One document matched: draft-sprecher-mpls-tp-oam-analysis-03.xml
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<front>
<title abbrev="MPLS-TP OAM Analysis">MPLS-TP OAM Analysis</title>
<author fullname="Nurit Sprecher" initials="N." role="editor" surname="Sprecher">
<organization>Nokia Siemens Networks</organization>
<address>
<postal>
<street>3 Hanagar St. Neve Ne'eman B</street>
<city>Hod Hasharon</city>
<region />
<code>45241</code>
<country>Israel</country>
</postal>
<email>nurit.sprecher@nsn.com</email>
</address>
</author>
<author fullname="Tom Nadeau" initials="T." role="editor"
surname="Nadeau">
<organization>BT</organization>
<address>
<postal>
<street />
<region />
<code />
<country>United States</country>
</postal>
<email>tom.nadeau@bt.com</email>
</address>
</author>
<author fullname="Huub van Helvoort" initials="H." role="editor" surname="van Helvoort">
<organization>Huawei</organization>
<address>
<postal>
<street>Kolkgriend 38, 1356 BC Almere</street>
<city></city>
<region />
<code></code>
<country>Netherlands</country>
</postal>
<email>hhelvoort@huawei.com</email>
<phone>+31 36 5316076</phone>
</address>
</author>
<author fullname="Yaacov Weingarten" initials="Y." role="" surname="Weingarten">
<organization>Nokia Siemens Networks</organization>
<address>
<postal>
<street>3 Hanagar St. Neve Ne'eman B</street>
<city>Hod Hasharon</city>
<region />
<code>45241</code>
<country>Israel</country>
</postal>
<email>yaacov.weingarten@nsn.com</email>
<phone>+972-9-775 1827</phone>
</address>
</author>
<date day="23" month="April" year="2009" />
<abstract>
<t>The intention of this document is to analyze the set of
requirements for Operations, Administration, and Maintenance (OAM) for the
Transport Profile of MPLS(MPLS-TP) as defined in [MPLS-TP OAM Requirements],
to evaluate whether existing MPLS OAM tools can be applied to these
requirements. Eventually, the purpose of the document is to recommend which
of the existing tools should be extended and what new tools should be defined
to support the set of OAM requirements for MPLS-TP.</t>
</abstract>
</front>
<middle>
<section title="Introduction">
<t>OAM (Operations, Administration, and Maintenance) plays a significant
and fundamental role in carrier networks, providing methods for fault
management and performance monitoring in both the transport and the
service layers in order to improve their ability to support services with
guaranteed and strict Service Level Agreements (SLAs) while reducing their
operational costs.</t>
<t>[MPLS-TP Requirements] in general, and [MPLS-TP OAM Requirements]
in particular define a set of requirements for OAM functionality in MPLS-Transport
Profile (MPLS-TP) for MPLS-TP Label Switched Paths (LSPs) (network infrastructure)
and Pseudowires (PWs) (services).</t>
<t>The purpose of this document is to analyze the OAM requirements and
evaluate whether existing OAM tools defined for MPLS can be used to
meet the requirements, identify which tools need to be extended to
comply with the requirements, and which new tools need to be defined.
The existing tools that are evaluated include LSP Ping (defined in
[LSP Ping]), MPLS Bi-directional Forwarding Detection (BFD) (defined in
[MPLS BFD]) and Virtual Circuit Connectivity Verification (VCCV) (defined in
[PW VCCV] and [VCCV BFD]).</t>
<section title="LSP Ping">
<t>LSP Ping is a variation of ICMP Ping and traceroute [ICMP] adapted to
the different needs of MPLS LSP. Forwarding, of the LSP Ping packets, is
based upon the LSP Label and label stack, in order to guarantee that the
echo messages are switched in-band (i.e. over the same data route) of the LSP.
