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Versions: (draft-weingarten-mpls-tp-linear-protection)
00 01 02 03 04 05 06 07 08 09 RFC 6378
Network Working Group S. Bryant, Ed.
Internet-Draft E. Osborne
Intended status: Standards Track Cisco
Expires: April 27, 2011 N. Sprecher, Ed.
Nokia Siemens Networks
A. Fulignoli, Ed.
Ericsson
Y. Weingarten
Nokia Siemens Networks
October 24, 2010
MPLS-TP Linear Protection
draft-ietf-mpls-tp-linear-protection-03.txt
Abstract
The Transport Profile for Multiprotocol Label Switching (MPLS-TP) is
being specified jointly by IETF and ITU-T. This document addresses
the functionality described in the MPLS-TP Survivability Framework
document [SurvivFwk] and defines a protocol that may be used to
fulfill the function of the Protection State Coordination for linear
protection, as described in that document.
This document is a product of a joint Internet Engineering Task Force
(IETF) / International Telecommunications Union Telecommunications
Standardization Sector (ITU-T) effort to include an MPLS Transport
Profile within the IETF MPLS and PWE3 architectures to support the
capabilities and functionalities of a packet transport network as
defined by the ITU-T.
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 April 27, 2011.
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Copyright Notice
Copyright (c) 2010 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
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This document may contain material from IETF Documents or IETF
Contributions published or made publicly available before November
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material may not have granted the IETF Trust the right to allow
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Without obtaining an adequate license from the person(s) controlling
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not be created outside the IETF Standards Process, except to format
it for publication as an RFC or to translate it into languages other
than English.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1. Protection architectures . . . . . . . . . . . . . . . . . 4
1.2. Scope of the document . . . . . . . . . . . . . . . . . . 5
1.3. Contributing authors . . . . . . . . . . . . . . . . . . . 6
2. Conventions used in this document . . . . . . . . . . . . . . 6
2.1. Acronyms . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.2. Definitions and Terminology . . . . . . . . . . . . . . . 7
3. Protection switching control logic . . . . . . . . . . . . . . 7
3.1. Protection switching control logical architecture . . . . 7
3.1.1. Local Request Logic . . . . . . . . . . . . . . . . . 8
3.1.2. Remote Requests . . . . . . . . . . . . . . . . . . . 10
3.1.3. PSC Process Logic . . . . . . . . . . . . . . . . . . 11
3.1.4. PSC Message Generator . . . . . . . . . . . . . . . . 11
3.1.5. Wait-to-Restore (WTR) timer . . . . . . . . . . . . . 12
3.1.6. PSC Control States . . . . . . . . . . . . . . . . . . 12
4. Protection state coordination (PSC) protocol . . . . . . . . . 13
4.1. Transmission and acceptance of PSC control packets . . . . 14
4.2. Protocol format . . . . . . . . . . . . . . . . . . . . . 14
4.2.1. PSC Ver field . . . . . . . . . . . . . . . . . . . . 15
4.2.2. PSC Request field . . . . . . . . . . . . . . . . . . 15
4.2.3. Protection Type (PT) . . . . . . . . . . . . . . . . . 16
4.2.4. Revertive (R) field . . . . . . . . . . . . . . . . . 17
4.2.5. Fault path (FPath) field . . . . . . . . . . . . . . . 17
4.2.6. Data path (Path) field . . . . . . . . . . . . . . . . 17
4.3. Principles of Operation . . . . . . . . . . . . . . . . . 18
4.3.1. Basic operation . . . . . . . . . . . . . . . . . . . 18
4.3.2. Priority of inputs . . . . . . . . . . . . . . . . . . 19
4.3.3. Operation of PSC States . . . . . . . . . . . . . . . 20
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 29
6. Security Considerations . . . . . . . . . . . . . . . . . . . 29
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 29
8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 29
8.1. Normative References . . . . . . . . . . . . . . . . . . . 29
8.2. Informative References . . . . . . . . . . . . . . . . . . 29
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 30
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1. Introduction
The MPLS Transport Profile (MPLS-TP) [TPFwk] is a framework for the
construction and operation of packet-switched transport networks
based on the architectures for MPLS ([RFC3031] and [RFC3032]) and for
Pseudowires (PWs) ([RFC3985] and [RFC5659]) and the requirements of
[RFC5654].
Network survivability is the ability of a network to recover traffic
delivery following failure, or degradation of network resources. The
MPLS-TP Survivability Framework [SurvivFwk] is a framework for
survivability in MPLS-TP networks, and describes recovery elements,
types, methods, and topological considerations, focusing on
mechanisms for recovering MPLS-TP Label Switched Paths (LSPs).
Linear protection in mesh networks - networks with arbitrary
interconnectivity between nodes - is described in Section 4.7 of
[SurvivFwk]. Linear protection provides rapid and simple protection
switching. In a mesh network, linear protection provides a very
suitable protection mechanism because it can operate between any pair
of points within the network. It can protect against a defect in an
intermediate node, a span, a transport path segment, or an end-to-end
transport path.
1.1. Protection architectures
Protection switching is a fully allocated survivability mechanism.
It is fully allocated in the sense that the route and bandwidth of
the recovery path is reserved for a selected working path or set of
working paths. It provides a fast and simple survivability
mechanism, that allows the network operator to easily grasp the
active state of the network, compared to other survivability
mechanisms.
As specified in the Survivability Framework document [SurvivFwk],
protection switching is applied to a protection domain. For the
purposes of this document, we define the protection domain of a P2P
LSP as consisting of two Label Edge Routers (LER) and the transport
paths that connect them. For a P2MP LSP the protection domain
includes the root (or source) LER, the destination (or sink) LERs,
and the transport paths that connect them.
In 1+1 unidirectional architecture as presented in [SurvivFwk], a
recovery transport path is dedicated to the working transport path.
Normal traffic is bridged (as defined in [RFC4427])and fed to both
the working and the recovery transport entities by a permanent bridge
at the source of the protection domain. The sink of the protection
domain selects which of the working or recovery entities to receive
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the traffic from, based on a predetermined criteria, e.g. server
defect indication. When used for bidirectional switching the 1+1
protection architecture must also support a Protection State
Coordination (PSC) protocol. This protocol is used to help
coordinate between both ends of the protection domain in selecting
the proper traffic flow.
