About Tl Port Alpa Caches; Displaying Tl Port Information - Cisco MDS 9000 Series Configuration Manual

TL Ports for Private Loops
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
Figure 2-3
Private
target (T1)

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 NX-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 NX-OS software discards an inactive cache entry (if available) to make space for
the new entry. See the

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
section on page
Cisco MDS 9000 Family NX-OS Interfaces Configuration Guide
2-30
TL Port Translation Support Examples
Private
initiator (I4)
NL port
NL port TL port
Private
loop
Public
target (3)
"TL Port" section on page 2-5
2-13).
Private
initiator (I1)
Public
target (T2)
NL port
Private
loop
N port
F port
TL port
FL port
Public
NL port
loop
NL port
Public
initiator (I3)
for more information on TL ports.
Chapter 2 Configuring Interfaces
Public
initiator (I2)
N port
F port
"Configuring Interface Modes"
OL-19445-02, Cisco MDS NX-OS Release 4.2(x)