Internet Draft Network Working Group Muneyoshi Suzuki INTERNET DRAFT NTT Expires June 15, 1999 December 15, 1998 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-01.txt> Status of this Memo This document is an Internet-Draft. 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 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". To view the entire list of current Internet-Drafts, please check the "1id-abstracts.txt" listing contained in the Internet-Drafts Shadow Directories on ftp.is.co.za (Africa), ftp.nordu.net (Northern Europe), ftp.nis.garr.it (Southern Europe), munnari.oz.au (Pacific Rim), ftp.ietf.org (US East Coast), or ftp.isi.edu (US West Coast). Abstract 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. This specification provides an indispensable framework for the implementation of long-lived session and QoS- sensitive session transfers over ATM. Suzuki Expires June, 1999 [Page 1] INTERNET DRAFT draft-ietf-mpls-git-uus-01.txt December, 1998 0. Background In the ITU-T SG11 Geneva meeting held in May 1998, SG11 WP1, which has responsibility for the B-ISDN signaling protocol recommendation, decided to enhance the Q.2941 Generic Identifier Transport based on this document and developed the Awaiting-review text. WP1 also decided to continue discussion on the User-to-user Signaling support for the Internet protocol. In the ITU-T SG11 WP1 Oostend meeting held in November 1998, WP1 developed the Cooling text (Draft Recommendations to be frozen in the next meeting, if no significant technical changes are proposed in that meeting) of Q.2941.2 GIT [4]. WP1 also decided to enhance the Q.2957 User-to-user Signaling based on this document and developed the Awaiting-review text [5]. Expected standard development process (fastest case) for the enhancement of the Generic Identifier and User-to-user Signaling is: March 1999: Freeze the Draft Recommendations and letter ballot is requested. February 2000: The Draft Recommendations are decided (final approval). 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. Note that the assignment rule for Generic Identifier and User-to-user Signaling described in this document may be subject to change. 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. Suzuki Expires June, 1999 [Page 2] INTERNET DRAFT draft-ietf-mpls-git-uus-01.txt December, 1998 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. Suzuki Expires June, 1999 [Page 3] INTERNET DRAFT draft-ietf-mpls-git-uus-01.txt December, 1998 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. Suzuki Expires June, 1999 [Page 4] INTERNET DRAFT draft-ietf-mpls-git-uus-01.txt December, 1998 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. Suzuki Expires June, 1999 [Page 5] INTERNET DRAFT draft-ietf-mpls-git-uus-01.txt December, 1998 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. Suzuki Expires June, 1999 [Page 6] INTERNET DRAFT draft-ietf-mpls-git-uus-01.txt December, 1998 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) and Part 2 (Q.2941.2) as an optional information element for the Q.2931 and Q.2971 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. Suzuki Expires June, 1999 [Page 7] INTERNET DRAFT draft-ietf-mpls-git-uus-01.txt December, 1998 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. Suzuki Expires June, 1999 [Page 8] INTERNET DRAFT draft-ietf-mpls-git-uus-01.txt December, 1998 Note: DSM-CC, H.310/H.321, Trunking, and MPOA 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. 0x03-0xFD: 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 and in Q.2971 annex D as an optional information element for the Q.2931 and Q.2971 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- Suzuki Expires June, 1999 [Page 9] INTERNET DRAFT draft-ietf-mpls-git-uus-01.txt December, 1998 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 Draft Q.2957 and Q.2971 annex D for detailed protocol specifications of the User-to-user Signaling. Suzuki Expires June, 1999 [Page 10] INTERNET DRAFT draft-ietf-mpls-git-uus-01.txt December, 1998 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. Suzuki Expires June, 1999 [Page 11] INTERNET DRAFT draft-ietf-mpls-git-uus-01.txt December, 1998 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. Suzuki Expires June, 1999 [Page 12] INTERNET DRAFT draft-ietf-mpls-git-uus-01.txt December, 1998 The calling party should confirm that the response message contains at least one Generic Identifier information element. 