In the 1:1 architecture, a recovery transport path is dedicated to
the working transport path of a single service and the traffic is
only transmitted either on the working or the recovery path, by using
a selector bridge at the source of the protection domain. A selector
at the sink of the protection domain then selects the path that
carries the normal traffic. Since the source and sink need to be
coordinated to ensure that the selector bridge at both ends select
the same path, this architecture must support a PSC protocol.
The 1:n protection architecture extends the 1:1 architecture above by
sharing the recovery path amongst n services. Again, the recovery
path is fully allocated and disjoint from any of the n working
transport paths that it is being used to protect. The normal data
traffic for each service is transmitted either on the normal working
path for that service or, in cases that trigger protection switching
(as defined in [SurvivFwk]), may be sent on the recovery path. The
switching action is similar to the 1:1 case where a selector bridge
is used at the source. It should be noted that in cases where
multiple working path services have triggered protection switching
that some services, dependent upon their Service Level Agreement
(SLA), may not be transmitted as a result of limited resources on the
recovery path. In this architecture there may be a need for
coordination of the protection switching, and also for resource
allocation negotiation. The procedures for this are for further
study and may be addressed in future documents.
1.2. Scope of the document
As was pointed out in the Survivability Framework [SurvivFwk] and
highlighted above, there is a need for coordination between the end
points of the protection domain when employing bidirectional
protection schemes. This is especially true when there is a need to
maintain traffic over a co-routed bidirectional LSP.
The scope of this draft is to present a protocol for the Protection
State Coordination of Linear Protection. The protocol addresses the
protection of LSPs in an MPLS-TP network as required by [RFC5654] (in
particular requirements 63-67 and 74-79) and described in
[SurvivFwk]. The basic protocol is designed for use in conjunction
with the 1:1 protection architecture (for both unidirectional and
bidirectional protection) and for 1+1 protection of a bidirectional
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path (for both unidirectional and bidirectional protection
switching). Applicability of the protocol for 1:n protection schemes
may be documented in a future document. The applicability of this
protocol to additional MPLS-TP constructs and topologies may be
documented in future documents.
While the unidirectional 1+1 protection architecture does not require
the use of a coordination protocol, the protocol may be used by the
ingress node of the path to notify the far-side end point that a
switching condition has occurred and verify the consistency of the
end point configuration. This use may be especially useful for
point-to-multipoint transport paths, that are unidirectional by
definition of [RFC5654].
1.3. Contributing authors
Hao Long (Huawei), Dan Frost (Cisco), Davide Chiara (Ericsson),
Francesco Fondelli (Ericsson),
2. 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].
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2.1. Acronyms
This draft uses the following acronyms:
DNR Do not revert
FS Forced Switch
G-ACh Generic Associated Channel Header
LER Label Switching Router
MPLS-TP Transport Profile for MPLS
MS Manual Switch
P2P Point-to-point
P2MP Point-to-multipoint
PSC Protection State Coordination Protocol
PST Path Segment Tunnel
SD Signal Degrade
SF Signal Fail
SLA Service Level Agreement
WTR Wait-to-Restore
2.2. Definitions and Terminology
The terminology used in this document is based on the terminology
defined in [RFC4427] and further adapted for MPLS-TP in [SurvivFwk].
In addition, we use the term LER to refer to a MPLS-TP Network
Element, whether it is a LSR, LER, T-PE, or S-PE.
3. Protection switching control logic
3.1. Protection switching control logical architecture
Protection switching processes the local triggers described in
requirements 74-79 of [RFC5654] together with inputs received from
the far-end LER. Based on these inputs the LER will take certain
protection switching actions, e.g. switching the Selector Bridge to
select the working or protection path, and transmit different
protocol messages.
The following figure shows the logical decomposition of the PSC
Control Logic into different logical processing units. These
processing units are presented in subsequent subsections of this
document.
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Server Indication Control Plane Indication
-----------------+ +-------------
Operator Command | | OAM Indication
----------------+ | | +---------------
| | | |
V V V V
+---------------+ +-------+
| Local Request |<--------| WTR |
| logic |WTR Exps | Timer |
+---------------+ +-------+
| ^
Highest local|request |
V | Start/Stop
+-----------------+ |
Remote PSC | PSC Process |------------+
------------>| logic |
Request +-----------------+
|
| Action +------------+
+---------------->| Message |
| Generator |
+------------+
|
Output PSC | Message
V
Figure 1: Protection switching control logic
Figure 1 describes the logical architecture of the protection
switching control. The Local Request logic unit accepts the triggers
from the OAM, external operator commands, from the local control
plane (when present), and the Wait-to-Restore timer. By considering
all of these local request sources it determines the highest priority
local request. This high-priority request is passed to the PSC
Process logic, that will cross-check this local request with the
information received from the far-end LER. The PSC Process logic
uses this input to determine what actions need to be taken, e.g.
local actions at the LER, or what message should be sent to the far-
end LER, and the current status of the protection domain.
3.1.1. Local Request Logic
The protection switching logic processes input triggers from five
sources:
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o Operator command - the network operator may issue commands that
trigger protection switching. The supported commands are Forced
Switch, Manual Switch, Clear, Lockout of Protection, (see
definitions in [RFC4427]).
o Server layer alarm indication - the underlying server layer of the
network detects failure conditions at the underlying layer and may
issue an indication to the MPLS-TP layer. The server layer may
employ its own protection switching mechanism, and therefore this
input MAY be controlled by a holdoff-timer that SHOULD be
configurable by the network operator.
o Control plane - if there is a control plane active in the network
(either signaling or routing), it MAY trigger protection switching
based on conditions detected by the control plane. If the control
plane is based on GMPLS [RFC3945] then the recovery process SHALL
comply with the process described in [RFC4872].
o OAM indication - OAM fault management or performance measurement
tools may detect a failure or degrade condition on the MPLS-TP
transport path and this SHOULD input an indication to the Local
Request Logic.
o WTR expires - The Wait-to-Restore timer is used in conjunction
with recovery from failure conditions on the working path in
revertive mode. The timer SHALL signal the PSC control process
when it expires and the end point SHOULD revert to the normal
transmission of the user data traffic.
