One document matched: draft-ietf-pwe3-redundancy-08.xml
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<rfc category="info" docName="draft-ietf-pwe3-redundancy-08" ipr="trust200902">
<front>
<title abbrev="PW Redundancy">Pseudowire Redundancy</title>
<author fullname="Praveen Muley" initials="P." surname="Muley">
<organization>Alcatel-Lucent</organization>
<address>
<postal>
<street></street>
<city></city>
<region></region>
<code></code>
<country></country>
</postal>
<email>praveen.muley@alcatel-lucent.com</email>
</address>
</author>
<author fullname="Mustapha Aissaoui" initials="M." surname="Aissaoui">
<organization>Alcatel-Lucent</organization>
<address>
<postal>
<street></street>
<city></city>
<region></region>
<code></code>
<country></country>
</postal>
<email>mustapha.aissaoui@alcatel-lucent.com</email>
</address>
</author>
<author fullname="Matthew Bocci" initials="M." surname="Bocci">
<organization>Alcatel-Lucent</organization>
<address>
<postal>
<street></street>
<city></city>
<region></region>
<code></code>
<country></country>
</postal>
<email>matthew.bocci@alcatel-lucent.com</email>
</address>
</author>
<date day="3" month="May" year="2012" />
<abstract>
<t>This document describes a framework comprised of a number of
scenarios and associated requirements for pseudowire (PW) redundancy. A
set of redundant PWs is configured between provider edge (PE) nodes in
single -segment PW applications, or between terminating PE (T-PE) nodes
in multi-segment PW applications. In order for the PE/T-PE nodes to
indicate the preferred PW to use for forwarding PW packets to one
another, a new PW status is required to indicate the preferential
forwarding status of active or standby for each PW in the redundancy
set.</t>
</abstract>
<note title="Requirements Language">
<t>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 <xref
target="RFC2119">RFC 2119</xref>.</t>
</note>
</front>
<middle>
<section title="Introduction">
<t>The objective of PW redundancy is to enable redundant attachment
circuits (ACs), provider edge nodes (PEs), and pseudowires (PWs) to
eliminate single points of failure in the path of an emulated service.
This is achieved while ensuring that only one active path exists between
a pair of customer edge nodes (CEs).</t>
<t>In single-segment PW (SS-PW) applications, protection for the PW is
provided by the packet switched network (PSN) layer. This may be a
resource reservation protocol with traffic engineering (RSVP-TE) labeled
switched path (LSP) with a fast-reroute (FRR) backup or an end-to-end
backup LSP. It is assumed that these mechanisms can restore PSN
connectivity rapidly enough to avoid triggering protection by PW
redundancy. PSN protection mechanisms cannot protect against the failure
of a PE node or the failure of the remote AC. Typically, this is
supported by dual-homing a customer edge (CE) node to different PE nodes
which provide a pseudowire emulated service across the PSN. A set of PW
mechanisms is therefore required that enables a primary and one or more
backup PWs to terminate on different PE nodes.</t>
<t>In multi-segment PW (MS-PW) applications, PSN protection mechanisms
cannot protect against the failure of a switching PE (S-PE). A set of
mechanisms that support the operation of a primary and one or more
backup PWs via a different set of S-PEs is therefore required. The paths
of these PWs are diverse in the sense that they are switched at
different S-PE nodes.</t>
<t>In both of these applications, PW redundancy is important to maximise
the resiliency of the emulated service.</t>
<t>This document describes the framework for these applications and its
associated operational requirements. The framework utilizes a new PW
status, called the Preferential Forwarding Status of the PW. This is
separate from the operational states defined in RFC4447 <xref
target="RFC4447"></xref>. The mechanisms for PW redundancy are modeled
