Beta Draft Confidential
Configuring CBX or GX Logical Ports
Setting Logical Port Attributes
ATM Services Configuration Guide for CBX 3500, CBX 500, GX 550, and B-STDX 9000 1/19/053-29
Table 3-4. Add Logical Port: ATM Tab Fields
Field Logical Port Action/Description
Connection: 
Class 
UNI 
DCE/DTE, 
NNI, or 
ATMoMPLS 
UNI/NNI
Displays the logical port connection type, either Direct or 
Virtual. This field is set to Direct when you configure the 
first UNI/NNI logical port on this physical port. When you 
configure subsequent UNI/NNI ports on this physical port, 
this field is set to “Virtual”.
For Trunk logical port types, this field defaults to Direct 
and cannot be changed.
Connection: 
Type
UNI DCE Displays whether this port connects to another switch or 
endsystem, or to a router or host. 
This option lets the switch know whether or not to send a 
configured node prefix over the ILMI channel to the 
attached device. This setting has no effect if ILMI is not 
enabled, or ILMI is enabled but you will not use ILMI 
address registration. 
Network <-> Endsystem – Port connects to a router or host 
(UNI-DCE ports only). If this port connects to a customer 
premise equipment (CPE) device a compliant configured 
node prefix will be sent over the ILMI channel to the device 
for ILMI address registration.
Network <-> Network – Port connects to another switch or 
an end system. If this port connects to another network 
switch, the node prefix should not be sent over the ILMI 
channel to the attached device.
The defaults are:
•DCE – Network <-> Endsystem
• DTE/NNI – Network <-> Network
Valid Bits: 
VPI
UNI 
DCE/DTE 
and NNI
Specify a value that is within the valid range for either the 
NNI or UNI call header format. See page 2-13 for details.
The default value is 4.
For virtual logical ports, this field is read-only.
Note: If you are using the 3-port Channelized DS3/1 IMA 
or 1-port Channelized STM-1/E1 IMA module on CBX 500 
or CBX 3500 configured in UNI mode, the default value for 
Number of Valid Bits in VPI is 8, based on an SVC 
Connection ID Range of 0 (zero) to 255. When the 3-port 
Channelized DS3/1 IMA module is configured in Inverse 
Multiplexing for ATM (IMA) mode, the standard ATM 
default value is used.