Himanshu Shah Tenor Networks PWE3 Working Group Internet Draft draft-shah-pwe3-control-protocol-extension-00.txt February 2003 Expires: August 2003 Extensions to Transport of Layer 2 frames over MPLS 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 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. Abstract This document describes extensions to [PWE3-CONTROL] draft to enable exchange of additional information about the Pseudowire without having to withdraw the VC-FEC first. 1.0 Specification of Requirements 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. 2.0 Introduction The [PWE3-CONTROL] draft describes how two PEs signal Pseudowire related information to each other in order to establish a Pseudowire. This information, called VC-FEC, is exchanged over the Shah, et al. Expires August 2003 1 Internet Draft draft-shah-pwe3-control-protocol-extension-00.txt targeted LDP session and contains Pseudowire specific information that is static. If any of this information is to change, label mapping for the VC-FEC must be withdrawn and re-advertised with the changed VC-FEC. This draft describes a mechanism whereby additional information about the Pseudowire that can be dispatched with the VC-FEC without having to first withdraw the PW-Label for the advertised VC-FEC. This additional information may either be related to the operations of the Pseudowire such as state of the Attachment circuit, IP address and/or MAC address of the attached CE, etc, or may affect setup of the Pseudowire, such as traffic engineering parameters, security related information, type of tunnel signaling used, VPN related information, etc. This document does not define all the information elements that can be passed optionally with the VC-FEC but rather a mechanism whereby such information can be passed either during the setup or as an update without having to first tearing down the existing Pseudowire. This document recommends that such information be passed as LDP TLVs in the optional parameter field of the Label Mapping message for the VC-FEC. 3.0 LDP The [PWE3-Control] uses downstream unsolicited Label Mapping message to advertise the VC-FEC for a given Pseudowire. The [LDP] document section 3.5.7 defines the encoding of Label Mapping message as follows. 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| Label Mapping (0x0400) | Message Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Message ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | FEC TLV | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Label TLV | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Optional Parameters | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Message ID 32-bit value used to identify this message. FEC TLV Specifies the FEC component of the FEC-Label mapping being advertised. The [PWE3-Control] document specifies the FEC Element for the Pseudowire for the FEC TLV. This is commonly referred to as VC-FEC. Shah, et al. Expires August 2003 2 Internet Draft draft-shah-pwe3-control-protocol-extension-00.txt Label TLV Specifies the Label component of the FEC-Label mapping. Optional Parameters This variable length field contains 0 or more parameters, each encoded as a TLV. This document specifies various TLVs that can be included in Optional Parameter field of Label Mapping Message as a mean to provide additional attributes for the Pseudowire. When these TLVs are passed as an update to an existing VC-FEC, the Label Mapping message is sent with the same VC-FEC and the label that was advertised earlier. 4.0 TLVs 4.1 Operational Status TLV The Operational Status TLV is used to notify the remote PE peer about the change in operational status of the attached circuit or the tunnel carrying the PW. The exchange of this information is an alternative to the current practice of withdrawing the PW label for such circumstances. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |1|0| Status TLV (TBD) | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | type | status | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ type 16-bit value is used to identify the interface type. A value of 1 means operational status is for the attachment circuit. A value of 2 means that operational status is for the unidirectional portion of the PW that spans from advertising PE to the receiving PE. Status 16-bit value specifies the operational status. A value of 0 means that AC or PW is down or inactive while a value of 1 means that AC or PW is up or active. The absence of status TLV in optional parameter of Label Mapping message for the VC-FEC must not be interpreted as status down. In fact, PEs should assume operational status of the remote attachment circuit and incoming PW as operational unless notified otherwise. The operational status down must then be followed by operational status up in order for remote PE to resume traffic. Shah, et al. Expires August 2003 3 Internet Draft draft-shah-pwe3-control-protocol-extension-00.txt The sender has the responsibility to coordinate the status notifications. The receiver may or may not react to these notifications. 4.2 IP Address TLV The IP Address TLV is used to notify the remote PE about the IP address of the locally attached CE. This information is useful for point-to-point Layer 2 interworking circuit [shah-arp]. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |1|0| IP Address TLV (TBD) | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IP Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ IP Address 32-bit field contains IP address of the attached CE. When value is zero, the IP address of the attached CE is not known or has become unknown. The [shah-arp] draft describes the need to exchange and how to process such information. 4.3 IP+MAC Address TLV The IP+MAC Address TLV is used to notify the remote PE about the IP and MAC address of the locally attached CE. This information is useful for multipoint-to-multipoint Pseudowire for IP as described in [shah-ipls] document. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |1|0| IP Address TLV (TBD) | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IP Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MAC Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MAC Address | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ IP Address 32-bit field contains IP address of the attached CE. When value is zero, the IP address of the attached CE is not known or has become unknown. MAC Address Shah, et al. Expires August 2003 4 Internet Draft draft-shah-pwe3-control-protocol-extension-00.txt 48-bit field contains MAC address of the attached CE. When the value is zero, the MAC address of the attached CE is not known or has become unknown. The [shah-ipls] draft describes the need to exchange and how to process such information. 4.4 Pseudowire QOS TLV The Pseudowire QOS TLV is used to notify the remote PE about tunnel signaling mechanisms and traffic engineering parameters to be used to setup the ingress Pseudowire from the remote to the advertising PE. As stated earlier, this information can also be passed as an update. It is possible that receiver may then respond to the update by first withdrawing the advertised PW label and re-advertise new PW label with same VC-FEC. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |1|0| PW QOS TLV (TBD) | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tunnel Type | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Committed Inforation Rate (CIR) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Peak Information Rate (PIR) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Committed Burst Size (CBS) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Peak Burst Size (PBS) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Tunnel Type 16-bit value identifies the signaling mechanisms to be used to setup the tunnel over which the PW is mapped. A value of 0 indicates that tunnel type is not specified. A value of 1 indicates use of LDP and a value of 2 indicate use of RSVP-TE. Traffic Engineering Parameters Each TE parameter is encoded as a 32-bit IEEE single precision floating-point number. The CIR and PIR are in units of bytes per second while CBS and PBS are in units of bytes. The PW QOS TLV conveys traffic engineering parameters that advertising PE would like remote PE to consider when establishing the Pseudowire from remote PE to the advertising PE. The traffic engineering parameters can also be used to select appropriate traffic shaper and policer for the attached circuit at the remote PE. Shah, et al. Expires August 2003 5 Internet Draft draft-shah-pwe3-control-protocol-extension-00.txt 5.0 General Procedures The TLVs described in this document are mandatory for some pseudowire types (e.g. ARP mediation, IPLS) while optional but useful for others. In general, where necessary, †withdrawË of optional parameters is realized by issuing the Label Mapping message with same TLVs as an update with value zero. This alleviates the need to cycle through Label Withdraw followed by Label Mapping message to convey new parameters. The receiving PE must always inspect Optional Parameter field of the Label Mapping message to detect the presence of these TLVs. When a Label Mapping message is received with the same PW label for the same VC-FEC from same remote Peer, TLVs must be examined to detect the change in attributes before discarding the message as a †duplicateË. The future revision of this document will contain more definitions of other TLVs that are useful as adjunct information for the VC-FEC. 6.0 Security Considerations The security aspects of this solution will be discussed at a later time. 7.0 References [PWE3-CONTROL] Martini et. Al., ŸTransport of Layer 2 Frames Over MPLS÷, draft-ietf-pwe3-control-protocol-01.txt, August 2002 (work in progress) [LDP] "LDP Specification." L. Andersson, P. Doolan, N. Feldman, A. Fredette, B. Thomas. January 2001. RFC3036 [shah-arp] Shah et. Al., ŸARP Mediation for IP interworking of Layer 2 VPN÷, Draft-shah-ppvpn-arp-mediation-01.txt, June 2002 (work in progress) [shah-ipls] Shah et. Al., ŸIP over LAN Service÷, Draft-shah-ppvpn- ipls-00.txt. October 2002. (work in progress). Author's Address Himanshu Shah Tenor Networks 100 Nagog Park Acton, MA 01720 Email: hshah@tenornetworks.com Full copyright statement Shah, et al. Expires August 2003 6 Internet Draft draft-shah-pwe3-control-protocol-extension-00.txt Copyright (C) The Internet Society (1999). All Rights Reserved. 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