MSAN-210
MVTX260x Port Mirroring
Application Note
Contents
1.0 Purpose
2.0 Scope
3.0 Features
3.1 Unmanaged mode
3.2 Managed Mode
4.0 Flexible Port Mirroring Support
1.0
Purpose
This application note describes the port mirroring
usage on the MVTX260x chipsets.
2.0
Scope
This document will cover Port Mirroring for the
MVTX260x device. The reader should be familiar with
the MVTX260x data sheet before reading this
application note
3.0
Issue 1
3.1
Unmanaged mode
The port mirroring functionality may be set by external
pins on the MVTX260x. If this option is selected, then
there can only be one mirroring pair, and the
destination port must be port 23. There are 6 pins
(PM_CT[5:0]). The first 5 bits select the port to be
mirrored. The last bit selects either ingress or egress
data. Again the unmanaged mode port mirroring
function does not apply to port 7 and 15. The port
mirroring control via external pins can be applied to the
managed mode as well.
3.2
Managed Mode
In management mode, the port mirroring is set via four
registers:
•
Features
This application note describes the port mirroring
usage on the MVTX260x chipsets. The MVTX260x
chips provide port-mirroring function on the 10/100M
ports. The traffic can be mirrored from either receive or
transmit stream except on ports 7 (8th), 15 (16th), and
23 (24th). Ports 7, 15, and 23 take advantage of the
Zarlink security mirroring feature which allows the
mirrored data to be viewed by the CPU through the
software steps outlined in this application note. For the
unmanaged switches, port 23 is the designated mirrorto port. The MVTX260x supports two such mirrored
source-destination pairs. A mirror port cannot also
serve as a data port.
October 2002
•
•
•
MIRROR1_SRC: Sets the source port for the first
port mirroring pair. Bits [4:0] select the source port
to be mirrored. An illegal port number is used to
disable mirroring (which is the default setting). Bit
[5] is used to select between ingress (Rx) or
egress (Tx) data. Bit [7] is used to select between
external pin controls and register control for port
mirroring.
MIRROR1_DEST: Sets the destination port for the
first port mirroring pair. Bits [4:0] select the
destination port to be mirrored. The default is port
23.
MIRROR2_SRC: Sets the source port for the
second port mirroring pair. Bits [4:0] select the
source port to be mirrored. An illegal port number
is used to disable mirroring (which is the default
setting). Bit [5] is used to select between ingress
(Rx) or egress (Tx) data.
MIRROR2_DEST: Sets the destination port for the
second port mirroring pair. Bits [4:0] select the
destination port to be mirrored. The default is port
0.
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1
MSAN-210
4.0
Application Note
Flexible Port Mirroring Support
This section describes a flexible software solution to selectively mirror the incoming or outgoing traffics of a given
MAC. If all MACs for the ingress and egress packets of a port are mirrored, then the function is similar to port
mirroring. The main approach is to utilize the secure mode hardware, which forwards the monitored traffics of a
given port to the CPU only. The driver then sets up the MAC entries that point the return traffics to the CPU port, so
the traffic can be captured.
In the MVTX260x driver, the port mirroring function for ports 7, 15, and 23 are provided as an option. The software
port mirroring implemented in the driver is described below.
First, the following MVTX2604 register needs to be program as follow:
•
The ECR2 register for the mirror source port need the Security Enabled field to be set to Send Packet to
CPU Only. Also for this register, the Learning Disable field needs to be set to 1. Setting these fields will
cause all ingress packets to be forwarded to the CPU.
The driver then needs to be modified to perform the following functions:
•
•
•
Ingress packets that have an unknown source MAC address needs to be learned by the driver. The driver
must also send a control frame to the MVTX2604 to have this new source MAC address added to the CPU
port.
Forward all ingress packets of the mirror source port to the destination port if the destination MAC address
has been learned. If the destination MAC address is unknown then flood the packet to the VLAN domain
ports. Also, forward the ingress packets to the mirror destination port.
Receive all packets destined for the mirror source port and forward it to the mirror source port.
If mirroring is disabled then the Security Enabled and Learning Disable field in the ECR2 register must be set to its
default value and the driver functions to support this solution must not be executed.
Note: This software solution may not provide line rate traffic between the mirror source port and any mirror-to port.
The actual line rate depends on the type and speed of the processor.
2
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