draft-ietf-mpls-git-uus-03.txt   draft-ietf-mpls-git-uus-04.txt 
Network Working Group Muneyoshi Suzuki A new Request for Comments is now available in online RFC libraries.
INTERNET DRAFT NTT
Expires January 26, 2000 July 26, 1999
The Assignment of the Information Field and Protocol Identifier
in the Q.2941 Generic Identifier and Q.2957 User-to-user Signaling
for the Internet Protocol
<draft-ietf-mpls-git-uus-03.txt>
Status of this Memo
This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC2026.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet-
Drafts.
Internet-Drafts are draft documents valid for a maximum of six months RFC 3033
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at Title: The Assignment of the Information Field and
http://www.ietf.org/ietf/1id-abstracts.txt Protocol Identifier in the Q.2941 Generic
Identifier and Q.2957 User-to-user Signaling for
the Internet Protocol
Author(s): M. Suzuki
Status: Standards Track
Date: January 2001
Mailbox: suzuki.muneyoshi@lab.ntt.co.jp
Pages: 25
Characters: 52188
Updates/Obsoletes/SeeAlso: None
The list of Internet-Draft Shadow Directories can be accessed at I-D Tag: draft-ietf-mpls-git-uus-04.txt
http://www.ietf.org/shadow.html.
Abstract URL: ftp://ftp.isi.edu/in-notes/rfc3033.txt
The purpose of this document is to specify the assignment of the The purpose of this document is to specify the assignment of the
information field and protocol identifier in the Q.2941 Generic information field and protocol identifier in the Q.2941 Generic
Identifier and Q.2957 User-to-user Signaling for the Internet Identifier and Q.2957 User-to-user Signaling for the Internet
protocol. protocol.
The assignment, that is specified in section 4 of this document, is The assignment, that is specified in section 4 of this document, is
designed for advanced B-ISDN signaling support of the Internet designed for advanced B-ISDN signaling support of the Internet
protocol, especially the B-ISDN signaling support for the connection protocol, especially the B-ISDN signaling support for the connection
that corresponds to the session in the Internet protocol which is that corresponds to the session in the Internet protocol which is
clarified in section 2. This specification provides an indispensable clarified in section 2. This specification provides an indispensable
framework for the implementation of long-lived session and QoS- framework for the implementation of long-lived session and
sensitive session transfers over ATM. QoS-sensitive session transfers over ATM.
1. Purpose of Document
The purpose of this document is to specify the assignment of the
information field and protocol identifier in the Q.2941 Generic
Identifier and Q.2957 User-to-user Signaling for the Internet
protocol.
The assignment, that is specified in section 4 of this document, is
designed for advanced B-ISDN signaling support of the Internet
protocol, especially the B-ISDN signaling support for the connection
that corresponds to the session in the Internet protocol which is
clarified in section 2. Needless to say, the purpose of this
specification is not limited to this support, and it should also be
applicable to other purposes.
This specification provides an indispensable framework for the
implementation of long-lived session and QoS-sensitive session
transfers over ATM. Note that this document only specifies the
assignment of the information field and protocol identifier, and that
it may not specify complete protocol that enables interoperable
implementation. This is because it is beyond the scope of this
document and will be specified in a separate document.
2. Session-related ATM Connection
With the development of new multimedia applications on the current
Internet, the demands for multimedia support are increasing in the IP
network, which currently supports best effort communications. In
particular, demands to support QoS guaranteed communications are
increasing with the development of voice, audio, and video
communications applications. And it may also be necessary to
introduce the mechanism that can efficiently transfer the huge volume
of traffic expected with these applications.
The major features of B-ISDN are high speed, logical multiplexing
with the VP/VC, and flexible QoS management per VC, so it is quite
natural to use these distinctive functions of B-ISDN to implement a
multimedia support mechanism in the IP network. The flexible QoS
management and logical multiplexing functions in B-ISDN are the
expected method of implementing the QoS guaranteed communications in
the Internet. And when a long-lived session is supported by a
particular VC, efficient packet forwarding may be possible using the
high speed and logical multiplexing of B-ISDN.
This section clarifies B-ISDN signaling functions that are required
when the session is supported by the VC, for advanced B-ISDN
signaling support of the Internet protocol.
2.1 Long-lived Session Signaling
An example scenario for establishing a VC for a long-lived session is
shown in Fig. 2.1.
