Internet DRAFT - draft-cdh-mpls-tp-psc-non-revertive
draft-cdh-mpls-tp-psc-non-revertive
MPLS Working Group T. Cheung
Internet-Draft ETRI
Intended status: Standards Track A. D'Alessandro
Expires: March 14, 2014 Telecom Italia
H. van Helvoort
Huawei Technologies
September 10, 2013
PSC protocol updates for non-revertive operation
draft-cdh-mpls-tp-psc-non-revertive-01.txt
Abstract
This document optionally updates [RFC6378], "MPLS Transport Profile
(MPLS-TP) Linear Protection", to change non-revertive operation to be
aligned with the behavior defined in [RFC4427] and in an effort to
satisfy the ITU-T's protection switching requirements. An operator
command, Manual Switch to Working (MS-W) is also included to revert
traffic to the working path in non-revertive operation.
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
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Internet-Drafts are draft documents valid for a maximum of six months
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on March 14, 2014.
Copyright Notice
Copyright (c) 2013 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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publication of this document. Please review these documents
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to this document. Code Components extracted from this document must
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described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Motivation for adding MS-W . . . . . . . . . . . . . . . 3
1.2. Behavior of MS-P and MS-W . . . . . . . . . . . . . . . . 3
1.3. Equal priority resolution . . . . . . . . . . . . . . . . 3
2. Conventions Used in This Document . . . . . . . . . . . . . . 4
3. Acronyms . . . . . . . . . . . . . . . . . . . . . . . . . . 4
4. Updates to the PSC RFC . . . . . . . . . . . . . . . . . . . 4
4.1. Updates to Section 2.1. Acronyms . . . . . . . . . . . . 4
4.2. Updates to Section 3.1. Local Request Logic . . . . . . . 5
4.3. Updates to Section 3.2. Remote Requests . . . . . . . . . 6
4.4. Updates to Section 3.6. PSC Control States . . . . . . . 6
4.5. Updates to Section 4.2.2. PSC Request Field . . . . . . . 7
4.6. Updates to Section 4.3.2. Priority of Inputs . . . . . . 7
4.7. Updates to Section 4.3.3.1. Normal State . . . . . . . . 9
4.8. Updates to Section 4.3.3.2. Unavailable State . . . . . . 11
4.9. Updates to Section 4.3.3.3. Protecting Administrative
State . . . . . . . . . . . . . . . . . . . . . . . . . . 12
4.10. Updates to Section 4.3.3.4. Protecting Failure State . . 15
4.11. Updates to Section 4.3.3.5. Wait-to-Restore State . . . . 16
4.12. Updates to Section 4.3.3.6. Do-not-Revert State . . . . . 17
4.13. Updates to Appendix A. PSC State Machine Tables . . . . . 19
5. Security considerations . . . . . . . . . . . . . . . . . . . 22
6. IANA considerations . . . . . . . . . . . . . . . . . . . . . 22
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 22
8. Normative References . . . . . . . . . . . . . . . . . . . . 22
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 22
1. Introduction
Non-revertive mode of protection switching is defined in [RFC4427].
In this mode, the traffic does not return to the working path when
switch-over requests are terminated.
However, PSC protocol defined in [RFC6378] supports this operation
only when recovering from a defect condition, but does not operate as
non-revertive when an operator's switch-over command such as Forced
Switch or Manual Switch is cleared. To be aligned with legacy
transport network behavior and [RFC4427], a node should go into the
Do-not-Revert (DNR) state not only when a failure condition on a
working path is cleared but also when an operator command requesting
switch-over is cleared.
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Changing the non-revertive operation introduces necessity of a new
operator command to revert traffic to the working path when in DNR
state. Moreover, according to Section 4.3.3.6 (Do-not-Revert State)
in [RFC6378], "to revert back to Normal state, the administrator
SHALL issue a Lockout of protection command followed by a Clear
command." This requirement introduces the potential risk of an
unprotected situation while the Lockout of protection is in effect.
Manual Switch-over for recovery LSP/span command, defined in
[RFC4427] and also defined in [RFC5654], Requirement 83, as one of
the mandatory external commands, should be used for this purpose, but
is not included in [RFC6378].
This document optionally updates [RFC6378] to change non-revertive
operation to be aligned with the behavior defined in [RFC4427] and to
meet the ITU-T's protection switching requirements, and add a new
operator command, Manual Switch to Working (MS-W) to avoid the
potential problem with the Lockout of protection command when the DNR
should be cleared. For the sake of clarity, Manual Switch (MS)
defined in [RFC6378] is renamed Manual Switch to Protection (MS-P).