However, it should be noted that the messages are transmitted using IP/UDP
encapsulation and IP addresses in the 127/8 (loopback) range. The use of
the loopback range guarantees that the LSP Ping messages will be terminated,
by a loss of connectivity or inability to continue on the path, without being
transmitted beyond the LSP. </t>
<t>LSP Ping extends the basic ICMP Ping operation (of data-plane connectivity and
continuity check) with functionality to verify data-plane vs. control-plane
consistency for a Forwarding Equivalence Class (FEC) and also Maximum Transmission
Unit (MTU) problems. The traceroute functionality may be used to isolate and localize
the MPLS faults, using the Time-to-live (TTL) indicator to incrementally identify the
sub-path of the LSP that is succesfully traversed before the faulty link or node. LSP
Ping is not dependent on the MPLS control-plane for its operation, i.e. even though the
propagation of the LSP label may be performed over the control-plane via the Label
Distribution Protocol (LDP).</t>
<t>LSP Ping can be activated both in on-demand and pro-active (asynchronous)
modes, as defined in [MPLS-TP OAM Requirements]. </t>
<t>[P2MP LSP Ping] clarifies the applicability of LSP Ping to MPLS P2MP
LSPs, and extends the techniques and mechanisms of LSP Ping to the MPLS
P2MP environment.</t>
<t>[LSP Ping over MPLS Tunnels] extends LSP Ping to operate over MPLS
tunnels or for a stitched LSP.</t>
<t>As pointed out above, TTL exhaust is the method used to terminate flows at
intermediate LSRs, usually to locate a problem that was discovered previously.</t>
<t>Some of the drawbacks identified with LSP Ping include - LSP Ping is considered
to be computational intensive as pointed out in [MPLS BFD]. When LSP bundling is
employed in the network, there is no guarantee that the LSP Ping packets will
follow the same physical path used by the data traffic.</t>
</section>
<section title="MPLS BFD">
<t>BFD (Bidirectional Forwarding Detection) is a mechanism that is defined
for fast fault detection for point-to-point connections. BFD defines a simple packet
that may be transmitted over any protocol, dependent on the application that is
employing the mechanism. BFD is dependent upon creation of a session that
is agreed upon by both ends of the link (which may be a single link, LSP,
etc.) that is being checked. In addition to the control packets that BFD
defines, BFD supports an echo function to check the continuity, and verify
the reachability of the desired destination. BFD does not support neither a
discovery mechanism nor a traceroute capability for fault localization, these
must be provided by use of other mechanisms. The BFD packets support
authentication between the routers being checked.</t>
<t>BFD can be used in pro-active (asynchronous) and on-demand modes, as defined
in [MPLS-TP OAM Requirements], of operation.</t>
<t>[MPLS BFD] defines the use of BFD for P2P LSP end-points and is used to
verify data-plane continuity. It uses a simple hello protocol which can be
easily implemented in hardware. The end-points of the LSP exchange hello packets
at negotiated regular intervals and an end-point is declared down when expected
hello packets do not show up. Failures in each direction can be monitored
independently using the same BFD session. The use of the BFD echo function and
on-demand activation are outside the scope of the MPLS BFD specification.</t>
<t>The BFD session mechanism requires an additional (external) mechanism to bootstrap
and bind the session to a particular LSP or FEC. LSP Ping is designated by [MPLS BFD]
as the bootstrap mechanism for the BFD session in an MPLS environment. The implication
is that the session establishment BFD messages for MPLS are transmitted using a
IP/UDP encapsulation.</t>
<t>In order to be able to identify certain extreme cases of mis-connectivity, it is
necessary that each managed connection have its own unique identifiers. BFD uses
Discriminator values to identify the connection being verified, at both ends of the path.
These discriminator values are set by each end-node to be unique only in the context of
that node. This limited scope of uniqueness would not identify a misconnection of crossing
paths that use the same discriminators at their end-points.</t>
</section>
<section title="PW VCCV">
<t>PW VCCV provides end-to-end fault detection and diagnostics for PWs
(regardless of the underlying tunneling technology). The VCCV switching function
provides a control channel associated with each PW (based on the PW Associated
Channel Header (ACH) which is defined in [PW-ACH]), and allows sending OAM packets in-band
with PW data (using CC Type 1: In-band VCCV)</t>
<t>VCCV supports the following OAM mechanisms: ICMP Ping, LSP Ping and BFD.
ICMP and LSP Ping are IP encapsulated before being sent over the PW ACH. BFD for
VCCV supports two modes of encapsulation - either IP/UDP encapsulated (with IP/UDP
header) or PW-ACH encapsulated (with no IP/UDP header) and provides support to
signal the AC status. The use of the VCCV control channel provides the context,
based on the MPLS-PW label, required to bind and bootstrap the BFD session to a
particular pseudo wire (FEC), eliminating the need to exchange Discriminator values.</t>
<t>VCCV consists of two components: (1) signaled component to communicate
VCCV capabilities as part of VC label, and (2) switching component to cause
the PW payload to be treated as a control packet.</t>
<t> VCCV is not directly dependent upon the presence of a control plane.
The VCCV capability negotiation may be performed as part of the PW signaling when LDP is used.