IP Router ATM SW ATM SW IP Router
+----+ Default VC +----+
| WS | +------+ UNI +-----+ +-----+ UNI +------+ | WS |
+--+-+ | /->|<------+-\-/-+--------+-\-/-+------>|<-\ | +-+--+
|.....|__/ |===||==| X |========| X |==||===| \__|.....|
| | | / \ | | / \ | | |
+------+ +-----+ +-----+ +------+
A. New session initially forwarded over a default VC.
IP Router ATM SW ATM SW IP Router
+----+ Default VC +----+
| WS | +------+ UNI +-----+ +-----+ UNI +------+ | WS |
+--+-+ | /->|<------+-\-/-+--------+-\-/-+------>|<-\ | +-+--+
|.....|__/ |===||==| X |========| X |==||===| \__|.....|
| |<------+-/-\-+--------+-/-\-+------>| |
+------+ +-----+ +-----+ +------+
New VC is set up
B. New VC is set up for the long-lived session.
IP Router ATM SW ATM SW IP Router
+----+ Default VC +----+
| WS | +------+ UNI +-----+ +-----+ UNI +------+ | WS |
+--+-+ | |<------+-\-/-+--------+-\-/-+------>| | +-+--+
|.....|__ |===||==| X |========| X |==||===| __|.....|
| \-->|<------+-/-\-+--------+-/-\-+------>|<--/ |
+------+ +-----+ +-----+ +------+
New VC
C. Transfer of the long-lived session to a new VC.
Fig. 2.1: Example scenario for establishing a VC for a long-lived session.
First, a session is multiplexed into the default VC connecting the
routers. Then, if a router detects that it is a long-lived session,
it sets up a new VC for the session. If the new VC is established
successfully, the long-lived session is moved to the new VC.
In this procedure involving an ATM VC setup, the B-ISDN signaling
entity in the called side router must detect that the incoming call
corresponds to a session of the Internet protocol and notify that
fact to the IP layer entity. Based on this information, the IP layer
entity moves the session to the new VC.
Therefore, to implement this signaling procedure, the B-ISDN
signaling must include an session identifier as an information
element. The B-LLI, B-HLI, User-user, and Generic Identifier
information elements are all capable of transferring this
information. Considering the original purposes of these information
elements, the most appropriate one to use is the Generic Identifier
information element.
2.2 QoS-sensitive Session Signaling
The major difference between QoS-sensitive session signaling and
long-lived session signaling is that call setup is not initiated by
the detection of a long-lived session, but is explicitly initiated by
the setup protocol such as ST2+ and RSVP. To implement QoS-sensitive
session signaling using ATM, the ATM network between the routers must
forward not only the session identifier but also the setup protocol.
There are two schemes for forwarding the setup protocol. One is to
multiplex the protocol into a default VC connecting the routers, or
to forward the protocol through a particular VC. In this case, the
QoS-sensitive session and the ATM VC are established sequentially.
The second scheme is to forward the setup protocol as an information
element in the B-ISDN signaling. In this case, the QoS-sensitive
session and the ATM VC are established simultaneously. The latter
scheme has the following advantages compared with the former one.
o Easier to implement.
- Admission control is simplified, because admission control for
the IP and ATM layers can be done simultaneously.
- Watchdog timer processing is simplified, because there is no need
to watch the IP layer establishment and ATM layer establishment
sequentially.
o If the setup protocol supports negotiation, then an ATM VC whose
QoS is based on the result of negotiation can be established.
However, the latter scheme, at least, cannot support a case where a
PVC is used to support a QoS-sensitive session. Therefore, both
procedures should be taken into account.
An example of a message sequence that simultaneously establishes a
QoS-sensitive session and an ATM VC is shown in Fig. 2.2.
IP Router ATM SW ATM SW IP Router
+----+ B-ISDN Signaling +----+
| WS | +------+ UNI +-----+ Setup +-----+ UNI +------+ | WS |
+--+-+ | /->|<------+-\-/--Protocol--\-/-+------>|<-\ | +-+--+
|.....|__/ |===||==| X |========| X |==||===| \__|.....|
| \-->|<------+-/-\-+--------+-/-\-+------>|<--/ |
+------+ +-----+ Data +-----+ +------+
QoS VC
N-CONNECT | |
---------->| | | | | |
|->| SETUP | | | |
| |------------>| | | |
| |<------------| | | |
| | CALL PROC |----------->| SETUP | |
| | | |------------>| |
| | | | |->| N-CONNECT
| | | | | |---------->
| | | | | |<----------
| | | | CONN |<-| N-CONNECT-ACK
| | | |<------------| |
| | | |------------>| |
| | CONN |<-----------| CONN ACK |->|
| |<------------| | | |
| |------------>| | | |
|<-| CONN ACK | | | |
<----------| | | | | |
N-CONNECT | |
-ACK
Fig. 2.2: Example procedure for simultaneous QoS-sensitive session and
ATM VC establishment.
Both ST2+ and RSVP are currently proposed for the setup protocol and
new setup protocols are likely to be developed in the near future.
Therefore, to generalize the discussion, the procedure for the setup
protocol in this example is the general connection setup procedure
using confirmed service.
To implement this signaling procedure, the B-ISDN signaling must
include the User-user information element that the capacity is
sufficient to forward the setup protocol.
3. Overview of the Generic Identifier and User-to-user Signaling
3.1 Overview of the Generic Identifier
The Generic Identifier enables the transfer of identifiers between
end-to-end users in the ATM network, and it is defined in the Q.2941
Part 1 (Q.2941.1) [3] and Part 2 (Q.2941.2) [4] as an optional
information element for the Q.2931 [1] and Q.2971 [2] UNI signaling
protocol. The SETUP, ALERTING, CONNECT, RELEASE, RELEASE COMPLETE,
ADD PARTY, PARTY ALERTING, ADD PARTY ACK, ADD PARTY REJECT, DROP
PARTY, and DROP PARTY ACK messages that are transferred between end-
to-end users in the ATM network may contain up to three Generic
Identifier information elements. The ATM network transfers the
Generic Identifier information element transparently if it contains
no coding rule errors.