1.1. Motivation for adding MS-W
Most of the operational interventions on working paths are executed
after operating a "Manual switch-over for normal traffic" switch
command that switches the normal traffic from the working path to the
protection path. This command will keep the traffic on the
protection path unless a "Manual switch-over for recovery LSP/span"
command is issued that switches the normal traffic back to the
working path. Using Lockout of protection command as currently
suggested in [RFC6378] may cause, in some circumstances, traffic
loss.
1.2. Behavior of MS-P and MS-W
The MS-P and MS-W commands SHALL have the same priority. If one of
these commands is already issued, and the other command is issued
afterwards, it SHALL be ignored. If two LERs are requesting opposite
operations simultaneously, i.e. one LER is sending MS-P while the
other LER is sending MS-W, the MS-W SHALL be considered to have a
higher priority than MS-P, and MS-P SHALL be ignored.
This behavior is described in Section 4.2 that proposes updates to
Section 3.1 "Local Request Logic" of [RFC6378].
1.3. Equal priority resolution
[RFC6378] defines only one rule for equal priority condition in
Section 4.3.2 as "The remote message from the far-end LER is assigned
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a priority just below the similar local input." In order to support
the manual switch behavior described in Section 1.2, additional rules
for equal priority resolution are required, and are described in
Section 4.6 that proposes updates to Section 4.3.2. "Priority of
Inputs" of [RFC6378].
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].
3. Acronyms
This draft uses the following acronyms:
MPLS-TP Transport Profile for MPLS
MS Manual Switch
MS-P Manual Switch to Protection
MS-W Manual Switch to Working
PSC Protection State Coordination Protocol
4. Updates to the PSC RFC
This section describes the changes required to change non-revertive
operation and add "Manual Switch to Working" operator command in the
PSC protocol defined in [RFC6378].
The term "Manual Switch" and its acronym "MS" used in [RFC6378] are
replaced respectively by "Manual Switch to Protection" and "MS-P" by
this document to avoid confusion with "Manual Switch to Working" and
its acronym "MS-W".
Also, the term "Protecting administrative state" used in [RFC6378] is
replaced by "Switching administrative state" by this document to
include the case where traffic is switched back to the working path
by administrative Manual Switch to Working command.
4.1. Updates to Section 2.1. Acronyms
Replace the following bullet item:
MS Manual Switch
With:
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MS-P Manual Switch to Protection
MS-W Manual Switch to Working
4.2. Updates to Section 3.1. Local Request Logic
Replace the following text in the bullet item for operator command:
The commands Forced Switch, Manual Switch, Clear, Lockout of
protection (defined in [RFC4427] as Forced switch-over, Manual
switch-over, Clear, and Lockout of recovery LSP/span,
respectively) MUST be supported.
With:
The commands Forced Switch, Manual Switch to Protection, Manual
Switch to Working, Clear, Lockout of protection (defined in
[RFC4427] as Forced switch-over for normal traffic, Manual switch-
over for normal traffic, Manual switch-over for recovery LSP/span,
Clear and Lockout of recovery LSP/span, respectively) MUST be
supported.
Replace the following bullet item in the local request list:
o Manual Switch (MS) - if the operator requested that traffic be
switched from the working path to the protection path. This is
only relevant if there is no currently active fault condition or
operator command.
With:
o Manual Switch to Protection (MS-P) - if the operator requested
that traffic be switched from the working path to the protection
path. This is only relevant if there is no currently active fault
condition or operator command.
o Manual Switch to Working (MS-W) - if the operator requested that
traffic be switched from the protection path to the working path.
This is only relevant if there is no currently active fault
condition or operator command.
Add the following text above the last paragraph:
The MS-P and MS-W commands SHALL have the same priority. If one
of these commands is already issued, and the other command is
issued afterwards, it SHALL be ignored. If two LERs are
requesting opposite operations simultaneously, i.e. one LER is
sending MS-P while the other LER is sending MS-W, the MS-W SHALL
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be considered to have a higher priority than MS-P, and MS-P SHALL
be ignored.
4.3. Updates to Section 3.2. Remote Requests
Replace the following bullet item in the remote request list:
o Remote MS - indicates that the remote end point is operating under
an operator command to switch the traffic from the working path to
the protection path.
With:
o Remote MS-P - indicates that the remote end point is operating
under an operator command to switch the traffic from the working
path to the protection path.
o Remote MS-W - indicates that the remote end point is operating
under an operator command to switch the traffic from the
protection path to the working path.
