The sequence of AS path segments. Each AS
path segment is represented by a triple
<type, length, value>.
The type is a 1-octet field which has two
possible values:
1 AS_SET: unordered set of ASs a route in the
UPDATE message has traversed
2 AS_SEQUENCE: ordered set of ASs a route in the
UPDATE message has traversed.
The length is a 1-octet field containing the
number of ASs in the value field.
The value field contains one or more AS
numbers, each AS is represented in the octet
string as a pair of octets according to the
following algorithm:
first-byte-of-pair = ASNumber / 256;
second-byte-of-pair = ASNumber & 255;