The format of the Generic Identifier information element specified in
the Q.2941 is shown in Fig. 3.1.
Bits
8 7 6 5 4 3 2 1 Octets
+-----+-----+-----+-----+-----+-----+-----+-----+
| Information element identifier |
| = Generic identifier transport IE (0x7F) | 1
+-----+-----+-----+-----+-----+-----+-----+-----+
| 1 | Coding | IE instruction field |
| Ext | standard |Flag |Res. | IE action ind. | 2
+-----+-----+-----+-----+-----+-----+-----+-----+
| Length of contents of information element | 3-4
+-----+-----+-----+-----+-----+-----+-----+-----+
| Identifier related standard/application | 5
+-----+-----+-----+-----+-----+-----+-----+-----+
| Identifier type | 6
+-----+-----+-----+-----+-----+-----+-----+-----+
| Identifier length | 7
+-----+-----+-----+-----+-----+-----+-----+-----+
| Identifier value | 8-
= =
+-----+-----+-----+-----+-----+-----+-----+-----+
= =
+-----+-----+-----+-----+-----+-----+-----+-----+
| Identifier type |
+-----+-----+-----+-----+-----+-----+-----+-----+
| Identifier length |
+-----+-----+-----+-----+-----+-----+-----+-----+
| Identifier value |
= =
+-----+-----+-----+-----+-----+-----+-----+-----+
Fig. 3.1: Format of the Generic Identifier information element.
The usage of the first 4 octets of fields is specified in section 4
of the Q.2931.
The Identifier related standard/application field identifies the
standard or application that uses the identifier. Assignment of the
Identifier related standard/application field for the Intenet
protocol is as follows. A leading 0x means hexadecimal.
0x03: IPv4.
0x04: ST2+.
0x05: IPv6.
0x06: MPLS.
Note: DSM-CC, H.310/H.321, MPOA, ATM VCC Trunking, AAL2, and
H.323/H.245 are also supported.
A transferred identifier is given by the combination of the
Identifier type, length and value fields, and a Generic Identifier
information element may contain multiple identifiers.
Assignment of the Identifier type field for the Intenet protocol is
as follows. A leading 0x means hexadecimal.
0x01: Session.
0x02: Resource.
0x10-0xFD: Reserved for IANA assignment.
0xFE: Experiment/Organization specific.
The maximum length of the Generic Identifier information element is
63 octets.
See the Q.2941.1 and Draft Q.2941.2 for detailed protocol
specifications of the Generic Identifier.
3.2 Overview of the User-to-user Signaling
The User-to-user Signaling enables the transfer of information
between end-to-end users in the ATM network, and it is defined in
Q.2957 [5, 6] and in Q.2971 annex D [2] as an optional information
element for the Q.2931 [1] and Q.2971 [2] UNI signaling protocol.
The SETUP, ALERTING, CONNECT, RELEASE, RELEASE COMPLETE, PROGRESS,
ADD PARTY, PARTY ALERTING, ADD PARTY ACK, ADD PARTY REJECT, DROP
PARTY, and DROP PARTY ACK messages that are transferred between end-
to-end users in the ATM network may contain a User-user information
element. The ATM network transfers the User-user information element
transparently if it contains no coding rule errors.
From the viewpoint of B-ISDN signaling applications, it seems the
Generic Identifier and User-to-user Signaling are similar functions.
But their rules for processing exceptions are not completely the
same, because their purposes are different. The Generic Identifier is
designed for the transfer of identifiers between the c-planes, while
the User-to-user Signaling is designed for the transfer of user data
via the c-planes. Another difference is that the latter supports
interworking with the user-user information element in the Q.931 N-
ISDN signaling, but the Generic Identifier does not. Note that the
ATM network may check the contents of the Generic Identifier
information element, but does not check the contents of the User-to-
user information element.
The format of the User-user information element is shown in Fig. 3.2.
Bits
8 7 6 5 4 3 2 1 Octets
+-----+-----+-----+-----+-----+-----+-----+-----+
| Information element identifier |
| = User-user information element (0x7E) | 1
+-----+-----+-----+-----+-----+-----+-----+-----+
| 1 | Coding | IE instruction field |
| Ext | standard |Flag |Res. | IE action ind. | 2
+-----+-----+-----+-----+-----+-----+-----+-----+
| Length of contents of information element | 3-4
+-----+-----+-----+-----+-----+-----+-----+-----+
| Protocol discriminator | 5
+-----+-----+-----+-----+-----+-----+-----+-----+
| User information | 6-
= =
| |
+-----+-----+-----+-----+-----+-----+-----+-----+
Fig. 3.2: Format of the User-user information element.
The usage of the first 4 octets of fields is specified in section 4
of the Q.2931.
