MPLS Working Group A. Fulignoli
Internet Draft Ericsson
Intended status: Standard Track Y.Weingarten
N.Sprecher
Nokia Siemens Networks
Expires: September 2009 March 3, 2009
MPLS-TP OAM Alarm Suppression Tools
draft-fulignoli-mpls-tp-ais-lock-tool-00.txt
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Abstract
The aim of this draft is to define an MPLS-TP OAM mechanism to meet
the requirements for Alarm Suppression functionality as required in
[3].
One packet format with two different function codes is here defined
in order to distinguish among packets with Alarm Indication
information and packets with Lock Indication Information.
Table of Contents
1. Introduction................................................2
1.1. Terminology............................................3
2. Fault Location TLV..........................................4
3. AIS and LOCK Packet.........................................5
4. Security Considerations.....................................7
5. IANA Considerations.........................................7
6. Acknowledgments.............................................7
7. References..................................................7
7.1. Normative References...................................7
7.2. Informative References.................................8
1. Introduction
The aim of this draft is to define an MPLS-TP OAM mechanism to meet
the requirements for Alarm Suppression functionality as required in
[3].
One packet format, with two different function codes, is here defined
in order to distinguish among packets with Alarm Indication
information and packets with Lock Indication Information.
Packets with Alarm Indication (AIS) information enable a server
(sub-)layer MEP to notify a failure condition to its client
(sub-)layer MEPs, while packets with Lock Indication (LOCK)
Information notify an administrative traffic locking condition.
Upon receiving a packet with AIS or LOCK information, a MEP detects
an AIS/LOCK defect condition and suppresses loss of continuity alarms
associated with all its peer MEPs. Both AIS and LOCK defect
contribute to the signal fail condition of the receiving MEPs that
may result, in turn, in the transmission of AIS packets to its own
client MEPs.
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For the detailed behavior description of the Alarm Indication Signal
function and Lock Indication function please refer to [5].
The periodicity of AIS and LOCK packet is fixed to one second.
The first packet is sent as soon as the associated event (defect
condition or administrative traffic locking) occurs.
1.1. Terminology
AIS Alarm Indication Signal
LME LSP Maintenance Entity
ME Maintenance Entity
MEP Maintenance End Point
MIP Maintenance Intermediate Point
PME PW Maintenance Entity
SME Section Maintenance Entity
TCME Tandem Connection Maintenance Entity
TPME Tandem PW Maintenance Entity
TLV Type Length Value
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 RFC-2119 [1].
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2. Fault Location TLV
One or more Fault Location TLV MAY be included, under operator
configuration, in the AIS or LOCK packet; the DEFAULT mode is not to
include it.
When a MEP receives an AIS/LOCK with the Fault Location TLV and it is
configured to (re)generate the AIS packet to its client MEP (in the
forward direction) the following cases can occur:
1. The MEP is configured to(re)generate AIS messages with no Fault
Location TLV
2. The MEP is configured to(re)generate AIS messages with the Fault
TLV carrying its own identifier; this can occur when the server
and client MEs are under different administrative domains such
that the client ME needs to know that the failure is located
within that specific server ME (i.e. it is not under its
responsibility to recover the failure) but not exactly where,
within the server ME, the failure is located
3. The MEP is configured to(re)generates AIS messages with the Fault
Location TLV copied from the received AIS/LOCK message; this is
useful when both the server and client MEs are under the same
administrative domain so the administrator can quickly identify
where is the failure to fix
The mechanism is applicable to TCM as well as to different
hierarchical (sub-)layer.
This section will be completed in the next version of the draft.
The Fault Location TLV has the following format:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = TBD | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Fault Location ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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Type
2 octet field; it identifies the specific format of the Fault
Location TLV, value = TBD;
Length
2 octets field; it identifies the length in octets of the TLV Section
that follows the length field. Set to 4 (octets) in case of IPv4
Address; set to 16 (octets) in case of IPv6 Address; set to 6
(octets) in case of MAC Address
Fault Location
Set to the IPv4/IPv6/MAC port/node address of the (Server)MEP
generating the AIS/LOCK packet.
3. AIS and LOCK Packet
The AIS and LOCK packet have both the following format:
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 0 0 1|0 0 0 0|0 0 0 0 0 0 0 0| MPLS-TP AIS(0xHH)or LOCK(0xYY)|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Vers | Res1 | Flags |S| Res2 | Per | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ Fault Location TLV(s) +
: ... :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The first four bytes represent the G-ACH ([2]):
- first nibble: set to 0001b to indicate a channel associated with a
PW, a LSP or a Section;
- G-ACH Version and Reserved fields are set to 0, as specified in
[2];
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- G-ACH Channel Type field with two different code point meaning,
respectively, "MPLS-TP AIS packet" and "MPLS-TP LOCK packet". Both
value MUST be assigned.
Version (Vers)
4 bit field, version number of the protocol; this document defines
protocol version 0;
Reserved (Res1)
4 bit field, reserved for future use; they MUST be set to all ZEROes
in transmission and ignored in reception;
Flags
7 bit field; reserved for future use; they MUST be set to all ZEROes
in transmission and ignored in reception;
Fault Location TLV present (S)
1 bit field; if set, the Fault Location TLV, as detailed in section
2. , is present.
Reserved (Res2)
5 bit field reserved for future use; they MUST be set to all ZEROes
in transmission and ignored in reception;
Period (Per)
3 bit field MUST be fixed to the ''100'' value indicating the
transmission period of 1 second.
Length
1 octet field; it is the total packet length in octet, excluded the
G-ACH header;
Fault Location TLV
Optional and variable length field containing one ore more Fault
Location TLV as detailed in section 2.
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4. Security Considerations
Security considerations for the authentication TLV need further
study.
5. IANA Considerations
<Add any IANA considerations>
6. Acknowledgments
<Add any acknowledgements>
This document was prepared using 2-Word-v2.0.template.dot.
7. References
7.1. Normative References
[1] Bradner, S., "Key words for use in RFCs to Indicate Requirement
Levels", BCP 14, RFC 2119, March 1997.
[2] Vigoureux, M., Bocci, M., Swallow, G., Ward, D., Aggarwal, R.,
"MPLS Generic Associated Channel ", draft-ietf-mpls-tp-gach-
gal-01 (work in progress), January 2009
[3] Vigoureux, M., Betts, M., Ward, D., "Requirements for OAM in
MPLS Transport Networks", draft-ietf-mpls-tp-oam-requirements-
00 (work in progress), November 2008
[4] Sprecher, N., Nadeau, T., van Helvoort, H., Weingarten, Y., "
MPLS-TP OAM Analysis", draft-sprecher-mpls-tp-oam-analysis-02
(work in progress), September 2008
[5] Busi,I., Niven-Jenkins, B. "MPLS-TP OAM Framework and
Overview", draft-busi-mpls-tp-oam-framework-00(work in
progress), October 2008
[6] S. Boutros, et. al., "Definition of ACH TLV Structure", draft-
bryant-mpls-tp-ach-tlv-00.txt, Work in Progress, January 2009.
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7.2. Informative References
Authors' Addresses
Annamaria Fulignoli
Ericsson
Email: annamaria.fulignoli@ericsson.com
Nurit Sprecher
Nokia Siemens Networks
Email: nurit.sprecher@nsn.com
Yaacov Weingarten
Nokia Siemens Networks
Email: yaacov.weingarten@nsn.com
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