The Local request logic SHALL process these different input sources
and, based on the priorities between them, SHOULD produce a current
local request. The different local requests that may be output from
the Local Request Logic are:
o Clear - if the operator cancels an active local administrative
command, i.e. LO/FS/MS.
o Lockout of Protection (LO) - if the operator requested to disable
the protection path.
o Signal Fail (SF) - if any of the Server Layer, Control plane, or
OAM indications signaled a failure condition on either the
protection path or one of the working paths.
o Signal Degrade (SD) - if any of the Server Layer, Control plane,
or OAM indications signaled a degraded transmission condition on
either the protection path or one of the working paths
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o Clear Signal Fail - if all of the Server Layer, Control plane, or
OAM indications are no longer indicating a failure condition on a
path that was peviously indicating a failure condition.
o Forced Switch (FS) - if the operator requested that traffic be
switched from one of the working paths to the protection path.
o Manual Switch (MS) - if the operator requested that traffic be
switched from its current path to the other path. This is only
relevant if there is no currently active Fault condition or
Operator command.
o WTR Expires - generated by the WTR timer completing its period.
If none of the input sources have generated any input then the
current local request SHALL be a No Request (NR) request.
3.1.2. Remote Requests
In addition to the local requests generated as a result of the local
triggers indicated in the previous subsection, the PSC Control Logic
SHALL accept PSC messages from the far-end LER of the transport path.
These remote messages indicate the status of the transport path from
the viewpoint of the far-end LER, and may indicate if the local MEP
SHOULD initiate a protection switch operation.
The following remote requests may be received by the PSC process:
o Remote LO - indicates that the remote end point is in Unavailable
state due to a Lockout of Protection operator command.
o Remote SF - indicates that the remote end point has detected a
Signal Fail condition on one of the transport paths in the
protection domain. This remote message SHALL include an
indication of which transport path is affected by the SF
condition. In addition, it should be noted that the SF condition
may be either a unidirectional or a bidirectional failure, even if
the transport path is bidirectional.
o Remote SD - indicates that the remote end point has detected a
Signal Degrade condition on one of the transport paths in the
protection domain. This remote message SHALL include an
indication of which transport path is affected by the SD
condition. In addition, it should be noted that the SD condition
may be either a unidirectional or a bidirectional failure, even if
the transport path is bidirectional.
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o Remote FS - indicates that the remote end point is operating under
an operator command to switch the traffic to the protection path.
o Remote MS - indicates that the remote end point is operating under
an operator command to switch the traffic to the path that was not
being used previously.
o Remote WTR - indicates that the remote end point has determined
that the failure condition has recovered and has started its WTR
timer in preparation for reverting to the Normal state.
o Remote DNR - indicates that the remote end point has determined
that the failure condition has recovered and will continue
transporting traffic on the protection path due to operator
configuration that prevents automatic reversion to the Normal
state.
o Remote NR - indicates that the remote end point has no abnormal
condition to report.
3.1.3. PSC Process Logic
The PSC Process Logic SHALL accept as input -
a. the Local request output from the Local Request Logic,
b. the remote request message from the remote end point of the
transport path, and
c. the current state of the PSC Control Logic (maintained internally
by the PSC Control Logic).
Based on the priorities between the different inputs, the PSC Process
Logic SHALL determine the new state of the PSC Control Logic and what
actions need to be taken.
The new state information should be retained by the PSC Process
Logic, while the requested action SHALL be sent to the PSC Message
Generator (see subsection 3.1.4) to generate and transmit the proper
PSC message to be transmitted to the remote end point of the
protection domain.
3.1.4. PSC Message Generator
Based on the action output from the Process Logic this unit formats
the PSC protocol message that is transmitted to the remote end point
of the protection domain. When the PSC information has changed,
three PSC messages SHOULD be transmitted in quick succession, and
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subsequent messages should be transmitted continually at a lower
rate.
The transmission of three rapid packets allows for fast protection
switching even if one or two PSC messages are lost or corrupted. For
protection switching within 50ms, it is RECOMMENDED that the default
interval of the first three PSC messages SHOULD be no larger than
3.3ms. The subsequent messages SHOULD be transmitted with an
interval of 5 sec, to avoid traffic congestion.
3.1.5. Wait-to-Restore (WTR) timer
The WTR timer is used to delay reversion to Normal state when
recovering from a failure condition on the working path and the
protection domain is configured for revertive behavior. The WTR may
be in one of two states - either Running or Stopped. The WTR timer
MAY be started or stopped by the PSC Process Logic.
If the WTR timer expires prior to being stopped it SHALL generate a
WTR Expires local signal that shall be processed by the Local Request
Logic. If the WTR timer is running, sending a Stop command SHALL
reset the timer but SHALL NOT generate a WTR Expires local signal.
If the WTR timer is not running, a Stop command SHALL be ignored.
3.1.6. PSC Control States
The PSC Control Logic SHOULD maintain information on the current
state of the protection domain. The state information SHALL include
information of the current state and an indication of the cause for
the current state (e.g. unavailable due to local LO command,
protecting due to remote FS). In particular, the state information
SHOULD include an indication if the state is related to a remote or
local condition.
It should be noted that when referring to the "transport" of the data
traffic, in the following descriptions and later in the document that
the data will be transmitted on both the working and the protection
paths when using 1+1 protection, and on either the working or the
protection path exclusively when using 1:1 protection. When using
1+1 protection, the receiving LER should select the proper
transmission, according to the state of the protection domain.
The states that are supported by the PSC Control Logic are:
o Normal state - Both the protection and working paths are fully
allocated and active, data traffic is being transported over (or
selected from) the working path, and no trigger events are
reported within the domain.
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o Unavailable state - The protection path is unavailable - either as
a result of an operator Lockout command or a failure/degrade
condition detected on the protection path.
o Protecting failure state - The working path has reported a
failure/degrade condition and the user traffic is being
transported (or selected) on the protection path.
o Protecting administrative state - The operator has issued a
command switching the user traffic to the protection path.
o Wait-to-restore state - The protection domain is recovering from a
SF/SD condition on the working path that is being controlled by
the Wait-to-Restore (WTR) timer.
o Do-not-revert state - The protection domain is recovering from a
Protecting state, but the operator has configured the protection
domain to not automatically revert to the Normal state upon
recovery. The protection domain SHALL remain in this state until
the operator issues a command to revert to the Normal state or
there is a new trigger to switch to a different state.