Replace the following bullet item:
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.
With:
o Remote DNR - indicates that the remote end point has determined
that the switch-over condition by administrative commands has
ceased or 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.
4.4. Updates to Section 3.6. PSC Control States
Replace the following bullet item in the protection domain states
list:
o Protecting administrative state - The operator has issued a
command switching the user traffic to the protection path.
With:
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o Switching administrative state - The operator has issued a command
switching the user traffic either from the working path to the
protection path or from the protection path to the working path.
4.5. Updates to Section 4.2.2. PSC Request Field
Replace the following bullet item in the request list:
o (5) Manual Switch - indicates that the transmitting end point has
switched traffic to the protection path 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).
With:
o (5) Manual Switch - indicates that the transmitting end point has
switched traffic to the protection path as a result of an
administrative Manual Switch to Protection (MS-P) command or to
the working path as a result of an administrative Manual Switch to
Working (MS-W) command. Two commands, MS-P and MS-W are
represented by the same Request Field value, but differentiated by
the FPath value. When traffic is switched to the protection path,
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). When traffic is switched to the working
path, the FPath field SHALL indicate that the protection path is
being blocked (i.e., FPath set to 0), and the Path field SHALL
indicate that user data traffic is being transported on the
working path (i.e., Path set to 0).
4.6. Updates to Section 4.3.2. Priority of Inputs
Replace the following number item:
8. Manual Switch (operator command)
With:
8. Manual Switch to Protection/Working (operator command)
Replace the following two paragraphs:
As was noted above, the Local Request logic SHALL always select
the local input indicator with the highest priority as the current
local request, i.e., only the highest priority local input will be
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used to affect the control logic. All local inputs with lower
priority than this current local request will be ignored.
The remote message from the far-end LER is assigned a priority
just below the similar local input. For example, a remote Forced
Switch would have a priority just below a local Forced Switch but
above a local Signal Fail on protection input. As mentioned in
Section 3.6.1, the state transition is determined by the higher
priority input between the highest priority local input and the
remote message. This also determines the classification of the
state as local or remote. The following subsections detail the
transition based on the current state and the higher priority of
these two inputs.
With:
As was noted above, the Local Request logic SHALL always select
the local input indicator with the highest priority as the current
local request, i.e., only the highest priority local input will be
used to affect the control logic. All local inputs with lower
priority than this current local request will be ignored. For
local inputs with same priority, first-come, first-served rule is
applied. For example, once MS-P (or MS-W) local input is
determined as the highest priority local input, then subsequent
MS-W (or MS-P) local input will be ignored and automatically
canceled.
The remote message from the far-end LER is assigned a priority
just below the same local input. For example, a remote Forced
Switch would have a priority just below a local Forced Switch but
above a local Signal Fail on protection input.
However, if the LER is in a remote state due to a remote message,
a subsequent local input having the same priority but requesting
different action to the control logic, will be considered as
having lower priority than the remote message, and will be
ignored. For example, if the LER is in remote Switching
administrative status due to a remote MS-P, then subsequent local
MS-W will be ignored and automatically canceled.
It should be noted that there is a reverse case where one LER
receives a local command and the other LER receives,
simultaneously, a command with the same priority but requesting
different action. In this case, each of the two LERs receives a
subsequent remote message having the same priority but requesting
different action, while the LER is in a local state due to the
local input. In this case, a priority must be set for the
commands with the same priority regardless of its orgin (local
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input or remote message). For example, one LER receives MS-P as a
local input and the other LER receives MS-W as a local input,
simultaneously. In this case, MS-W SHALL be considered as having
higher priority than MS-P at both LERs.
In order to resolve the equal priority conditions described above,
following rules are defined:
* If two local inputs having same priority but requesting
different action come to the Local Request logic, then the
input coming first SHALL be considered to have a higher
priority than the other coming later (first-come, first-
served).
* If the LER receives both a local input and a remote message
with the same priority and requesting the same action, i.e.,
the same PSC Request Field and the same FPath value, then the
local input SHALL be considered to have a higher priority than
the remote message.
* If the LER receives both a local input and a remote message
with the same priority but requesting different actions, i.e.,
the same PSC Request Field but different FPath value, then the
first-come, first-served rule SHALL be applied. If the remote
message comes first, then the state SHALL be a remote state and
subsequent local input is ignored. However, if the local input
comes first, the first-come, first-served rule cannot be
applied and must be viewed as simultaneous condition. This is
because the subsequent remote message will not be an
acknowledge of the local input by the far-end node. In this
case, the priority SHALL be determined by rules for each
simultaneous conditions.