The Protocol discriminator field identifies the upper layer protocol
that uses the user-user information.
The User information field contains the user-user information to be
transferred.
The maximum length of the User-user information element is 133
octets.
See Q.2957, Draft Q.2957 amendment 1, and Q.2971 annex D for detailed
protocol specifications of the User-to-user Signaling.
4. Information Field and Protocol Identifier Assignment
4.1 Assignment in the Generic Identifier Information Element
4.1.1 Use of Generic Identifier
The information field and protocol identifier assignment principle
for the Internet protocol in the Generic Identifier information
element is shown in Fig. 4.1.
Bits
8 7 6 5 4 3 2 1 Octets
+-----+-----+-----+-----+-----+-----+-----+-----+
| Information element identifier |
| = Generic identifier transport IE (0x7F) | 1
+-----+-----+-----+-----+-----+-----+-----+-----+
| 1 | Coding | IE instruction field |
| Ext | standard |Flag |Res. | IE action ind. | 2
+-----+-----+-----+-----+-----+-----+-----+-----+
| Length of contents of information element | 3-4
+-----+-----+-----+-----+-----+-----+-----+-----+
| Identifier related standard/application |
| = IPv4, ST2+, IPv6, or MPLS | 5
+-----+-----+-----+-----+-----+-----+-----+-----+
| Identifier type |
| = Session, Resource, or Experiment | 6
+-----+-----+-----+-----+-----+-----+-----+-----+
| Identifier length | 7
+-----+-----+-----+-----+-----+-----+-----+-----+
| Identifier value | 8-
= =
+-----+-----+-----+-----+-----+-----+-----+-----+
= =
+-----+-----+-----+-----+-----+-----+-----+-----+
| Identifier type |
| = Session, Resource, or Experiment |
+-----+-----+-----+-----+-----+-----+-----+-----+
| Identifier length |
+-----+-----+-----+-----+-----+-----+-----+-----+
| Identifier value |
= =
+-----+-----+-----+-----+-----+-----+-----+-----+
Fig. 4.1: Principle of assignment in the Generic Identifier
information element.
The Identifier related standard/application field is the IPv4, ST2+,
IPv6, or MPLS.
The Identifier type field is the Session, Resource, or
Experiment/Organization specific.
The Identifier value field is assigned to Internet protocol related
information which is identified by the Identifier related
standard/application field and Identifier type field. The following
identifiers are specified.
Std./app. Id type
IPv4 session identifier IPv4 Session
ST2+ session identifier ST2+ Session
IPv6 session identifier IPv6 Session
MPLS VCID MPLS Resource
Exp./Org. specific IPv4/ST2+/IPv6/MPLS Experiment
As described in section 3.1, the B-ISDN signaling message transferred
between end-to-end users may contain up to three Generic Identifier
information elements. These elements may contain multiple
identifiers. This document does not specify the order of identifiers
when multiple identifiers appear in a signaling message.
This document also does not specify the semantics when multiple
identifiers having the same Identifier type appear in a signaling
message, or when a signaling message contains a Generic Identifier
information element that does not contain identifiers.
When a B-ISDN signaling message containing a Generic Identifier
information element enters an ATM network that does not support the
Generic Identifier, the network clears the call, discards the
information element, or discards the signaling message. (See
sections 4.5.1 and 5.6.8.1 of Q.2931 and section 9.3 of Q.2941.1 for
details.)
To enable reliable Generic Identifier information element transfer,
when the calling party sends a SETUP or ADD PARTY message with up to
three Generic Identifier information elements, the CONNECT or ADD
PARTY ACK message returned by the called party must contain at least
one Generic Identifier information element. The called party may not
respond with the same identifiers received from the calling party.
The calling party should confirm that the response message contains
at least one Generic Identifier information element. This rule
enables identifier negotiation; this document does not specify the
detailed procedure of this negotiation.
4.1.2 IPv4 session identifier
If the Identifier related standard/application field in the Generic
Identifier information element is the IPv4, and the Identifier type
field in the identifier is the Session, the identifier is the IPv4
session identifier. The format of the IPv4 session identifier is
shown in Fig. 4.2.
Bits Octet
8 7 6 5 4 3 2 1 length
+-----+-----+-----+-----+-----+-----+-----+-----+
| Identifier type |
| = Session (0x01) | 1
+-----+-----+-----+-----+-----+-----+-----+-----+
| Identifier length |
| = 13 octets (0x0D) | 1
+-----+-----+-----+-----+-----+-----+-----+-----+
| Source IPv4 address | 4
+-----+-----+-----+-----+-----+-----+-----+-----+
| Destination IPv4 address | 4
+-----+-----+-----+-----+-----+-----+-----+-----+
| Protocol | 1
+-----+-----+-----+-----+-----+-----+-----+-----+
| Source Port | 2
+-----+-----+-----+-----+-----+-----+-----+-----+
| Destination Port | 2
+-----+-----+-----+-----+-----+-----+-----+-----+
Fig. 4.2: IPv4 session identifier.
The Identifier type field is the Session (0x01).