See section 4.3.1 for details on what actions are taken by the PSC
Process Logic for each state and the relevant input.
4. Protection state coordination (PSC) protocol
Bidirectional protection switching, as well as unidirectional 1:1
protection, requires coordination between the two end points in
determining which of the two possible paths, the working or recovery
path, is transmitting the data traffic in any given situation. When
protection switching is triggered as described in section 3.1, the
end points must inform each other of the switch-over from one path to
the other in a coordinated fashion.
There are different possibilities for the type of coordinating
protocol. One possibility is a two-phased coordination in which the
LER that is initiating the protection switching sends a protocol
message indicating the switch but the actual switch-over is performed
only after receiving an 'Ack' from the far-end LER. The other
possibility is a single-phased coordination, in which the initiating
LER performs the protection switchover to the alternate path and
informs the far-end LER of the switch, and the far-end LER MUST
complete the switchover.
This protocol is a single-phase protocol, as described above. In the
following subsections we describe the protocol messages that SHALL be
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used between the two end points of the protection domain.
4.1. Transmission and acceptance of PSC control packets
The PSC control packets SHALL be transmitted over the protection path
only. This allows the transmission of the messages without affecting
the normal data traffic in the most prevalent case, i.e. the Normal
state. In addition, limiting the transmission to a single path
avoids possible conflicts and race conditions that could develop if
the PSC messages were sent on both paths.
When the PSC information is changed due to a local input, three PSC
messages SHOULD be transmitted as quickly as possible, to allow for
rapid protection switching. This set of three rapid messages allows
for fast protection switching even if one or two of these packets are
lost or corrupted. When the PSC information changes due to a remote
message there is no need for the aforementioned rapid transmission of
three messages. The exception (e.g. when the rapid tranmission is
still required) is when going from WTR state to Normal state as a
result of a remote NR message.
The frequency of the three rapid messages and the separate frequency
of the continual transmission SHOULD be configurable by the operator.
For protection switching within 50ms, the default interval of the
first three PSC messages is RECOMMENDED to be no larger than 3.3ms.
The continuous transmission interval is RECOMMENDED to be 5 seconds.
If no valid PSC specific information is received, the last valid
received information remains applicable. In the event a signal fail
condition is detected on the protection path, the received PSC
specific information should be evaluated.
4.2. Protocol format
The protocol messages SHALL be sent over the G-ACh as described in
[RFC5586]. There is a single channel type for the set of PSC
messages [to be assigned by IANA]. The actual message function SHALL
be identified by the Request field of the ACH payload as described
below. The following figure shows the format for the complete PSC
message:.
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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|Version| Reserved | Channel Type = MPLS-TP PSC |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ACH TLV Header |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ Optional TLVs ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Ver|Request|PT |R| Reserved | FPath | Path |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: Format of PSC packet with a G-ACh header
Where:
o MPLS-TP PSC Channel Code is the G-ACh channel number assigned to
the PSC = TBD
o The ACH TLV Header is described in [RFC5586]
o The following subsections describe the fields of the PSC payload.
4.2.1. PSC Ver field
The Ver field identifies the version of the protocol. For this
version the value SHALL be 0.
4.2.2. PSC Request field
The PSC protocol SHALL support transmission of the following requests
between the two end points of the protection domain:
o (1110) Lockout of protection - indicates that the end point has
disabled the protection path as a result of an administrative
command. Both the FPath and Path fields SHALL be set to 0.
o (1101) Forced switch - indicates that the transmitting end point
has switched traffic to the protection path as a result of an
administrative command. The Fpath field SHALL indicate that the
working path is being blocked (i.e. Fpath set to 1), and the Path
field SHALL indicate that user data traffic is being transported
on the protection path (i.e. Path set to 1).
o (0110) Signal Fail - indicates that the transmitting end point has
identified a signal fail condition on either the working or
protection path. The Fpath field SHALL identify the path that is
reporting the failure condition (i.e. if protection path then
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Fpath set to 0 and if working path then Fpath set to 1), and the
Path field SHALL indicate where the data traffic is being
transported (i.e. if protection path is blocked then Path set to 0
and if working path is blocked then Path set to 1).
o (0101) Signal Defect - indicates that that the transmitting end
point has identified a degradation of the signal, or integrity of
the packet transmission on either the working or protection path.
The specifics for the method of identifying this degradation is
out-of-scope for this document. The details of the actions to be
taken for this situation is left for future specification.
o (0100) Manual switch - indicates that the transmitting end point
has switched traffic as a result of an administrative Manual
Switch command. The Fpath field SHALL indicate that the working
path is being blocked (i.e. Fpath set to 1), and the Path field
SHALL indicate that user data traffic is being transported on the
protection path (i.e. Path set to 1).
o (0011) Wait to restore - indicates that the transmitting end point
is recovering from a failure condition of the working path and has
started the Wait-to-Restore timer. Fpath SHALL be set to 0 and
ignored upon receipt. Path SHALL indicate the working path that
is currently being protected (i.e. Path set to 1).
o (0010) Do not revert - indicates that the transmitting end point
is recovering from a failure/blocked condition, but due to the
local settings is requesting that the protection domain continues
to transmit data over the protection path, rather than revert to
the Normal state. Fpath SHALL be set to 0 and ignored upon
receipt. Path SHALL indicate the working path that is currently
being protected (i.e. Path set to 1).
o (0000) No request - indicates that the transmitting end point has
nothing to report, Fpath and Path fields SHALL be set to according
to the state of the end point, see section 4.3.3 for detailed
scenarios.