* If the LER receives both MS-P and MS-W commands either as local
input or remote message and the LER is in a local Switching
administrative state, then the MS-W command SHALL be considered
to have a higher priority than the MS-P command.
As mentioned in Section 3.6.1, the state transition is determined
by the higher priority input between the highest priority local
input and the remote message. This also determines the
classification of the state as local or remote. The following
subsections detail the transition based on the current state and
the higher priority of these two inputs.
4.7. Updates to Section 4.3.3.1. Normal State
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Replace the following bullet item in the reaction to local input
list:
o A local Forced Switch input SHALL cause the LER to go into local
Protecting administrative state and begin transmission of an
FS(1,1) message.
With:
o A local Forced Switch input SHALL cause the LER to go into local
Switching administrative state and begin transmission of an
FS(1,1) message.
Replace the following bullet item in the reaction to local input
list:
o A local Manual Switch input SHALL cause the LER to go into local
Protecting administrative state and begin transmission of an
MS(1,1) message.
With:
o A local Manual Switch Protection input SHALL cause the LER to go
into local Switching administrative state and begin transmission
of an MS(1,1) message.
o A local Manual Switch Working input SHALL cause the LER to go into
local Switching administrative state and begin transmission of an
MS(0,0) message.
Replace the following bullet item in the reaction to remote message
list:
o A remote Forced Switch message SHALL cause the LER to go into
remote Protecting administrative state and begin transmitting an
NR(0,1) message.
With:
o A remote Forced Switch message SHALL cause the LER to go into
remote Switching administrative state and begin transmitting an
NR(0,1) message.
Replace the following bullet item in the reaction to remote message
list:
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o A remote Manual Switch message SHALL cause the LER to go into
remote Protecting administrative state, and transmit an NR(0,1)
message.
With:
o A remote Manual Switch to Protection message SHALL cause the LER
to go into remote Switching administrative state, and transmit an
NR(0,1) message.
o A remote Manual Switch to Working message SHALL cause the LER to
go into remote Switching administrative state, while continuing to
transmit the NR(0,0) message.
4.8. Updates to Section 4.3.3.2. Unavailable State
Replace the following bullet item in the reaction to local input
list:
o A local Forced Switch SHALL be ignored by the PSC Control logic
when in Unavailable state as a result of a (local or remote)
Lockout of protection. If in Unavailable state due to an SF on
protection, then the FS SHALL cause the LER to go into local
Protecting administrative state and begin transmitting an FS(1,1)
message. It should be noted that due to the unavailability of the
protection path (i.e., due to the SF condition) that this FS may
not be received by the far-end until the SF condition is cleared.
With:
o A local Forced Switch SHALL be ignored by the PSC Control logic
when in Unavailable state as a result of a (local or remote)
Lockout of protection. If in Unavailable state due to an SF on
protection, then the FS SHALL cause the LER to go into local
Switching administrative state and begin transmitting an FS(1,1)
message. It should be noted that due to the unavailability of the
protection path (i.e., due to the SF condition) that this FS may
not be received by the far-end until the SF condition is cleared.
Replace the following bullet item in the reaction to remote message
list:
o A remote Forced Switch message SHALL be ignored by the PSC Control
logic when in Unavailable state as a result of a (local or remote)
Lockout of protection. If in Unavailable state due to a local or
remote SF on protection, then the FS SHALL cause the LER to go
into remote Protecting administrative state; if in Unavailable
state due to local SF, begin transmitting an SF(0,1) message.
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With:
o A remote Forced Switch message SHALL be ignored by the PSC Control
logic when in Unavailable state as a result of a (local or remote)
Lockout of protection. If in Unavailable state due to a local or
remote SF on protection, then the FS SHALL cause the LER to go
into remote Switching administrative state; if in Unavailable
state due to local SF, begin transmitting an SF(0,1) message.
4.9. Updates to Section 4.3.3.3. Protecting Administrative State
Replace the title of this section with "Switching Administrative
State".
Replace the following text in the first paragraph:
In the Protecting administrative state, the user data traffic
SHALL be transported on the protection path, while the working
path is blocked due to an operator command, i.e., Forced Switch or
Manual Switch.
With:
In the Switching administrative state, the user data traffic SHALL
be transported on either the protection path or working path,
depending on an operator command. If FS or MS-P command is in
effect, the working path is blocked and the traffic SHALL be
transported on the protection path. If MS-W command is in effect,
the protection path is blocked and the traffic SHALL be
transported on the working path.