In case of manual configuration of the PW, it is the responsibility of the operator
to set consistent options at both ends. </t>
</section>
<section title="Acronyms">
<texttable>
<preamble>This draft uses the following acronyms:</preamble>
<ttcol align="left"/>
<ttcol align="left"/>
<c>AC</c><c>Attachment Circuit</c>
<c>ACH</c><c>Associated Channel Header</c>
<c>BFD</c><c>Bidirectional Forwarding Detection</c>
<c>FEC</c><c>Forwarding Equivalence Class</c>
<c>LDP</c><c>Label Distribution Protocol</c>
<c>LSP</c><c>Label Switched Path</c>
<c>ME</c><c>Maintenance Entitity</c>
<c>MEP</c><c>Maintenance End Point</c>
<c>MIP</c><c>Maintenance Intermediate Point</c>
<c>MPLS-TP</c><c>Transport Profile for MPLS</c>
<c>OAM</c><c>Operations, Administration, and Maintenance</c>
<c>PW</c><c>Pseudowire</c>
<c>RDI</c><c>Remote Defect Indication</c>
<c>SLA</c><c>Service Level Agreement</c>
<c>TC</c><c>Tandem Connection</c>
<c>TCME</c><c>Tandem Connection Maintenance Entity</c>
<c>TTL</c><c>Time-to-live</c>
<c>VCCV</c><c>Virtual Circuit Connectivity Verification</c>
<c>VPCV</c><c>Virtual Path Connectivity Verification</c>
</texttable>
</section>
<section title="Organization of the document">
<t>Section 2 of the document analyzes the requirements that are documented in
[MPLS-TP OAM Requirements] and provides basic principles of operation for the OAM
functionality that is required.</t>
<t>Section 3 evaluates which existing tools can provide coverage for the different OAM
functions that are required to support MPLS-TP.</t>
<t>Section 4 provides recommendations on what functionality could be covered by the
existing toolset and what extensions or new tools would be needed in order to provide
full coverage of the OAM functionality for MPLS-TP.</t>
</section>
</section>
<section title="Architectural requirements and general principles of operation">
<t />
<t>[MPLS-TP OAM Requirements] defines a set of requirements on OAM architecture
and general principles of operations which are evaluated below:</t>
<t>
<list style="symbols">
<t>[MPLS-TP OAM Requirements] requires that OAM mechanisms in MPLS-TP
are independent of the transmission media and of the client service
being emulated by the PW. The existing tools comply with this
requirement.</t>
<t>[MPLS-TP OAM Requirements] requires that MPLS-TP OAM MUST be able
to operate without IP functionality and without relying on control
and/or management planes. It is required that OAM functionality MUST
NOT be dependent on IP routing and forwarding capabilities. The
existing tools do not rely on control and/or management plane, however
the following should be observed regarding the reliance on IP functionality:</t>
<list style="symbols">
<t>LSP Ping, VCCV Ping, and MPLS BFD makes use of IP header (UDP/IP)
and do not comply with the requirement. In the on-demand mode, LSP Ping also
uses IP forwarding to reply back to the source router. This dependence on
IP, has further implications concerning the use of LSP Ping as the
bootstrap mechanism for BFD for MPLS.</t>
<t>VCCV BFD supports the use of PW-ACH encapsulated BFD sessions
for PWs and can comply with the requirement.</t>
</list>
<t>[MPLS-TP OAM Requirements] requires that OAM tools for fault
management do not rely on user traffic, and the existing MPLS OAM
tools already comply with this requirement. </t>
<t> It is also required that OAM packets and the user traffic are congruent (i.e.
OAM packets are transmitted in-band) and there is a need to differentiate OAM
packets from user-plane ones. </t>
<list style="symbols">
<t>For PWs, VCCV provides a control channel that can be associated with each
PW which allows sending OAM packets in band of PWs and allow the
receiving end-point to intercept, interpret, and process them
locally as OAM messages. VCCV defines different VCCV Connectivity
Verification Types for MPLS (like ICMP Ping, LSP Ping and IP/UDP
encapsulated BFD and PW-ACH encapsulated BFD).</t>
<t>Currently there is no distinct OAM payload identifier in MPLS
shim. BFD and LSP Ping packets for LSPs are carried over UDP/IP
and are addressed to the loopback address range. The router at
the end-point intercepts, interprets, and processes the packets.</t>
</list>
<t>[MPLS-TP OAM Requirements] requires that the MPLS-TP OAM mechanism
allows the propagation of AC (Attachment Circuit) failures and their
clearance across a MPLS-TP domain</t>
<list style="symbols">
<t>BFD for VCCV supports a mechanism for "Fault detection and
AC/PW Fault status signaling." This can be used for both IP/UDP
encapsulated or PW-ACH encapsulated BFD sessions, i.e. by setting
the appropriate VCCV Connectivity Verification Type.This mechanism
could support this requirement.</t>
</list>
<t>[MPLS-TP OAM Requirements] defines Maintenance Domain, Maintenance
End Points (MEPs) and Maintenance Intermediate Points (MIPs). Means
should be defined to provision these entities, both by static
configuration (as it is required to operate OAM in the absence of
any control plane or dynamic protocols) and by a control plane.</t>
<t>[MPLS-TP OAM Requirements] requires a single OAM technology and
consistent OAM capabilities for LSPs, PWs, MPLS-TP Links, and Tandem Connections.
There is currently no mechanism in the IETF to support OAM for Tandem Connections.
