draft-ietf-ippm-type-p-monitor-00.txt   draft-ietf-ippm-type-p-monitor-01.txt 
Network Working Group J. Hedin Network Working Group J. Hedin
Internet-Draft G. Mirsky Internet-Draft G. Mirsky
Intended status: Standards Track S. Baillargeon Intended status: Standards Track S. Baillargeon
Expires: June 21, 2015 Ericsson Expires: June 21, 2015 Ericsson
December 18, 2014 December 18, 2014
Differentiated Service Code Point and Explicit Congestion Notification Differentiated Service Code Point and Explicit Congestion Notification
Monitoring in Two-Way Active Measurement Protocol (TWAMP) Monitoring in Two-Way Active Measurement Protocol (TWAMP)
draft-ietf-ippm-type-p-monitor-00 draft-ietf-ippm-type-p-monitor-01
Abstract Abstract
This document describes an OPTIONAL feature for TWAMP [RFC5357] This document describes an OPTIONAL extension for Two-Way Active
allowing the monitoring of the Differentiated Service Code Point and Measurement Protocol (TWAMP) allowing the monitoring of the
Explicit Congestion Notification fields with the TWAMP-Test protocol. Differentiated Service Code Point and Explicit Congestion
Notification fields with the TWAMP-Test protocol.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
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2. TWAMP Extensions . . . . . . . . . . . . . . . . . . . . . . 3 2. TWAMP Extensions . . . . . . . . . . . . . . . . . . . . . . 3
2.1. Setting Up Connection to Monitor DSCP and ECN . . . . . . 3 2.1. Setting Up Connection to Monitor DSCP and ECN . . . . . . 3
2.2. TWAMP-Test Extension . . . . . . . . . . . . . . . . . . 4 2.2. TWAMP-Test Extension . . . . . . . . . . . . . . . . . . 4
2.2.1. Session-Reflector Packet Format for DSCP and ECN 2.2.1. Session-Reflector Packet Format for DSCP and ECN
Monitoring . . . . . . . . . . . . . . . . . . . . . 4 Monitoring . . . . . . . . . . . . . . . . . . . . . 4
2.2.2. DSCP and ECN Monitoring with RFC 6038 extensions . . 7 2.2.2. DSCP and ECN Monitoring with RFC 6038 extensions . . 7
2.2.3. Consideration for TWAMP Light mode . . . . . . . . . 8 2.2.3. Consideration for TWAMP Light mode . . . . . . . . . 8
3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8 3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
4. Security Considerations . . . . . . . . . . . . . . . . . . . 8 4. Security Considerations . . . . . . . . . . . . . . . . . . . 8
5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 8 5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 8
6. References . . . . . . . . . . . . . . . . . . . . . . . . . 9 6. Normative References . . . . . . . . . . . . . . . . . . . . 9
6.1. Normative References . . . . . . . . . . . . . . . . . . 9
6.2. Informative References . . . . . . . . . . . . . . . . . 9
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9
1. Introduction 1. Introduction
One-Way Active Measurement Protocol (OWAMP) [RFC4656] defines Type-P One-Way Active Measurement Protocol (OWAMP) [RFC4656] defines Type-P
descriptor and negotiation of its value in OWAMP-Control protocol. descriptor and negotiation of its value in OWAMP-Control protocol.
Two-Way Active Measurement Protocol (TWAMP) [RFC5357] states that Two-Way Active Measurement Protocol (TWAMP) [RFC5357] states that
only Differentiated Service Code Point (DSCP) value can be defined by only Differentiated Service Code Point (DSCP) values can be defined
Type-P descriptor and the negotiated value must be used by both by Type-P descriptor and the negotiated value must be used by both
Session-Sender and Session-Reflector. The TWAMP specification also Session-Sender and Session-Reflector. The TWAMP specification also
states that the same value of DSCP (found in the Session-Sender states that the same DSCP value (found in the Session-Sender packet)
packet) MUST be used in the test packet reflected by the Session- MUST be used in the test packet reflected by the Session-Reflector.
Reflector. However the TWAMP-Test protocol does not specify any However the TWAMP-Test protocol does not specify any methods to
methods to determine or report when the DSCP value has changed or is determine or report when the DSCP value has changed or is different
different than expected in the forward or reverse direction. Re- than expected in the forward or reverse direction. Re-marking the
marking the DSCP (changing its original value) in IP networks is DSCP (changing its original value) in IP networks is possible and
possible and often accomplished by a Diffserv policy configured o a often accomplished by a Diffserv policy configured on a single node
single node along the IP path. In many cases, a change of the DSCP along the IP path. In many cases, a change of the DSCP value
value of indicates an unintentional or errorneous behavior. At best, indicates an unintentional or erroneous behavior. At best, the
the Session-Sender can detect a change of the DSCP reverse direction Session-Sender can detect a change of the DSCP reverse direction
assuming such change is actually detectable. assuming such change is actually detectable.