4.2.3. Protection Type (PT)
The PT field indicates the currently configured protection
architecture type, this SHOULD be validated to be consistent for both
ends of the protection domain. If an inconsistency is detected then
an alarm SHALL be sent to the management system. The following are
the possible values:
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o 11: bidirectional switching using a permanent bridge
o 10: bidirectional switching using a selector bridge
o 01: unidirectional switching using a permanent bridge
o 00: unidirectional switching using a selector bridge
As described in the introduction (section 1.1) a 1+1 protection
architecture is characterized by the use of a permanent bridge at the
source node, whereas the 1:1 and 1:n protection architectures are
characterized by the use of a selector bridge at the source node.
4.2.4. Revertive (R) field
This field indicates that the transmitting end point is configured to
work in revertive mode. If there is an inconsistency between the two
end points, i.e. one end point is configured for revertive action and
the second end point is in non-revertive mode, then the management
system SHOULD be notified. Possible values are:
o 0 - non-revertive mode
o 1 - revertive mode
4.2.5. Fault path (FPath) field
The Fpath field indicates which path (i.e. working or protection) is
identified to be in a fault condition or affected by an
administrative command. The following are the possible values:
o 0: indicates that the anomaly condition is on the protection path
o 1: indicates that the anomaly condition is on the working path
o 2-255: for future extensions
4.2.6. Data path (Path) field
The Path field indicates which data is being transmitted on the
protection path. Under normal conditions, the protection path
(especially in 1:1 or 1:n architecture) does not need to carry any
user data traffic. If there is a failure/degrade condition on one of
the working paths, then that working path's data traffic will be
transmitted over the protection path. The following are the possible
values:
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o 0: indicates that the protection path is not transporting user
data traffic (in 1:n architecture) or transporting redundant user
data traffic (in 1+1 architecture).
o 1: indicates that the protection path is transmitting user traffic
replacing the use of the working path.
o 2-255: for future extensions
4.3. Principles of Operation
In all of the following subsections, assume a protection domain
between LER-A and LER-Z, using paths W (working) and P (protection)
as shown in figure 3.
+-----+ //=======================\\ +-----+
|LER-A|// Working Path \\|LER-Z|
| /| |\ |
| ?< | | >? |
| \|\\ Protection Path //|/ |
+-----+ \\=======================// +-----+
|--------Protection Domain--------|
Figure 3: Protection domain
4.3.1. Basic operation
The purpose of the PSC protocol is to allow the end points of the
protection domain to notify their peer of the status of the domain
that is known at the end point and coordinate the transmission of the
data traffic. The current state of the end point is expressed in the
values of the Request field [reflecting the local requests at that
end point] and the Fpath field [reflecting knowledge of a blocked
path]. The coordination between the end points is expressed by the
value of the Path field [indicating where the data traffic is being
transmitted]. The value of the Path field SHOULD be identical for
both end points at any particular time. The values of the Request
and Fpath fields may not be identical between the two end points.In
particular it should be noted that a remote message MAY not cause the
end point to change the Request field that is being transmitted while
it does affect the Path field (see details in the following
subsections).
The protocol is a single-phase protocol. Single-phase implies that
each end point notifies its peer of a change in the operation
(switching to or from the protection path) and makes the switch
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without waiting for acknowledgement.
The following subsections will identify the messages that SHALL be
transmitted by the end point in different scenarios. The messages
are described as REQ(FP, P) - where REQ is the value of the Request
field, FP is the value of the Fpath field, and P is the value of the
Path field. All examples assume a protection domain between LER-A
and LER-Z with a single working path and single protection path (as
shown in figure 3). Again it should be noted that when using 1:1
protection the data traffic will be transmitted exclusively on either
the protection or working path, while when using 1+1 protection the
traffic will be transmitted on both paths and the receiving LER
should select the appropriate signal based on the state. The text
will refer to this transmission/selection as "transport" of the data
traffic.
4.3.2. Priority of inputs
As noted above (in section 3.1.1) the PSC Control Process accepts
input from five local input sources. There is a definition of
priority between the different inputs that may be triggered locally.
The list of local requests in order of priority are (from highest to
lowest priority):
1. Clear (Operator command)
2. Lockout of protection (Operator command)
3. Signal Fail on protection (OAM/Control Plane/Server Indication)
4. Forced switch (Operator command)
5. Signal Fail on working (OAM/Control Plane/Server Indication)
6. Signal Degrade on working (OAM/Control Plane/Server Indication)
7. Clear Signal Fail/Degrade (OAM/Control Plane/Server Indication)
8. Manual switch (Operator command)
9. WTR expires (WTR Timer)
The determination of whether a remote message is accepted or ignored
is a function of the current state of the local LER and the current
local request (see section 3.1.3). Part of this consideration will
be included in the following subsections describing the operation in
the different states.
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4.3.3. Operation of PSC States
4.3.3.1. Normal State
When the protection domain has no special condition in effect, the
ingress LER SHALL forward the user data along the working path, and,
in the case of 1+1 protection, the Permanent Bridge will bridge the
data to the recovery path as well. The receiving LER SHALL read the
data from the working path.
When the end point is in Normal State it SHALL transmit a NR(0,0)
message, indicating - Nothing to report and data traffic is being
transported on the working path.
When the LER (assume LER-A) is in Normal State the following
transitions are relevant in reaction to a local input (new state
SHOULD be marked as local):
o A local Lockout of protection input SHALL cause the LER to go into
Unavailable State and begin transmission of a LO(0,0) message to
the far-end LER (LER-Z).
o A local Forced switch input SHALL cause the LER to go into
Protecting administrative state and begin transmission of a
FS(1,1) message to the far-end LER (LER-Z).
o A local Signal Fail indication on the protection path SHALL cause
the LER to go into Unavailable state and begin transmission of a
SF(0,0) message to the far-end LER (LER-Z).
o A local Signal Fail indication on the working path SHALL cause the
LER to go into Protecting failure state and begin transmission of
a SF(1,1) message to the far-end LER (LER-Z).
o A local Manual switch input SHALL cause the LER to go into
Protecting administrative state and begin transmission of a
MS(1,1) message to the far-end LER (LER-Z).
o All other local inputs SHOULD be ignored.
In Normal state, remote messages would cause the following reaction
from the LER (new state SHOULD be marked as remote):
o A remote Lockout of protection message SHALL cause the LER (LER-A)
to go into Unavailable state, while continuing to transmit the
NR(0,0) message.
