CCAMP O. Aboul-Magd Internet Draft Nortel Networks Document: draft-aboulmagd-ccamp-crldp-ason-ext-01.txt October 2002 Category: Informational CR-LDP Extensions for ASON Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026 except that the right to produce derivative works is not granted. 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 Automatic Switched Optical Network (ASON) is an network architecture for the introduction of control plane for optical networks. The development and the standardization of ASON have been going on at the ITU-T and its recommendation G.8080 [1]. The control plane architecture introduces a set of reference points between the different architectural components. ASON signaling that runs across those interfaces are described in G.7713 [2]. CR-LDP is one of the protocols under consideration at the ITU for the realization of G.7713 and its dynamic connection management. The work specific to CR-LDP extensions for ASON is documented in G.7713.3 (scheduled for consent in January 2003). This draft introduces those CR-LDP extensions that are specific to ASON. This draft should be considered in junction with RFC 3036 [3], RFC 3212 [4], and RFC (CR-LDP extensions for GMPLS) [5]. 2. Overview of CR-LDP Extensions for ASON O. Aboul-Magd Informational- Expires: March 2003 1 Draft-aboulmagd-crldp-ason-ext-01.txt October 2002 In addition to the CR-LDP GMPLS extensions [5], this draft describes ASON specific CR-LDP extensions covering the following ASON signaling requirements: - Call and connection control separation - Support of soft permanent connections (SPC) - Crankback - Additional error codes An important ASON architectural principle is the separation between the call and the connection controller as described in G.8080. Call and connection control separation allows for a call with multiple connections associated to it. It also allows for a call with no connections (a temporary situation that might be useful during recovery). There are two models to achieve this separation. The first model is a one where the call set up request is always accompanied by a connection request. The second model is the one in which call set up is done independent from connection set up. The first model is usually referred to as logical separation, while the second model is usually referred to as complete separation. CR-LDP extensions for ASON support the two separation models. Two new messages are introduced for call operations (set up and release). The Call Setup message is used for those cases where complete separation is required. Otherwise the LDP Label Request message is used for logical separation. Connection set up request must indicate the call to which the connection needs to be associated to. A Call ID TLV is introduced to achieve this goal. The structure of the Call ID allows it to have a global or an operator scope. Call release is always achieved using Call Release message. The reception of the call Release messages signifies the intention to remove all connections that are associated to the call. Connection release is achieved using the same CR-LDP label release procedure (using LDP Label Release and Label Withdraw messages). A Call Capability TLV is also introduced to explicitly indicate the capability of the requested call. An SPC service assumes that both source and destination user-to- network connection segments are provisioned while the network connection segment is set up via control plane. For example when the initial request is received from an external source, e.g. from a management system, there is an implicit assumption that the control plane has adequate information to determine the specific destination (network-to-user) link connection to use. Support for CR-LDP is provided by the use of the Egress Label TLV as defined in OIF UNI 1.0 [6] and [7]. O. Aboul-Magd Informational- Expires: March 2003 2 Draft-aboulmagd-crldp-ason-ext-01.txt October 2002 3. CR-LDP Messages for ASON This section describes the formats and the procedures of the two messages that are required for ASON call and connection control separation. Those messages are the Call Setup messages and the Call Release message. 3.1 Call Setup 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| Call Setup (TBD) | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Message ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Source ID TLV | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Dest ID TLV | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Call ID TLV | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Call Capability TLV | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Optional Parameters | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Message ID: Is as defined in RFC3036 [3]. Source ID TLV: Is as defined in UNI 1.0 [6] and in [7] Dest ID TLV: Is as defined in UNI 1.0 [6] and in [7] Call ID TLV: Is as defined in section 4.1 of this draft Call Capability TLV: Is as defined in section 4.2 of this draft 3.1.2 Call Setup Procedure The Calling party sends the Call Setup message whenever a new call needs to be set up with no connection associated to it. The Call Setup message SHALL contain all the information required by the O. Aboul-Magd Informational- Expires: March 2003 3 Draft-aboulmagd-crldp-ason-ext-01.txt October 2002 network to process the call. In Particular the Call Setup message shall include the calling and called party addresses as specified by the Source ID and Dest ID TLV. The setup message MUST include Call ID TLV. The call control entity shall identify the call using the selected identifier for the lifetime of the call. 