One document matched: draft-nitinb-mpls-tp-lsp-ping-extensions-00.txt
Network Working Group N. Bahadur
Internet-Draft R. Aggarwal
Intended status: Standards Track Juniper Networks, Inc.
Expires: April 22, 2010 S. Boutros
Cisco Systems, Inc.
E. Gray
Ericsson
October 19, 2009
LSP-Ping extensions for MPLS-TP
draft-nitinb-mpls-tp-lsp-ping-extensions-00
Status of this Memo
This Internet-Draft is submitted to IETF in full conformance with the
provisions of BCP 78 and BCP 79.
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.
This Internet-Draft will expire on April 22, 2010.
Copyright Notice
Copyright (c) 2009 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 in effect on the date of
publication of this document (http://trustee.ietf.org/license-info).
Please review these documents carefully, as they describe your rights
and restrictions with respect to this document.
Bahadur, et al. Expires April 22, 2010 [Page 1]
Internet-Draft LSP-Ping extensions for MPLS-TP October 2009
Abstract
LSP-Ping is an existing and widely deployment OAM mechanism for MPLS
LSPs. This document describes extensions to LSP-Ping so that LSP-
Ping can be used to perform OAM on MPLS-TP LSPs. It also clarifies
the procedures to be used for processing the OAM packets. Further,
it describes how LSP-Ping can be used to perform Connectivity
Verification, Route Tracing and Adjacency functions in MPLS-TP
networks.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Conventions used in this document . . . . . . . . . . . . 3
1.2. LSP-Ping for MPLS-TP LSPs using IP encapsulation . . . . . 3
1.3. LSP-Ping for MPLS-TP LSPs using non-IP encapsulation . . . 3
2. LSP-Ping extensions . . . . . . . . . . . . . . . . . . . . . 4
2.1. New address type for Downstream Mapping TLV . . . . . . . 4
2.2. Source Address TLV . . . . . . . . . . . . . . . . . . . . 4
2.3. Destination Address TLV . . . . . . . . . . . . . . . . . 4
2.4. MEP and MIP Identifier . . . . . . . . . . . . . . . . . . 5
2.5. Specifications for statically provisioned LSPs . . . . . . 5
3. Performing LSP-Ping over MPLS-TP LSPs . . . . . . . . . . . . 5
3.1. LSP-Ping with IP encapsulation . . . . . . . . . . . . . . 5
3.2. Non-IP based LSP-Ping . . . . . . . . . . . . . . . . . . 6
3.3. P2MP Considerations . . . . . . . . . . . . . . . . . . . 6
4. Performing LSP Traceroute over MPLS-TP LSPs . . . . . . . . . 7
4.1. LSP Traceroute with IP encapsulation . . . . . . . . . . . 7
4.2. Non-IP based LSP Traceroute . . . . . . . . . . . . . . . 7
4.2.1. Ingress node procedure for sending echo request
packets . . . . . . . . . . . . . . . . . . . . . . . 7
4.2.2. Ingress node procedure for receiving echo response
packets . . . . . . . . . . . . . . . . . . . . . . . 7
4.2.3. Transit and egress node procedure . . . . . . . . . . 8
4.3. P2MP Considerations . . . . . . . . . . . . . . . . . . . 8
4.4. ECMP Considerations . . . . . . . . . . . . . . . . . . . 8
5. Applicability . . . . . . . . . . . . . . . . . . . . . . . . 8
6. Security Considerations . . . . . . . . . . . . . . . . . . . 8
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
8. Contributing Authors . . . . . . . . . . . . . . . . . . . . . 9
9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 9
9.1. Normative References . . . . . . . . . . . . . . . . . . . 9
9.2. Informative References . . . . . . . . . . . . . . . . . . 9
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 10
Bahadur, et al. Expires April 22, 2010 [Page 2]
Internet-Draft LSP-Ping extensions for MPLS-TP October 2009
1. Introduction
LSP-Ping [RFC4379]is an OAM mechanism for MPLS LSPs. This document
describes extensions to LSP-Ping so that LSP-Ping can be used to
perform OAM on MPLS-TP LSPs. It also clarifies the procedures to be
used for processing the OAM packets. Further, it describes how LSP-
Ping can be used to perform Connectivity Verification, Route Tracing
and Adjacency functions specified in
[I-D.ietf-mpls-tp-oam-requirements].