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o A remote Forced switch message SHALL cause the LER (LER-A) to go
into Protecting administrative state, and transmit a NR(0,1)
message.
o A remote Signal Fail message that indicates that the failure is on
the protection path SHALL cause the LER (LER-A) to go into
Unavailable state, while continuing to transmit the NR(0,0)
message.
o A remote Signal Fail message that indicates that the failure is on
the working path SHALL cause the LER (LER-A) to go into Protecting
failure state, and transmit a NR(0,1) message.
o A remote Manual switch message SHALL cause the LER (LER-A) to go
into Protecting administrative state, and transmit a NR(0,1)
message.
o All other remote messages SHOULD be ignored.
4.3.3.2. Unavailable State
When the protection path is unavailable - either as a result of a
Lockout operator command, or as a result of a SF or SD detected on
the protection path - then the protection domain is in the
unavailable state. In this state, the data traffic is transported on
the working path.
The protection domain will exit the unavailable state and revert to
the normal state when, either the operator clears the Lockout command
or the protection path recovers from the signal fail or degraded
situation. Both ends will resume sending the PSC packets over the
protection path, as a result of this recovery.
When in unavailable state the data traffic is being transported on
the working path and is not protected. When the domain is in
unavailable state the PSC messages may not get through and therefore
the protection is more dependent on the local inputs rather than the
remote messages (that may not be received).
When the LER (assume LER-A) is in Unavailable State the following
transitions are relevant in reaction to a local input (new state
SHOULD be marked as local):
o A local Clear input SHOULD be ignored if the LER is in remote
Unavailable state. If in local Unavailable state due to a Lockout
command, then the input SHALL cause the LER to go to Normal state
and begin transmitting a NR(0,0) message.
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o A local Lockout of protection input SHALL cause the LER to remain
in Unavailable State and begin transmission of a LO(0,0) message
to the far-end LER (LER-Z).
o A local Clear SF in local Unavailable state due to a Signal Fail
on the protection path and the Clear SF indicates that the
protection path is now cleared, then the input SHALL cause the LER
to go to Normal state and begin transmitting a NR(0,0) message.
If the LER is in remote Unavailable state but is under a local SF
condition, then the local Clear SF SHALL clear the SF local
condition and the LER SHALL begin transmitting NR(0,0) messages,
maintaining the remote Unavailable state. In all other cases the
local Clear SF SHOULD be ignored.
o A local Forced switch SHOULD be ignored by the PSC Process Logic.
o A local Signal Fail indication on the protection path SHALL cause
the LER to remain in Unavailable state and begin transmission of a
SF(0,0) message.
o All other local inputs SHOULD be ignored.
If remote messages are being received over the protection path then
they would have the following affect:
o A remote Lockout of protection message SHALL cause the LER to
remain in Unavailable state, and continue transmission of the
current message (either NR(0,0) or LO(0,0) or SF(0,0))
o A remote Signal Fail message that indicates that the failure is on
the protection path SHALL cause the LER to remain in Unavailable
state and continue transmission of the current message (either
NR(0,0) or SF(0,0) or LO(0,0)).
o A remote No Request, when the LER is remote Unavailable state
SHALL cause the LER to go into Normal state and begin transmission
of a NR(0,0) message. When in local Unavailable state, the
message SHALL be ignored.
o All other remote messages SHOULD be ignored.
4.3.3.3. Protecting administrative state
In the protecting state the user data traffic is being transported on
the protection path, while the working path is blocked due to an
operator command, i.e. Forced Switch or Manual Switch.
The following describe the reaction to local input:
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o A local Clear SHOULD be ignored if in remote Protecting state. If
in local Protecting administrative state then this input SHALL
cause the LER to go into Normal state and begin transmitting a
NR(0,0) message.
o A local Lockout of protection input SHALL cause the LER to go into
Unavailable state and begin transmission of a LO(0,0) message.
o A local Forced switch input SHALL cause the LER to remain in
Protecting administrative state and begin transmission of a
FS(1,1) message.
o A local Signal Fail indication on the protection path SHALL cause
the LER to go into Unavailable state and begin transmission of a
SF(0,0) message.
o A local Signal Fail indication on the working path SHOULD be
filtered by the Local Request Logic if the protecting state was
entered due to an active local Forced switch operator command. If
the protecting state is due to a remote Forced switch message,
then this local indication SHOULD be filtered by the PSC Process
Logic. If the current state is due to a (local or remote) Manual
switch operator command, it SHALL cause the LER to go into
Protecting failure state and begin transmitting a SF(1,1) message.
o A local Clear SF when in remote Protecting administrative state
SHOULD clear any local SF condition that may exist. The LER SHALL
stop transmitting the SF(1,1) message and begin transmitting an
NR(0,1) message.
o A local Manual switch input SHALL be filtered by the Local Request
Logic if there is an active local Forced switch. If the
protecting state is due to a remote Forced switch command, then
this local indication SHOULD be filtered by the PSC Process Logic.
If the current state is due to a (local or remote) Manual switch
operator command, it SHALL cause the LER to remain in Protecting
administrative state and begin transmission of a MS(1,1) message.
o All other local inputs SHOULD be ignored.
While in Protecting administrative state the LER may receive and
react as follows to remote PSC messages:
o A remote Lockout of protection message SHALL cause the LER to go
into Unavailable state and begin transmitting a NR(0,0) message.
It should be noted that this automatically cancels the current
Forced switch or Manual switch command and data traffic is
reverted to the working path.
