Cisco Small Business 300 Administration Manual page 105

Administration: Diagnostics
Configuring Port and VLAN Mirroring
STEP 1
STEP 2
STEP 3
Cisco Small Business 300 Series Managed Switch Administration Guide
A packet that is received on a network port assigned to a VLAN that is subject to
mirroring is mirrored to the analyzer port even if the packet was eventually
trapped or discarded. Packets sent by the device are mirrored when Transmit (Tx)
mirroring is activated.
Mirroring does not guarantee that all traffic from the source port(s) is received on
the analyzer (destination) port. If more data is sent to the analyzer port than it can
support, some data might be lost.
VLAN mirroring is not active on a VLAN that was not manually created. For
example, if VLAN 23 was created by GVRP, and you manually created VLAN 34,
and you create port mirroring that includes VLAN 23, VLAN 34, or both, and later
on delete VLAN 34, the status in port mirroring is set to Not Ready, because the
VLAN34 is no longer in the database and VLAN23 was not created manually.
Only one instance of mirroring is supported system-wide. The analyzer port (or
target port for VLAN mirroring or port mirroring) is the same for all the mirrored
VLANs or ports.
To enable mirroring:
Click Administration > Diagnostics > Port and VLAN Mirroring.
This page contains the following fields:
• Destination Port—Port to which traffic is to be copied; the analyzer port.
• Source Interface—Interface, port, or VLAN from which traffic is sent to the
analyzer port.
• Type—Type of monitoring: incoming to the port (Rx), outgoing from the port
(Tx), or both.
• Status— Displays one of the following values:
- Active—Both source and destination interfaces are up and forwarding
traffic.
- Not Ready—Either source or destination (or both) are down or not
forwarding traffic for some reason.
Click Add to add a port or VLAN to be mirrored.
Enter the parameters:
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