Network Working Group L. Jin Internet-Draft R. Chen Intended status: Standards Track ZTE Expires: September 5, 2012 March 4, 2012 Static pseudowire configuration checking using Generic Associated Channel (G-ACh) Advertisement Protocol draft-jc-pwe3-mpls-tp-static-checking-00.txt Abstract This draft introduces a way to do static pseudowire configuration checking, so as to easy the trouble shooting of static PW in MPLS-TP. The idea is to use Generic Associated Channel (G-ACh) Advertisement Protocol (GAP) [I-D.ietf-mpls-gach-adv] in underlying PSN Tunnel to transfer PW configuration parameters, to achieve static PW configuration checking. Status of this Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. 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." This Internet-Draft will expire on September 5, 2012. Copyright Notice Copyright (c) 2012 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of Jin & Chen Expires September 5, 2012 [Page 1] Internet-Draft draft-jc-pwe3-mpls-tp-static-checking-00 March 2012 the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Motivation . . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. GAP Extensions . . . . . . . . . . . . . . . . . . . . . . . . 3 3.1. Message Encoding . . . . . . . . . . . . . . . . . . . . . 3 3.2. PE Procedure . . . . . . . . . . . . . . . . . . . . . . . 5 3.2.1. PE message processing . . . . . . . . . . . . . . . . . 5 3.2.2. PW Configuration Check Process . . . . . . . . . . . . 6 4. Security Considerations . . . . . . . . . . . . . . . . . . . . 7 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 7 6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 7 7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 7 7.1. Normative references . . . . . . . . . . . . . . . . . . . 7 7.2. Informative References . . . . . . . . . . . . . . . . . . 7 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 8 Jin & Chen Expires September 5, 2012 [Page 2] Internet-Draft draft-jc-pwe3-mpls-tp-static-checking-00 March 2012 1. Introduction This draft introduces a way to do static pseudowire configuration checking, so as to easy the trouble shooting of static PW in MPLS-TP. The idea is to use Generic Associated Channel (G-ACh) Advertisement Protocol (GAP) [I-D.ietf-mpls-gach-adv] in underlying PSN Tunnel to transfer PW configuration parameters, to achieve static PW configuration checking. A precondition of this functionality is that the underlying PSN Tunnel is already operational, and with GAP enabled. 2. Motivation The manual configuration of static PW in MPLS-TP requires configuring many parameters at two PE sides, and these parameters should be aligned, so as to make PW be operational. If one of the parameters on the two PE mis-matching, the PW would not operate correctly. For the dynamic PW, the parameters would be negotiated by signaling session, and easy to find out the configuration error if PW is not operational UP. But for static PW, there is no such kind of signaling session, it is difficult for operators to do trouble shooting, to figure out which parameters mis-match at two PE sides. In order to ease the trouble shooting of static PW, this draft relies on GAP running on underlying PSN Tunnel to transfer PW configuration parameters, so as to check PW configuration parameters automatically on each PE to figure out parameter mis-matching. 3. GAP Extensions 3.1. Message Encoding A new GAP application "static PW checking" is defined in this draft. The default lifetime would be 120 seconds. Two new TLV objects "local static PW element" and "remote static PW element" are defined for this application, see the format below. Jin & Chen Expires September 5, 2012 [Page 3] Internet-Draft draft-jc-pwe3-mpls-tp-static-checking-00 March 2012 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | PW Element | Reserved | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | + Generalized ID FEC + | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Interface Parameters | | " | | " | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0|0| Incoming Label (0x0200) | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Label | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0|0| Outgoing Label (0x0200) | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Label | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 1 Local static PW element type: to be assigned by IANA. Remote static PW element type: to be assigned by IANA. The value of "local&remote static PW element" TLV should carry local static PW configuration and remote static PW configuration separately. Multiple "local&remote static PW element" TLVs could be included in "static PW configuration" application data block. The value of "local&remote static PW element" TLV object would include: 1. Generalized PWid FEC (type 129) [RFC4447] along with AII Type 2 [RFC5003]; 2. Interface parameters TLV for Generalized PWid FEC defined in [RFC4447]; 3. Incoming and outgoing generic label as defined in [RFC5036]; The Generalized PWid FEC and incoming generic label MUST be included in static PW element. The Incoming and outgoing will use same generic label type, and the first label should be the incoming label, and second label should be outgoing label. The remote static PW element SHOULD be sent only along with local static PW element, where the two PW elements belong to the same PW Path. That means remote static PW element should not be sent Jin & Chen Expires September 5, 2012 [Page 4] Internet-Draft draft-jc-pwe3-mpls-tp-static-checking-00 March 2012 independently. The GAP Suppress message defined in [I-D.ietf-mpls-gach-adv] is only applied for one application. We implement one particular static PW element suppressing by defining a new TLV, called PW Suppress TLV, to indicate suppressing special PW