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o A remote Forced switch message SHOULD be ignored by the PSC
Process Logic if there is an active local Forced switch operator
command. If the Protecting state is due to a remote Forced switch
message then the LER SHALL remain in Protecting administrative
state and continue transmission of the last message. If the
Protecting state is due to either a local or remote Manual switch
then the LER SHALL remain in Protecting administrative state
(updating the state information with the proper relevant
information) and begin transmitting a NR(0,1) message.
o A remote Signal Fail message indicating a failure on the
protection path SHALL cause the LER to go into Unavailable state
and begin transmitting a NR(0,0) message. It should be noted that
this automatically cancels the current Forced switch or Manual
switch command and data traffic is reverted to the working path.
o A remote Signal Fail message indicating a failure on the working
path SHALL be ignored if there is an active local Forced switch
command. If the Protecting state is due to a local or remote
Manual switch then the LER SHALL go to Protecting failure state
and begin transmitting a NR(0,1) message.
o A remote Manual switch message SHALL be ignored by the PSC Process
Logic if in Protecting state due to a local or remote Forced
switch. If in Protecting state due to a remote Manual switch then
the LER SHALL remain in Protecting administrative state and
continue transmitting the current message. If in Protecting state
due to an active local Manual switch then the LER SHALL remain in
Protecting administrative state and continue transmission of the
MS(1,1) message.
o A remote DNR(0,0) message SHALL be ignored if in Protecting state
due to a local input. If in Protecting state due to a remote
message then the LER SHALL go to Do-not-revert state and begin
transmitting a NR(0,0) message.
o A remote NR(0,0) message SHALL be ignored if in Protecting state
due to a local input. If in Protecting state due to a remote
message then the LER SHALL go to Normal state and begin
transmitting a NR(0,0) message.
o All other remote messages SHOULD be ignored.
4.3.3.4. Protecting failure state
When the protection mechanism has been triggered and the protection
domain has performed a protection switch, the domain is in the
protecting failure state. In this state the normal data traffic is
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transported on the protection path.
The following describe the reaction to local input:
o A local Clear SF SHOULD be ignored if in remote Protecting state.
If the Clear SF indicates that the protection path is now cleared
(but working is still in SF condition) then the indicateion SHOULD
be ignored. If in local Protecting failure state and the LER is
configured for revertive behavior then this input SHALL cause the
LER to go into Wait-to-restore state, start the WTR timer, and
begin transmitting a WTR(0,1) message. If in local Protecting
failure state and the LER is configured for non-revertive behavior
then this input SHALL cause the LER to go into Do-not-revert state
and begin transmitting a DNR(0,1) message.
o A local Lockout of protection input SHALL cause the LER to go into
Unavailable state and begin transmission of a LO(0,0) message.
o A local Forced switch input SHALL cause the LER to go into
Protecting administrative state and begin transmission of a
FS(1,1) message.
o A local Signal Fail indication on the protection path SHALL cause
the LER to go into Unavailable state and begin transmission of a
SF(0,0) message.
o A local Signal Fail indication on the working path SHALL cause the
LER to remain in Protecting failure state and begin transmitting a
SF(1,1) message.
o All other local inputs SHOULD be ignored.
While in Protecting failure state the LER may receive and react as
follows to remote PSC messages:
o A remote Lockout of protection message SHALL cause the LER to go
into Unavailable state and if in protecting failure state due to a
local SF condition then the LER SHALL begin transmitting a SF(1,0)
message, otherwise it SHALL transmit a NR(0,0) message. It should
be noted that this may cause loss of user data since the working
path is still in a failure condition.
o A remote Forced switch message SHALL cause the LER go into
Protecting administrative state and if in protecting failure state
due to a local SF condition the LER SHALL begin transmitting the
SF(1,1) message, otherwise it SHALL begin transmitting NR(0,0).
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o A remote Signal Fail message indicating a failure on the
protection path SHALL cause the LER to go into Unavailable state
and if in protecting failure state due to a local SF condition
then the LER SHALL begin transmitting a SF(1,0) message, otherwise
it SHALL begin transmitting NR(0,0) message. It should be noted
that this may cause loss of user data since the working path is
still in a failure condition.
o If in Protecting state due to a remote message, a remote Wait-to-
Restore message SHALL cause the LER to go into Wait-to-Restore
state and continue transmission of the current message.
o If in Protecting state due to a remote message, a remote Do-not-
revert message SHALL cause the LER to go into Do-not-revert state
and continue transmission of the current message.
o All other remote messages SHOULD be ignored.
4.3.3.5. Wait-to-restore state
The Wait-to-Restore state is used by the PSC protocol to delay
reverting to the normal state, when recovering from a failure
condition on the working path, for the period of the WTR timer to
allow the recovering failure to stabilize. While in the Wait-to-
Restore state the data traffic SHALL continue to be transported on
the protection path. The natural transition from the Wait-to-Restore
state to Normal state will occur when the WTR timer expires.
When in Wait-to-Restore state the following describe the reaction to
local inputs:
o A local Lockout of protection command SHALL cause the LER to Stop
the WTR timer, go into Unavailable state, and begin transmitting a
LO(0,0) message.
o A local Forced switch command SHALL cause the LER to Stop the WTR
timer, go into Protecting administrative state, and begin
transmission of a FS(1,1) message.
o A local Signal Fail indication on the protection path SHALL cause
the LER to Stop the WTR timer, go into Unavailable state, and
begin transmission of a SF(0,0) message.
o A local Signal Fail indication on the working path SHALL cause the
LER to Stop the WTR timer, go into Protecting failure state, and
begin transmission of a SF(1,1) message.
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o A local Manual switch input SHALL cause the LER to Stop the WTR
timer, go into Protecting administrative state and begin
transmission of a MS(1,1) message.
o A local WTR expires input SHALL cause the LER to remain in Wait-
to-Restore state and begin transmitting a NR(0,1) message.
o All other local inputs SHOULD be ignored.
When in Wait-to-Restore state the following describe the reaction to
remote messages:
o A remote Lockout of protection message SHALL cause the LER to Stop
the WTR timer, go into Unavailable state, and begin transmitting a
NR(0,0) message.
o A remote Forced switch message SHALL cause the LER to Stop the WTR
timer, go into Protecting administrative state, and begin
transmission of a NR(0,1) message.
o A remote Signal Fail message for the protection path SHALL cause
the LER to Stop the WTR timer, go into Unavailable state, and
begin transmission of a NR(0,0) message.
o A remote Signal Fail message for the working path SHALL cause the
LER to Stop the WTR timer, go into Protecting failure state, and
begin transmission of a NR(0,1) message.
o A remote Manual switch message SHALL cause the LER to Stop the WTR
timer, go into Protecting administrative state and begin
transmission of a NR(0,1) message.
o If the WTR timer is running then a remote NR message SHALL be
ignored. If the WTR timer is no longer running then a remote NR
message SHALL cause the LER to go into Normal state and begin
transmitting a NR(0,0) message.
o All other remote messages SHOULD be ignored.
