One document matched: draft-bryant-mpls-oam-udp-return-01.xml
<?xml version="1.0" encoding="US-ASCII"?>
<!DOCTYPE rfc SYSTEM "rfc2629.dtd">
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<?rfc tocdepth="3"?>
<?rfc tocindent="yes"?>
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<rfc category="std" docName="draft-bryant-mpls-oam-udp-return-01"
ipr="trust200902">
<front>
<title abbrev="MPLS PM UDP Return">MPLS Performance Measurement UDP Return
Path</title>
<author fullname="Stewart Bryant" initials="S" surname="Bryant">
<organization>Cisco Systems</organization>
<address>
<email>stbryant@cisco.com</email>
</address>
</author>
<author fullname="Siva Sivabalan" initials="S" surname="Sivabalan">
<organization>Cisco Systems</organization>
<address>
<postal>
<street></street>
<city></city>
<region></region>
<code></code>
<country></country>
</postal>
<phone></phone>
<facsimile></facsimile>
<email>msiva@cisco.com</email>
<uri></uri>
</address>
</author>
<author fullname="Sagar Soni" initials="S" surname="Soni">
<organization>Cisco Systems</organization>
<address>
<postal>
<street></street>
<city></city>
<region></region>
<code></code>
<country></country>
</postal>
<phone></phone>
<facsimile></facsimile>
<email>sagsoni@cisco.com</email>
<uri></uri>
</address>
</author>
<date year="2014" />
<area>Routing</area>
<workgroup>MPLS</workgroup>
<keyword>MPLS</keyword>
<keyword>Internet-Draft</keyword>
<abstract>
<t>This document specifies the proceedure to be used by the Packet Loss
and Delay Measurement for MPLS Networks protocol defined in RFC6374 when
sending and processing MPLS performance management out-of-band responses
for delay and loss measurements over an IP/UDP return path.</t>
</abstract>
</front>
<middle>
<section anchor="PS" title="Introduction">
<t>The Packet Loss and Delay Measurement for MPLS Networks protocol
(MPLS-PLDM) defined in<xref target="RFC6374"></xref> does not define how
an MPLS-PLDM out-of-band response delivered over IP will be transmitted
to the Querier. </t>
<t>In a highly scaled system some MPLS-PLDM sessions may be off-loaded
to a specific node within a the distributed system that comprises the
LSR as a whole. In such systems the response may arrive via any
interface in the LSR and need to internally forwarded to the processor
tasked with handling the particular MPLS-PLDM measurement. Currently the
MPLS-PLDM protocol does not have any mechanism to deliver the PLDM
Response message to particular node within a multi-CPU LSR.</t>
<t>The procedure described in this specification describes how the
queryer requests delivery of the MPLS-PLDM response over IP to a dynamic
UDP port. It makes no other changes to the protocol and thus does not
affect the case where the reponse is delivered over a MPLS Associated
Channel <xref target="RFC5586"></xref>.</t>
</section>
<section 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"></xref>.</t>
</section>
<section title="Solution Overview">
<t>This document specifies that, unless configured otherwise, the
Addressing Object defined in <xref target="RFC6374"></xref> SHALL be
sent in MPLS-PLDM query messages to tell the responder the IP return
address to be used. This document also defines Return UDP Port object
which, unless configured otherwise SHALL be used to the return UDP port.
