Brocade Fabric OS Troubleshooting and Diagnostics Guide v6.2.0 (53-1001187-01, April 2009)

Fabric OS Troubleshooting and Diagnostics Guide 81
53-1001187-01
Port mirroring
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For example, in a three-domain fabric containing switches 4100A, 4100B, and 4100C, a mirror
connection that is created between 4100A and 4100B only allows 4100A to add mirror
connections for those ports on 4100B. To mirror traffic between 4100A and 4100C, add a
mirror connection on 4100C. The first connection defines the restriction on the domain, which
can be either the local domain or a remote domain.
• A switch that is capable of port mirroring can support a maximum of four mirror connections.
Each Field Description Block (FDB) defines an offset to search. Each offset can have up to four
values that can be defined for a filter. If any of the four values match, the filter will match.
• Mirror port bandwidth limits mirror connections.
The bandwidth of the mirror port is unidirectional. The host (SID) talks to multiple storage
devices (DIDs) and does not send full line rate to a single target. A mirror port configured at
2GB can only support up to 2GB of traffic. A normal 2G F_Port is bidirectional and can support
up to 4GB of traffic (two to transmit and two to receive). If the mirror port bandwidth is
exceeded, the receiver port is not returned any credits and the devices in the mirror connection
see degraded performance.
• Deleting a port mirroring connection with In Order Deliver (IOD) enabled causes frame drop
between two endpoints.
• Using the firmware download procedure to downgrade to previous Fabric OS releases that do
not support port mirroring requires that you remove all the port mirroring connections. If you
downgrade to a previous versions of Fabric OS, you cannot proceed until the mirroring
connections are removed.
Port mirroring management
The method for adding a port mirror connection between two local switch ports and between a
local switch port and a remote switch port is the same. First you must configure a port to be a
mirror port before you can perform a portMirror
--add, or portMirror --delete.
Configuring a port to be a mirror port
1. Connect to the switch and log in using an account assigned to the admin role.
2. Enter the portCfg mirrorport [slot number/]<port number>
--enable command.
NOTE
The enable command enables the port as a mirror port. The disable command disables the mirror
port configuration.
Adding a port mirror connection
1. Connect to the switch and log in using an account assigned to the admin role.
2. Enter the portMirror
--add slotnumber/portnumber SourceID DestID command.
NOTE
The lower 8 bits of the address is ignored. For example, the ALPA for loop devices.