The value of tbgp4PathAttrASPathSegment specifies the sequence of
Autonomous System (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 4-byte AS numbers. Each AS is
represented in the octet string as four octets.