1.1. 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].
1.2. LSP-Ping for MPLS-TP LSPs using IP encapsulation
LSP-Ping requires IP addressing on the egress and transit LSRs for
performing OAM on MPLS signaled LSPs and pseudowires. In particular,
in these cases the LSP-Ping packets generated by an ingress LSR are
encapsulated in an IP/UDP header with the destination address from
the 127/8 range and then encapsulated in the MPLS label stack
([RFC4379] , [I-D.ietf-bfd-mpls]). Egress LSRs use the presence of
the 127/8 destination address to identify the OAM packets and rely
further on the UDP port number to determine whether the packet is a
LSP-Ping packet. It is to be noted that this determination does not
require IP forwarding capabilities. It requires the presence of an
IP host stack which enables egress LSRs to process packets with a
destination address from the 127/8 range. [RFC1122] allocates the
127/8 range as "Internal host loopback address" and [RFC1812] states
that "a router SHOULD NOT forward, except over a loopback interface,
any packet that has a destination address on network 127".
1.3. LSP-Ping for MPLS-TP LSPs using non-IP encapsulation
In certain MPLS-TP deployment scenarios IP addressing might not be
available or it may be preferred to use non-IP encapsulation for LSP-
Ping and BFD packets. In such scenarios, LSP-Ping must be run
without IP addressing, using the ACH channel type specified in
[I-D.nitinb-mpls-tp-lsp-ping-bfd-procedures].
Sections Section 3.2 and Section 4.2 describe the theory of operation
for performing LSP-Ping over MPLS-TP LSPs with a non-IP
encapsulation.
Bahadur, et al. Expires April 22, 2010 [Page 3]
Internet-Draft LSP-Ping extensions for MPLS-TP October 2009
2. LSP-Ping extensions
2.1. New address type for Downstream Mapping TLV
[RFC4379] defines the Downstream Mapping TLV. This document defines
the following new Address type which is added to the Downstream
Mapping TLV:
Type # Address Type K Octets
------ -------------- --------
0 Not Applicable 8
Figure 1: Downstream Mapping TLV new Address Type
The new address type indicates that no address is present in the
Downstream Mapping TLV. Multipath type MAY be set to 0 (no
multipath) when using this address type.
When this address type is used, on receipt of a LSP-Ping echo
request, interface verification MUST be bypassed. Thus the receiving
node SHOULD only perform mpls label control-plane/data-plane
consistency checks.
The new address type is also applicable to the Detailed Downstream
Mapping TLV defined in [I-D.ietf-mpls-lsp-ping-enhanced-dsmap].
2.2. Source Address TLV
When sending LSP-Ping packets using ACH, without IP encapsulation,
there MAY be a need to identify the source address of the packet.
This source address will be specified via the Source Address TLV,
being defined in [I-D.ietf-mpls-tp-ach-tlv]. Only 1 source address
TLV MUST be present in a LSP-Ping packet. The source address MUST
specify the address of the originator of the packet. If more than 1
such TLV is present in a LSP-Ping request packet, then an error of
"Malformed echo request received" SHOULD be returned. If more than 1
source address TLV is present, then the packet SHOULD be dropped
without further processing.
2.3. Destination Address TLV
When sending LSP-Ping packets using ACH, without IP encapsulation,
there MAY be a need to identify the destination address of the
packet. This destination address will be specified via the
Destination Address TLV, being defined in [I-D.ietf-mpls-tp-ach-tlv].
One or more of this TLVs MAY be included. The destination address
MUST specify the intended receipient(s) of the packet. If the
Bahadur, et al. Expires April 22, 2010 [Page 4]
Internet-Draft LSP-Ping extensions for MPLS-TP October 2009
destination address specified in any of the Destination Address TLVs
does not match any address associated with the node which receives
the LSP-Ping packet, then the LSP-Ping packet SHOULD be dropped
without further processing.