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 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. 3.2 The Call Release Message This format of the Call Release 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| Call Release (TBD) | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Message ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Source ID TLV | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Dest ID TLV | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Call ID TLV | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Optional Parameters | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 3.2.1 Call Release Procedure: The Call Release message is sent by any entity of the network to indicate the desire to terminate an already established call. The Call Release message MUST include the Call ID TLV of the call to be terminated. Confirmation of call release is indicated to the request initiator using a Notification message with the appropriate status code. Reception and processing of the Call Release message MUST trigger the release of all connections that are associated to that call. Connection release follows the normal CR-LDP procedure using Label Release and Label Withdraw messages. 4. CR-LDP TLV for ASON This section describes the Call ID TLV and the Call Capability TLV introduced for ASON. 4.1 Call ID TLV O. Aboul-Magd Informational- Expires: March 2003 4 Draft-aboulmagd-crldp-ason-ext-01.txt October 2002 An established call may be identified by a Call ID. The Call ID is a globally unique identifier that is set by the source network. The structure for the Call ID (to guarantee global uniqueness) is to concatenate a globally unique fixed identifier (composed of country code, carrier code, unique access point code) with an operator specific identifier (where the operator specific identifier is composed of a source transport network element address and a local Identifier). Therefore, a generic CALL_ID with global uniqueness includes (composed of plus plus ) and (composed of plus ). For a CALL_ID that only requires operator specific uniqueness only the is needed, while for a CALL_ID that requires to be globally unique both and are needed. The shall consist of a three-character International Segment (the ) and a twelve-character National Segment (the plus ). These characters shall be coded according to ITU-T Recommendation T.50. The International Segment (IS) field provides a 3 character ISO 3166 Geographic/Political Country Code. The country code shall be based on the three-character uppercase alphabetic ISO 3166 Country Code (e.g., USA, FRA). The National Segment (NS) field consists of two sub-fields: the ITU Carrier Code followed by a Unique Access Point Code. The ITU Carrier Code is a code assigned to a network operator/service provider, maintained by the ITU-T Telecommunication Service Bureau in association with Recommendation M.1400. This code shall consist of 1-6 left-justified characters, alphabetic, or leading alphabetic with trailing numeric. The unique access point code shall be a matter for the organization to which the country code and ITU carrier code have been assigned, provided that uniqueness is guaranteed. This code shall consist of 6-11 characters, with trailing NULL, completing the 12-character National Segment. The format of the operator specific (Op-Sp) CALL_ID TLV: 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|Op-Sp Call ID (TBD) | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Source Transport Element Address (STEA Sub TLV) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Local Identifier | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ O. Aboul-Magd Informational- Expires: March 2003 5 Draft-aboulmagd-crldp-ason-ext-01.txt October 2002 STEA Sub TLV: The Source Transport Element Address is an address of the transport network element (SSN) controlled by the source network. Its length can be 4, 6, 16, or 20 byte long. The STEA Sub TLV is TLV Type 1. Local Identifier: A 64-bit identifier that remains constant over the life of the call. The format of the globally unique (GU) Call ID TLV: 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|GU Call ID (TBD) | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Reserved | IS | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | NS | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Source Transport Element Address (STEA sub