The Addressing Object and the Return UDP PORT object carried in the
MPLS-PLDM query message are used to specify to the Responder how to
return the response message.</t>
<t>The procedures defined in this document may be applied to both
unidirectional tunnels and Bidirectional LSPs. In this document, the
term bidirectional LSP includes the co-routed Bidirectional LSP defined
in <xref target="RFC3945"></xref> and the associated bidirectional LSP
that is constructed from a pair of unidirectional LSPs (one for each
direction) that are associated with one another at the LSP's
ingress/egress points <xref target="RFC5654"></xref>. The mechanisms
defined in this document can apply to both IP/MPLS and the MPLS
Transport Profile (MPLS-TP).</t>
<section title="Return UDP Port Object">
<t>The format of the Return UDP Port Object is as follows:</t>
<figure>
<artwork><![CDATA[
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| UDP TLV Type | Length = 2 | UDP Destination Port |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
]]></artwork>
</figure>
<t>The Return UDP Port Object TLV Type (UDP TLV Type) has a value of
<TBD>.</t>
<t>The Return UDP Port Object MUST NOT appear in a response.</t>
</section>
</section>
<section title="Theory of Operation">
<t>This document defines the Return UDP Port Object and uses the
Addressing Object to enable the MPLS-PLDM Querier to specify the return
path for the MPLS-PLDM reply using IP/UDP encapsulation.</t>
<t>When the MPLS-PLDM Response is requested out-of-band by setting
Control Code of the MPLS-PLDM Query to "Out-of-band Response
Requested”, the responder SHOULD send the response back to Querier
on the specified destination UDP port at the specified destination IP
address as received in the Return UDP Port Object and Return Address
Object respectively.</t>
<t>If either the Return Address Object or Return UDP Port Object is not
present in Query message and an MPLS-PLDM Response is requested
out-of-band, the Query message MUST NOT be processed further. If
received over a bidirectional LSP, the control code of the Response
message MUST be set to “Error - Missing TLV” and a Response
SHOULD be sent over the reverse LSP. The receipt of such a mal-formed
request SHOULD be notified to the operator through the management
system, taking the normal precautions with respect to the prevention of
overload of the error reporting system.</t>
<section title="Missing TLV">
<t>The control code "Missing TLV", which is classified as an Error
response code, indicates that the operation failed because one or more
required TLV Objects was not sent in the query message.</t>
</section>
<section title="Sending an MPLS-PM Query ">
<t>When sending an MPLS-PLDM Query message, in addition to the rules
and procedures defined in <xref target="RFC6374"></xref>; the Control
Code of the MPLS-PLDM Query MUST be set to "Out-of-band Response
Requested", and a “Return UDP Port TLV” along with
“Return Address TLV” MUST be carried in the MPLS-PLDM
Query message.</t>
<t>Since the Querier uses the UDP port to de-multiplex response for
different measurement type, there SHOULD be a different UDP port for
each measurement type (Delay, loss and delay-loss combined).</t>
<t>An implementation MAY use multiple UDP ports for same measurement
type to direct the response to the correct management process in the
LSR.</t>
</section>
<section title="Receiving an MPLS PM Query Request ">
<t>The processing of MPLS-PLDM query messages as defined in <xref
target="RFC6374"></xref> applies in this document. In addition, when
an MPLS-PLDM Query request is received, with the Control Code of the
MPLS-PLDM Query set to "Out-of-band Response Requested" with a Return
address TLV and Return UDP TLV is present, then the Responder SHOULD
use that IP address and UDP port to send MPLS-PLDM response back to
Querier.</t>
<t>If an Out-of-band response is requested and either the Return
Address TLV or the Return UDP port TLV is missing, the Query SHOULD be
dropped in the case of unidirectional LSP. If either of these TLVs is
missing on a bidirectional LSP, the control code of Response message
should set to “Invalid Message” and the response SHOULD be
sent over the reverse LSP. In either case the receipt of such a
mal-formed request SHOULD be notified to the operator through the
management system, taking the normal precautions with respect to the
prevention of overload of the error reporting system.</t>
</section>
<section title="Sending an MPLS-PM Response">
<t>As specified in <xref target="RFC6374"></xref> the MPLS-PLDM
Response can be sent over either the reverse MPLS LSP for a
bidirectional LSP or over an IP path. It MUST NOT be sent other than
in response to an MPLS-PLDM Query message.</t>
<t>When the requested return path is an IP forwarding path and this
method is in use, the destination IP address and UDP port SHOULD be
copied from the Return Address TLV and the Return UDP TLV
respectively. The source IP address and the source UDP port of
Response packet is left to discretion of the Responder subject to the
normal management and security considerations. The packet format for
the MPLS-PLDM response after the UDP header is as specified in <xref
target="RFC6374"></xref>. As shown in <xref target="encap"></xref> the
Associate Channel Header (ACH) <xref target="RFC5586"></xref> is not
incuded. The information provided by the ACH is not needed since the
correct binding between the Querry and Response messages is achieved
though the UDP Port and the Session Indentifier contained in the
RFC6374 message.</t>
<t>As noted in </t>
<figure anchor="encap" title="Response packet Format">
<artwork><![CDATA[ +----------------------------------------------------------+
| IP Header |
. Source Address = Responders IP Address |
. Destination Addess = Return Address TLV.Address |
. Protocol = UDP .
