RFC6374 UDP Return Path
draft-ietf-mpls-rfc6374-udp-return-path-04
The information below is for an old version of the document.
| Document | Type | Active Internet-Draft (mpls WG) | |
|---|---|---|---|
| Authors | Stewart Bryant , Siva Sivabalan , Sagar Soni | ||
| Last updated | 2016-01-07 (Latest revision 2015-08-26) | ||
| Replaces | draft-ietf-mpls-pm-udp-return | ||
| Stream | Internet Engineering Task Force (IETF) | ||
| Formats | plain text xml htmlized pdfized bibtex | ||
| Reviews |
OPSDIR Last Call review
Has Issues
GENART Last Call review
Ready
SECDIR Last Call review
Has Issues
RTGDIR Early review
Has Issues
|
||
| Stream | WG state | Submitted to IESG for Publication | |
| Document shepherd | Loa Andersson | ||
| Shepherd write-up | Show Last changed 2015-10-21 | ||
| IESG | IESG state | IESG Evaluation::Revised I-D Needed | |
| Consensus boilerplate | Yes | ||
| Telechat date |
(None)
Needs a YES. Needs 9 more YES or NO OBJECTION positions to pass. |
||
| Responsible AD | Deborah Brungard | ||
| Send notices to | (None) | ||
| IANA | IANA review state | IANA OK - Actions Needed |
draft-ietf-mpls-rfc6374-udp-return-path-04
MPLS S. Bryant
Internet-Draft S. Sivabalan
Intended status: Standards Track S. Soni
Expires: February 27, 2016 Cisco Systems
August 26, 2015
RFC6374 UDP Return Path
draft-ietf-mpls-rfc6374-udp-return-path-04
Abstract
This document specifies the procedure 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.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on February 27, 2016.
Copyright Notice
Copyright (c) 2015 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
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
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1. Introduction
This document describes how Packet Loss and Delay Measurement for
MPLS Networks protocol (MPLS-PLDM) [RFC6374] out-of-band responses
can be delivered to the querier using UDP/IP.
The use of UDP may be required to support data path management such
as passage through firewalls, or to provide the necessary
multiplexing needed in bistatic operation where the querier and the
collector are not co-located and the collector is gathering the
response information for a number of responders. In a highly scaled
system some MPLS-PLDM sessions may be off-loaded to a specific node
within the distributed system that comprises the Label Switching
Router (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.
The procedure described in this specification describes how the
querier 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 [RFC5586].
2. Requirements Language
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. Solution Overview
This document specifies that, unless configured otherwise, if a UDP
Return Object (URO) is present in a MPLS-PLDM Query, the responder
MUST use the IP address and UDP port in the URO to reply back to the
querier. Multiple UROs MAY be present in a MPLS-PLDM Query
indicating that an identical responses SHOULD be sent to each
address-port pair. A responder MAY be designed or configured to only
transmit a single response, in which case the response MUST be sent
using the parameters specified in the first URO in the query packet.
The procedures defined in this document may be applied to both
unidirectional and bidirectional LSPs. In this document, the term
bidirectional LSP includes the co-routed bidirectional LSP defined in
[RFC3945] and the associated bidirectional LSP that is constructed
from a pair of unidirectional LSPs (one for each direction) that are
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associated with one another at the LSP's ingress/egress points
[RFC5654]. The mechanisms defined in this document can apply to both
IP/MPLS and to the MPLS Transport Profile (MPLS-TP)[RFC5654],
[RFC5921]
3.1. UDP Return Object
NOTE TO RFC Editor please delete the following paragraph before
publication.
START DELETE
Note to reviewers - We considered a number of approaches to the
design. The first was to use the existing address object and a
separate UDP object, but concern was expressed in the WG that there
may be more than one collector that required this information, and
the combined size of the two objects was large. The next approach
considered by the authors was to create a new object by appending a
UDP port to the existing generalized address object. However, noting
that UDP is only likely to be sent over IP and that it will be a long
time before we design a third major version of IP we can compress the
object either by having separate IPv4 and IPv6 objects, or using the
address length as the discriminator. The object design below uses
the latter approach. The resultant combined UDP port + address
object is thus the same size as the original address object.
END DELETE
The format of the UDP Return Object (URO) is as follows:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| URO TLV Type | Length={6,18} | UDP-Destination-Port |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ Address ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Type and Length fields are each 8 bits long. The Length field
indicates the size in bytes of the remainder of the object (i.e. is
the size of the address in bytes plus 2). When the address is IPv4
the length field is thus 6 and when the address is IPv6 the length
field is thus 18. The length field therefore acts as both the TLV
parsing parameter and the address family type indicator.
The UDP Return Object Type (URO TLV Type) has a value of 131.
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The UDP Destination Port is a UDP Destination port as specified in
[RFC0768].
The Address is either an IPv4 or an IPv6 address.
The URO MUST NOT appear in a response.
4. Theory of Operation
This document defines the UDP Return Object to enable the MPLS-PLDM
querier to specify the return path for the MPLS-PLDM reply using IP/
UDP encapsulation.
When the MPLS-PLDM Response is requested out-of-band by setting the
Control Code of the MPLS-PLDM query to "Out-of-band Response
Requested", and the URO is present, the responder SHOULD send the
response back to querier on the specified destination UDP port at the
specified destination IP address contained in the URO.
If the URO is expected but is not present in a query message and an
MPLS-PLDM Response is requested out-of-band, the query message MUST
NOT be processed further, and if possible an "Error - Invalid
Message" ([RFC6374] Section 3.1) SHOULD be send to the querier and
the operator notified via the management system (see Section 4.2 for
further details.
