| Description | If the value of this object is 'bidirectional(0)',
a given VCI, within a given VPI, is used as a
label for both directions independently.
If the value of this object is 'unidirectional(1)',
a given VCI within a VPI designates one direction.
This is the EXACT value for the ATM Session Parameter,
field D (for VC Directionality). The ATM Session
Parameter is an optional parameter in the
Initialization Message.
The description from rfc3036.txt is:
'D, VC Directionality
A value of 0 specifies bidirectional VC capability,
meaning the LSR can (within a given VPI) support
the use of a given VCI as a label for both link
directions independently. A value of 1
specifies unidirectional VC capability, meaning
(within a given VPI) a given VCI may appear in
a label mapping for one direction on the link
only. When either or both of the peers
specifies unidirectional VC capability, both
LSRs use unidirectional VC label assignment for
the link as follows. The LSRs compare their
LDP Identifiers as unsigned integers. The LSR
with the larger LDP Identifier may assign
only odd-numbered VCIs in the VPI/VCI
range as labels. The system with the smaller
LDP Identifier may assign only even-numbered
VCIs in the VPI/VCI range as labels.'
Please refer to the following reference
for a complete description of this feature. |