. .
+----------------------------------------------------------+
| UDP Header |
. Source Port = As chosen by Responder .
. Destination Port = Return UDP Port TLV.UDP Dest Port .
. .
+----------------------------------------------------------+
| Message as specified in RFC6374 |
. .
+----------------------------------------------------------+
]]></artwork>
<postamble></postamble>
</figure>
<t></t>
<t>If the return path is IP path, only one-way delay or one-way loss
measurement can be carried out. In this case timestamps 3 and 4 MUST
be zero as specified in [RFC6374].</t>
</section>
<section title="Receiving an MPLS-PM Response">
<t>If the response was received over UDP/IP and an out-of-band
response was expected, the Response message SHOULD be directed to the
appropriate measurement process as determined by the destination UDP
Port, and processed using the corresponding measurement type procedure
specified in <xref target="RFC6374"></xref>.</t>
<t>If the Response was received over UDP/IP and an out-of-band
response was not requested, that response should be dropped and the
event SHOULD be notified to the operator through the management
system, taking the normal precautions with respect to the prevention
of overload of the error reporting system.</t>
</section>
</section>
<section title="Manageability Considerations">
<t>The manageability considerations described in Section 7 of <xref
target="RFC6374"></xref> are applicable to this specification.
Additional manageability considerations are noted within the elements of
procedure of this document.</t>
<t>Nothing in this document precludes the use of a configured UDP/IP
return path in a deployment in which configuration is preferred to
signalling. In these circumstances the address and UDP port TLVs MAY be
omitted from the MPLS-PLDM messages.</t>
</section>
<section title="Security Considerations">
<t>The MPLS-PLDM system is not intended to be deployed on the public
Internet. It is intended for deployment in well manages private and
service provider networks. The security considerations described in
Section 8 of <xref target="RFC6374"></xref> are applicable to this
specification and the reader's attention is drawn to the last two
paragraphs. Cryptographic measures may be enhanced by the correct
configuration of access control lists and firewalls.</t>
<t>There is no additional exposure of information to pervasive
monitoring systems observing LSPs that are being monitored.</t>
</section>
<section title="IANA Considerations">
<t>IANA is requested to assign a new Optional TLV type from MPLS
Loss/Delay Measurement TLV Object Registry contained within the
g-ach-parameters registry set.</t>
<figure>
<artwork><![CDATA[ Code Description Reference
TBD Return UDP Port [This]]]></artwork>
</figure>
<t>The TLV 131 is recommended.</t>
<t>IANA is requested to assign a new response code in the MPLS
Loss/Delay Measurement Control Code Registry contained within the
g-ach-parameters registry set.</t>
<figure>
<artwork><![CDATA[ Code Description Reference
TBD Missing TLV [This]]]></artwork>
</figure>
<t>The response code 0x1E is recommended.</t>
</section>
<section title="Acknowledgements">
<t>We acknowledge the contribution of Joseph Chin and Rakesh Gandhi,
both with Cisco Systems. We thank Loa Andersson for his review
comments.</t>
<t>We thank all who have reviewed this text and provided feedback.</t>
</section>
</middle>
<back>
<references title="Normative References">
<?rfc include='reference.RFC.2119'?>
<?rfc include='reference.RFC.6374'?>
<?rfc include='reference.RFC.3945'?>
<?rfc include='reference.RFC.5654'?>
<?rfc include='reference.RFC.5586'?>
</references>
</back>
</rfc>
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