User's Manual

Configuration Guide of XGS-5240-Series
66-1
Chapter 66 RSPAN Configuration
66.1 Introduction to RSPAN
Port mirroring refers to the duplication of data frames sent/received on a port to a
nother port. The duplicated port is referred to as mirror source port and the duplicating
port is referred to as mirror destination port. It is more convenience for network admin
istrator to monitor and manage the network and diagnostic after the mirroring function a
chieved. But it only used for such instance that the mirror source port and the mirror d
estination ports are located in the same switch.
RSPAN (remote switched port analyzer) refers to remote port mirroring. It eliminate
s the limitation that the source port and the destination port must be located on the sa
me switch. This feature makes it possible for the source port and the destination port t
o be located on different devices in the network, and facilitates the network administrat
or to manage remote switches. It can’t forward traffic flows on remote mirror VLAN.
There are three types of switches with the RSPAN enabled:
1. Source switch: The switch to which the monitored port belongs. The source swit
ch copies the mirrored traffic flows to the Remote VLAN, and then through Laye
r 2 forwarding, the mirrored flows are sent to an intermediate switch or destinati
on switch.
2. Intermediate switch: Switches between the source switch and destination switch
on the network. Intermediate switch forwards mirrored flows to the next intermed
iate switch or the destination switch. Circumstances can occur where no interme
diate switch is present, if a direct connection exists between the source and de
stination switches.
3. Destination switch: The switch to which the destination port for remote mirroring
belongs. It forwards mirrored flows it received from the Remote VLAN to the m
onitoring device through the destination port.
When configuring the RSPAN mirroring of the source switch, reflector port mode or
destination mirror port mode can be selected. The destination switch will redirect all th
e data frames in the RSPAN VLAN to the RSPAN destination port. For RSPAN mirrorin
g, normal mode and advanced mode can be chosen, normal is introduced by default a
nd fit the normal user. The advanced mode fit the advanced user.
1. Advanced mode: To redirect data frames in RSPAN VLAN to the RSPAN destin
ation port, the intermediary and destination devices should support the redirectio
n of flow.