Replace the reaction to local input list with:
o A local Clear SHALL be ignored if in remote Switching
administrative state. If in local Switching administrative state
due to local FS or MS-P, then this input SHALL cause the LER to go
into Normal state when the LER is configured for revertive
behavior, or Do-not-Revert State when the LER is configured for
non-revertive behavior. If in local Switching administrative
state due to local MS-W, then this input SHALL cause the LER to go
into Normal state.
o A local Lockout of protection input SHALL cause the LER to go into
local Unavailable state and begin transmission of an LO(0,0)
message.
o A local Forced Switch input SHALL cause the LER to remain in local
Switching administrative state and transmit an FS(1,1) message.
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o A local Signal Fail indication on the protection path SHALL cause
the LER to go into local Unavailable state and begin transmission
of an SF(0,0) message, if the current state is due to a (local or
remote) MS-P or MS-W command. If the LER is in (local or remote)
Switching administrative state due to an FS situation, then the SF
on protection SHALL be ignored.
o A local Signal Fail indication on the working path SHALL cause the
LER to go into local Protecting failure state and begin
transmitting an SF(1,1) message, if the current state is due to a
(local or remote) MS-P or MS-W command. If the LER is in remote
Switching administrative state due to a remote Forced Switch
command, then this local indication SHALL cause the LER to remain
in remote Switching administrative state and transmit an SF(1,1)
message. If the LER is in local Switching administrative state
due to a local Forced Switch command, then this indication SHALL
be ignored (i.e., the indication should have been blocked by the
Local Request logic).
o A local Clear SF SHALL clear any local SF condition that may
exist. If in remote Switching administrative state, the LER SHALL
stop transmitting the SF(x,1) message and begin transmitting an
NR(0,1) message.
o A local Manual Switch to Protection input SHALL be ignored if in
remote Switching administrative state due to a remote Forced
Switch command. If the current state is due to a (local or
remote) Manual Switch to Protection operator command, it SHALL
cause the LER to remain in local Switching administrative state
and transmit an MS(1,1) message. If the current state is due to a
(local or remote) Manual Switch to Working operator command, the
local MS-P SHALL be ignored.
o A local Manual Switch to Working input SHALL be ignored if in
remote Switching administrative state due to a remote Forced
Switch command. If the current state is due to a (local or
remote) Manual Switch to Working operator command, it SHALL cause
the LER to remain in local Switching administrative state and
transmit an MS(0,0) message. If the current state is due to a
(local or remote) Manual Switch to Protection operator command,
the local MS-W SHALL be ignored.
o All other local inputs SHALL be ignored.
Replace the reaction to remote message list with:
o A remote Lockout of protection message SHALL cause the LER to go
into remote Unavailable state and begin transmitting an NR(0,0)
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message. It should be noted that this automatically cancels the
current Forced Switch, Manual Switch to Protection or Manual
Switch to Working command and data traffic is reverted to the
working path, if required.
o A remote Forced Switch message SHALL be ignored by the PSC Process
logic if there is an active local Forced Switch operator command.
If the Switching administrative state is due to a remote Forced
Switch message, then the LER SHALL remain in remote Switching
administrative state and continue transmitting the last message.
If the Switching administrative state is due to either a local or
remote Manual Switch to Protection or Manual Switch to Working
command, then the LER SHALL remain in remote Switching
administrative state (updating the state information with the
proper relevant information) and begin transmitting an NR(0,1)
message.
o A remote Signal Fail message indicating a failure on the
protection path SHALL cause the LER to go into remote Unavailable
state and begin transmitting an NR(0,0) message, if the Switching
administrative state is due to a Manual Switch to Protection or
Manual Switch to Working command. It should be noted that this
automatically cancels the current Manual Switch to Protection or
Manual Switch to Working command, and data traffic is reverted to
the working path, if required.
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 Switching administrative state is due to a local
or remote Manual Switch to Protection or Manual Switch to Working,
then the LER SHALL go to remote Protecting failure state and begin
transmitting an NR(0,1) message.
o A remote Manual Switch to Protection message SHALL be ignored by
the PSC Control logic if in Switching administrative state due to
a local or remote Forced Switch. If in Switching administrative
state due to a remote Manual Switch to Protection, then the LER
SHALL remain in remote Switching administrative state and continue
transmitting the current message. If in local Switching
administrative state due to an active Manual Switch to Protection,
then the LER SHALL remain in local Switching administrative state
and continue transmission of the MS(1,1) message. If in Switching
administrative state due to a remote MS-W, then the LER SHALL
remain in remote Switching administrative state, and begin
transmitting an NR(0,1) message. If in Switching administrative
state due to a local MS-W, then the remote MS-P message SHALL be
ignored.