This document describes an OPTIONAL feature for TWAMP. It is called This document describes an OPTIONAL feature for TWAMP. It is called
the DSCP and ECN monitoring feature. This feature allows the the DSCP and ECN monitoring feature. This feature allows the
Session-Sender to know the actual DSCP value received at the Session- Session-Sender to know the actual DSCP value received at the Session-
Reflector. Furthermore this OPTIONAL feature also tracks the Reflector. Furthermore this OPTIONAL feature tracks the Explicit
Explicit Congestion Notification (ECN) value received at the Session- Congestion Notification (ECN) value received at the Session-
Reflector. This is helpful to determine if ECN is actually operating Reflector. This is helpful to determine if ECN is actually operating
or if an ECN-capable node has detected congestion in the forward or if an ECN-capable node has detected congestion in the forward
direction. direction.
1.1. Conventions used in this document 1.1. Conventions used in this document
1.1.1. Terminology 1.1.1. Terminology
DSCP: Differentiated Service Codepoint DSCP: Differentiated Service Codepoint
ECN: Explicit Congestion Notification ECN: Explicit Congestion Notification
IPPM: IP Performance Measurement IPPM: IP Performance Measurement
TWAMP: Two-Way Active Measuremnt Protocol TWAMP: Two-Way Active Measurement Protocol
OWAMP: One-Way Active Measurement Protocol OWAMP: One-Way Active Measurement Protocol
1.1.2. Requirements Language 1.1.2. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in "OPTIONAL" in this document are to be interpreted as described in
[RFC2119]. [RFC2119].
2. TWAMP Extensions 2. TWAMP Extensions
TWAMP connection establishment follows the procedure defined in TWAMP connection establishment follows the procedure defined in
Section 3.1 of [RFC4656] and Section 3.1 of [RFC5357] where the Modes Section 3.1 of [RFC4656] and Section 3.1 of [RFC5357] where the Modes
field been used to identify and select specific communication field is used to identify and select specific communication
capabilities. At the same time the Modes field been recognized and capabilities. At the same time the Modes field been recognized and
used as extension mechanism [RFC6038]. The new feature requires new used as an extension mechanism [RFC6038]. The new feature requires a
bit position to identify the ability of a Session-Reflector to return new bit position to identify the ability of a Session-Reflector to
value of received DSCP and ECN values back to a Session-Sender, and return value of received DSCP and ECN values back to a Session-
to support the new Session-Reflector packet format in the TWAMP-Test Sender, and to support the new Session-Reflector packet format in the
protocol. See the Section 3 for details on the assigned value and TWAMP-Test protocol. See the Section 3 for details on the assigned
bit position. value and bit position.
2.1. Setting Up Connection to Monitor DSCP and ECN 2.1. Setting Up Connection to Monitor DSCP and ECN
The Server sets DSCP and ECN Monitoring flag in Modes field of the The Server sets DSCP and ECN Monitoring flag in Modes field of the
Server Greeting message to indicate its capabilities and willingness Server Greeting message to indicate its capabilities and willingness
to monitor them. If the Control-Client agrees to monitor DSCP and to monitor them. If the Control-Client agrees to monitor DSCP and
ECN on some or all test sessions invoked with this control ECN on some or all test sessions invoked with this control
connection, it MUST set the DSCP and ECN Monitoring flag in Modes connection, it MUST set the DSCP and ECN Monitoring flag in the Modes
field in the Setup Response message. field in the Setup Response message.
2.2. TWAMP-Test Extension 2.2. TWAMP-Test Extension
Monitoring of DSCP and ECN requires support by Session-Reflector and Monitoring of DSCP and ECN requires support by the Session-Reflector
changes format of its test packet format both in unauthenticated, and changes the format of its test packet format both in
authenticated and encrypted modes. Monitoring of DSCP and ECN does unauthenticated, authenticated and encrypted modes. Monitoring of
not alter Session-Sender test packet format but certain DSCP and ECN does not alter the Session-Sender test packet format but
considerations must be taken when and if this mode is accepted in certain considerations must be taken when and if this mode is
combination with Symmetrical Size mode[RFC6038]. accepted in combination with Symmetrical Size mode [RFC6038].
