S e n d d o c u m e n t a t i o n c o m m e n t s t o m d s f e e d b a c k - d o c @ c i s c o . c o m
12-30
Cisco MDS 9000 Family CLI Configuration Guide
OL-16184-01, Cisco MDS SAN-OS Release 3.x
Chapter 12 Configuring Interfaces
TL Ports for Private Loops
Figure 12-4
TL Port Translation Support Examples
About TL Port ALPA Caches
Although TL ports cannot be automatically configured, you can manually configure entries in arbitrated
loop physical address (ALPA) caches. Generally, ALPA cache entries are automatically populated when
an ALPA is assigned to a device. Each device is identified by its port world wide name (pWWN). When
a device is allocated an ALPA, an entry for that device is automatically created in the ALPA cache.
A cache contains entries for recently allocated ALPA values. These caches are maintained on various TL
ports. If a device already has an ALPA, the Cisco SAN-OS software attempts to allocate the same ALPA
to the device each time. The ALPA cache is maintained in persistent storage and saves information across
switch reboots. The maximum cache size is 1000 entries. If the cache is full, and a new ALPA is
allocated, the Cisco SAN-OS software discards an inactive cache entry (if available) to make space for
the new entry. See the
“TL Port” section on page 12-5
for more information on TL ports.
Displaying TL Port Information
Private loop devices refer to legacy devices that reside on arbitrated loops. These devices are not aware
of a switch fabric because they only communicate with devices on the same physical loop.
The legacy devices are used in Fibre Channel networks and devices outside the loop may need to
communicate with them.The communication functionality is provided through TL ports.
Use the
switchport mode
command to configure a TL port (see the
“Configuring Interface Modes”
section on page 12-13
).
NL port
NL port
NL port
NL port
NL port
N port
N port
F port
F port
TL port
TL port
FL port
Private
loop
Private
loop
Public
loop
Private
initiator (I4)
Private
initiator (I1)
Public
initiator (I2)
Public
initiator (I3)
Public
target (T2)
Private
target (T1)
Public
target (3)
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