Also, the existing set of tools defines a different way of operating
the OAM functions (e.g. LSP Ping to bootstrap MPLS BFD vs. VCCV).</t>
<t>[MPLS-TP OAM Requirements] requires allowing OAM packets to be
directed to an intermediate node (MIP) of a LSP/PW. Technically, this could be
supported by the proper setting of the TTL value. However, the applicability
of such a solution needs to be examined per OAM function. For details, see below.</t>
<t>[MPLS-TP OAM Requirements] suggests that OAM messages MAY be
authenticated. BFD has a support for authentication. Other tools
should support this capability as well.</t>
</list>
</t>
<section title="Architectural and Principles of Operation – Recommendations and Guidelines">
<t>Based on the requirements analysis above, the following guidelines
should be followed to create an OAM environment that could more fully
support the requirements cited:</t>
<t><list style="symbols">
<t>Extend the PW Associate Channel Header (ACH) to provide a control
channel at the path and section levels. This could then be associated
with a MPLS-TP Link, LSP, or a Tandem Connection (TC). The ACH should then
become a common mechanism for PW, LSP, MPLS-TP Link, and Tandem Connection.</t>
<t>Create a VPCV (Virtual Path Connectivity Verification) definition
that would apply the definitions and functionality of VCCV to the
MPLS-TP environment for LSP or Tandem Connection. Need a generalized addressing
scheme that can also support unique identification of the monitored paths (or
connections).</t>
<t>Create or extend the VCCV definition to define a mechanism that would
apply the definitions and functionality of VCCV to PW Tandem Connections</t>
<t>Apply BFD to these new mechanisms using the control channel
encapsulation, as defined above – allowing use of BFD for MPLS-TP
independent of IP functionality.</t>
<t>Define a mechanism to create TCME and allow transmission
of the traffic via the Tandem Connection using label stacking.</t>
<t>Define a mechanism that could be used to address a MIP of a path in a unique
way, to support the maintenance functions. This addressing should be flexible to
allow support for different addressing schemes, and would supplement the TTL
addressing of intermediate points.</t>
</list></t>
<t>Creating these extensions/mechanisms would fulfill the following architectural
requirements, mentioned above:</t>
<t><list style="symbols">
<t>Independence of IP forwarding and routing.</t>
<t>OAM packets should be transmitted in-band.</t>
<t>Support a single OAM technology for LSP, PW, MPLS-TP Link, and TC.</t>
</list></t>
<t>In addition, the following additional requirements can be satisfied:</t>
<t><list style="symbols">
<t>Provide the ability to carry other types of communications (e.g.,
APS, Management Control Channel (MCC), Signalling Control Channel
(SCC)), by defining new types of communication channels for PWs, MPLS-TP Links,
and LSPs.</t>
<t>The design of the OAM mechanisms for MPLS-TP MUST allow the
ability to support vendor specific and experimental OAM functions.</t>
</list></t>
</section>
</section>
<section title="MPLS-TP OAM Functions">
<t>The following sections discuss the required OAM functions that were
identified in [MPLS-TP OAM Requirements].</t>
<t>LSP Ping is not considered a candidate to fulfill the required
functionality, due its failure to comply with the basic architectural requirement
for independence from IP routing and forwarding, as documented in Section
2 of this document. However, usage of LSP Ping, in addition to the MPLS-TP
OAM tools, or in MPLS-TP deployments with IP functionality is not
precluded.</t>
<section title="Continuity and Connectivity Verification">
<t>Continuity and Connectivity Verification (CC-V) are OAM operations
generally used in tandem, and compliment each other. Together they are used to
detect loss of traffic continuity and misconnections between
MEPs and are useful for applications like Fault Management, Performance
Monitoring and Protection Switching, etc. To guarantee that CC-V can identify
misconnections from cross-connections it is necessary that the tool use
network-wide unique identifiers for the path that is being checked in the session.</t>
<section title="Existing tools">
<t>BFD defines functionality that can be used to support the pro-active OAM CC-V
function when operated in the asynchronous mode. However, the current definition
of basic BFD is dependent on use of LSP Ping to bootstrap the BFD session. Regarding
the connectivity functional aspects, basic BFD has a limitation that it uses only
locally unique session identifiers.</t>
<t>VCCV can be used to carry BFD packets that are not IP/UDP
encapsulated for CC-V on a PW and use the PW label to identify the path.</t>
</section>
<section title="Gap analysis">
<t>There is currently no tool that gives coverage for both aspects of CC-V
functionality.</t>
<t>One possible option, is to extend BFD to fill the gaps indicated above.
