draft-ietf-ippm-twamp-reflect-octets-08.txt   draft-ietf-ippm-twamp-reflect-octets-09.txt 
Network Working Group A. Morton Network Working Group A. Morton
Internet-Draft L. Ciavattone Internet-Draft L. Ciavattone
Updates: 5357 (if approved) AT&T Labs Updates: 5357 (if approved) AT&T Labs
Intended status: Standards Track August 13, 2010 Intended status: Standards Track August 17, 2010
Expires: February 14, 2011 Expires: February 18, 2011
TWAMP Reflect Octets and Symmetrical Size Features TWAMP Reflect Octets and Symmetrical Size Features
draft-ietf-ippm-twamp-reflect-octets-08 draft-ietf-ippm-twamp-reflect-octets-09
Abstract Abstract
This memo describes two closely-related features for the core This memo describes two closely-related features for the core
specification of TWAMP - the Two-Way Active Measurement Protocol: an specification of TWAMP - the Two-Way Active Measurement Protocol: an
optional capability where the responding host returns some of the optional capability where the responding host returns some of the
command octets or padding octets to the sender, and an optional command octets or padding octets to the sender, and an optional
sender packet format that ensures equal test packet sizes are used in sender packet format that ensures equal test packet sizes are used in
both directions. both directions.
skipping to change at page 1, line 42 skipping to change at page 1, line 42
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 February 14, 2011. This Internet-Draft will expire on February 18, 2011.
Copyright Notice Copyright Notice
Copyright (c) 2010 IETF Trust and the persons identified as the Copyright (c) 2010 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
skipping to change at page 7, line 45 skipping to change at page 7, line 45
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
It is important to note that the "Padding Length" Field continues to It is important to note that the "Padding Length" Field continues to
specify the number of padding octets that the Session-Sender will specify the number of padding octets that the Session-Sender will
append to ALL TWAMP-Test packets associated with this test session. append to ALL TWAMP-Test packets associated with this test session.
See below for considerations on the minimum length of the padding See below for considerations on the minimum length of the padding
octets, following the definitions of the two new fields that follow octets, following the definitions of the two new fields that follow
the Type-P Descriptor. the Type-P Descriptor.
Note that the number of padding octets appended to the Session- Note that the number of padding octets appended to the Session-
Reflector's test packet depends on support for the RECOMMENDED Reflector's test packet depends on support for the truncation process
truncation process in TWAMP section 4.2.1 [RFC5357]. that TWAMP section 4.2.1 [RFC5357] recommends.
The "Octets to be reflected" Field SHALL be 2 octets long, as shown The "Octets to be reflected" Field SHALL be 2 octets long, as shown
and contains the octets that the Server MUST reflect in the Accept and contains the octets that the Server MUST reflect in the Accept
Session message as specified below. Session message as specified below.
The "Length of padding to reflect" Field SHALL be 2 octets long, and The "Length of padding to reflect" Field SHALL be 2 octets long, and
contain an unsigned binary value in units of octets. This field contain an unsigned binary value in units of octets. This field
communicates the length of the padding in the TWAMP-Test Packet that communicates the length of the padding in the TWAMP-Test Packet that
the Session-Sender expects to be reflected, and the length of octets the Session-Sender expects to be reflected, and the length of octets
that the Session-Reflector SHALL return in its TWAMP-Test packet that the Session-Reflector SHALL return in its TWAMP-Test packet
format (see section 4.2). By including this length field in the format (see section 4.2). By including this length field in the
Request-TW-Session message, a Server is able to determine if it can Request-TW-Session message, a Server is able to determine if it can
comply with a specific request to reflect padding in the TWAMP-Test comply with a specific request to reflect padding in the TWAMP-Test
packets, and to arrange for the Session-Reflector processing in packets, and to arrange for the Session-Reflector processing in
advance. advance.
The "Padding Length" SHOULD be >= 27 octets when specifying a test The "Padding Length" SHOULD be >= 27 octets when specifying a test
session using the Unauthenticated TWAMP-Test mode, to allow for the session using the Unauthenticated TWAMP-Test mode, to allow for the
RECOMMENDED truncation process in TWAMP section 4.2.1 [RFC5357]. truncation process that TWAMP section 4.2.1 [RFC5357] recommends.
The "Padding Length" SHOULD be >= 56 octets when specifying a test The "Padding Length" SHOULD be >= 56 octets when specifying a test
session using the Authenticated or Encrypted TWAMP-Test modes, to session using the Authenticated or Encrypted TWAMP-Test modes, to
allow for the RECOMMENDED truncation process in TWAMP section 4.2.1 allow for the truncation process that TWAMP section 4.2.1 [RFC5357]
[RFC5357]. recommends.
The "Padding Length" SHALL be > the "Length of padding to reflect" The "Padding Length" SHALL be > the "Length of padding to reflect"
when specifying a test session using the OPTIONAL Reflect Octets when specifying a test session using the OPTIONAL Reflect Octets
mode. mode.
In Unauthenticated TWAMP-Test mode, the "Padding Length" SHALL be >= In Unauthenticated TWAMP-Test mode, the "Padding Length" SHALL be >=
27 + "Length of padding to reflect" octets when specifying a test 27 + "Length of padding to reflect" octets when specifying a test
session using both the OPTIONAL Reflect Octets mode and the session using both the OPTIONAL Reflect Octets mode and the
RECOMMENDED truncation process in TWAMP section 4.2.1 [RFC5357]. truncation process that TWAMP section 4.2.1 [RFC5357] recommends.
In Authenticated or Encrypted TWAMP-Test modes, the "Padding Length" In Authenticated or Encrypted TWAMP-Test modes, the "Padding Length"
SHALL be >= 56 + "Length of padding to reflect" octets when SHALL be >= 56 + "Length of padding to reflect" octets when
specifying a test session using both the OPTIONAL Reflect Octets mode specifying a test session using both the OPTIONAL Reflect Octets mode
and the RECOMMENDED truncation process in TWAMP section 4.2.1 and the truncation process that TWAMP section 4.2.1 [RFC5357]
[RFC5357]. recommends.
3.3. Reflect Octets: Accept Session Packet Format 3.3. Reflect Octets: Accept Session Packet Format
The bits designated for the Reflect Padding feature in the Accept The bits designated for the Reflect Padding feature in the Accept
Session command are as shown in the packet format below. Session command are as shown in the packet format below.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Accept | MBZ | Port | | Accept | MBZ | Port |
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