4.1. Sending an MPLS-PM Query
When sending an MPLS-PLDM query message, in addition to the rules and
procedures defined in [RFC6374]; the Control Code of the MPLS-PLDM
query MUST be set to "Out-of-band Response Requested", and a URO MUST
be carried in the MPLS-PLDM query message.
If the querier uses the UDP port to de-multiplexing of the response
for different measurement type, there MUST be a different UDP port
for each measurement type (Delay, loss and delay-loss combined).
An implementation MAY use multiple UDP ports for same measurement
type to direct the response to the correct management process in the
LSR.
4.2. Receiving an MPLS PM Query Request
The processing of MPLS-PLDM query messages as defined in [RFC6374]
applies in this document. In addition, when an MPLS-PLDM query
message is received, with the control code of the MPLS-PLDM query set
to "Out-of-band Response Requested" with a URO present, then the
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responder SHOULD use that IP address and UDP port to send MPLS-PLDM
response back to querier.
If an Out-of-band response is requested and the Address object or the
URO is missing, the query SHOULD be dropped in the case of a
unidirectional LSP. If both these TLVs are missing on a
bidirectional LSP, the control code of Response message should set to
0x1C indicating "Error - Invalid Message" ([RFC6374] Section 3.1) and
the 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.
4.3. Sending an MPLS-PM Response
As specified in [RFC6374] 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.
When the requested return path is an IP forwarding path and this
method is in use, the destination IP address and UDP port MUST be
copied from the URO. 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
[RFC6374]. As shown in Figure 1 the Associate Channel Header (ACH)
[RFC5586] is not included. The information provided by the ACH is
not needed since the correct binding between the query and response
messages is achieved though the UDP Port and the session indentifier
contained in the RFC6374 message.
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+----------------------------------------------------------+
| IP Header |
. Source Address = Responders IP Address |
. Destination Address = URO.Address |
. Protocol = UDP .
. .
+----------------------------------------------------------+
| UDP Header |
. Source Port = As chosen by Responder .
. Destination Port = URO.UDP-Destination-Port .
. .
+----------------------------------------------------------+
| Message as specified in RFC6374 |
. .
+----------------------------------------------------------+
Figure 1: Response packet Format
If the return path is an 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].
4.4. Receiving an MPLS-PM Response
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 [RFC6374].
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.
5. Manageability Considerations
The manageability considerations described in Section 7 of [RFC6374]
are applicable to this specification. Additional manageability
considerations are noted within the elements of procedure of this
document.
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 URO MAY be omitted from the
MPLS-PLDM messages.
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6. Security Considerations
The MPLS-PLDM system is not intended to be deployed on the public
Internet. It is intended for deployment in well managed private and
service provider networks. The security considerations described in
Section 8 of [RFC6374] 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.
There is no additional exposure of information to pervasive
monitoring systems observing LSPs that are being monitored.
7. IANA Considerations
IANA has made an early allocation of a new Optional TLV type from
MPLS Loss/Delay Measurement TLV Object Registry contained within the
Generic Associated Channel (G-ACh) Parameters registry set. IANA is
requested to modify the description text as shown below.
Code Description Reference
131 UDP Return [This]
8. Acknowledgements
We acknowledge the contribution of Joseph Chin and Rakesh Gandhi,
both with Cisco Systems. We thank Loa Andersson, Eric Osborne,
Mustapha Aissaoui, Jeffrey Zhang and Ross Callon for their review
comments.
We thank all who have reviewed this text and provided feedback.
9. References
9.1. Normative References
[RFC0768] Postel, J., "User Datagram Protocol", STD 6, RFC 768,
DOI 10.17487/RFC0768, August 1980,
<http://www.rfc-editor.org/info/rfc768>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
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[RFC3945] Mannie, E., Ed., "Generalized Multi-Protocol Label
Switching (GMPLS) Architecture", RFC 3945,
DOI 10.17487/RFC3945, October 2004,
<http://www.rfc-editor.org/info/rfc3945>.
[RFC5586] Bocci, M., Ed., Vigoureux, M., Ed., and S. Bryant, Ed.,
"MPLS Generic Associated Channel", RFC 5586,
DOI 10.17487/RFC5586, June 2009,
<http://www.rfc-editor.org/info/rfc5586>.
[RFC5654] Niven-Jenkins, B., Ed., Brungard, D., Ed., Betts, M., Ed.,
Sprecher, N., and S. Ueno, "Requirements of an MPLS
Transport Profile", RFC 5654, DOI 10.17487/RFC5654,
September 2009, <http://www.rfc-editor.org/info/rfc5654>.
[RFC6374] Frost, D. and S. Bryant, "Packet Loss and Delay
Measurement for MPLS Networks", RFC 6374,
DOI 10.17487/RFC6374, September 2011,
<http://www.rfc-editor.org/info/rfc6374>.
9.2. Informative References
[RFC5921] Bocci, M., Ed., Bryant, S., Ed., Frost, D., Ed., Levrau,
L., and L. Berger, "A Framework for MPLS in Transport
Networks", RFC 5921, DOI 10.17487/RFC5921, July 2010,
<http://www.rfc-editor.org/info/rfc5921>.
Authors' Addresses
Stewart Bryant
Cisco Systems
Email: stbryant@cisco.com
Siva Sivabalan
Cisco Systems
Email: msiva@cisco.com
Sagar Soni
Cisco Systems
Email: sagsoni@cisco.com
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