CCAMP WG O. Aboul-Magd Document: draft-aboulmagd-ccamp-crldp-00.txt Nortel Networks Feb. 2002 Supporting Call and Connection Control Separation using CR-LDP Status of this Memo This document is an Internet-Draft and is in full conformance wit all provisions of Section 10 of RFC2026 [1]. 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." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. 1. Abstract There has been a recent activity towards the use of GMPLS-based protocols (CR-LDP and RSVP-TE) for automatic switched optical networks (ASON) at the ITU-T. ASON control plane requirements mandates the separate treatment of call and connection control. This draft proposes additional CR-LDP messages necessary for satisfying this goal. 2. Conventions used in this document The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC-2119 [2]. 3. Introduction Automatic Switched optical networks (ASON) architecture [3] and GMPLS are progressing in parallel at the ITU-T and IETF respectively. As it has been pointed out in [4], the two efforts are complementary in the sense that GMPLS-based protocol could be used for the realization of ASON control plane. Recently GMPLS-based Aboul-Magd Expires August 2002 1 Draft-aboulmagd-ccamp-call-connection-separation-00.txt Feb. 2002 protocols have been submitted to ITU-T [5,6] as possible candidates for ASON signaling implementation as defined in G.7713 [7]. One important architecture principle of ASON is that call and connection control are treated separately. With this separation there could be the case where a single call has one or more connections associated to it. It is also quite possible to have a call with no connections associated to it, for example during recovery times. The current set of GMPLS signaling protocols, i.e. CR-LDP and RSVP- TE do not support this requirement. In reality the notion of a call is absent in both protocols. A label switched path (LSP), or a connection, is set end-to-end by assigning a set of labels on the different nodes along the path. Once an LSP is deleted, all the information regarding its end points is lost. This draft describes messages necessary to introduce call and connection control separation to CR-LDP. 4. CR-LDP Call Control As it has been stated in [8], (CR-)LDP employs four categories of messages. Those categories are: 1. Discovery messages, use to announce and maintain the presence of a network element in the network 2. Session messages, used to establish, maintain, and terminate LDP sessions between LDP pairs 3. Advertisement messages, used to create, change, and delete label mappings 4. Notification messages, used to provide advisory information to signal error information. A new category related to query messages was introduced in [9] and is used to query different information related to an operational LSP (connection). The third category of the above list is the one that is supposed to be used for connection creation, deletion, and modification in an optical network. New connection is created by assigning a generalized ingress and egress labels at every node along the path of the connection. This process is achieved using Label Request and Label Mapping messages, which carry in their TLVs the necessary characteristics of the required connection. Label Request and Label Mapping requests and confirm the assignment of a generalized label to a connection. In a similar way Label Withdraw and Label Release Messages are used to delete a connection by releasing the label assigned to it. Aboul-Magd Expires August 2002 2 Draft-aboulmagd-ccamp-call-connection-separation-00.txt Feb. 2002 The processes described here are all at the connection level since they all involve request, assignment, or release of a label. In contrast to that, with the separation of call and connection in mind, the setup of a call MUST not involve any of those processes. A call setup is mainly for the exchange of call control information between the two end points of a call. Thus there is the need for the introduction of a new category specifically for call control. The new category is called here "call control messages". 4.1 CR-LDP Call Control Messages This section describes those additional messages that are needed to support the separation of call and connection control requirements in ASON. A mechanism for call setup and deletion is needed for CR-LDP to support call control that is separate from that of the connection control part described previously. This mechanism necessitates the introduction of two CR-LDP messages, Call Setup and Call Delete messages. The calling party sends the Call Setup message and it carries information related to the calling and called parties, e.g. their addresses, etc. It may also carry information related to the service level agreement (SLA) associated to a particular call. The Call Delete message could be initiated by any network entity (network or client) to terminate a call. All connections associated with this call have to be cleared before clearing the call. The formats and procedures for Call Setup and Call Delete are given in section 5. 4.2 Impact on Other (CR-)LDP Messages The introduction of call control messages is expected to have some impact on other (CR-)LDP messages in two ways. The first impact is related to new TLV added to some of the messages. For instance, with the call and connection control separation, it is necessary to introduce a call association indication to the Label Request message to indicate the call for which the requested connection is associated. The impact on LDP messages are described in section 6. 5. Call Setup and Call Delete Messages This section describes the encoding of the two messages related to CR-LDP call control. 