on general protection switching principles.</t>
</section>
<section title="Terminology">
<t><list style="symbols">
<t>Up PW: A PW which has been configured (label mapping exchanged
between PEs) and is not in any of the PW defect states specified in
<xref target="RFC4447"></xref>. Such a PW is is available for
forwarding traffic.</t>
<t>Down PW: A PW that has either not been fully configured, or has
been configured and is in any one of the PW defect states specified
in <xref target="RFC4447"></xref>. Such a PW is not available for
forwarding traffic.</t>
<t>Active PW: An UP PW used for forwarding user, OAM and control
plane traffic.</t>
<t>Standby PW: An UP PW that is not used for forwarding user traffic
but may forward OAM and specific control plane traffic.</t>
<t>PW Endpoint: A PE where a PW terminates on a point where native
service processing is performed, e.g., A single-segment PW (SS-PW)
PE, a multi-segment pseudowire (MS-PW) terminating PE (T-PE), or a
hierarchical VPLS MTU-s or PE-rs.</t>
<t>Primary PW: The PW which a PW endpoint activates (i.e. uses for
forwarding) in preference to any other PW when more than one PW
qualifies for the active state. When the primary PW comes back up
after a failure and qualifies for the active state, the PW endpoint
always reverts to it. The designation of primary is performed by
local configuration for the PW at the PE and is only required when
revertive behaviour is used.</t>
<t>Secondary PW: When it qualifies for the active state, a secondary
PW is only selected if no primary PW is configured or if the
configured primary PW does not qualify for active state (e.g., is
DOWN). By default, a PW in a redundancy PW set is considered
secondary. There is no revertive mechanism among secondary PWs.</t>
<t>Revertive protection switching: Traffic will be carried by the
primary PW if it is UP and a wait-to-restore timer expires and the
primary PW is made the active PW.</t>
<t>Non-revertive protection switching: Traffic will be carried by
the last PW selected as a result of previous active PW entering the
operationally DOWN state.</t>
<t>Manual selection of a PW: The ability to manually select the
primary/secondary PWs.</t>
<t>MTU-s: A hierarchical virtual private LAN service multi-tenant
unit switch, as defined in RFC4762 <xref
target="RFC4762"></xref>.</t>
<t>PE-rs: A hierarchical virtual private LAN service switch, as
defined in RFC4762.</t>
<t>n-PE: A network facing provider edge node, as defined in RFC4026
<xref target="RFC4026"></xref>.</t>
</list></t>
<t>This document uses the term ‘PE’ to be synonymous with
both PEs as per RFC3985<xref target="RFC3985"></xref> and T-PEs as per
RFC5659 <xref target="RFC5659"></xref>.</t>
<t>This document uses the term ‘PW’ to be synonymous with
both PWs as per RFC3985 and SS-PWs, MS-PWs, and PW segments as per
RFC5659.</t>
</section>
<section title="Reference Models">
<t>The following sections show the reference architecture of the PE for
PW redundancy and the usage of the architecture in different topologies
and applications.</t>
<section title="PE Architecture">
<t><xref target="pe-arch"></xref> shows the PE architecture for PW
redundancy when more than one PW in a redundant set is associated with
a single AC. This is based on the architecture in Figure 4b of RFC3985
<xref target="RFC3985"></xref>. The forwarder selects which of the
redundant PWs to use based on the criteria described in this
document.</t>
<t><figure anchor="pe-arch" title="PE Architecture for PW redundancy">
<artwork><![CDATA[ +----------------------------------------+
| PE Device |
+----------------------------------------+
Single | | Single | PW Instance
AC | + PW Instance X<===========>
| | |
| |----------------------|
<------>o | Single | PW Instance
| Forwarder + PW Instance X<===========>
| | |
| |----------------------|
| | Single | PW Instance
| + PW Instance X<===========>