The Identifier length is 13 octets.
The Source IPv4 address, Destination IPv4 address, Protocol, Source
Port, and Destination Port [7, 9, 10] are assigned in that order to
the Identifier value field.
Note: This specific session identifier is intended for use only with
the explicit reservation. If wild card associations are needed at a
later date, another identifier type will be used.
4.1.3 ST2+ session identifier
If the Identifier related standard/application field in the Generic
Identifier information element is the ST2+, and the Identifier type
field in the identifier is the Session, the identifier is the ST2+
session identifier. The format of the ST2+ session identifier is
shown in Fig. 4.3.
Bits Octet
8 7 6 5 4 3 2 1 length
+-----+-----+-----+-----+-----+-----+-----+-----+
| Identifier type |
| = Session (0x01) | 1
+-----+-----+-----+-----+-----+-----+-----+-----+
| Identifier length |
| = 6 octets (0x06) | 1
+-----+-----+-----+-----+-----+-----+-----+-----+
| Stream ID (SID) | 6
+-----+-----+-----+-----+-----+-----+-----+-----+
Fig. 4.3: ST2+ session identifier.
The Identifier type field is the Session (0x01).
The Identifier length is 6 octets.
The Stream ID (SID) [11] is assigned to the Identifier value field.
4.1.4 IPv6 session identifier
If the Identifier related standard/application field in the Generic
Identifier information element is the IPv6, and the Identifier type
field in the identifier is the Session, the identifier is the IPv6
session identifier. The format of the IPv6 session identifier is
shown in Fig. 4.4.
Bits Octet
8 7 6 5 4 3 2 1 length
+-----+-----+-----+-----+-----+-----+-----+-----+
| Identifier type |
| = Session (0x01) | 1
+-----+-----+-----+-----+-----+-----+-----+-----+
| Identifier length |
| = 37 octets (0x25) | 1
+-----+-----+-----+-----+-----+-----+-----+-----+
| Source IPv6 address | 16
+-----+-----+-----+-----+-----+-----+-----+-----+
| Destination IPv6 address | 16
+-----+-----+-----+-----+-----+-----+-----+-----+
| Protocol | 1
+-----+-----+-----+-----+-----+-----+-----+-----+
| Source Port | 2
+-----+-----+-----+-----+-----+-----+-----+-----+
| Destination Port | 2
+-----+-----+-----+-----+-----+-----+-----+-----+
Fig. 4.4: IPv6 session identifier.
The Identifier type field is the Session (0x01).
The Identifier length is 37 octets.
The Source IPv6 address, Destination IPv6 address, Protocol, Source
Port, and Destination Port [8, 9, 10] are assigned in that order to
the Identifier value field.
Note: This specific session identifier is intended for use only with
the explicit reservation. If wild card associations are needed at a
later date, another identifier type will be used.
4.1.5 MPLS VCID
If the Identifier related standard/application field in the Generic
Identifier information element is the MPLS, and the Identifier type
field in the identifier is the Resource, the identifier is the MPLS
VCID. The format of the MPLS VCID is shown in Fig. 4.5.
Bits Octet
8 7 6 5 4 3 2 1 length
+-----+-----+-----+-----+-----+-----+-----+-----+
| Identifier type |
| = Resource (0x02) | 1
+-----+-----+-----+-----+-----+-----+-----+-----+
| Identifier length |
| = 4 octets (0x04) | 1
+-----+-----+-----+-----+-----+-----+-----+-----+
| MPLS VCID | 4
+-----+-----+-----+-----+-----+-----+-----+-----+
Fig. 4.5: MPLS VCID.
The Identifier type field is the Resource (0x02).
The Identifier length is 4 octets.
The MPLS VCID [13] is assigned to the Identifier value field.
4.1.6 Experiment/Organization specific
If the Identifier related standard/application field in the Generic
Identifier information element is the IPv4, ST2+, IPv6, or MPLS, and
the Identifier type field in the identifier is the
Experiment/Organization specific, the identifier is the
Experiment/Organization specific. The format of the
Experiment/Organization specific is shown in Fig. 4.6.
Bits Octet
8 7 6 5 4 3 2 1 length
+-----+-----+-----+-----+-----+-----+-----+-----+
| Identifier type |
| = Experiment/Organization specific (0xFE) | 1
+-----+-----+-----+-----+-----+-----+-----+-----+
| Identifier length | 1
+-----+-----+-----+-----+-----+-----+-----+-----+
| Organizationally unique identifier (OUI) | 3
+-----+-----+-----+-----+-----+-----+-----+-----+
| Experiment/Organization specific info. |
= =
| |
+-----+-----+-----+-----+-----+-----+-----+-----+
Fig. 4.6: Experiment/Organization specific.
The Identifier type field is the Experiment/Organization specific
(0xFE).
The first 3 octets in the Identifier value field must contain the
Organizationally unique identifier (OUI) (as specified in IEEE 802-
1990; section 5.1).
4.2 Assignment in the User-user Information Element
4.2.1 Use of User-to-user Signaling
The information field and protocol identifier assignment principle
for the Internet protocol in the User-user information element is
shown in Fig. 4.7.
