draft-ietf-tram-stun-path-data-04.txt   draft-ietf-tram-stun-path-data-05.txt 
TRAM P. Martinsen TRAM P. Martinsen
Internet-Draft T. Reddy Internet-Draft T. Reddy
Intended status: Standards Track D. Wing Intended status: Standards Track D. Wing
Expires: December 22, 2016 Cisco Expires: February 24, 2017 Cisco
V. Singh V. Singh
callstats.io callstats.io
June 20, 2016 August 23, 2016
Measurement of Round Trip Time and Fractional Loss Using STUN Measurement of Round Trip Time and Fractional Loss Using STUN
draft-ietf-tram-stun-path-data-04 draft-ietf-tram-stun-path-data-05
Abstract Abstract
A host with multiple interfaces needs to choose the best interface A host with multiple interfaces needs to choose the best interface
for communication. Oftentimes, this decision is based on a static for communication. Oftentimes, this decision is based on a static
configuration and does not consider the path characteristics, which configuration and does not consider the path characteristics, which
may affect the user experience. may affect the user experience.
This document describes a mechanism for an endpoint to measure the This document describes a mechanism for an endpoint to measure the
path characteristics fractional loss and RTT using Session Traversal path characteristics fractional loss and RTT using Session Traversal
skipping to change at page 1, line 40 skipping to change at page 1, line 40
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/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on December 22, 2016. This Internet-Draft will expire on February 24, 2017.
Copyright Notice Copyright Notice
Copyright (c) 2016 IETF Trust and the persons identified as the Copyright (c) 2016 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
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TRANSACTION_TRANSMIT_COUNTER with a STUN Type TBD-CA. This type is TRANSACTION_TRANSMIT_COUNTER with a STUN Type TBD-CA. This type is
in the comprehension-optional range, which means that STUN agents can in the comprehension-optional range, which means that STUN agents can
safely ignore the attribute. If ICE is in use it will fallback to safely ignore the attribute. If ICE is in use it will fallback to
normal procedures. normal procedures.
If a client wishes to measure RTT, it inserts the If a client wishes to measure RTT, it inserts the
TRANSACTION_TRANSMIT_COUNTER attribute in a STUN request. In this TRANSACTION_TRANSMIT_COUNTER attribute in a STUN request. In this
attribute the client sends the number of times the STUN request is attribute the client sends the number of times the STUN request is
transmitted with the same Transaction ID. The server would echo back transmitted with the same Transaction ID. The server would echo back
the transmission count in the response so that client can distinguish the transmission count in the response so that client can distinguish
STUN responses from the re-transmitted requests. Hence, the endpoint between STUN responses coming from re-transmitted requests. Hence,
can use the STUN requests and responses to determine the round-trip the endpoint can use the STUN requests and responses to determine the
time (RTT). The server may also convey the number of responses it round-trip time (RTT). The server may also convey the number of
has sent for the STUN request to the client. Further, this responses it has sent for the STUN request to the client. Further,
information enables the client to get a hint regarding what direction this information enables the client to get a hint regarding what
the packet loss occurred. In some cases, it is impossible to direction the packet loss occurred. In some cases, it is impossible
distinguish between packet reordering and packet loss. However if to distinguish between packet reordering and packet loss. However if
this information is collected as network metrics from several clients this information is collected as network metrics from several clients
over a longer time period it will be easier to detect a pattern that over a longer time period, it will be easier to detect a pattern that
can provide useful information. can provide useful information.
3.1. TRANSACTION_TRANSMIT_COUNTER attribute 3.1. TRANSACTION_TRANSMIT_COUNTER attribute
The TRANSACTION_TRANSMIT_COUNTER attribute in a STUN request takes a The TRANSACTION_TRANSMIT_COUNTER attribute in a STUN request takes a
32-bit value. This document updates one of the STUN message 32-bit value. This document updates one of the STUN message
structuring rules explained in Section 6 of [RFC5389] wherein resends structuring rules explained in Section 6 of [RFC5389] wherein
of the same request reuse the same transaction ID and are bit-wise retransmit of the same request reuse the same transaction ID and are
identical to the previous request. For idempotent packets, the Req bit-wise identical to the previous request. For idempotent packets,
and Resp fields in the TRANSACTION_TRANSMIT_COUNTER attribute will be the Req and Resp fields in the TRANSACTION_TRANSMIT_COUNTER attribute
incremented by 1 by the client or server for every transmission with will be incremented by 1 by the client or server for every
the same transaction id. Any re-transmitted STUN request MUST be transmission with the same transaction id. Any re-transmitted STUN
bit-wise identical to the previous request except for the values in request MUST be bit-wise identical to the previous request except for
the TRANSACTION_TRANSMIT_COUNTER attribute. the values in the TRANSACTION_TRANSMIT_COUNTER attribute.
The IANA assigned STUN type for the new attribute is TBD-CA. The IANA assigned STUN type for the new attribute is TBD-CA.
The format of the value in TRANSACTION_TRANSMIT_COUNTER attribute in The format of the value in TRANSACTION_TRANSMIT_COUNTER attribute in
the request is: the request is:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved (Padding) | Req | Resp | | Reserved (Padding) | Req | Resp |
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Dan Wing Dan Wing
Cisco Systems, Inc. Cisco Systems, Inc.
170 West Tasman Drive 170 West Tasman Drive
San Jose, California 95134 San Jose, California 95134
USA USA
Email: dwing@cisco.com Email: dwing@cisco.com
Varun Singh Varun Singh
Nemu Dialogue System Oy CALLSTATS I/O Oy
Itaemerenkatu 5 Runeberginkatu 4c A 4
Helsinki 00150 Helsinki 00100
Finland Finland
Email: varun@callstats.io Email: varun@callstats.io
URI: https://www.callstats.io/about
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