2.4. MEP and MIP Identifier
When sending LSP-Ping packets using ACH, there MAY be a need to
identify the maintenance end point (MEP) and/or the maintenance
intermediate point (MIP) being monitored. The MEP/MIP identifiers
defined in [I-D.swallow-mpls-tp-identifiers] MAY be carried in the
ACH TLVs [I-D.ietf-mpls-tp-ach-tlv] for identification. Only one
identifier (MEP or MIP) may be present in a packet. The MEP/MIP
identifiers associated with the packet MUST be checked for the
MPLS-TP LSP path/section that is being monitored. If the identifier
does not match the LSP path/section, then the packet MUST be dropped.
2.5. Specifications for statically provisioned LSPs
Details of LSP-Ping for statically provisioned LSPs will be specified
in a future revision of this document.
3. Performing LSP-Ping over MPLS-TP LSPs
This section specifies how LSP-Ping ping can be used in the context
of MPLS-TP LSPs. The LSP-Ping ping function meets the Connectivity
Verification requirement specified in
[I-D.ietf-mpls-tp-oam-requirements]. This function SHOULD be
performed on-demand. This function SHOULD be performed between End
Points (MEPs) and Intermediate Points (MIPs) of PWs and LSPs, and
between End Points of PWs, LSPs and Sections. In order for the LSP-
Ping packet to be processed at the desired MIP, the TTL of the MPLS
label should be set such that it expires at the MIP to be probed.
3.1. LSP-Ping with IP encapsulation
LSP-Ping packets as specified in [RFC4379] are sent over the MPLS LSP
for which OAM is being performed and contain an IP/UDP packet within
them. The IP header is not used for forwarding (since the LSP is
forward using MPLS label switching). The IP header is used mainly
for addressing and can be used in the context of MPLS-TP LSPs. This
form of LSP-Ping OAM MUST be supported for MPLS-TP LSPs when IP
addressing is in use. The LSP-Ping Reply mode [RFC4379] in the LSP-
Ping echo request MUST be set to 4 (Reply via application level
control channel).
The LSP-Ping echo response message MUST be sent on the reverse path
Bahadur, et al. Expires April 22, 2010 [Page 5]
Internet-Draft LSP-Ping extensions for MPLS-TP October 2009
of the LSP. The reply MUST contain IP/UDP headers followed by the
LSP-Ping payload. The destination address in the IP header MUST be
set to that of the sender of the echo request message. The source
address in the IP address MUST be set to a valid address of the
replying node.
3.2. Non-IP based LSP-Ping
The OAM procedures defined in [RFC4379] require the use of IP
addressing and in some cases IP routing to perform OAM functions.
When the ACH header is used, IP addressing and routing is not needed.
This section describes procedures for performing lsp-ping without a
dependency on IP addressing and routing.
When using LSP-Ping over the ACH header, the LSP-Ping Reply mode
[RFC4379] in the LSP-Ping echo request MUST be set to 4 (Reply via
application level control channel).
The ingress node MAY attach a Source Address TLV (Section 2.2) to
identify the node originating the request.
The LSP-Ping reply message MUST be sent on the reverse path of the
LSP using ACH. The LSP-Ping payload MUST directly follow the ACH
header (and any ACH TLVs) and no IP and/or UDP headers MUST be
attached. If the request message contained the Source Address TLV
and a response is being sent to the originator, then a Destination
Address TLV (Section 2.3) SHOULD be added to the reply message. The
contents of the LSP-Ping request Source Address TLV should be copied
into the LSP-Ping response Destination Address TLV. The responding
node MAY attach a Source Address TLV to identify the node sending the
response.
If a node receives an MPLS echo request packet over ACH, without IP/
UDP headers and if that node does not have a return MPLS LSP path to
the echo request source, then the node MUST drop the echo request
packet and not attempt to send a response.
3.3. P2MP Considerations
[I-D.ietf-mpls-p2mp-lsp-ping] describes how LSP-Ping can be used for
OAM on P2MP LSPs with IP encapsulation. This MUST be supported for
MPLS-TP P2MP LSPs when IP addressing is used. When IP addressing is
not used, then the procedures described in Section 3.2 can be applied
to P2MP MPLS-TP LSPs as well.