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 [6, 8, 9] 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. Suzuki Expires June, 1999 [Page 13] INTERNET DRAFT draft-ietf-mpls-git-uus-01.txt December, 1998 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) [10] is assigned to the Identifier value field. Suzuki Expires June, 1999 [Page 14] INTERNET DRAFT draft-ietf-mpls-git-uus-01.txt December, 1998 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 [7, 8, 9] 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. Suzuki Expires June, 1999 [Page 15] INTERNET DRAFT draft-ietf-mpls-git-uus-01.txt December, 1998 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 [12] is assigned to the Identifier value field. Suzuki Expires June, 1999 [Page 16] INTERNET DRAFT draft-ietf-mpls-git-uus-01.txt December, 1998 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). Suzuki Expires June, 1999 [Page 17] INTERNET DRAFT draft-ietf-mpls-git-uus-01.txt December, 1998 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. Suzuki Expires June, 1999 [Page 18] INTERNET DRAFT draft-ietf-mpls-git-uus-01.txt December, 1998 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. Suzuki Expires June, 1999 [Page 19] INTERNET DRAFT draft-ietf-mpls-git-uus-01.txt December, 1998 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 [10] 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. Suzuki Expires June, 1999 [Page 20] INTERNET DRAFT draft-ietf-mpls-git-uus-01.txt December, 1998 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 [11] 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. Suzuki Expires June, 1999 [Page 21] INTERNET DRAFT draft-ietf-mpls-git-uus-01.txt December, 1998 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). Suzuki Expires June, 1999 [Page 22] INTERNET DRAFT draft-ietf-mpls-git-uus-01.txt December, 1998 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. 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 Suzuki Expires June, 1999 [Page 23] INTERNET DRAFT draft-ietf-mpls-git-uus-01.txt December, 1998 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," Draft ITU-T New Recommendation Q.2941.2, November 1998. (http://www.nal.ecl.net/SG11WP1/itu-t-sg11-tmp- doc-td87r2.ps) [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)," Draft ITU-T New Recommendation Q.2957, November 1998. (http://www.nal.ecl.net/SG11WP1/itu-t-sg11-tmp-doc- td103.ps) [6] J. Postel Ed., "Internet Protocol," RFC 791, September 1981. [7] S. Deering and R. Hinden, "Internet Protocol, Version 6 (IPv6) Specification," RFC 2460, December 1998. [8] J. Postel, "User Datagram Protocol," RFC 768, August 1980. [9] J. Postel Ed., "Transmission Control Protocol," RFC 793, September 1981. [10] L. Delgrossi and L. Berger, Ed., "Internet Stream Protocol Version 2 (ST2) Protocol Specification - Version ST2+," RFC 1819, August 1995. [11] R. Braden Ed., "Resource ReSerVation Protocol (RSVP)-Version 1 Functional Specification," RFC 2205, September 1997. [12] K. Nagami, N. Demizu, H. Esaki, Y. Katsube, and P. Doolan, "VCID Notification over ATM link," Internet Draft, November 1998, <draft-ietf-mpls-vcid-atm-02.txt>. [13] P. Newman, T. Lyon, and G. Minshall, "Flow Labelled IP: A Connectionless Approach to ATM," Proc. IEEE Infocom, March 1996. [14] S. Damaskos and A. Gavras, "Connection Oriented Protocols over ATM: A case study," Proc. SPIE, Vol. 2188, pp.226-278, February 1994. [15] ITU-T, "Integrated Services Digital Network (ISDN) Overall Network Aspects and Functions ISDN Protocol Reference Model," ITU-T Recommendation I.320, November 1993. Suzuki Expires June, 1999 [Page 24] INTERNET DRAFT draft-ietf-mpls-git-uus-01.txt December, 1998 [16] ITU-T, "Digital Subscriber Signaling System No. 1 (DSS 1) Specification of a Synchronization and Coordination Function for the Provision of the OSI Connection-mode Network Service in an ISDN Environment," ITU-T Recommendation Q.923, February 1995. [17] K. Kitami, "Proposed Direction for B-ISDN & Multimedia Signaling," ITU-T SG11 Delayed Contribution D.647, January 1998, (http://www.nal.ecl.net/SG11WP1/itu-t-sg11-del-contrib-d647.ps). Acknowledgments I would like to thank Kenichi Kitami of the NTT Network Innovation Planning and Promotion Dept., who is also the chair of ITU-T SG11 WP1, Shinichi Kuribayashi, Hiroshi Yao, and Takumi Ohba of the NTT Network Service Systems Labs., and Noriyuki Takahashi of the NTT Multimedia Networks Labs. for their valuable comments and discussions. And I would also like to thank the active members of IETF, ITU-T, and ATM Forum, especially Joel Halpern of Newbridge Networks, Andrew Malis of Ascend Communications, George Swallow and Bruce Davie of Cisco Systems, Rao Cherukuri of IBM, Rajiv Kapoor of AT&T, Greg Ratta of Lucent, Kaoru Kenyoshi of NEC, 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 ST2+ over ATM project at the NTT Multimedia Joint Project with NACSIS. I would like to thank Professor Shoichiro Asano of the National Center for Science Information Systems for his invaluable advice in this area. Author's Address Muneyoshi Suzuki NTT Multimedia Networks Laboratories 3-9-11, Midori-cho Musashino-shi, Tokyo 180-8585, Japan Phone: +81-422-59-2119 Fax: +81-422-59-2829 EMail: suzuki@nal.ecl.net Suzuki Expires June, 1999 [Page 25]