than two.
By default, mirroring of all the segmented packets is disabled.
Configuring Cisco SCE to Mirror the TCP-Segmented HTTP GET packets
You can configure Cisco SCE to mirror the TCP-segmented HTTP GET packets using the
GT_SEG_GET_MIRROR tunable.
To configure Cisco SCE to mirror the TCP segmented HTTP GET packets, from the SCE(config if)#
prompt, enter:
Command
Purpose
tunable GT_SEG_GET_MIRROR value true
Enables the mirroring of all the TCP-segmented
HTTP GET packets.
tunable GT_SEG_GET_MIRROR value false
Disables the mirroring of all the TCP-segmented
HTTP GET packets.