RFC 2383 (rfc2383) - Page 2 of 50
ST2+ over ATM Protocol Specification - UNI 3
Alternative Format: Original Text Document
RFC 2383 ST2+ over ATM August 1998
Therefore, in this document, ATM is only a subnet technology for the
ST2+ stream. This specification is designed to enable resource-
reservation communications across ATM and non-ATM networks.
1.2 Features of ST2+ over ATM Protocol
o Enables resource-reservation communications across ATM and non-ATM
networks.
ATM native API supports resource-reservation communications only
within an ATM network; it cannot support interworking with non-ATM
networks. This is because
- ATM native API cannot connect terminals without an ATM interface.
- ATM native API does not support IP addressing and SAP (port)
addressing systems.
o Extends UNI 3.1/4.0 signaling functions.
ST2+ SCMP supports MTU-size negotiation at all hops in an ST2+
tree-structure stream. UNI 3.1/4.0 supports only max CPCS_SDU
(i.e., MTU) negotiation with the called party of a point-to-point
call or with the first leaf of a point-to-multipoint call.
o Reduces UNI 4.0 LIJ signaling limitations.
The ST2+ over ATM protocol supports UNI 4.0 LIJ Call Identifier
notification from the root to the leaf by using an ST2+ SCMP
extension. LIJ Call Identifier discovery at the leaf is one of the
major unsolved problems of UNI 4.0, and the ST2+ over ATM protocol
provides a solution.
Note: The UNI 3.1 version of the ST2+ over ATM protocol does not
support the above feature. It will be supported by the UNI 3.1/4.0
version.
1.3 Goals and Non-goals of ST2+ over ATM Protocol
The ST2+ over ATM protocol is designed to achieve the following
goals.
o Specify protocol interaction between ST2+ [4] and ATM on the ATM
Forum Private UNI 3.1/4.0 (Sb point) [10, 11].
Note: The UNI 3.1 version of the ST2+ over ATM protocol does not
support UNI 4.0. It will be supported by the UNI 3.1/4.0 version.
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