5.1 Call Setup Message Aboul-Magd Expires August 2002 3 Draft-aboulmagd-ccamp-call-connection-separation-00.txt Feb. 2002 The format of the Call Setup message is: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |U|F| Call Setup (TBD) | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Message ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Calling Party Number TLV | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Called Party Number TLV | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Call ID TLV | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Message ID: 32-bit value used to identify this message Calling Party Number TLV: The address of the party that is initiating the call request. It has the same format as the Transport Network Assigned (TNA) address in [10] Called Party Number TLV: The address of the called party. It has the same format as the TNA in [10] Call ID TLV: The purpose of the call identifier (Call ID) TLV is to locally identify a call in the context of separated call and connection control environment. The format of the Call Identifier TLV is: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |U|F| Call ID (TBD) | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Call ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Procedure: The Calling party initiates a call setup by sending the Call Setup message. The Call Setup message SHALL contain all the information required by the network to process the call. In Particular the calling and called party addresses. The Call Setup message MUST include call identifier TLV. The call control entity shall identify the call using the selected identifier for the lifetime of the call. Aboul-Magd Expires August 2002 4 Draft-aboulmagd-ccamp-call-connection-separation-00.txt Feb. 2002 The Call Setup message shall progress through the network to the called party. The called party may accept or reject the incoming call. An LDP Notification message with the appropriate status code (to be defined) shall be used to inform the calling party whether the setup is successful. The call can be rejected by either the network, e.g. for policy reasons, or by the called party. 5.2 Call Delete Message The format of the Call Setup message is: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |U|F| Call Delete (TBD) | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Message ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Calling Party Number TLV | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Called Party Number TLV | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Call ID TLV | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Message ID: 32-bit value used to identify this message Calling Party Number TLV: Same as for Call Setup Message Called Party Number TLV: Same as for Call Setup message Call ID TLV: Same as for Call Setup message Procedure: The Call Delete message is sent by any entity of the network to indicate the desire to terminate an already established call. The Call Setup message SHALL contain all the information required by the network to process the call. In Particular the calling and called party addresses. Confirmation of call deletion is indicated to the request initiator using a Notification message with the appropriate status code. 6. Impact on Other LDP Messages The separation of call and connection control allows one or more connection to be associated to the same call. This will have an impact on existing LDP messages relevant to the establishment and deletion of a connection (LSP). The full impact on LDP messages in Aboul-Magd Expires August 2002 5 Draft-aboulmagd-ccamp-call-connection-separation-00.txt Feb. 2002 terms of additional TLVs and procedures will be addressed in future revisions pf the draft. 7. Security Considerations This draft doesn't introduce any new security issues other than those defined in RFC 3036 and RFC 3212 8. References 1 Bradner, S., "The Internet Standards Process -- Revision 3", BCP 9, RFC 2026, October 1996. 2 Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997 3 M. Mayer, Ed., "Architecture for Automatic Switched Optical Networks (ASON)", ITU G.8080/Y1304, V1.0, October 2001 4 O. Aboul-Magd, et. al., "Automatic Switched Optical Networks (ASON) Architecture and its Related Protocols", draft-ietf-ipo- ason-02.txt, work in progress, Feb. 2002. 5 S. Shew, "A Proposal for DCM Signaling Using GMPLS CR-LDP", ITU Contribution, WD25, Feb. 2002. 6 D. Pendarakis, "Proposal for G.7713.2 Based on GMPLS", ITU Contribution, WD06, Feb. 2002 7 Z. Lin, Ed., "Distributed Call and Connection Management", ITU G.7713/Y.1704, October 2001 8 Anderson, L., et. al., "LDP Specification", RFC 3036, January 2001 9 P. Ashwood-Smith, et. al., "MPLS LDP Query Message Description", draft-ietf-mpls-lsp-query-txt.03, work in progress, August 2001. 10 Rajagopalan, B. Editor, "User Network Interface (UNI) 1.0 Signaling Specifications", OIF Contribution, OIF2000.125.7, October 2001 9. Author's Addresses Osama Aboul-Magd Aboul-Magd Expires August 2002 6 Draft-aboulmagd-ccamp-call-connection-separation-00.txt Feb. 2002 Nortel Networks P.O. Box 3511, Station "C" Ottawa, Ontario, Canada K1Y - 4H7 Phone: 613-763-5827 Email: osama@nortelnetworks.com Aboul-Magd Expires August 2002 7 Draft-aboulmagd-ccamp-call-connection-separation-00.txt Feb. 2002 Full Copyright Statement "Copyright (C) The Internet Society (date). All Rights Reserved. This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implmentation may be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works. However, this document itself may not be modified in any way, such as by removing the copyright notice or references to the Internet Society or other Internet organizations, except as needed for the purpose of developing Internet standards in which case the procedures for copyrights defined in the Internet Standards process must be followed, or as required to translate it into. Aboul-Magd Expires August 2002 8