Bahadur, et al. Expires April 22, 2010 [Page 6]
Internet-Draft LSP-Ping extensions for MPLS-TP October 2009
4. Performing LSP Traceroute over MPLS-TP LSPs
This section specifies how LSP-Ping traceroute can be used in the
context of MPLS-TP LSPs. The LSP-Ping traceroute function meets the
Adjancency and Route Tracing requirement specified in
[I-D.ietf-mpls-tp-oam-requirements]. This function SHOULD be
performed on-demand. This function SHOULD be performed between End
Points and Intermediate Points of PWs and LSPs, and between End
Points of PWs, LSPs and Sections.
When performing lsp-ping traceroute, the ingress node inserts a
Downstream Mapping TLV to get the downstream node information and to
enable LSP verification along the transit nodes. The Downstream
Mapping TLV can be used as is for performing the traceroute. If IP
addressing is not in use, then the Address Type field in the
Downstream Mapping TLV can be set to "Not applicable" (Section 2.1).
The Downstream Mapping TLV address type field can be extended to
include other address types as need be.
4.1. LSP Traceroute with IP encapsulation
The mechanics of LSP-Ping traceroute are similar to that described
for ping in Section 3.1. Traceroute packets sent by the LSP ingress
MUST follow procedures described in [RFC4379]. This form of LSP-Ping
OAM MUST be supported for MPLS-TP LSPs, when IP addressing is used.
4.2. Non-IP based LSP Traceroute
This section describes the procedures for performing LSP traceroute
when using the ACH header and without any dependency on IP
addressing. The procedures specified in Section 3.2 with regards to
Source Address TLV, Destination Address TLV and MEP/MIP identifiers
apply to LSP traceroute as well.
4.2.1. Ingress node procedure for sending echo request packets
Traceroute packets sent by the LSP ingress MUST adhere to the format
described in Section 3.2. MPLS-TTL expiry (as described in
[RFC4379]) will be used to direct the packets to specific nodes along
the LSP path.
4.2.2. Ingress node procedure for receiving echo response packets
The LSP-Ping traceroute responses will be received on the LSP itself
and the presence of an ACH header with channel type of LSP-Ping is an
indicator that the packet contains LSP-ping payload.
Bahadur, et al. Expires April 22, 2010 [Page 7]
Internet-Draft LSP-Ping extensions for MPLS-TP October 2009
4.2.3. Transit and egress node procedure
When a echo request reaches the transit or egress, the presence of
the ACH channel type of LSP-Ping will indicate that the packet
contains LSP-Ping data. The LSP-Ping data, the label stack and the
MEP/MIP identifier should be able to identify the LSP associated with
the echo request packet. In case if there is an error and the node
is unable to idenfity the LSP on which the echo response should to be
sent, the node MUST drop the echo request packet and not send any
response back. All responses MUST always be sent on a LSP path using
the ACH header and ACH channel type of LSP-Ping.
4.3. P2MP Considerations
[I-D.ietf-mpls-p2mp-lsp-ping] describes how LSP-Ping can be used for
OAM on P2MP LSPs. This MUST be supported for MPLS-TP P2MP LSPs when
IP addressing is used. When IP addressing is not used, then the
procedures described in Section 4.2 can be applied to P2MP MPLS-TP
LSPs as well.
4.4. ECMP Considerations
LSP-Ping using ACH SHOULD NOT be used when there is ECMP (equal cost
multiple paths) for a given LSP. The addition of the additional ACH
header may modify the hashing behavior for OAM packets which may
result in incorrect monitoring of path taken by data traffic.
5. Applicability
The non-IP addressing based procedures specified in this document
apply only to MPLS-TP LSPs. They also apply to PWs when IP
encapsulation is not desired. However, when IP addressing is used,
as in non MPLS-TP LSPs, procedures specified in [RFC4379] MUST be
used.
6. Security Considerations
The draft does not introduce any new security considerations. Those
discussed in [RFC4379] are also applicable to this document.
7. IANA Considerations
This document has no actions for IANA.