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o A remote Manual Switch to Working message SHALL be ignored by the
PSC Control logic if in Switching administrative state due to a
local or remote Forced Switch. If in Switching administrative
state due to a remote MS-W, then the LER SHALL remain in remote
Switching administrative state and continue transmission of an
NR(0,0) message. If in Switching administrative state due to a
local MS-W, then the remote MS-W message SHALL be ignored. If in
Switching administrative state due to a remote MS-P, then the LER
SHALL remain in remote Switching administrative state and begin
transmitting an NR(0,0) message. If in Switching administrative
state due to a local MS-P, then the LER SHALL go into remote
Switching administrative state and begin transmitting an NR(0,0)
message. It should be noted that this automatically cancels the
current MS-P command.
o A remote DNR(0,1) message SHALL be ignored if in local Switching
administrative state. If in remote Switching administrative state
due to a remote FS or MS-P, then the LER SHALL go to Do-not-Revert
state and continue transmitting an NR(0,1) message. If in remote
Switching administrative state due to a remote MS-W, then the
remote DNR message SHALL be ignored.
o A remote NR(0,0) message SHALL be ignored if in local Switching
administrative state. If in remote Switching administrative state
due to remote FS and there is no active local Signal Fail
indication, then the LER SHALL go into Normal state and begin
transmitting an NR(0,0) message. If there is a local Signal Fail
on the working path, the LER SHALL go into local Protecting
failure state and begin transmitting an SF(1,1) message. If in
remote Switching administrative state due to remote MS-P or MS-W,
then the LER SHALL go into Normal state and begin transmitting an
NR(0,0) message. If in local Switching administrative state due
to local MS-P or MS-W, then the remote NR(0,0) message SHALL be
ignored.
o All other remote messages SHALL be ignored.
4.10. Updates to Section 4.3.3.4. Protecting Failure State
Replace the following bullet item in the reaction to local input
list:
o A local Forced Switch input SHALL cause the LER to go into
Protecting administrative state and begin transmission of an
FS(1,1) message.
With:
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o A local Forced Switch input SHALL cause the LER to go into
Switching administrative state and begin transmission of an
FS(1,1) message.
Replace the following bullet item in the reaction to remote message
list:
o A remote Forced Switch message SHALL cause the LER go into remote
Protecting administrative state, and if in local Protecting
failure state, the LER SHALL transmit the SF(1,1) message;
otherwise, it SHALL transmit NR(0,1).
With:
o A remote Forced Switch message SHALL cause the LER go into remote
Switching administrative state, and if in local Protecting failure
state, the LER SHALL transmit the SF(1,1) message; otherwise, it
SHALL transmit NR(0,1).
4.11. Updates to Section 4.3.3.5. Wait-to-Restore State
Replace the following bullet item in the reaction to local input
list:
o A local Forced Switch command SHALL send the Stop command to the
WTR timer, go into local Protecting administrative state, and
begin transmission of an FS(1,1) message.
With:
o A local Forced Switch command SHALL send the Stop command to the
WTR timer, go into local Switching administrative state, and begin
transmission of an FS(1,1) message.
Replace the following bullet item in the reaction to local input
list:
o A local Manual Switch input SHALL send the Stop command to the WTR
timer, go into local Protecting administrative state, and begin
transmission of an MS(1,1) message.
With:
o A local Manual Switch to Protection input SHALL send the Stop
command to the WTR timer, go into local Switching administrative
state, and begin transmission of an MS(1,1) message.
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o A local Manual Switch to Working input SHALL send the Stop command
to the WTR timer, go into local Switching administrative state,
and begin transmission of an MS(0,0) message.
Replace the following bullet item in the reaction to remote message
list:
o A remote Forced Switch message SHALL send the Stop command to the
WTR timer, go into remote Protecting administrative state, and
begin transmission of an NR(0,1) message.
With:
o A remote Forced Switch message SHALL send the Stop command to the
WTR timer, go into remote Switching administrative state, and
begin transmission of an NR(0,1) message.
Replace the following bullet item in the reaction to remote message
list:
o A remote Manual Switch message SHALL send the Stop command to the
WTR timer, go into remote Protecting administrative state, and
begin transmission of an NR(0,1) message.
With:
o A remote Manual Switch to Protection message SHALL send the Stop
command to the WTR timer, go into remote Switching administrative
state, and begin transmission of an NR(0,1) message.
o A remote Manual Switch to Working message SHALL send the Stop
command to the WTR timer, go into remote Switching administrative
state, and begin transmission of an NR(0,0) message.