| | |
+----------------------------------------+
]]></artwork>
</figure></t>
</section>
<section title="PW Redundancy Network Reference Scenarios">
<t>This section presents a set of reference scenarios for PW
redundancy.</t>
<section title="Single Multi-Homed CE">
<t>The following figure illustrates an application of single segment
pseudowire redundancy. This scenario is designed to protect the
emulated service against a failure of one of the PEs or ACs attached
to the multi-homed CE. Protection against failures of the PSN
tunnels is provided using PSN mechanisms such as MPLS fast reroute,
so that these failures do not impact the PW.</t>
<t>CE1 is dual-homed to PE1 and PE3. A dual homing control protocol,
the details of which are outside the scope of this document, selects
which AC CE1 should use to forward towards the PSN, and which PE
(PE1 or PE3) should forward towards CE1.</t>
<t><figure anchor="one-multi-homed-ce"
title="PW Redundancy with One Multi-Homed CE">
<artwork><![CDATA[ |<-------------- Emulated Service ---------------->|
| |
| |<------- Pseudo Wire ------>| |
| | | |
| | |<-- PSN Tunnels-->| | |
| V V V V |
V AC +----+ +----+ AC V
+-----+ | | PE1|==================| | | +-----+
| |----------|....|...PW1.(active)...|....|----------| |
| | | |==================| | | CE2 |
| CE1 | +----+ |PE2 | | |
| | +----+ | | +-----+
| | | |==================| |
| |----------|....|...PW2.(standby)..| |
+-----+ | | PE3|==================| |
AC +----+ +----+
]]></artwork>
</figure>In this scenario, only one of the PWs should be used for
forwarding between PE1 / PE3, and PE2. PW redundancy determines
which PW to make active based on the forwarding state of the ACs so
that only one path is available from CE1 to CE2.</t>
<t>Consider the example where the AC from CE1 to PE1 is initially
active and the AC from CE1 to PE3 is initially standby. PW1 is made
active and PW2 is made standby in order to complete the path to
CE2.</t>
<t>On failure of the AC between CE1 and PE1, the forwarding state of
the AC on PE3 transitions to Active. The preferential forwarding
state of PW2 therefore needs to become active, and PW1 standby, in
order to reestablish connectivity between CE1 and CE2. PE3 therefore
uses PW2 to forward towards CE2, and PE2 uses PW2 instead of PW1 to
forward towards CE1. PW redundancy in this scenario requires that
the forwarding status of the ACs at PE1 and PE3 be signaled to PE2
so that PE2 can choose which PW to make active.</t>
<t>Changes occurring on the dual-homed side of the network due to a
failure of the AC or PE are not propagated to the ACs on the other
side of the network. Furthermore, failures in the PSN are not
propagated to the attached CEs.</t>
</section>
<section title="Multiple Multi-Homed CEs">
<t>This scenario, illustrated in <xref
target="multi-multi-homed-ces"></xref>, is also designed to protect
the emulated service against failures of the ACs and failures of the
PEs. Both CE1 and CE2, are dual-homed to their respective PEs, PE1
and PE2, and PE3 and PE4. The method used by the CEs to choose which
AC to use to forward traffic towards the PSN is determined by a
dual-homing control protocol. The details of this protocol are
outside the scope of this document.</t>
<t>Note that the PSN tunnels are not shown in this figure for
clarity. However, it can be assumed that each of the PWs shown is
encapsulated in a separate PSN tunnel. Protection against failures
of the PSN tunnels is provided using PSN mechanisms such as MPLS
fast reroute, so that these failures do not impact the PW.</t>
<figure anchor="multi-multi-homed-ces"
title="Multiple Multi-Homed CEs with PW Redundancy">
<artwork><![CDATA[ |<-------------- Emulated Service ---------------->|
| |
| |<------- Pseudowire ------->| |
| | | |
| | |<-- PSN Tunnels-->| | |
| V V V V |
V AC +----+ +----+ AC V
+-----+ | |....|.......PW1........|....| | +-----+