2.2.1. Session-Reflector Packet Format for DSCP and ECN Monitoring 2.2.1. Session-Reflector Packet Format for DSCP and ECN Monitoring
When Session-Reflector supports DSCP and ECN Monitoring it MUST When the Session-Reflector supports DSCP and ECN Monitoring it MUST
construct Sender DSCP and ECN (S-DSCP-ECN) field for each test packet construct the Sender DSCP and ECN (S-DSCP-ECN) field for each test
it sends to Session-Sender according to the following procedure: packet it sends to Session-Sender according to the following
procedure:
- first six bits MUST be copied Differentiated Service field from o the first six bits of the Differentiated Service field MUST be
received Session-Sender test packet into Sender DSCP (S-DSCP) copied from received Session-Sender test packet into Sender DSCP
field; (S-DSCP) field;
- following two bits MUST be copied ECN field from received o the following two bits of the ECN field MUST be copied from
Session-Sender test packet into Sender ECN (S-ECN) field. received Session-Sender test packet into Sender ECN (S-ECN) field.
0 1 2 3 4 5 6 7 8 0 1 2 3 4 5 6 7 8
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| S-DSCP | S-ECN | | S-DSCP | S-ECN |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: Sender DSCP and ECN field format Figure 1: Sender DSCP and ECN field format
For unauthenticated mode: For unauthenticated mode:
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. . . .
. Packet Padding . . Packet Padding .
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3: Session-Reflector test packet format with DSCP and ECN Figure 3: Session-Reflector test packet format with DSCP and ECN
monitoring in authenticated or encrypted modes monitoring in authenticated or encrypted modes
The DSCP value is often copied into reflected test packets with The DSCP value is often copied into reflected test packets with
current TWAMP implementations (with or without TWAMP-Control current TWAMP implementations (with or without TWAMP-Control
protocol). With DSCP and ECN Monitoring Extenstion Session-Reflector protocol). With DSCP and ECN Monitoring Extension, the Session-
handles DSCP as following: Reflector handles DSCP as following:
The Session-Reflector MUST extracts the S-DSCP-ECN value from the o the Session-Reflector MUST extracts the S-DSCP-ECN value from the
DSCP and ECN values of received packets; DSCP and ECN values of received packets;
The Session-Reflector MUST transmit each reflected test packet o the Session-Reflector MUST transmit each reflected test packet
with DSCP set to the negotiated/provisioned value; with DSCP set to the negotiated/provisioned value;
If the negotiated/provisioned DSCP value is not known (e.g. TWAMP o if the negotiated/provisioned DSCP value is not known (e.g. TWAMP
Light), the choice of the DSCP is implementation specific. For Light), the choice of the DSCP is implementation specific. For
instance, Session-Reflector MAY copy the DSCP value from the instance, Session-Reflector MAY copy the DSCP value from the
received test packet and set it as DSCP in a reflected packet. received test packet and set it as DSCP in a reflected packet.
2.2.2. DSCP and ECN Monitoring with RFC 6038 extensions 2.2.2. DSCP and ECN Monitoring with RFC 6038 extensions
[RFC6038] defined two extensions to TWAMP. First, to ensure that [RFC6038] defined two extensions to TWAMP. First, to ensure that
Session-Sender and Session-Reflector exchange TWAMP-Test packets of Session-Sender and Session-Reflector exchange TWAMP-Test packets of
equal size. Second, to specify number of octets to be reflected by equal size. Second, to specify number of octets to be reflected by
Session-Reflector. If DSCP and ECN monitoring and Symmetrical Size Session-Reflector. If DSCP and ECN monitoring and Symmetrical Size
and/or Reflects Octets modes being negotiated between Server and and/or Reflects Octets modes are being negotiated between Server and
Control-Client in Unauthenticated mode, then because Sender DSCP and Control-Client in Unauthenticated mode, then, because Sender DSCP and
Sender ECN increase size of unauthenticated Session-Reflector packet Sender ECN increase size of unauthenticated Session-Reflector packet
by 4 octets the Padding Length value SHOULD be >= 28 octets to allow by 4 octets, the Padding Length value SHOULD be >= 28 octets to allow
for the truncation process that TWAMP recommends in Section 4.2. 1 of for the truncation process that TWAMP recommends in Section 4.2. 1 of
[RFC5357]. [RFC5357].
0 1 2 3 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 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence Number | | Sequence Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Timestamp | | Timestamp |
| | | |
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. . . .
. Packet Padding . . Packet Padding .