The extension would include:
<list style="symbols">
<t>A mechanism should be defined to carry BFD packets over LSP without
reliance on IP functionality.</t>
<t>A mechanism should be defined to bootstrap BFD sessions for
MPLS that is not dependent on UDP.</t>
<t>BFD needs to be used in conjunction with "globally" unique
identifiers for the path or ME being checked to allow connectivity
verfication support. There are two possibilities, to allow BFD to support
this new type of identifier –
<list style="symbols">
<t>Change the semantics of the two Discriminator fields that exist in
BFD and have each node select the ME unique identifier. This may have
backward compatibility implications.</t>
<t>Create a new optional field in the packet carrying the BFD that would
identify the path being checked, in addition to the existing session
identifiers.</t>
</list>
</t>
<t>Extensions to BFD would be needed to cover P2MP connections.</t>
</list>
</t>
<t>An additional option would be to create a new tool that would give coverage
for both aspects of CC-V according to the requirements and the principles of operation
(see section 2.1). This option is less preferable.</t>
</section>
<section title="Recommendations and Guidelines">
<t>Extend BFD to resolve the gaps, using a new optional field for the unique
path identifier.</t>
<t>Note that [MP BFD] defines a method for using BFD to provide
verification of multipoint or multicast connectivity.</t>
</section>
</section>
<section title="Alarm Suppression">
<t>Alarm Suppression is a function that is used by a server layer MEP
to notify a failure condition to its client layer MEP(s) in order to
suppress alarms that may be generated by maintenance domains of the
client layer as a result of the failure condition in the server layer.
This function should also have the capability to differentiate an administrative
lock from a failure condition at a different execution level.</t>
<section title="Existing tools">
<t>There is no mechanism defined in the IETF to support this function.</t>
</section>
<section title="Recommendations and Guidelines">
<t>Define a tool to support Alarm Suppression.</t>
</section>
</section>
<section title="Packet Loss Measurement">
<t>Packet Loss Measurement is a function that is used to verify the quality of
the service. This function indicates the ratio of packets that are not delivered
out of all packets that are transmitted by the path source.</t>
<t>There are two possible ways of determining this measurement –
<list style="symbols">
<t>Using OAM packets, it is possible to compute the statistics based on a
series of OAM packets. This, however, has the disadvantage of being artificial,
and may not be representative since part of the packet loss may be dependent
upon packet sizes.</t>
<t>Sending delimiting messages for the start and end of a measurement period
during which the source and sink of the path count the packets transmitted and
received. After the end delimiter, the ratio would be calculated by the path
OAM entity.</t>
</list></t>
<section title="Existing tools">
<t>There is no mechanism defined in the IETF to support this function.</t>
</section>
<section title="Recommendations and Guidelines">
<t>Define a mechanism to support Packet Loss Measurement, based on the delimiting
messages. This would include a way for delimiting the periods for monitoring the
packet transmissions to measure the loss ratios, and computation of the ratio
between received and transmitted packets.</t>
</section>
</section>
<section title="Diagnostic Test">
<t>A diagnostic test is a function that is used between MEPs to verify
bandwidth throughput, packet loss, bit errors, etc.</t>
<section title="Existing tools">
<t>There is no mechanism defined in the IETF to support this function.</t>
</section>
<section title="Recommendations and Guidelines">
<t>Define a tool to support Diagnostic Test.</t>
</section>
</section>
<section title="Route Determination">
<t>Route Determination is used to determine the route of a
connection across the MPLS transport network.</t>
<section title="Existing tools">
<t>LSP Ping supports a trace route function that could be used but as it does
not comply with the requirement for OAM functions to be independent of IP routing and
forwarding capabilities. Therefore, it can not be utilized for MPLS-TP</t>
</section>
<section title="Recommendations and Guidelines">
<t>Define a new tool to support Route Determination.</t>
</section>
</section>
<section title="Delay Measurement">
<t>Delay Measurement is a function that is used to measure one-way or
two-way delay of a packet transmission between a pair of MEPs. Where:</t>
<t><list style="symbols">
<t>One-way packet delay is the time elapsed from the start of
transmission of the first bit of the packet by a source node until the
reception of the first bit of that packet by the destination node.</t>
<t>Two-way packet delay is the time elapsed from the start of transmission
of the first bit of the packet by a source node until the reception of
the last bit of the loop-backed packet by the same source node, when
