draft-ietf-ippm-twamp-reflect-octets-02.txt   draft-ietf-ippm-twamp-reflect-octets-03.txt 
Network Working Group A. Morton Network Working Group A. Morton
Internet-Draft L. Ciavattone Internet-Draft L. Ciavattone
Intended status: Standards Track AT&T Labs Intended status: Standards Track AT&T Labs
Expires: January 14, 2010 July 13, 2009 Expires: April 25, 2010 October 22, 2009
TWAMP Reflect Octets Feature TWAMP Reflect Octets and Symmetrical Size Features
draft-ietf-ippm-twamp-reflect-octets-02 draft-ietf-ippm-twamp-reflect-octets-03
Status of this Memo Status of this Memo
This Internet-Draft is submitted to IETF in full conformance with the This Internet-Draft is submitted to IETF in full conformance with the
provisions of BCP 78 and BCP 79. This document may contain material provisions of BCP 78 and BCP 79. This document may contain material
from IETF Documents or IETF Contributions published or made publicly from IETF Documents or IETF Contributions published or made publicly
available before November 10, 2008. The person(s) controlling the available before November 10, 2008. The person(s) controlling the
copyright in some of this material may not have granted the IETF copyright in some of this material may not have granted the IETF
Trust the right to allow modifications of such material outside the Trust the right to allow modifications of such material outside the
IETF Standards Process. Without obtaining an adequate license from IETF Standards Process. Without obtaining an adequate license from
skipping to change at page 1, line 42 skipping to change at page 1, line 42
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."
The list of current Internet-Drafts can be accessed at The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt. http://www.ietf.org/ietf/1id-abstracts.txt.
The list of Internet-Draft Shadow Directories can be accessed at The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html. http://www.ietf.org/shadow.html.
This Internet-Draft will expire on January 14, 2010. This Internet-Draft will expire on April 25, 2010.
Copyright Notice Copyright Notice
Copyright (c) 2009 IETF Trust and the persons identified as the Copyright (c) 2009 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 in effect on the date of Provisions Relating to IETF Documents in effect on the date of
publication of this document (http://trustee.ietf.org/license-info). publication of this document (http://trustee.ietf.org/license-info).
Please review these documents carefully, as they describe your rights Please review these documents carefully, as they describe your rights
and restrictions with respect to this document. and restrictions with respect to this document.
Abstract Abstract
The IETF has completed its work on the core specification of TWAMP - The IETF has completed its work on the core specification of TWAMP -
the Two-Way Active Measurement Protocol. This memo describes a new the Two-Way Active Measurement Protocol. This memo describes two
feature for TWAMP: an optional capability where the responder host closely-related features for TWAMP: an optional capability where the
returns some of the command octets or padding octets to the responder host returns some of the command octets or padding octets
controller, and/or ensures that the same test packet sizes are used to the controller, a new sender packet format that ensures equal test
in both directions. packet sizes are used in both directions.
Requirements Language 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", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119]. document are to be interpreted as described in RFC 2119 [RFC2119].