| |----------| PE1|...... .........| PE3|----------| |
| CE1 | +----+ \ / PW3 +----+ | CE2 |
| | +----+ X +----+ | |
| | | |....../ \..PW4....| | | |
| |----------| PE2| | PE4|--------- | |
+-----+ | |....|.....PW2..........|....| | +-----+
AC +----+ +----+ AC
]]></artwork>
</figure>
<t>PW1 and PW4 connect PE1 to PE3 and PE4, respectively. Similarly,
PW2 and PW3 connect PE2 to PE4 and PE3. PW1, PW2, PW3 and PW4 are
all UP. In order to support N:1 or 1:1 protection, only one PW MUST
be selected to forward traffic. This document defines an additional
PW state that reflects this forwarding state, which is separate from
the operational status of the PW. This is the ‘Preferential
Forwarding Status’.</t>
<t>If a PW has a preferential forwarding status of
‘active’, it can be used for forwarding traffic. The
actual UP PW chosen by the combined set of PEs connected to the CEs
is determined by considering the preferential forwarding status of
each PW at each PE. The mechanisms for communicating the
preferential forwarding status are outside the scope of this
document. Only one PW is used for forwarding.</t>
<t>The following failure scenario illustrates the operation of PW
redundancy in <xref target="multi-multi-homed-ces"></xref>. In the
initial steady state, when there are no failures of the ACs, one of
the PWs is chosen as the active PW, and all others are chosen as
standby. The dual-homing protocol between CE1 and PE1/PE2 chooses to
use the AC to PE2, while the protocol between CE2 and PE3/PE4
chooses to use the AC to PE4. Therefore the PW between PE2 and PE4
is chosen as the active PW to complete the path between CE1 and
CE2.</t>
<t>On failure of the AC between the dual-homed CE1 and PE2, the
preferential forwarding status of the PWs at PE1, PE2, PE3 and PE4
needs to change so as to re-establish a path from CE1 to CE2.
Different mechanisms can be used to achieve this and these are
beyond the scope of this document. After the change in status, the
algorithm needs to revaluate and select which PW to forward traffic
on. In this application, each dual-homing algorithm, i.e., {CE1,
PE1, PE2} and {CE2, PE3, PE4}, selects the active AC independently.
There is therefore a need to signal the active status of each AC
such that the PEs can select a common active PW for forwarding
between CE1 and CE2.</t>
<t>Changes occurring on one side of network due to a failure of the
AC or PE are not propagated to the ACs on the other side of the
network. Furthermore, failures in the PSN are not propagated to the
attached CEs. Note that end-to-end native service protection
switching can also be used to protect the emulated service in this
scenario. In this case, PW3 and PW4 are not necessary.</t>
<t>If the CEs do not perform native service protection switching,
they may instead use load balancing across the paths between the
CEs.</t>
</section>
<section title="Single-Homed CE With MS-PW Redundancy">
<t>This application is shown in <xref target="SH-CE-MS-PW"></xref>.
The main objective is to protect the emulated service against
failures of the S-PEs.</t>
<t><figure anchor="SH-CE-MS-PW"
title="Single-Homed CE with MS-PW Redundancy">
<artwork><![CDATA[ Native |<----------- Pseudowires ----------->| Native
Service | | Service
(AC) | |<-PSN1-->| |<-PSN2-->| | (AC)
| V V V V V V |
| +-----+ +-----+ +-----+ |
+----+ | |T-PE1|=========|S-PE1|=========|T-PE2| | +----+
| |-------|......PW1-Seg1.......|.PW1-Seg2......|-------| |
| CE1| | |=========| |=========| | | CE2|
| | +-----+ +-----+ +-----+ | |
+----+ |.||.| |.||.| +----+
|.||.| +-----+ |.||.|
|.||.|=========| |========== .||.|
|.||...PW2-Seg1......|.PW2-Seg2...||.|
|.| ===========|S-PE2|============ |.|
|.| +-----+ |.|
|.|============+-----+============= .|
|.....PW3-Seg1.| | PW3-Seg2......|
==============|S-PE3|===============
| |
+-----+
]]></artwork>
</figure>CE1 is connected to PE1 and CE2 is connected to PE2.