the loopback is performed at the packet's destination node.</t>
</list></t>
<t>Similarly to the packet loss measurement this could be performed in one of
two ways –</t>
<t><list style="symbols">
<t>Using OAM packets – checking delay (either one-way or two-way) in
transmission of OAM packets. May not fully reflect delay of larger packets,
however, gives feedback on general service level.</t>
<t>Using delimited periods of transmission – may be too intrusive on the
client traffic.</t>
</list></t>
<section title="Existing tools">
<t>There is no mechanism defined in the IETF that fulfills all of the
MPLS-TP OAM requirements.</t>
</section>
<section title="Recommendations and Guidelines">
<t>Define a mechanism that would allow to support Delay Measurement. The
mechanism should be based on measurement of the delay in transmission and
reception of OAM packets, transmitted in-band with normal traffic.</t>
</section>
</section>
<section title="Remote Defect Indication">
<t>Remote Defect Indication (RDI) is used by a MEP to notify its peer
MEP that a defect is detected on a bi-directional connection between
them.</t>
<t>This function should be supported in pro-active mode.</t>
<section title="Existing tools">
<t>There is no mechanism defined in the IETF to fully support this
functionality, however BFD supports a mechanism of informing the far-end
that the session has gone down, and the Diagnostic field indicates the
reason.</t>
</section>
<section title="Recommendations and Guidelines">
<t>Either create a dedicated mechanism for this functionality or extend
the BFD session functionality to support the functionality without
disrupting the CC or CV functionality.</t>
</section>
</section>
<section title="Client Fail Indication">
<t>Client Fail Indication (CFI) function is used to propagate an indication of
a failure to the far-end sink when alarm suppression in the client layer
is not supported.</t>
<section title="Existing tools">
<t>There is a possibility of using the BFD over VCCV mechanism for "Fault
detection and AC/PW Fault status signalling". However, there is a need to
differentiate between faults on the AC and the PW.</t>
</section>
<section title="Recommendations and Guidelines">
<t>Either extend the BFD tool or define a tool to support Client Fail Indication
propagation.</t>
</section>
</section>
</section>
<section title="Recommendations">
<t>
<list style="symbols">
<t>Define a maintenance entity that could be applied both to LSPs and PWs that
would support management of a sub-path. This entity should allow for
transmission of traffic by means of label stacking and proper TTL setting.</t>
<t>Extend the control and the management planes to support the
configuration of the OAM maintenance entities and the set of functions
to be supported by these entities.</t>
<t>Extend the ACH to provide a control channel for MPLS-TP Links, LSPs, and
Tandem Connections.</t>
<t>Define a mechanism that would allow the unique addressing of the elements
that need to be monitored, e.g., the connections, MEPs, and MIPs of a path.
This mechanism needs to be flexible enough to support different addressing
schemes, e.g. IP addresses, NSAP, connection names.</t>
<t>Define a VPCV mechanism for LSP and Tandem Connection. This mechanism
should reuse, as much as possible, the same principles of operation as VCCV.
The ACH should be extended to support CV types for each of the tools that are
defined below, in a way that is consistent for PW, LSP and Tandem Connection.</t>
<t>The appropriate assignment of network-wide unique identifiers needed to
support connectivity verification should be considered.</t>
<t>Tools should be defined to support the following functions:</t>
<list style="symbols">
<t>On-demand connectivity verification</t>
<t>Alarm suppression</t>
<t>Packet loss measurement</t>
<t>Diagnostic test</t>
<t>Route determination</t>
<t>Delay measurement</t>
<t>Remote defect indication</t>
<t>Client fail indication</t>
</list>
<t>The tools may have the capability to authenticate the messages.</t>
</list> </t>
</section>
<section anchor="IANA" title="IANA Considerations">
<t>This document makes no request of IANA.</t>
<t>Note to RFC Editor: this section may be removed on publication as an
RFC.</t>
</section>
<section anchor="Security" title="Security Considerations">
<t>This document does not by itself raise any particular security
considerations.</t>
</section>
<section anchor="Acknowledgements" title="Acknowledgements">
<t>The authors wish to thank xxxxxxx for his review and proposed
enhancements to the text.</t>
</section>
</middle>
<back>
<references title="Informative References">
<!-- Begin inclusion reference.RFC.2119.xml. -->
<reference anchor="RFC2119">
<front>
<title abbrev="RFC Key Words">Key words for use in RFCs to Indicate
Requirement Levels</title>
<author fullname="Scott Bradner" initials="S." surname="Bradner">
<organization>Harvard University</organization>
<address>
<postal>
<street>1350 Mass. Ave.</street>
<street>Cambridge</street>
<street>MA 02138</street>
</postal>
<phone>- +1 617 495 3864</phone>
<email>sob@harvard.edu</email>
</address>
</author>