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Purpose and Scope . . . . . . . . . . . . . . . . . . . . . . 4 2. Purpose and Scope . . . . . . . . . . . . . . . . . . . . . . 4
3. TWAMP Control Extensions . . . . . . . . . . . . . . . . . . . 5 3. TWAMP Control Extensions . . . . . . . . . . . . . . . . . . . 5
3.1. Connection Setup with Reflect Padding Feature . . . . . . 5 3.1. Connection Setup with New Features . . . . . . . . . . . . 5
3.2. Request-TW-Session Packet Format . . . . . . . . . . . . . 6 3.2. Reflect Octets: Request-TW-Session Packet Format . . . . . 6
3.3. Accept Session Packet Format . . . . . . . . . . . . . . . 8 3.3. Reflect Octets: Accept Session Packet Format . . . . . . . 8
3.4. Additional considerations . . . . . . . . . . . . . . . . 8 3.4. Additional considerations . . . . . . . . . . . . . . . . 9
4. Extended TWAMP Test . . . . . . . . . . . . . . . . . . . . . 9 4. Extended TWAMP Test . . . . . . . . . . . . . . . . . . . . . 10
4.1. Sender Behavior . . . . . . . . . . . . . . . . . . . . . 9 4.1. Sender Behavior . . . . . . . . . . . . . . . . . . . . . 10
4.1.1. Packet Timings . . . . . . . . . . . . . . . . . . . . 9 4.1.1. Packet Timings . . . . . . . . . . . . . . . . . . . . 10
4.1.2. Packet Formats and Contents . . . . . . . . . . . . . 9 4.1.2. Reflect Octets: Packet Formats and Contents . . . . . 10
4.1.3. Padding Truncation . . . . . . . . . . . . . . . . . . 11 4.1.3. Reflect Octets: Interaction with Padding Truncation . 12
4.2. Reflector Behavior . . . . . . . . . . . . . . . . . . . . 12 4.1.4. Symmetrical Size: Session-Sender Packet Format . . . . 13
4.2.1. Packet Format and Contents . . . . . . . . . . . . . . 12 4.1.5. Symmetrical Size AND Reflect Octets:
4.2.2. Padding Truncation . . . . . . . . . . . . . . . . . . 13 Session-Sender Packet Format . . . . . . . . . . . . . 13
5. Possible Alternative . . . . . . . . . . . . . . . . . . . . . 14 4.2. Reflector Behavior . . . . . . . . . . . . . . . . . . . . 14
6. Security Considerations . . . . . . . . . . . . . . . . . . . 16 4.2.1. Reflect Octets: Session-Reflector Packet Format
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 16 and Contents . . . . . . . . . . . . . . . . . . . . . 15
7.1. Registry Specification . . . . . . . . . . . . . . . . . . 17 4.2.2. Symmetrical Size: Session-Reflector Packet Format . . 16
7.2. Registry Management . . . . . . . . . . . . . . . . . . . 17 4.2.3. Symmetrical Size AND Reflect Octets:
7.3. Experimental Numbers . . . . . . . . . . . . . . . . . . . 17 Session-Sender Packet Format . . . . . . . . . . . . . 16
7.4. Registry Contents . . . . . . . . . . . . . . . . . . . . 17 5. Security Considerations . . . . . . . . . . . . . . . . . . . 16
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 18 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 16
9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 18 6.1. Registry Specification . . . . . . . . . . . . . . . . . . 17
9.1. Normative References . . . . . . . . . . . . . . . . . . . 18 6.2. Registry Management . . . . . . . . . . . . . . . . . . . 17
9.2. Informative References . . . . . . . . . . . . . . . . . . 18 6.3. Experimental Numbers . . . . . . . . . . . . . . . . . . . 17
6.4. Registry Contents . . . . . . . . . . . . . . . . . . . . 17
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 18
8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 18
8.1. Normative References . . . . . . . . . . . . . . . . . . . 18
8.2. Informative References . . . . . . . . . . . . . . . . . . 18
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 18 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 18
1. Introduction 1. Introduction
The IETF has completed its work on the core specification of TWAMP - The IETF has completed its work on the core specification of TWAMP -
the Two-Way Active Measurement Protocol [RFC5357]. TWAMP is an the Two-Way Active Measurement Protocol [RFC5357]. TWAMP is an
extension of the One-way Active Measurement Protocol, OWAMP extension of the One-way Active Measurement Protocol, OWAMP
[RFC4656]. The TWAMP specification gathered wide review as it [RFC4656]. The TWAMP specification gathered wide review as it
approached completion, and the by-products were several approached completion, and the by-products were several
recommendations for new features in TWAMP. There are a growing recommendations for new features in TWAMP. There are a growing
number TWAMP implementations at present, and wide-spread usage is number TWAMP implementations at present, and wide-spread usage is
expected. There are even devices that are designed to test expected. There are even devices that are designed to test
implementations for protocol compliance. implementations for protocol compliance.
This memo describes a new feature for TWAMP. This feature adds the This memo describes two closely-related features for TWAMP.
