This attribute specifies four NSAP prefixes which are distributed to
all other Passport nodes within a Topology region and by which this
node can be identified. These prefixes are used by PORS.
PORS calls that use NSAP addressing (for example, CES) will look
for the node with the longest NSAP prefix that matches the called
party address. The NSAP prefixes that PORS matches against are
the alternatePorsPrefixes and the nodePrefix.
These prefixes may contain up to 40 hexadecimal characters.