<date month="March" year="1997" />
<area>General</area>
<keyword>keyword</keyword>
<abstract>
<t>In many standards track documents several words are used to
signify the requirements in the specification. These words are
often capitalized. This document defines these words as they
should be interpreted in IETF documents. Authors who follow these
guidelines should incorporate this phrase near the beginning of
their document: <list>
<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 RFC 2119.</t>
</list></t>
<t>Note that the force of these words is modified by the
requirement level of the document in which they are used.</t>
</abstract>
</front>
<seriesInfo name="BCP" value="14" />
<seriesInfo name="RFC" value="2119" />
<format octets="4723" target="ftp://ftp.isi.edu/in-notes/rfc2119.txt"
type="TXT" />
<format octets="16553"
target="http://xml.resource.org/public/rfc/html/rfc2119.html"
type="HTML" />
<format octets="5703"
target="http://xml.resource.org/public/rfc/xml/rfc2119.xml"
type="XML" />
</reference>
<!-- End inclusion reference.RFC.2119.xml. -->
<!--Begin inclusion reference.RFC.4379 -->
<reference anchor="LSP Ping">
<front>
<title>Detecting Multi-Protocol Label Switched (MPLS) Data Plane Failures</title>
<author initials="K." surname="Kompella" fullname="K. Kompella">
<organization />
</author>
<author initials="G." surname="Swallow" fullname="G. Swallow">
<organization />
</author>
<date year="2006" month="February" />
<abstract>
<t>This document describes a simple and efficient mechanism that can be
used to detect data plane failures in Multi-Protocol Label Switching
(MPLS) Label Switched Paths (LSPs). There are two parts to this document:
information carried in an MPLS "echo request" and "echo reply" for the
purposes of fault detection and isolation, and mechanisms for reliably
sending the echo reply. [STANDARDS TRACK]</t>
</abstract>
</front>
<seriesInfo name="RFC" value="4379" />
<format type="TXT" octets="116872" target="ftp://ftp.isi.edu/in-notes/rfc4379.txt" />
</reference>
<!-- End inclusion reference.RFC.4379 -->
<!-- Begin inclusion reference.RFC.4385 -->
<reference anchor="PW ACH">
<front>
<title>Pseudowire Emulation Edge-to-Edge (PWE3) Control Word for Use over an MPLS PSN</title>
<author initials="S." surname="Bryant" fullname="S. Bryant">
<organization />
</author>
<author initials="G." surname="Swallow" fullname="G. Swallow">
<organization />
</author>
<author initials="L." surname="Martini" fullname="L. Martini">
<organization />
</author>
<author initials="D." surname="McPherson" fullname="D. McPherson">
<organization />
</author>
<date year="2006" month="February" />
<abstract>
<t>This document describes the preferred design of a Pseudowire Emulation Edge-to-Edge (PWE3) Control Word to be used over an MPLS packet switched n twork, and the Pseudowire Associated Channel Header. The design of these fields is chosen so that an MPLS Label Switching Router performing MPLS payload inspection will not confuse a PWE3 payload with an IP payload. [STANDARDS TRACK]</t>
</abstract>
</front>
<seriesInfo name="RFC" value="4385" />
<format type="TXT" octets="22440" target="ftp://ftp.isi.edu/in-notes/rfc4385.txt" />
</reference>
<!-- End inclusion reference.RFC.4385 -->
<!-- Begin inclusion reference.RFC.5085 -->
<reference anchor="PW VCCV">
<front>
<title>Pseudowire Virtual Circuit Connectivity Verification (VCCV): A Control Channel for Pseudowires</title>
<author initials="T." surname="Nadeau" fullname="T. Nadeau">
<organization />
</author>
<author initials="C." surname="Pignataro" fullname="C. Pignataro">
<organization />
</author>
<date year="2007" month="December" />
<abstract>
<t>This document describes Virtual Circuit Connectivity Verification (VCCV), which provides a control channel that is associated with a pseudowire (PW), as well as the corresponding operations and management functions (such as connectivity verification) to be used over that control channel. VCCV applies to all supported access circuit and transport types currently defined for PWs. [STANDARDS TRACK]</t>
</abstract>
</front>
<seriesInfo name="RFC" value="5085" />
<format type="TXT" octets="67847" target="ftp://ftp.isi.edu/in-notes/rfc5085.txt" />
</reference>
<!-- End inclusion reference.RFC.5085 -->
<!-- Begin inclusion reference.draft.MP.BFD -->
<reference anchor="MP BFD">
<front>
<title>BFD for Multipoint Networks</title>
<author initials="D." surname="Katz" fullname="Dave Katz">
<organization />
</author>
<author initials="D." surname="Ward" fullname="David Ward">
<organization />
</author>
<date year="2007" month="December" />
<abstract>
<t>This document describes Virtual Circuit Connectivity Verification (VCCV), which provides a control channel that is associated with a pseudowire (PW), as well as the corresponding operations and management functions (such as connectivity verification) to be used over that control channel. VCCV applies to all supported access circuit and transport types currently defined for PWs. [STANDARDS TRACK]</t>
</abstract>
</front>
<seriesInfo name="ID" value="draft-katz-ward-bfd-multipoint-01.txt" />
</reference>
