--- 1/draft-ietf-mpls-icmp-07.txt 2007-02-01 22:12:36.000000000 +0100 +++ 2/draft-ietf-mpls-icmp-08.txt 2007-02-01 22:12:36.000000000 +0100 @@ -1,21 +1,21 @@ MPLS Working Group R. Bonica Internet-Draft D. Gan Intended status: Standards Track Juniper Networks -Expires: June 15, 2007 D. Tappan +Expires: August 4, 2007 D. Tappan C. Pignataro Cisco Systems, Inc. - December 12, 2006 + January 31, 2007 ICMP Extensions for MultiProtocol Label Switching - draft-ietf-mpls-icmp-07 + draft-ietf-mpls-icmp-08 Status of this Memo By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that @@ -26,43 +26,45 @@ 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. - This Internet-Draft will expire on June 15, 2007. + This Internet-Draft will expire on August 4, 2007. Copyright Notice - Copyright (C) The Internet Society (2006). + Copyright (C) The IETF Trust (2007). Abstract This memo defines an extension object that can be appended to selected multi-part ICMP messages. This extension permits Label Switching Routers to append MPLS information to ICMP messages, and has already been widely deployed. Table of Contents 1. Conventions Used In This Document . . . . . . . . . . . . . . . 3 2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Application to TRACEROUTE . . . . . . . . . . . . . . . . . . . 4 4. Disclaimer . . . . . . . . . . . . . . . . . . . . . . . . . . 4 5. MPLS Label Stack Object . . . . . . . . . . . . . . . . . . . . 5 6. Security Considerations . . . . . . . . . . . . . . . . . . . . 6 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6 - 8. Normative References . . . . . . . . . . . . . . . . . . . . . 7 + 8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 7 + 8.1. Normative References . . . . . . . . . . . . . . . . . . . 7 + 8.2. Informative References . . . . . . . . . . . . . . . . . . 7 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 7 Intellectual Property and Copyright Statements . . . . . . . . . . 9 1. 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 RFC2119 [RFC2119]. 2. Introduction @@ -72,22 +74,23 @@ source hosts. Network operators use this information to diagnose routing problems. When a router receives an undeliverable IP datagram, it can send an ICMP message to the host that originated the datagram. The ICMP message indicates why the datagram could not be delivered. It also contains the IP header and leading payload octets of the "original datagram" to which the ICMP message is a response. MPLS Label Switching Routers (LSR) also use ICMP to convey control - information to source hosts. Sections 2.3 and 2.4 of [RFC3032] - describe the interaction between MPLS and ICMP. + information to source hosts. Section 2.3 of [RFC3032] describes the + interaction between MPLS and ICMP, and Sections 2.4 and 3 of + [RFC3032] provide applications of that interaction. When an LSR receives an undeliverable MPLS encapsulated datagram, it removes the entire MPLS label stack, exposing the previously encapsulated IP datagram. The LSR then submits the IP datagram to an error processing module. Error processing can include ICMP message generation. The ICMP message indicates why the original datagram could not be delivered. It also contains the IP header and leading octets of the original datagram. @@ -108,21 +111,21 @@ ICMP Extension Structure Header and an ICMP Object Header. Both are defined in [I-D.bonica-internet-icmp]. The ICMP extension defined in this document is equally applicable to ICMPv4 [RFC0792] and ICMPv6 [RFC4443]. Throughout this document, unless otherwise specified, the acronym ICMP refers to multi-part ICMP messages, encompassing both ICMPv4 and ICMPv6. 3. Application to TRACEROUTE - The ICMP extensions defined in this memo support enhancements to + The ICMP extension defined in this memo supports enhancements to TRACEROUTE. Enhanced TRACEROUTE applications, like older implementations, indicate which nodes the original datagram visited en route to its destination. They differ from older implementations in that they also reflect the original datagram's MPLS encapsulation status as it arrived at each node. Figure 1 contains sample output from an enhanced TRACEROUTE implementation. > traceroute 192.0.2.1 @@ -165,28 +168,30 @@ message. Figure 2 depicts the MPLS Label Stack Object. It must be preceded by an ICMP Extension Structure Header and an ICMP Object Header. Both are defined in [I-D.bonica-internet-icmp]. In the object payload, octets 0-3 depict the first member of the MPLS label stack. Each remaining member of the MPLS label stack is represented by another 4 octets that share the same format. - MPLS Label Stack Class = 1, C-Type = 1. + Class-Num = 1, MPLS Label