There are three multi-segment PWs. PW1 is switched at S-PE1, PW2 is
switched at S-PE2, and PW3 is switched at S-PE3.</t>
<t>Since there is no multi-homing running on the ACs, the T-PE nodes
advertise 'active' for the preferential forwarding status based on a
priority for the PW. The priority associates a meaning of 'primary
PW' and 'secondary PW' to a PW. These priorities MUST be used if
revertive mode is used and the active PW to use for forwarding
determined accordingly. The priority can be derived via
configuration or based on the value of the PW FEC. For example, a
lower value of PWid FEC can be taken as a higher priority. However,
this does not guarantee selection of same PW by the T-PEs because
of, for example, a mismatch in the configuration of the PW priority
at each T-PE. The intent of this application is for T-PE1 and T-PE2
to synchronize the transmit and receive paths of the PW over the
network. In other words, both T-PE nodes are required to transmit
over the PW segment which is switched by the same S-PE. This is
desirable for ease of operation and troubleshooting.</t>
</section>
<section title="PW Redundancy Between MTU-s in H-VPLS">
<t>The following figure (based on the architecture shown in Figure 3
of <xref target="RFC4762"></xref>) illustrates the application of PW
redundancy to hierarchical VPLS (H-VPLS). Note that the PSN tunnels
are not shown for clarity, and only one PW of a PW group is shown.
Here, a multi-tenant unit switch (MTU-s) is dual-homed to two PE
router switches (PE-rs).</t>
<t><figure anchor="mtu-dual-homing"
title="MTU-s Dual Homing in H-VPLS Core">
<artwork><![CDATA[
PE1-rs
+--------+
| VSI |
Active PW | -- |
Group..........|../ \..|.
CE-1 . | \ / | .
\ . | -- | .
\ . +--------+ .
\ MTU-s . . . PE3-rs
+--------+ . . . +--------+
| VSI | . . H-VPlS .| VSI |
| -- ..|.. . Core |.. -- |
| / \ | . PWs | / \ |
| \ /..|.. . | \ / |
| -- | . . .|.. -- |
+--------+ . . . +--------+
/ . . .
/ . +--------+ .
/ . | VSI | .
CE-2 . | -- | .
..........|../ \..|.
Standby PW | \ / |
Group | -- |
+--------+
PE2-rs
]]></artwork>
</figure>In <xref target="mtu-dual-homing"></xref>, the MTU-s is
dual homed to PE1-rs and PE2-rs and has spoke PWs to each of them.
The MTU-s needs to choose only one of the spoke PWs (the active PW)
to forward traffic to one of the PEs, and sets the other PW to
standby. The MTU-s can derive the status of the PWs based on local
policy configuration. PE1-rs and PE2-rs are connected to the H-VPLS
core on the other side of network. The MTU-s communicates the status
of its member PWs for a set of virtual switching instances (VSIs)
that share a common status of active or standby. Here, the MTU-s
controls the selection of PWs used to forward traffic. Signaling
using PW grouping with a common group-id in the PWid FEC Element, or
a Grouping TLV in Generalized PWid FEC Element as defined in <xref
target="RFC4447"></xref>, to PE1-rs and PE2-rs, is recommended for
improved scaling.</t>
<t>Whenever an MTU-s performs a switchover of the active PW group,
it needs to communicate this status change the PE2-rs. That is, it
informs PE2-rs that the status of the standby PW group has changed
to active.</t>
<t>In this scenario, PE devices are aware of switchovers at the
MTU-s and could generate MAC Withdraw messages to trigger MAC
flushing within the H-VPLS full-mesh. By default, MTU-s devices
should still trigger MAC withdraw messages as defined in <xref
target="RFC4762"></xref> to prevent two copies of MAC withdraws to
be sent (one by the MTU-s and another one by the PE-rs'). Mechanisms
to disable the MAC withdraw trigger in certain devices are out of
the scope of this document.</t>
</section>
<section title="PW Redundancy Between VPLS Network Facing PEs (n-PEs)">
<t>The following figure illustrates the use of PW redundancy for
dual-homed connectivity between PEs in a ring topology. As above,
PSN tunnels are not shown and only one PW of a PW group is shown for
clarity.</t>
<t><figure anchor="VPLS-Ring" title="Redundancy in a Ring Topology">
<artwork><![CDATA[
PE1 PE2
+--------+ +--------+
| VSI | | VSI |
| -- | | -- |
......|../ \..|.....................|../ \..|.......
| \ / | PW Group 1 | \ / |
| -- | | -- |
+--------+ +--------+
. .