4.12. Updates to Section 4.3.3.6. Do-not-Revert State
Replace the first paragraph:
Do-not-Revert state is a continuation of the Protecting failure
state when the protection domain is configured for non-revertive
behavior. While in Do-not-Revert state, data traffic SHALL
continue to be transported on the protection path until the
administrator sends a command to revert to Normal state. It
should be noted that there is a fundamental difference between
this state and Normal -- whereas Forced Switch in Normal state
actually causes a switch in the 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
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be transported on the protection path! To revert back to Normal
state, the administrator SHALL issue a Lockout of protection
command followed by a Clear command.
With:
Do-not-Revert state is a continuation of either the Protecting
failure state or Switching administrative state due to Forced
Switch or Manual Switch to Protection when the protection domain
is configured for non-revertive behavior. While in Do-not-Revert
state, data traffic SHALL continue to be transported on the
protection path until the administrator sends a command to revert
to Normal state. When the LER transitions into the Do-not-Revert
state, the PSC Control Process SHALL check the persistent state of
the local triggers to decide if it should further transition into
a new state. If the result of this check is a transition into a
new state, the LER SHALL transmit the corresponding message
described in this section and SHALL use the data path
corresponding to the new state. When the protection domain
remains in Do-not-Revert state, the end point SHALL transmit an
DNR(0,1) message if the state is local, or an NR(0,1) message if
the state is remote, indicating -- Nothing to report and data
traffic is being transported on the protection path.
Replace the following bullet item in the reaction to local input
list:
o A local Forced Switch command SHALL cause the LER to go into local
Protecting administrative state and begin transmission of an
FS(1,1) message.
With:
o A local Forced Switch command SHALL cause the LER to go into local
Switching administrative state and begin transmission of an
FS(1,1) message.
Replace the following bullet item in the reaction to local input
list:
o A local Manual Switch input SHALL cause the LER to go into local
Protecting administrative state and begin transmission of an
MS(1,1) message.
With:
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o A local Manual Switch to Protection input SHALL cause the LER to
go into local Switching administrative state and begin
transmission of an MS(1,1) message.
o A local Manual Switch to Working input SHALL cause the LER to go
into local Switching administrative state and begin transmission
of an MS(0,0) message.
Replace the following bullet item in the reaction to remote message
list:
o A remote Forced Switch message SHALL cause the LER to go into
remote Protecting administrative state and begin transmission of
an NR(0,1) message.
With:
o A remote Forced Switch message SHALL cause the LER to go into
remote Switching administrative state and begin transmission of an
NR(0,1) message.
Replace the following bullet item in the reaction to remote message
list:
o A remote Manual Switch message SHALL cause the LER to go into
remote Protecting administrative state and begin transmission of
an NR(0,1) message.
With:
o A remote Manual Switch to Protection message SHALL cause the LER
to go into remote Switching administrative state and begin
transmission of an NR(0,1) message.
o A remote Manual Switch to Working message SHALL cause the LER to
go into remote Switching administrative state and begin
transmission of an NR(0,0) message.
4.13. Updates to Appendix A. PSC State Machine Tables
Modify the state machine as follows (only modified cells are shown):
Part 1: Local input state machine
+---------+------+---------+--------+--------+--------+-----+
| | OC | LO | SF-P | FS | SF-W | SFc |
+---------+------+---------+--------+--------+--------+-----+
| N | | | | SA:F:L | | |
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| UA:LO:L | | | | | | |