Bits
8 7 6 5 4 3 2 1 Octets
+-----+-----+-----+-----+-----+-----+-----+-----+
| Information element identifier |
| = User-user information element (0x7E) | 1
+-----+-----+-----+-----+-----+-----+-----+-----+
| 1 | Coding | IE instruction field |
| Ext | standard |Flag |Res. | IE action ind. | 2
+-----+-----+-----+-----+-----+-----+-----+-----+
| Length of contents of information element | 3-4
+-----+-----+-----+-----+-----+-----+-----+-----+
| Protocol discriminator |
| = Internet protocol/application (0x06) | 5
+-----+-----+-----+-----+-----+-----+-----+-----+
| Internet protocol/application identifier | 6
+-----+-----+-----+-----+-----+-----+-----+-----+
| Internet protocol/application related info. | 7-
= =
| |
+-----+-----+-----+-----+-----+-----+-----+-----+
Fig. 4.7: Principle of assignment in the User-user information element.
The Protocol discriminator field is the Internet protocol/application
(0x06). In this case, the first 1 octet in the User information
field is the Internet protocol/application identifier field.
Assignment of the Internet protocol/application identifier field is
as follows. A leading 0x means hexadecimal.
0x00: Reserved.
0x01: ST2+ SCMP.
0x02: RSVP message.
0x03-0xFD: Reserved for IANA assignment.
0xFE: Experiment/Organization specific.
0xFF: Reserved.
The field that follows the Internet protocol/application identifier
field is assigned to Internet protocol/application related
information that is identified by the Internet protocol/application
identifier field.
When a B-ISDN signaling message containing a User-user information
element enters an ATM network that does not support the User-to-user
Signaling, the network clears the call, discards the information
element, or discards the signaling message. (See sections 4.5.1 and
5.6.8.1 of Q.2931, section 1.9 of Q.2957, and Q.2971 annex D for
details.)
To enable reliable User-user information element transfer, when the
calling party sends a SETUP or ADD PARTY message with a User-user
information element, the CONNECT or ADD PARTY ACK message returned by
the called party must contain a User-user information element. The
called party may not respond with the same user information received
from the calling party. The calling party should confirm that the
response message contains a User-user information element. This rule
enables negotiation; this document does not specify the detailed
procedure of this negotiation.
4.2.2 ST2+ SCMP
The format of the ST2+ SCMP is shown in Fig. 4.8.
Bits
8 7 6 5 4 3 2 1 Octets
+-----+-----+-----+-----+-----+-----+-----+-----+
| Information element identifier |
| = User-user information element (0x7E) | 1
+-----+-----+-----+-----+-----+-----+-----+-----+
| 1 | Coding | IE instruction field |
| Ext | standard |Flag |Res. | IE action ind. | 2
+-----+-----+-----+-----+-----+-----+-----+-----+
| Length of contents of information element | 3-4
+-----+-----+-----+-----+-----+-----+-----+-----+
| Protocol discriminator |
| = Internet protocol/application (0x06) | 5
+-----+-----+-----+-----+-----+-----+-----+-----+
| Internet protocol/application identifier |
| = ST2+ SCMP (0x01) | 6
+-----+-----+-----+-----+-----+-----+-----+-----+
| ST2+ SCMP | 7-
= =
| |
+-----+-----+-----+-----+-----+-----+-----+-----+
Fig. 4.8: ST2+ SCMP.
The Internet protocol/application identifier field is the ST2+ SCMP
(0x01).
The ST2+ SCMP [11] is assigned to the Internet protocol/application
related information field. The SETUP and ADD PARTY messages may
contain the ST2+ SCMP CONNECT message. The CONNECT and ADD PARTY ACK
messages may contain the ST2+ SCMP ACCEPT message. The RELEASE and
DROP PARTY messages may contain the ST2+ SCMP DISCONNECT message.
The RELEASE, RELEASE COMPLETE, ADD PARTY REJECT, and DROP PARTY
messages may contain the ST2+ SCMP REFUSE message.
4.2.3 RSVP message
The format of the RSVP message is shown in Fig. 4.9.
Bits
8 7 6 5 4 3 2 1 Octets
+-----+-----+-----+-----+-----+-----+-----+-----+
| Information element identifier |
| = User-user information element (0x7E) | 1
+-----+-----+-----+-----+-----+-----+-----+-----+
| 1 | Coding | IE instruction field |
| Ext | standard |Flag |Res. | IE action ind. | 2
+-----+-----+-----+-----+-----+-----+-----+-----+
| Length of contents of information element | 3-4
+-----+-----+-----+-----+-----+-----+-----+-----+
| Protocol discriminator |
| = Internet protocol/application (0x06) | 5
+-----+-----+-----+-----+-----+-----+-----+-----+
| Internet protocol/application identifier |
| = RSVP message (0x02) | 6
+-----+-----+-----+-----+-----+-----+-----+-----+
| RSVP message | 7-
= =
| |
+-----+-----+-----+-----+-----+-----+-----+-----+
Fig. 4.9: RSVP message.