<!-- End inclusion reference.draft.MP.BFD -->
<!-- Begin inclusion reference.draft.VCCV.BFD -->
<reference anchor="VCCV BFD">
<front>
<title>Bidirectional Forwarding Detection (BFD) for the Pseudowire Virtual Circuit Connectivity Verification (VCCV)</title>
<author initials="T." surname="Nadeau" fullname="T. Nadeau">
<organization />
</author>
<author initials="C." surname="Pignataro" fullname="C. Pignataro">
<organization />
</author>
<date year="2008" month="February" />
<abstract>
<t>This document describes Virtual Circuit Connectivity Verification (VCCV), which provides a control channel that is associated with a pseudowire (PW), as well as the corresponding operations and management functions (such as connectivity verification) to be used over that control channel. VCCV applies to all supported access circuit and transport types currently defined for PWs. [STANDARDS TRACK]</t>
</abstract>
</front>
<seriesInfo name="ID" value="draft-ietf-pwe3-vccv-bfd-01.txt" />
</reference>
<!-- End inclusion reference.draft.bfd.vccv -->
<!-- Begin inclusion reference.draft.p2mp.LSP.Ping -->
<reference anchor="P2MP LSP Ping">
<front>
<title>Detecting Data Plane Failures in Point-to-Multipoint Multiprotocol Label Switching (MPLS) - Extensions to LSP Ping</title>
<author initials="T." surname="Nadeau" fullname="T. Nadeau">
<organization />
</author>
<author initials="A." surname="Farrel" fullname="Adrian Farrel">
<organization />
</author>
<date year="2008" month="June" />
<abstract>
<t>This document describes Virtual Circuit Connectivity Verification (VCCV), which provides a control channel that is associated with a pseudowire (PW), as well as the corresponding operations and management functions (such as connectivity verification) to be used over that control channel. VCCV applies to all supported access circuit and transport types currently defined for PWs. [STANDARDS TRACK]</t>
</abstract>
</front>
<seriesInfo name="ID" value="draft-ietf-mpls-p2mp-lsp-ping-06.txt" />
</reference>
<!-- End inclusion reference.draft.p2mp.LSP.Ping -->
<!-- Begin inclusion reference.draft.LSP.Ping.MPLS -->
<reference anchor="MPLS LSP Ping">
<front>
<title>Mechanism for performing LSP-Ping over MPLS tunnels</title>
<author initials="N." surname="Bahadur" fullname="Nitin Bahadur">
<organization />
</author>
<author initials="K." surname="Kompella" fullname="Kireeti Kompella">
<organization />
</author>
<date year="2008" month="June" />
<abstract>
<t>This document describes Virtual Circuit Connectivity Verification (VCCV), which provides a control channel that is associated with a pseudowire (PW), as well as the corresponding operations and management functions (such as connectivity verification) to be used over that control channel. VCCV applies to all supported access circuit and transport types currently defined for PWs. [STANDARDS TRACK]</t>
</abstract>
</front>
<seriesInfo name="ID" value="draft-ietf-mpls-lsp-ping-enhanced-dsmap-00" />
</reference>
<!-- End inclusion reference.draft.LSP.Ping.MPLS -->
<!-- Begin inclusion reference.draft.MPLS.TP.OAM.Reqs -->
<reference anchor="MPLS-TP OAM Requirements">
<front>
<title>Requirements for OAM in MPLS Transport Networks</title>
<author initials="M." surname="Vigoureux" fullname="Martin Vigoureux">
<organization />
</author>
<author initials="M." surname="Betts" fullname="Malcolm Betts">
<organization />
</author>
<author initials="D." surname="Ward" fullname="Dave Ward">
<organization />
</author>
<date year="2008" month="July" />
<abstract>
<t>This document describes Virtual Circuit Connectivity Verification (VCCV), which provides a control channel that is associated with a pseudowire (PW), as well as the corresponding operations and management functions (such as connectivity verification) to be used over that control channel. VCCV applies to all supported access circuit and transport types currently defined for PWs. [STANDARDS TRACK]</t>
</abstract>
</front>
<seriesInfo name="ID" value="draft-vigoureux-mpls-tp-oam-requirements-00" />
</reference>
<!-- End inclusion reference.draft.MPLS.TP.OAM.Reqs -->
<!-- Begin inclusion reference.draft.MPLS.TP.Reqs -->
<reference anchor="MPLS-TP Requirments">
<front>
<title>Requirements for the Trasport Profile of MPLS</title>
<author initials="T." surname="Nadeau" fullname="T. Nadeau">
<organization />
</author>
<author initials="C." surname="Pignataro" fullname="C. Pignataro">
<organization />
</author>
<date year="2008" month="July" />
<abstract>
<t>This documen describes Virtual Circuit Connectivity Verification (VCCV), which provides a control channel that is associated with a pseudowire (PW), as well as the corresponding operations and management functions (such as connectivity verification) to be used over that control channel. VCCV applies to all supported access circuit and transport types currently defined for PWs. [STANDARDS TRACK]</t>
</abstract>
</front>
<seriesInfo name="ID" value="draft-jenkins-mpls-mplstp-requirements-00" />
</reference>
<!-- End inclusion reference.draft.MPLS.TP.Reqs -->
</references>
</back>
</rfc>| PAFTECH AB 2003-2026 | 2026-04-23 10:57:49 |