| UA:P:L | | | | SA:F:L | | |
| UA:LO:R | | | | | | |
| UA:P:R | | | | SA:F:L | | |
| PF:W:L | | | | SA:F:L | | |
| PF:W:R | | | | SA:F:L | | |
| SA:F:L | [20] | | | | | |
| SA:MW:L | N | UA:LO:L | UA:P:L | SA:F:L | PF:W:L | i |
| SA:MP:L | [20] | | | SA:F:L | | |
| SA:F:R | | | | SA:F:L | | |
| SA:MW:R | i | UA:LO:L | UA:P:L | SA:F:L | PF:W:L | i |
| SA:MP:R | | | | SA:F:L | | |
| WTR | | | | SA:F:L | | |
| DNR | | | | SA:F:L | | |
+---------+------+---------+--------+--------+--------+-----+
+---------+---------+---------+--------+
| | MS-W | MS-P | WTRExp |
+---------+---------+---------+--------+
| N | SA:MW:L | SA:MP:L | |
| UA:LO:L | i | | |
| UA:P:L | i | | |
| UA:LO:R | i | | |
| UA:P:R | i | | |
| PF:W:L | i | | |
| PF:W:R | i | | |
| SA:F:L | i | | |
| SA:MW:L | i | i | i |
| SA:MP:L | i | | |
| SA:F:R | i | | |
| SA:MW:R | SA:MW:L | i | i |
| SA:MP:R | i | SA:MP:L | |
| WTR | i | SA:MP:L | |
| DNR | SA:MW:L | SA:MP:L | |
+---------+---------+---------+--------+
Part 2: Remote messages state machine
+---------+---------+--------+--------+------+---------+---------+
| | LO | SF-P | FS | SF-W | MS-W | MS-P |
+---------+---------+--------+--------+------+---------+---------+
| N | | | SA:F:R | | SA:MW:R | SA:MP:R |
| UA:LO:L | | | | | i | |
| UA:P:L | | | | | i | |
| UA:LO:R | | | | | i | |
| UA:P:R | | | SA:F:R | | i | |
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| PF:W:L | | | SA:F:R | | i | |
| PF:W:R | | | SA:F:R | | i | |
| SA:F:L | | | | | i | |
| SA:MW:L | UA:LO:R | UA:P:R | SA:F:R | [13] | i | i |
| SA:MP:L | | | SA:F:R | | SA:MW:R | |
| SA:F:R | | | | | i | |
| SA:MW:R | UA:LO:R | UA:P:R | SA:F:R | [13] | i | SA:MP:R |
| SA:MP:R | | | SA:F:R | | SA:MW:R | |
| WTR | | | SA:F:R | | SA:MW:R | SA:MP:R |
| DNR | | | SA:F:R | | SA:MW:R | SA:MP:R |
+---------+---------+--------+--------+------+---------+---------+
+---------+-----+-----+----+
| | WTR | DNR | NR |
+---------+-----+-----+----+
| N | | | |
| UA:LO:L | | | |
| UA:P:L | | | |
| UA:LO:R | | | |
| UA:P:R | | | |
| PF:W:L | | | |
| PF:W:R | | | |
| SA:F:L | | | |
| SA:MW:L | i | i | i |
| SA:MP:L | | | |
| SA:F:R | | | |
| SA:MW:R | i | i | i |
| SA:MP:R | | | |
| WTR | | | |
| DNR | | | |
+---------+-----+-----+----+
Replace the following item in the footnotes for the table:
[4] Remain in the current state (PA:F:R) and transmit SF(1,1).
[8] Remain in PA:F:R and transmit NR(0,1).
[19] Transition to PA:F:R and send SF (0,1).
With:
[4] Remain in the current state (SA:F:R) and transmit SF(1,1).
[8] Remain in SA:F:R and transmit NR(0,1).
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[19] Transition to SA:F:R and send SF(0,1).
Add the following item in the footnotes for the table:
[20] If domain configured for revertive behavior transition to N,
else transition to DNR.
5. Security considerations
No specific security issue is raised in addition to those ones
already documented in [RFC6378]
6. IANA considerations
This document makes no request of IANA.
Note to RFC Editor: this section may be removed on publication as an
RFC.
7. Acknowledgements
8. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC4427] Mannie, E. and D. Papadimitriou, "Recovery (Protection and
Restoration) Terminology for Generalized Multi-Protocol
Label Switching (GMPLS)", RFC 4427, March 2006.
[RFC5654] Niven-Jenkins, B., Brungard, D., Betts, M., Sprecher, N.,
and S. Ueno, "Requirements of an MPLS Transport Profile",
RFC 5654, September 2009.
[RFC6378] Weingarten, Y., Bryant, S., Osborne, E., Sprecher, N., and
A. Fulignoli, "MPLS Transport Profile (MPLS-TP) Linear
Protection", RFC 6378, October 2011.
Authors' Addresses
Taesik Cheung
ETRI
218 Gajeongno
Yuseong-gu, Daejeon 305-700
South Korea
Phone: +82-42-860-5646
Email: cts@etri.re.kr
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Alessandro D'Alessandro
Telecom Italia
via Reiss Romoli, 274
Torino 10141
Italy
Phone: +39 011 2285887
Email: alessandro.dalessandro@telecomitalia.it
Huub van Helvoort
Huawei Technologies
Karspeldreef 4
Amsterdam 1101 CJ
The Netherlands
Phone: +31 20 4300832
Email: huub.van.helvoort@huawei.com
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