The Internet protocol/application identifier field is the RSVP
message (0x02).
The RSVP message [12] is assigned to the Internet
protocol/application related information field. The SETUP message
may contain the RSVP Resv message. The CONNECT message may contain
the RSVP ResvConf message. The RELEASE message may contain the RSVP
ResvErr or ResvTear message.
4.2.4 Experiment/Organization specific
The format of the Experiment/Organization specific is shown in Fig.
4.10.
Bits
8 7 6 5 4 3 2 1 Octets
+-----+-----+-----+-----+-----+-----+-----+-----+
| Information element identifier |
| = User-user information element (0x7E) | 1
+-----+-----+-----+-----+-----+-----+-----+-----+
| 1 | Coding | IE instruction field |
| Ext | standard |Flag |Res. | IE action ind. | 2
+-----+-----+-----+-----+-----+-----+-----+-----+
| Length of contents of information element | 3-4
+-----+-----+-----+-----+-----+-----+-----+-----+
| Protocol discriminator |
| = Internet protocol/application (0x06) | 5
+-----+-----+-----+-----+-----+-----+-----+-----+
| Internet protocol/application identifier |
| = Experiment/Organization specific (0xFE) | 6
+-----+-----+-----+-----+-----+-----+-----+-----+
| Organizationally unique identifier (OUI) | 7-9
+-----+-----+-----+-----+-----+-----+-----+-----+
| Experiment/Organization specific info. | 10-
= =
| |
+-----+-----+-----+-----+-----+-----+-----+-----+
Fig. 4.10: Experiment/Organization specific.
The Internet protocol/application identifier field is the
Experiment/Organization specific (0xFE).
The first 3 octets in the Internet protocol/application related
information field must contain the Organizationally unique identifier
(OUI) (as specified in IEEE 802-1990; section 5.1).
5. Open Issues
The following issues are still remain in this document.
o Generic Identifier support for session aggregation.
Session aggregation support may be needed in a backbone
environment. Wild card style aggregated session identifier may be
feasible. However, before specifying Generic Identifier support
for it, session aggregation model in ATM VCs should be clarified.
o Generic Identifier support for the IPv6 flow label and traffic
classes.
The IPv6 flow label and traffic classes support may be needed in
future. However, currently their semantics are not clear.
6. IANA Considerations
When the Identifier related standard/application field in the
Q.2941.2 Generic Identifier information element is the IPv4, ST2+,
IPv6, or MPLS, numbers between 0x10-0xFD in the Identifier type field
are reserved for IANA assignment. (See section 3.1). Following the
policies outlined in [14], these numbers are allocated through an
IETF Consensus action.
When the Protocol discriminator field in the Q.2957 User-user
information element is the Internet protocol/application, numbers
between 0x03-0xFD in the Internet protocol/application identifier
field are reserved for IANA assignment. (See section 4.2.1).
Following the policies outlined in [14], these numbers are allocated
through an IETF Consensus action.
7. Security Considerations
This document specifies the information field and protocol identifier
assignment in the Q.2941 Generic Identifier and Q.2957 User-to-user
Signaling for the Internet protocol, so these do not weaken the
security of the B-ISDN signaling.
In a called party of the B-ISDN signaling, if the incoming SETUP
message contains the calling party number and if it is verified and
passed by the ATM network or it is provided by the network, then it
is feasible to use the calling party number for part of the calling
party authentication to strengthen security.
References
[1] ITU-T, "Broadband Integrated Services Digital Network (B-
ISDN)-Digital Subscriber Signaling System No. 2 (DSS 2)-User-
Network Interface (UNI) Layer 3 Specification for Basic
Call/Connection Control," ITU-T Recommendation Q.2931, September
1995.
[2] ITU-T, "Broadband Integrated Services Digital Network (B-
ISDN)-Digital Subscriber Signaling System No. 2 (DSS 2)-User-
Network Interface Layer 3 Specification for Point-to-Multipoint
Call/Connection Control," ITU-T Recommendation Q.2971, October
1995.
[3] ITU-T, "Broadband Integrated Services Digital Network (B-ISDN)
Digital Subscriber Signaling System No. 2 (DSS 2): Generic
Identifier Transport," Draft ITU-T New Recommendation Q.2941.1,
September 1997.
[4] ITU-T, "Broadband Integrated Services Digital Network (B-ISDN)
Digital Subscriber Signaling System No. 2 (DSS 2): Generic
Identifier Transport Extensions," Draft ITU-T New Recommendation
Q.2941.2, July 1999.
[5] ITU-T, "Stage 3 Description for Additional Information
Transfer Supplementary Service Using B-ISDN Digital Subscriber
Signaling System No. 2 (DSS 2)-Basic Call Clause 1-User-to-User
Signalling (UUS)," ITU-T Recommendation Q.2957, February 1995.
[6] ITU-T, "Stage 3 Description for Additional Information
Transfer Supplementary Service Using B-ISDN Digital Subscriber
Signaling System No. 2 (DSS 2)-Basic Call Clause 1-User-to-User
Signalling (UUS)," Draft ITU-T Recommendation Q.2957 Amendment 1,
July 1999.