TLV) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Local Identifier | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ International Segment (IS): To be coded according to ITU-T recommendation T.50. It provides a 3 character uppercase country code, e.g. USA, FRA, etc. National Segment (NS): NS consists of two fields, the ITU carrier Code followed by a Unique Access Point Code. 4.1.1 Call ID Procedure The following processing rules are applicable to the CALL ID TLV: - For initial calls, the calling/originating party call controller must set the CALL ID values to all-zeros - For a new call request, the source networks call controller (SNCC) sets the appropriate type and value for the CALL ID. - For an existing call (in case Call ID is non zero) the SNCC verifies existence of the call - The Call ID TLV on all messages MUST be sent from ingress call controller to egress call controller by all other intermediate controlling without altering. - The destination user/client receiving the request uses the CALL ID values as reference to the requested call between the source user and itself. Subsequent actions related to the call uses the CALL ID as the reference identifier. O. Aboul-Magd Informational- Expires: March 2003 6 Draft-aboulmagd-crldp-ason-ext-01.txt October 2002 4.2 Call Capability TLV The format of the Call Capability 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 Capabaility(TBD) | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Call Capability | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The Call Capability TLV is used to explicitly indicate the configuration potentiality of the call. 4.3 Crankback TLV Crankback requires that when the Label Request message is blocked at a particular node due to unavailable resources, the node will inform the initiator of the Label Request message of the location of the blockage. The initiator can then re-compute new explicit routes that avoid the area where resource shortage is detected. A new Label Request message is sent that includes the new route. The support of crankback in CR-LDP is facilitated by the introduction of a Crankback TLV. An LDP Notification message is used to inform the Label Request message initiator of the blocking condition. The Notification message includes the Crankback TLV that indicates the location of resource shortage. The location of the resource shortage is identified using the ER-HOP TLV. The encoding of the Crankbck 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| Crankback(TBD) | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ER-HOP TLV | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 5. Additional Error Codes G.7713 includes a number of error conditions that are currently missing from CR-LDP related RFCs. The list of those error conditions is given below. There is the need to assign status codes to them. Invalid SNP ID Calling Party busy Unavailable SNP ID Invalid SNPP ID O. Aboul-Magd Informational- Expires: March 2003 7 Draft-aboulmagd-crldp-ason-ext-01.txt October 2002 Unavailable SNPP ID Failed to create SNC Failed to establish LC Invalid A End-User Name Invalid Z End-User Name Invalid CoS Unavailable CoS Invalid GoS Unavailable GoS Failed Security Check TimeOut Invalid Call Name Failed to Release SNC Failed to Free LC 6. IANA Consideration This draft uses the LDP RFC 3036 [3] name spaces; see http://www.iana.org/assignments/ldp-namespaces, which require assignment for the following messages: Call Setup Call Release The assignment for the following TLVs Op-Sp Call ID TLV GU Call ID TLV Call Capability TLV Crankback TLV In addition to those TLVs described here, G.7713.3 requires a code point for the Link Feedback TLV as described in "draft-ietf-mpls-te- feed-05.txt" The assignment for the new error codes as listed in section 5 of this draft. 9. References 1 M. Mayer, "Architecture for Automatic Switched Optical Networks (ASON)", ITU G.8080/Y1304, V1.0, October 2001. 2 Z. Li, "Distributed Call and Connection Management", ITU G.7713/Y1704, October 2001. 3 L. Andersson,et. al., "LDP Specifications", RFC 3036, January 2001. O. Aboul-Magd Informational- Expires: March 2003 8 Draft-aboulmagd-crldp-ason-ext-01.txt October 2002 4 B. Jamoussi, Ed., "Constraint-Based LSP Setup Using LDP", RFC 3212, January 2002. 5 P. Ashwood-Smith, et. al., "Generalized MPLS Signaling-CR-LDP Extensions", draft-ietf-mpls-generalized-cr-ldp-07.txt, August 2002 6 B. Rajagopalan, "User Network Interface (UNI) 1.0 Signaling Specification", OIF-UNI-01.1, October 2001. 7 B. Rajagopalan, "LDP and RSVP Extensions for Optical UNI Signaling" draft-bala-uni-ldp-rsvp-extensions-02.txt, work in progress, 2002. 11. Author's Addresses Osama Aboul-Magd Nortel Networks P.O. Box 3511, Station "C" Ottawa, Ontario, Canada K1Y-4H7 Phone: 613-599-9104 Email: osama@nortelnetworks.com O. Aboul-Magd Informational- Expires: March 2003 9 Draft-aboulmagd-crldp-ason-ext-01.txt October 2002 Full Copyright Statement "Copyright (C) The Internet Society (date). All Rights Reserved. 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