Status and Statistics
Switched Port Analyzer (SPAN and RSPAN)
Cisco Sx350, SG350X, SG350XG, Sx550X & SG550XG Series Managed Switches, Firmware Release 2.2.5.x
52
4
Figure 1
RSPAN Switch Deployment:
The traffic for each RSPAN session is carried over a user-specified RSPAN VLAN that is
dedicated for that RSPAN session in all participating switches. The traffic from the source
interfaces on the start device is copied to the RSPAN VLAN through a reflector port and then
forwarded over trunk ports on the intermediate devices to the destination session on the final
switch, which is monitoring the RSPAN VLAN.
The reflector port is the mechanism that copies packets to an RSPAN VLAN. It is a network
port that handles various types of traffic.
The RSPAN VLAN must be configured on all the intermediate switches.
NOTE
RSPAN does not always successfully copy all the packets when they are arrive from multiple
sources simultaneously. If accurate monitoring is required, the TCAM-based mirror policy can
be used.
RSPAN Workflow
The following workflow describes how to configure the start, intermediate and final switches:
•
•
•
Start Switch
1. Define the RSPAN VLAN. This RSPAN VLAN must be the same in all switches.
2. Define one or more source interfaces, which can be ports or a VLAN, and ensure that it is
not
a member of the RSPAN VLAN.
Start Switch
Intermediate
Switch(es)
2
3
1
4
Final Switch
8
7
Define RSPAN VLAN
(ex. 10)
Define RSPAN VLAN
10 with port 2 and 3 as
members
Define RSPAN VLAN
10, with port 7 as
member but not port 8
Source
Port
Reflector
Port
Source
Port
Analyzer
Port