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4: Session-Sender test packet format with DSCP and ECN Figure 4: Session-Sender test packet format with DSCP and ECN
monitoring and Symmetrical Test Packet in unauthenticated mode monitoring and Symmetrical Test Packet in unauthenticated mode
2.2.3. Consideration for TWAMP Light mode 2.2.3. Consideration for TWAMP Light mode
Appendix I of [RFC5357] does not explicitly state how value of Type-P Appendix I of [RFC5357] does not explicitly state how the value of
descriptor synchronized between Session-Sender and Session-Reflector the Type-P descriptor is synchronized between Session-Sender and
and whether different values considered as error condition and should Session-Reflector and whether different values are considered as
be reported. We assume that by some means Session-Sender and error condition and SHOULD be reported. We assume that by some means
Session-Reflector of given TWAMP-Test session informed to use the the Session-Sender and the Session-Reflector of the given TWAMP-Test
same DSCP value. Same means, i.e. configuration, could be used to session been informed to use the same DSCP value. Same means, i.e.
inform Session-Reflector to support DSCP and ECN monitoring mode by configuration, could be used to inform Session-Reflector to support
copying data from received TWAMP test packets. Then Session-Sender DSCP and ECN monitoring mode by copying data from received TWAMP test
may be informed to use Sender DSCP and ECN field in reflected TWAMP packets. Then Session-Sender may be informed to use Sender DSCP and
test packet. ECN field in reflected TWAMP test packet.
3. IANA Considerations 3. IANA Considerations
The TWAMP-Modes registry defined in [RFC5618]. The TWAMP-Modes registry defined in [RFC5618].
IANA is requested to reserve a new DSCP and ECN Monitoring Capability IANA is requested to reserve a new DSCP and ECN Monitoring Capability
as follows: as follows:
+------------+--------------------+---------------------+-----------+ +------------+--------------------+---------------------+-----------+
| Value | Description | Semantics | Reference | | Value | Description | Semantics | Reference |
skipping to change at page 8, line 47 skipping to change at page 8, line 47
Monitoring of DSCP and ECN does not appear to introduce any Monitoring of DSCP and ECN does not appear to introduce any
additional security threat to hosts that communicate with TWAMP as additional security threat to hosts that communicate with TWAMP as
defined in [RFC5357], and existing extensions [RFC6038]. The defined in [RFC5357], and existing extensions [RFC6038]. The
security considerations that apply to any active measurement of live security considerations that apply to any active measurement of live
networks are relevant here as well. See the Security Considerations networks are relevant here as well. See the Security Considerations
sections in [RFC4656] and [RFC5357]. sections in [RFC4656] and [RFC5357].
5. Acknowledgements 5. Acknowledgements
Authors greatly appreciate thorough review and thoughtful comments by Authors greatly appreciate thorough review and thoughtful comments by
Chritofer Flinta and Samita Chakrabarti. Bill Cerveny, Christofer Flinta and Samita Chakrabarti.
6. References
6.1. Normative References 6. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2474] Nichols, K., Blake, S., Baker, F., and D. Black,
"Definition of the Differentiated Services Field (DS
Field) in the IPv4 and IPv6 Headers", RFC 2474, December
1998.
[RFC4656] Shalunov, S., Teitelbaum, B., Karp, A., Boote, J., and M. [RFC4656] Shalunov, S., Teitelbaum, B., Karp, A., Boote, J., and M.
Zekauskas, "A One-way Active Measurement Protocol Zekauskas, "A One-way Active Measurement Protocol
(OWAMP)", RFC 4656, September 2006. (OWAMP)", RFC 4656, September 2006.
[RFC5357] Hedayat, K., Krzanowski, R., Morton, A., Yum, K., and J. [RFC5357] Hedayat, K., Krzanowski, R., Morton, A., Yum, K., and J.
Babiarz, "A Two-Way Active Measurement Protocol (TWAMP)", Babiarz, "A Two-Way Active Measurement Protocol (TWAMP)",
RFC 5357, October 2008. RFC 5357, October 2008.
[RFC5618] Morton, A. and K. Hedayat, "Mixed Security Mode for the [RFC5618] Morton, A. and K. Hedayat, "Mixed Security Mode for the
Two-Way Active Measurement Protocol (TWAMP)", RFC 5618, Two-Way Active Measurement Protocol (TWAMP)", RFC 5618,
August 2009. August 2009.
[RFC6038] Morton, A. and L. Ciavattone, "Two-Way Active Measurement [RFC6038] Morton, A. and L. Ciavattone, "Two-Way Active Measurement
Protocol (TWAMP) Reflect Octets and Symmetrical Size Protocol (TWAMP) Reflect Octets and Symmetrical Size
Features", RFC 6038, October 2010. Features", RFC 6038, October 2010.
6.2. Informative References
[RFC2629] Rose, M., "Writing I-Ds and RFCs using XML", RFC 2629,
June 1999.
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 5226,
May 2008.
Authors' Addresses Authors' Addresses
Jonas Hedin Jonas Hedin
Ericsson Ericsson
Email: jonas.hedin@ericsson.com Email: jonas.hedin@ericsson.com
Greg Mirsky Greg Mirsky
Ericsson Ericsson
Email: gregory.mirsky@ericsson.com Email: gregory.mirsky@ericsson.com
Steve Baillargeon Steve Baillargeon
Ericsson Ericsson
Email: steve.baillargeon@ericsson.com Email: steve.baillargeon@ericsson.com
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