OPTIONAL capability for the responder host to return a limited number
of unassigned (padding) octets to the Control-Client or Session- One is the OPTIONAL capability for the responder host to return a
Sender entities. With this capability, the Control-Client or limited number of unassigned (padding) octets to the Control-Client
Session-Sender can embed octets of information it deems useful and or Session-Sender entities. With this capability, the Control-Client
or Session-Sender can embed octets of information it deems useful and
have the assurance that the corresponding reply/test packet will have the assurance that the corresponding reply/test packet will
contain that information when it is reflected and returned (by the contain that information when it is reflected and returned (by the
Server or Session-Reflector. The feature also adds the Session- Server or Session-Reflector.
Reflector capability to assure that reflected test packets SHALL have
their padding octets truncated, so that TWAMP-Test protocol uses the The memo also adds an OPTIONAL capability to assure that reflected
same packet size in both directions of transmission. test packets are the same size in both directions of transmission.
This is accomplished by specifying a new TWAMP-Test Session-Sender
packet format.
The relationship between this memo and TWAMP is intended to be an The relationship between this memo and TWAMP is intended to be an
update to [RFC5357] when published. update to [RFC5357] when published.
2. Purpose and Scope 2. Purpose and Scope
The purpose of this memo is to describe a new feature for TWAMP The purpose of this memo is to define two new closely-related
[RFC5357]. The feature enhances the TWAMP responder's capabilities features for TWAMP [RFC5357]. The features enhance the TWAMP
to perform simple operations on control and test packets: the responder's capabilities to perform simple operations on control and
reflection of octets or padding and the guaranteed truncation of test packets: the reflection of octets or padding and symmetrical
padding to compensate for the different sizes of TWAMP fields in the sizes of fields in the TWAMP-Test packets. Motivations include
test packets. Motivations include permitting the controller host to permitting the controller host to tag packets with an index for
tag packets with an index for simplified identification, and/or simplified identification, and/or assert that the same size test
assert that the same size test packets MUST be used in each packets will be used in each direction.
direction.
The scope of the memo is currently limited to specifications of the The scope of the memo is currently limited to specifications of the
following feature: following features:
o Extension of the modes of operation through assignment of new o Reflect Octets: the capability of the Server/Session-Reflector to
values in the Mode Field (see section 3.1 [RFC4656] for the format reflect specific octets back to the Client/Session-Sender.
of the Server Greeting message), while retaining backward
compatibility with the core TWAMP [RFC5357] implementations. o Symmetrical Size: the capability to ensure that TWAMP-Test
These two values identify the ability of the Server/ protocol uses the same packet size in both directions through
Session-Reflector to reflect specific octets back to the Client/ support of a new TWAMP-Test Session-Sender test packet format in
Session-Sender, and/or to truncate padding octets and ensure that both the Session-Sender and the Session-Reflector.
TWAMP-Test protocol uses the same packet size in both directions.
Extension of the modes of operation through assignment of two new
values in the Mode Field (see section 3.1 of[RFC4656] for the format
of the Server Greeting message), while retaining backward
compatibility with the core TWAMP [RFC5357] implementations. The two
new values correspond to the two features defined in this memo.
When the Server and Control-Client have agreed to use the Reflect
Octets mode during control connection setup, then the Control-Client,
the Server, the Session-Sender, and the Session-Reflector MUST all
conform to the requirements of that mode, as identified below.
When the Server and Control-Client have agreed to use the Symmetrical
Size mode during control connection setup, then the Control-Client,
the Server, the Session-Sender, and the Session-Reflector MUST all
conform to the requirements of that mode, as identified below.
3. TWAMP Control Extensions 3. TWAMP Control Extensions
TWAMP-Control protocol [RFC5357] uses the Modes Field to identify and TWAMP-Control protocol [RFC5357] uses the Modes Field to identify and
select specific communication capabilities, and this field is a select specific communication capabilities, and this field is a
recognized extension mechanism. The following sections describe one recognized extension mechanism. The following sections describe two
such extension. such extensions.