information transmission. Multiple Generalized ID FEC elements could be included in this TLV. The format would be 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |PW Suppress TLV| Reserved | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | + Generalized ID FEC + | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Multiple Generalized ID FEC! | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 2 The type of PW suppress TLV is to be assigned by IANA. The format of Generalized ID FEC is defined in [RFC4447]. The C-bit, PW type in Generalized ID FEC should be zero. A GAP message could contain both local&remote static PW element TLV and PW Suppress TLV. 3.2. PE Procedure 3.2.1. PE message processing The GAP message of static PW checking application should be sent at least three times within lifetime. For the static PW, the parameters of one pseudowire needed would include: PW Path Identifier [RFC6370], PW type, Control Work, In&Out PW Label, interface parameters and etc. When constructing "static PW element" TLV, all the PW parameters should be carried. When a PW is configured on the PE, and corresponding PSN Tunnel is operational UP, PE SHOULD send its local PW configuration information through GAP with local static PW element TLV. If PE has already received remote PW configuration information belong to the same PW Path through "local static PW element" TLV from remote PE, the GAP Jin & Chen Expires September 5, 2012 [Page 5] Internet-Draft draft-jc-pwe3-mpls-tp-static-checking-00 March 2012 message SHOULD additionally include exactly the same received TLV in "remote static PW element" TLV. When the remote PE receives GAP message with static PW element TLV, it SHOULD save the PW parameters in "local static PW element" TLV as remote PW information for a period of "lifetime" which is specified in the GAP message. If the receiving GAP message also has "remote static PW element" TLV, PE should check local PW parameters with that in "remote static PW element" TLV. If the same, PE should send GAP message with PW suppress TLV contained the specified PW information to peer PE. If not, PE send GAP message with local PW configuration information carried in "local static PW element" TLV, and the received remote PW configuration information carried in "remote static PW element" TLV. Whenever PE receives the GAP message with PW suppress TLV, it SHOULD stop sending GAP message with specified PW information. Whenever the PE updates locally PW configuration information, PE could send GAP message with static PW element to update information in remote PE. 3.2.2. PW Configuration Check Process The PE would associate a PW with Generalized PWid FEC of: AGI = AGI SAII = A1-{Global_ID::Node_ID::AC_ID} TAII = Z9-{Global_ID::Node_ID::AC_ID} and a PW with Generalized PWid FEC of: AGI = AGI SAII = Z9-{Global_ID::Node_ID::AC_ID} TAII = A1-{Global_ID::Node_ID::AC_ID} as one PW Path. When the PE has both local and remote PW parameters for one PW, it should do parameter checking as follows: 1. Check control word, if both sides have same capability. If not, an error would report. 2. Check PW type, if both sides have the same. If not, an error would report. 3. Check and negotiate interface parameters as defined in [RFC4447]. 4. Check In&Out PW label, if local in_label equals remote out_label, and local out_label equals remote in_label. If not, an error would report. The mechanism described in this draft could also be used as label advertisement, so as to avoid out_label negotiation manually between two PE, and to avoid mis-configuration. Then the static PW is allowed to configure only in_label instead of both in&out label. Then if the remote PE does not send the out_label, PE will not check local in_label and remote out_label. If PE does not have local Jin & Chen Expires September 5, 2012 [Page 6] Internet-Draft draft-jc-pwe3-mpls-tp-static-checking-00 March 2012 out_label, it should use remote in_label as local out_label. 4. Security Considerations No new security threat is introduced by the mechanism in this draft. 5. IANA Considerations IANA is requested to allocate a new Application ID in the "G-Ach Advertisement Protocol Applications and Data Types" registry. A new TLV Object "Local Static PW Element" type is requested to be allocated, suggested value would be 1. A new TLV Object "Remote Static PW Element" type is requested to be allocated, suggested value would be 2. A new TLV Object "PW Suppress TLV" type is requested to be allocated, suggested value would be 3. 6. Acknowledgements The authors would like to thank Stewart Bryant for the his review and contributions. 7. References 7.1. Normative references [I-D.ietf-mpls-gach-adv] Frost, D., Bocci, M., and S. Bryant, "MPLS Generic Associated Channel (G-ACh) Advertisement Protocol", draft-ietf-mpls-gach-adv-00 (work in progress), January 2012. 7.2. Informative References [RFC4447] Martini, L., Rosen, E., El-Aawar, N., Smith, T., and G. Heron, "Pseudowire Setup and Maintenance Using the Label Distribution Protocol (LDP)", RFC 4447, April 2006. [RFC5003] Metz, C., Martini, L., Balus, F., and J. Sugimoto, "Attachment Individual Identifier (AII) Types for Aggregation", RFC 5003, September 2007. Jin & Chen Expires September 5, 2012 [Page 7] Internet-Draft draft-jc-pwe3-mpls-tp-static-checking-00 March 2012 [RFC5036] Andersson, L., Minei, I., and B. Thomas, "LDP Specification", RFC 5036, October 2007. [RFC6370] Bocci, M., Swallow, G., and E. Gray, "MPLS Transport Profile (MPLS-TP) Identifiers", RFC 6370, September 2011. Authors' Addresses Lizhong Jin ZTE Corporation 889, Bibo Road Shanghai, 201203, China Email: lizhong.jin@zte.com.cn Ran Chen ZTE Corporation No.19 East Huayuan Road Beijing, 100191, China Email: chen.ran@zte.com.cn Jin & Chen Expires September 5, 2012 [Page 8]