Stack Class + C-Type = 1, Incoming MPLS Label Stack + Length = 4 + 4 * (number of MPLS LSEs) 0 1 2 3 +-------------+-------------+-------------+-------------+ | Label |EXP |S| TTL | +-------------+-------------+-------------+-------------+ | | - | // Remaining MPLS Stack Entries // | + | // Remaining MPLS Label Stack Entries // | | | +-------------+-------------+-------------+-------------+ Figure 2: MPLS Label Stack Object Label: 20 bits Exp: Experimental Use, 3 bits S: Bottom of Stack, 1 bit @@ -201,21 +205,21 @@ extension that allows an MPLS router to append MPLS information to multi-part ICMP messages, and therefore can provide the user of the traceroute application with additional information. Consequently, a network operator may wish to provide this information selectively based on some policy; for example, only include the MPLS extensions in ICMP messages destined to addresses within the network management blocks with administrative control over the router. An implementation could determine whether to include the MPLS Label Stack extensions based upon the destination address of the ICMP message, or based on a global configuration option in the router. - Alternativelly, an implementation may determine whether to include + Alternatively, an implementation may determine whether to include these MPLS extensions when TTL expires based on the number of label stack entries (depth of the label stack) of the incoming packet. Finally, an operator can make use of the TTL treatment on MPLS Pipe Model LSPs defined in [RFC3443] for a TTL-transparent mode of operation, that would prevent ICMP Time Exceeded altogether when tunneled over the MPLS LSP. 7. IANA Considerations IANA is requested to assign the following object Class-num in the @@ -229,66 +233,71 @@ MPLS Label Stack Class Sub-types: C-Type Description 1 Incoming MPLS Label Stack 0xF7-0xFF Reserved for private use C-Type values are assignable on a first-come-first-serve (FCFS) basis [RFC2434]. -8. Normative References +8. References + +8.1. Normative References [I-D.bonica-internet-icmp] - Bonica, R., "Modifying ICMP to Support Multi-part - Messages", draft-bonica-internet-icmp-13 (work in - progress), December 2006. + Bonica, R., "Extended ICMP to Support Multi-part + Messages", draft-bonica-internet-icmp-16 (work in + progress), January 2007. [RFC0792] Postel, J., "Internet Control Message Protocol", STD 5, RFC 792, September 1981. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC2434] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA Considerations Section in RFCs", BCP 26, RFC 2434, October 1998. [RFC3032] Rosen, E., Tappan, D., Fedorkow, G., Rekhter, Y., Farinacci, D., Li, T., and A. Conta, "MPLS Label Stack Encoding", RFC 3032, January 2001. + [RFC4443] Conta, A., Deering, S., and M. Gupta, "Internet Control + Message Protocol (ICMPv6) for the Internet Protocol + Version 6 (IPv6) Specification", RFC 4443, March 2006. + +8.2. Informative References + [RFC3034] Conta, A., Doolan, P., and A. Malis, "Use of Label Switching on Frame Relay Networks Specification", RFC 3034, January 2001. [RFC3035] Davie, B., Lawrence, J., McCloghrie, K., Rosen, E., Swallow, G., Rekhter, Y., and P. Doolan, "MPLS using LDP and ATM VC Switching", RFC 3035, January 2001. [RFC3443] Agarwal, P. and B. Akyol, "Time To Live (TTL) Processing in Multi-Protocol Label Switching (MPLS) Networks", RFC 3443, January 2003. - [RFC4443] Conta, A., Deering, S., and M. Gupta, "Internet Control - Message Protocol (ICMPv6) for the Internet Protocol - Version 6 (IPv6) Specification", RFC 4443, March 2006. - Authors' Addresses Ronald P. Bonica Juniper Networks 2251 Corporate Park Drive Herndon, VA 20171 US Email: rbonica@juniper.net + Der-Hwa Gan Juniper Networks 1194 N. Mathilda Ave. Sunnyvale, CA 94089 US Email: dhg@juniper.net Daniel C. Tappan Cisco Systems, Inc. @@ -301,32 +310,32 @@ Carlos Pignataro Cisco Systems, Inc. 7025 Kit Creek Road Research Triangle Park, N.C. 27709 US Email: cpignata@cisco.com Full Copyright Statement - Copyright (C) The Internet Society (2006). + Copyright (C) The IETF Trust (2007). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS - OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET - ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, - INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE - INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED + OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND + THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS + OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF + THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. 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