. .
VPLS Domain A . . VPLS Domain B
. .
. .
. .
+--------+ +--------+
| VSI | | VSI |
| -- | | -- |
......|../ \..|.....................|../ \..|........
| \ / | PW Group 2 | \ / |
| -- | | -- |
+--------+ +--------+
PE3 PE4
]]></artwork>
</figure>In <xref target="VPLS-Ring"></xref>, PE1 and PE3 from
VPLS domain A are connected to PE2 and PE4 in VPLS domain B via PW
group 1 and PW group 2. The PEs are connected to each other in such
a way as to form a ring topology. Such scenarios may arise in
inter-domain H-VPLS deployments where rapid spanning tree (RSTP) or
other mechanisms may be used to maintain loop free connectivity of
the PW groups.</t>
<t><xref target="RFC4762"></xref> outlines multi-domain VPLS
services without specifying how multiple redundant border PEs per
domain and per VPLS instance can be supported. In the example above,
PW group 1 may be blocked at PE1 by RSTP and it is desirable to
block the group at PE2 by exchanging the PW preferential forwarding
status of standby. The details of how PW grouping is achieved and
used is deployment specific and is outside the scope of this
document.</t>
</section>
<section title="Redundancy in a VPLS Bridge Module Model">
<t><figure anchor="vpls-bridge" title="Bridge Module Model">
<artwork><![CDATA[ |<----- Provider ----->|
Core
+------+ +------+
| n-PE |::::::::::::::::::::::| n-PE |
Provider | (P) |.......... .........| (P) | Provider
Access +------+ . . +------+ Access
Network X Network
(1) +------+ . . +------+ (2)
| n-PE |.......... .........| n-PE |
| (B) |......................| (B) |
+------+ +------+
]]></artwork>
</figure></t>
<t><figure title="Bridge Module Model">
<artwork><![CDATA[
]]></artwork>
</figure></t>
<t><xref target="vpls-bridge"></xref> shows a scenario with two
provider access networks. Each network has two n-Pes. These n-PEs
are connected via a full mesh of PWs for a given VPLS instance. As
shown in the figure, only one n-PE in each access network serves as
the primary PE (P) for that VPLS instance and the other n-PE serves
as the backup PE (B). In this figure, each primary PE has two active
PWs originating from it. Therefore, when a multicast, broadcast, or
unknown unicast frame arrives at the primary n-PE from the access
network side, the n-PE replicates the frame over both PWs in the
core even though it only needs to send the frames over a single PW
(shown with :::: in the figure) to the primary n-PE on the other
side. This is an unnecessary replication of the customer frames that
consumes core-network bandwidth (half of the frames get discarded at
the receiving n-PE). This issue gets aggravated when there is three
or more n-PEs per provider, access network. For example if there are
three n-PEs or four n-PEs per access network, then 67% or 75% of
core bandwidthfor multicast, broadcast and unknown unicast are
wasted, respectively.</t>
<t>In this scenario, the n-PEs can communicate the active or standby
status of the PWs among them. This status can be derived from the
active or backup state of an n-PE for a given VPLS.</t>
</section>
</section>
</section>
<section title="Generic PW Redundancy Requirements">
<t></t>
<section title="Protection Switching Requirements">
<t><list style="symbols">
<t>Protection architectures such as N:1,1:1 or 1+1 are possible.