[7] J. Postel Ed., "Internet Protocol," RFC 791, September 1981.
[8] S. Deering and R. Hinden, "Internet Protocol, Version 6 (IPv6)
Specification," RFC 2460, December 1998.
[9] J. Postel, "User Datagram Protocol," RFC 768, August 1980.
[10] J. Postel Ed., "Transmission Control Protocol," RFC 793,
September 1981.
[11] L. Delgrossi and L. Berger, Ed., "Internet Stream Protocol
Version 2 (ST2) Protocol Specification - Version ST2+," RFC 1819,
August 1995.
[12] R. Braden Ed., "Resource ReSerVation Protocol (RSVP)-Version
1 Functional Specification," RFC 2205, September 1997.
[13] K. Nagami, N. Demizu, H. Esaki, Y. Katsube, and P. Doolan,
"VCID Notification over ATM link for LDP," Work in Progress.
[14] T. Narten and H. Alvestrand, "Guidelines for Writing an IANA
Considerations Section in RFCs," RFC 2434, October 1998.
[15] P. Newman, T. Lyon, and G. Minshall, "Flow Labelled IP: A
Connectionless Approach to ATM," Proc. IEEE Infocom, March 1996.
[16] S. Damaskos and A. Gavras, "Connection Oriented Protocols
over ATM: A case study," Proc. SPIE, Vol. 2188, pp.226-278,
February 1994.
[17] ITU-T, "Integrated Services Digital Network (ISDN) Overall
Network Aspects and Functions ISDN Protocol Reference Model,"
ITU-T Recommendation I.320, November 1993.
[18] ITU-T, "Digital Subscriber Signaling System No. 1 (DSS 1) This document is a product of the Multiprotocol Label Switching
Specification of a Synchronization and Coordination Function for Working Group of the IETF.
the Provision of the OSI Connection-mode Network Service in an
ISDN Environment," ITU-T Recommendation Q.923, February 1995.
Acknowledgments This is now a Proposed Standard Protocol.
I would like to thank Kenichi Kitami of the NTT Information This document specifies an Internet standards track protocol for
Sharing Lab. Group, who is also the chair of ITU-T SG11 WP1, the Internet community, and requests discussion and suggestions
Shinichi Kuribayashi of the NTT Information Sharing Platform for improvements. Please refer to the current edition of the
Labs., Hiroshi Yao and Takumi Ohba of the NTT Network Service "Internet Official Protocol Standards" (STD 1) for the
Systems Labs., and Noriyuki Takahashi of the NTT Information standardization state and status of this protocol. Distribution
Sharing Platform Labs., for their valuable comments and of this memo is unlimited.
discussions.
And I would also like to thank the active members of IETF, ITU-T, This announcement is sent to the IETF list and the RFC-DIST list.
and ATM Forum, especially Joel Halpern of Newbridge Networks, Requests to be added to or deleted from the IETF distribution list
Andrew Malis of Ascend Communications, George Swallow and Bruce should be sent to IETF-REQUEST@IETF.ORG. Requests to be
Davie of Cisco Systems, Rao Cherukuri of IBM, Rajiv Kapoor of added to or deleted from the RFC-DIST distribution list should
AT&T, Greg Ratta of Lucent, Kaoru Kenyoshi of NEC, Hiroto Uno of be sent to RFC-DIST-REQUEST@RFC-EDITOR.ORG.
Hitachi, Hiroshi Esaki and Kenichi Nagami of Toshiba, and
Noritoshi Demizu of NAIST for their valuable comments and
suggestions.
Also this specification is based on various discussions during the Details on obtaining RFCs via FTP or EMAIL may be obtained by sending
ST2+ over ATM project at the NTT Multimedia Joint Project with an EMAIL message to rfc-info@RFC-EDITOR.ORG with the message body
NACSIS. I would like to thank Professor Shoichiro Asano of the help: ways_to_get_rfcs. For example:
National Center for Science Information Systems for his invaluable
advice in this area.
Author's Address To: rfc-info@RFC-EDITOR.ORG
Subject: getting rfcs
Muneyoshi Suzuki help: ways_to_get_rfcs
NTT Information Sharing Platform Laboratories
3-9-11, Midori-cho
Musashino-shi, Tokyo 180-8585, Japan
Phone: +81-422-59-2119 Requests for special distribution should be addressed to either the
Fax: +81-422-59-3203 author of the RFC in question, or to RFC-Manager@RFC-EDITOR.ORG. Unless
EMail: suzuki@nal.ecl.net specifically noted otherwise on the RFC itself, all RFCs are for
unlimited distribution.echo
Submissions for Requests for Comments should be sent to
RFC-EDITOR@RFC-EDITOR.ORG. Please consult RFC 2223, Instructions to RFC
Authors, for further information.
 End of changes. 

This html diff was produced by rfcdiff 1.23, available from http://www.levkowetz.com/ietf/tools/rfcdiff/