Bahadur, et al. Expires April 22, 2010 [Page 8]
Internet-Draft LSP-Ping extensions for MPLS-TP October 2009
8. Contributing Authors
The following individuals also contributed to this document:
o Thomas D. Nadeau, BT
o Nurit Sprecher, Nokia Siemens Networks
o Yaacov Weingarten, Nokia Siemens Networks
9. References
9.1. Normative References
[I-D.nitinb-mpls-tp-lsp-ping-bfd-procedures]
Bahadur, N., Aggarwal, R., Nadeau, T., Sprecher, N., and
Y. Weingarten, "LSP-Ping and BFD for MPLS-TP",
draft-nitinb-mpls-tp-lsp-ping-bfd-procedures-00 (work in
progress), July 2009.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC4379] Kompella, K. and G. Swallow, "Detecting Multi-Protocol
Label Switched (MPLS) Data Plane Failures", RFC 4379,
February 2006.
9.2. Informative References
[I-D.ietf-bfd-mpls]
Aggarwal, R., Kompella, K., Nadeau, T., and G. Swallow,
"BFD For MPLS LSPs", draft-ietf-bfd-mpls-07 (work in
progress), June 2008.
[I-D.ietf-mpls-lsp-ping-enhanced-dsmap]
Bahadur, N., Kompella, K., and G. Swallow, "Mechanism for
performing LSP-Ping over MPLS tunnels",
draft-ietf-mpls-lsp-ping-enhanced-dsmap-03 (work in
progress), July 2009.
[I-D.ietf-mpls-p2mp-lsp-ping]
Yasukawa, S., Farrel, A., Ali, Z., Fenner, B., Swallow,
G., Nadeau, T., and S. Saxena, "Detecting Data Plane
Failures in Point-to-Multipoint Multiprotocol Label
Switching (MPLS) - Extensions to LSP Ping",
draft-ietf-mpls-p2mp-lsp-ping-08 (work in progress),
August 2009.
[I-D.ietf-mpls-tp-ach-tlv]
Boutros, S., Bryant, S., Sivabalan, S., Swallow, G., and
Bahadur, et al. Expires April 22, 2010 [Page 9]
Internet-Draft LSP-Ping extensions for MPLS-TP October 2009
D. Ward, "Definition of ACH TLV Structure",
draft-ietf-mpls-tp-ach-tlv-00 (work in progress),
June 2009.
[I-D.ietf-mpls-tp-oam-requirements]
Vigoureux, M., Ward, D., and M. Betts, "Requirements for
OAM in MPLS Transport Networks",
draft-ietf-mpls-tp-oam-requirements-03 (work in progress),
August 2009.
[I-D.swallow-mpls-tp-identifiers]
Bocci, M. and G. Swallow, "MPLS-TP Identifiers",
draft-swallow-mpls-tp-identifiers-01 (work in progress),
July 2009.
[RFC1122] Braden, R., "Requirements for Internet Hosts -
Communication Layers", STD 3, RFC 1122, October 1989.
[RFC1812] Baker, F., "Requirements for IP Version 4 Routers",
RFC 1812, June 1995.
Authors' Addresses
Nitin Bahadur
Juniper Networks, Inc.
1194 N. Mathilda Avenue
Sunnyvale, CA 94089
US
Phone: +1 408 745 2000
Email: nitinb@juniper.net
URI: www.juniper.net
Rahul Aggarwal
Juniper Networks, Inc.
1194 N. Mathilda Avenue
Sunnyvale, CA 94089
US
Phone: +1 408 745 2000
Email: rahul@juniper.net
URI: www.juniper.net
Bahadur, et al. Expires April 22, 2010 [Page 10]
Internet-Draft LSP-Ping extensions for MPLS-TP October 2009
Sami Boutros
Cisco Systems, Inc.
3750 Cisco Way
San Jose, CA 95134
US
Phone:
Fax:
Email: sboutros@cisco.com
URI:
Eric Gray
Ericsson
900 Chelmsford Street
Lowell, MA 01851
US
Phone: +1 978 275 7470
Fax:
Email: eric.gray@ericsson.com
URI:
Bahadur, et al. Expires April 22, 2010 [Page 11]
| PAFTECH AB 2003-2026 | 2026-04-23 23:29:28 |