1:1 protection MUST be supported. The N:1 protection case is less
efficient in terms of the resources that must be allocated and
hence this SHOULD be supported. 1+1 protection MAY be used in the
scenarios described in the document. However, the details of its
usage are outside the scope of this document.</t>
<t>Non-revertive behavior MUST be supported, while revertive
behavior is OPTIONAL. This avoids the need to designate one PW as
primary unless revertive behavior is explicitly required.</t>
<t>Protection switchover can be initiated from a PE e.g. using a
manual lockout/force switchover, or it may be triggered by a
signal failure i.e. a defect in the PW or PSN. Manual switchover
may be necessary if it is required to disable one PW in a
redundant set. Both methods MUST be supported and signal failure
triggers MUST be treated with a higher priority than any local or
far-end manual trigger.</t>
<t>Note that a PE MAY be able to forward packets received from a
PW with a standby status in order to avoid black holing of
in-flight packets during switchover. However, in the case of use
of VPLS, all VPLS application packets received from standby PWs
MUST be dropped, except for OAM packets.</t>
</list></t>
<t></t>
</section>
<section title="Operational Requirements">
<t><list style="symbols">
<t>(T-)PEs involved in protecting a PW SHOULD automatically
discover and attempt to resolve inconsistencies in the
configuration of primary/secondary PW.</t>
<t>(T-)PEs involved in protecting a PW SHOULD automatically
discover and attempt to resolve inconsistencies in the
configuration of revertive/non-revertive protection switching
mode.</t>
<t>(T-)PEs that do not automatically discover or resolve
inconsistencies in the configuration of primary/secondary,
revertive/non-revertive, or other parameters MUST generate an
alarm upon detection of an inconsistent configuration.</t>
<t>(T-)PEs participating in PW redundancy MUST support the
configuration of revertive or non-revertive protection switching
modes if both modes are supported.</t>
<t>(T-)PEs participating in PW redundancy SHOULD support the local
invocation of protection switching.</t>
<t>(T-)PEs participating in PW redundancy SHOULD support the local
invocation of a lockout of protection switching.</t>
</list></t>
</section>
</section>
<section anchor="IANA" title="Security Considerations">
<t>This document requires extensions to the Label Distribution Protocol
(LDP) that are needed for protecting pseudowires. These will inherit at
least the same security properties as LDP <xref target="RFC5036"></xref>
and the PW control protocol <xref target="RFC4447"></xref>.</t>
</section>
<section title="IANA Considerations">
<t>This document has no actions for IANA.</t>
</section>
<section title="Major Contributing Authors">
<t>The editors would like to thank Pranjal Kumar Dutta, Marc Lasserre,
Jonathan Newton, Hamid Ould-Brahim, Olen Stokes, Dave Mcdysan, Giles
Heron and Thomas Nadeau who made a major contribution to the development
of this document.</t>
<t><figure>
<artwork><![CDATA[Pranjal Dutta
Alcatel-Lucent
Email: pranjal.dutta@alcatel-lucent.com
Marc Lasserre
Alcatel-Lucent
Email: marc.lasserre@alcatel-lucent.com
Jonathan Newton
Cable & Wireless
Email: Jonathan.Newton@cw.com
Olen Stokes
Extreme Networks
Email: ostokes@extremenetworks.com
Hamid Ould-Brahim
Nortel
Email: hbrahim@nortel.com
Dave McDysan
Verizon
Email: dave.mcdysan@verizon.com
Giles Heron
Cisco Systems
Email: giles.heron@gmail.com
Thomas Nadeau
Computer Associates
Email: tnadeau@lucidvision.com
]]></artwork>
</figure></t>
</section>
<section anchor="Acknowledgements" title="Acknowledgements">
<t>The authors would like to thank Vach Kompella, Kendall Harvey,
Tiberiu Grigoriu, Neil Hart, Kajal Saha, Florin Balus and Philippe Niger
for their valuable comments and suggestions.</t>
</section>
</middle>
<back>
<references title=" Normative References">
<?rfc include="reference.RFC.2119"?>
<?rfc include='reference.RFC.4447'?>
<?rfc include='reference.RFC.3985'?>
<?rfc include='reference.RFC.5036'?>
<?rfc include='reference.RFC.4762'?>
<?rfc ?>
<?rfc include='reference.RFC.4026'?>
<?rfc include='reference.RFC.5659'?>
</references>
<references title="Informative References">
<?rfc include='reference.RFC.6073'?>
</references>
</back>
</rfc>
| PAFTECH AB 2003-2026 | 2026-04-23 21:43:43 |