4.3.3.6. Do-not-revert state
Do-not-revert state is a continuation of the protecting state when
the protection domain is configured for non-revertive behavior.
While in Do-not-revert state, data traffic continues to be
transported on the protection path until the administrator sends a
command to revert to the Normal state. It should be noted that there
is a fundemental difference between this state and Normal - whereas
Forced Switch in Normal state actually causes a switch in the
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transport path used, in Do-not-revert state the Forced switch just
switches the state (to Protecting administrative state) but the
traffic would continue to be transported on the protection path! The
command to revert back to Normal state could either be a Lockout of
protection (followed be a Clear command), a Clear command, or a new
form of the Manual switch command [note: This would also require some
kind of agreement, although it seems to have been adopted by ITU-T in
G.8031 for Ethernet]. The following description of operation is
based on the Lockout/Clear option mentioned!
When in Do-not-revert state the following describe the reaction to
local input:
o A local Lockout of protection command SHALL cause the LER to go
into Unavailable state and begin transmitting a LO(0,0) message.
o A local Forced switch command SHALL cause the LER to go into
Protecting administrative state and begin transmission of a
FS(1,1) message.
o A local Signal Fail indication on the protection path SHALL cause
the LER to go into Unavailable state and begin transmission of a
SF(0,0) message.
o A local Signal Fail indication on the working path SHALL cause the
LER to go into Protecting failure state and begin transmission of
a SF(1,1) message.
o A local Manual switch input SHALL cause the LER to go into
Protecting administrative state and begin transmission of a
MS(1,1) message.
o All other local inputs SHOULD be ignored.
When in Do-not-revert state the following describe the reaction to
remote messages:
o A remote Lockout of protection message SHALL cause the LER to go
into Unavailable state and begin transmitting a NR(0,0) message.
o A remote Forced switch message SHALL cause the LER to go into
Protecting administrative state and begin transmission of a
NR(0,1) message.
o A remote Signal Fail message for the protection path SHALL cause
the LER to go into Unavailable state and begin transmission of a
NR(0,0) message.
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o A remote Signal Fail message for the working path SHALL cause the
LER to go into Protecting failure state, and begin transmission of
a NR(0,1) message.
o A remote Manual switch message SHALL cause the LER to go into
Protecting administrative state and begin transmission of a
NR(0,1) message.
o All other remote messages SHOULD be ignored.
5. IANA Considerations
To be added in future version.
6. Security Considerations
To be added in future version.
7. Acknowledgements
The authors would like to thank all members of the teams (the Joint
Working Team, the MPLS Interoperability Design Team in IETF and the
T-MPLS Ad Hoc Group in ITU-T) involved in the definition and
specification of MPLS Transport Profile.
8. References
8.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC5654] Niven-Jenkins, B., Brungard, D., Betts, M., Sprecher, N.,
and S. Ueno, "Requirements of an MPLS Transport Profile",
RFC 5654, September 2009.
8.2. Informative References
[RFC3031] Rosen, E., Viswanathan, A., and R. Callon, "Multiprotocol
Label Switching Architecture", RFC 3031, Jan 2001.
[RFC3032] Rosen, E., Tappan, D., Fedorkow, G., Rekhter, Y.,
Farinacci, D., Li, T., and A. Conta, "MPLS Label Stack
Encoding", RFC 3032, Jan 2001.
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[RFC5659] Bocci, M. and S. Bryant, "An Architecture for Multi-
Segment Pseudowire Emulation Edge-to-Edge", RFC 5659,
October 2009.
[RFC3985] Bryant, S. and P. Pate, "Pseudowire Emulation Edge-to-Edge
(PWE3) Architecture", RFC 3985, March 2005.
[RFC5085] Nadeau, T. and C. Pignataro, "Pseudowire Virtual Circuit
Connectivity Verification (VCCV): A Control Channel for
Pseudowires", RFC 5085, December 2007.
[TPFwk] Bocci, M., Bryant, S., and L. Levrau, "A Framework for
MPLS in Transport Networks",
ID draft-ietf-mpls-tp-framework-06.txt, July 2009.
[RFC5586] Vigoureux,, M., Bocci, M., Swallow, G., Aggarwal, R., and
D. Ward, "MPLS Generic Associated Channel", RFC 5586,
May 2009.
[RFC4427] Mannie, E. and D. Papadimitriou, "Recovery Terminology for
Generalized Multi-Protocol Label Switching", RFC 4427,
Mar 2006.
[SurvivFwk]
Sprecher, N., Farrel, A., and H. Shah, "Multi-protocol
Label Switching Transport Profile Survivability
Framework", ID draft-ietf-mpls-tp-survive-fwk-02.txt,
Feb 2009.
[RFC4872] Lang, J., Papadimitriou, D., and Y. Rekhter, "RSVP-TE
Extensions in Support of End-to-End Generalized Multi-
Protocol Label Switching (GMPLS) Recovery", RFC 4872,
May 2007.
[RFC3945] Mannie, E., "Generalized Multi-Protocol Label Switching
(GMPLS) Architecture", RFC 3945, Oct 2004.
Authors' Addresses
Stewart Bryant (editor)
Cisco
United Kingdom
Email: stbryant@cisco.com
Bryant, et al. Expires April 27, 2011 [Page 30]
Internet-Draft MPLS-TP LP October 2010
Eric Osborne
Cisco
United States
Email: eosborne@cisco.com
Nurit Sprecher (editor)
Nokia Siemens Networks
3 Hanagar St. Neve Ne'eman B
Hod Hasharon, 45241
Israel
Email: nurit.sprecher@nsn.com
Annamaria Fulignoli (editor)
Ericsson
Italy
Phone:
Email: annamaria.fulignoli@ericsson.com
Yaacov Weingarten
Nokia Siemens Networks
3 Hanagar St. Neve Ne'eman B
Hod Hasharon, 45241
Israel
Phone: +972-9-775 1827
Email: yaacov.weingarten@nsn.com
Bryant, et al. Expires April 27, 2011 [Page 31]
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