3.1. Connection Setup with Reflect Padding Feature 3.1. Connection Setup with New Features
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]. The new section 3.1 of [RFC4656] and section 3.1 of [RFC5357]. The new
feature requires two new bit positions (and values) to identify the features require two new bit positions (and values) to identify the
ability of the Server/Session-Reflector to reflect specific octets ability of the Server/Session-Reflector to reflect specific octets
back to the Control-Client/Session-Sender, and to truncate padding back to the Control-Client/Session-Sender, and to support the new
octets when required. With this added feature, the complete set of Session-Sender packet format in TWAMP-Test Protocol. With this added
TWAMP Modes Field bit positions and values would be as follows: feature, the complete set of TWAMP Modes Field bit positions and
values would be as follows:
Value Description Reference/Explanation Value Description Reference/Explanation
0 Reserved 0 Reserved
1 Unauthenticated RFC4656, Section 3.1 1 Unauthenticated RFC4656, Section 3.1
2 Authenticated RFC4656, Section 3.1 2 Authenticated RFC4656, Section 3.1
4 Encrypted RFC4656, Section 3.1 4 Encrypted RFC4656, Section 3.1
8 Unauth. TEST protocol, draft-ietf-more-twamp (3) 8 Unauth. TEST protocol, RFC5681, Section 3.1
Encrypted CONTROL Encrypted CONTROL
-------------------------------------------------------- --------------------------------------------------------
xxx Reflect Octets new bit position (X) xxx Reflect Octets new bit position (X)
Capability Capability
yyy Truncate Padding new bit position (Y) yyy Symmetrical Size new bit position (Y)
Capability Sender Test Packet Format
In the original OWAMP Modes Field, setting bit positions 0, 1 or 2 In the original OWAMP Modes Field, setting bit positions 0, 1 or 2
indicated the security mode of the Control protocol, and the Test indicated the security mode of the Control protocol, and the Test
protocol inherited the same mode (see section 4 of [RFC4656]). In protocol inherited the same mode (see section 4 of [RFC4656]). In
the memo [I-D.ietf-ippm-more-twamp], bit position 3 allows [RFC5618], bit position 3 allows unauthenticated TWAMP Test protocol
unauthenticated TWAMP Test protocol to be used with encryption on the to be used with encryption on the TWAMP-Control protocol in a mixed
TWAMP-Control protocol. mode of operation.
The Server sets one or both of the new bit positions (X and Y) in the The Server sets one or both of the new bit positions (X and Y) in the
Modes Field of the Server Greeting message to indicate its Modes Field of the Server Greeting message to indicate its
capabilities and willingness to operate in these modes if desired. capabilities and willingness to operate in either of these modes (or
>>>IANA: change X and Y to the assigned values <<< both) if desired.
>>>IANA: change xxx, yyy, X, and Y to the assigned values <<<
If the Control-Client intends to operate all test sessions invoked If the Control-Client intends to operate all test sessions invoked
with this control connection using one or both of the new modes, it with this control connection using one or both of the new modes, it
MUST set the Modes Field bit corresponding to that function in the MUST set the Modes Field bit corresponding to that function in the
Setup Response message. Setup Response message.
3.2. Request-TW-Session Packet Format 3.2. Reflect Octets: Request-TW-Session Packet Format
The bits designated for the Reflect Octets feature in the Request-TW- The bits designated for the Reflect Octets feature in the Request-TW-
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 5 | MBZ | IPVN | Conf-Sender | Conf-Receiver | | 5 | MBZ | IPVN | Conf-Sender | Conf-Receiver |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Number of Schedule Slots | | Number of Schedule Slots |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. . . .
. ... Many fields (66 octets) not shown ... . . ... Many fields (66 octets) not shown ... .
. . . .
. . . .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Padding Length | | Padding Length (4 octets) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Start Time, (8 octets) | | Start Time, (8 octets) |
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Timeout, (8 octets) | | Timeout, (8 octets) |
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type-P Descriptor | | Type-P Descriptor |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Octets to be reflected | Length of padding to reflect | | Octets to be reflected | Length of padding to reflect |
skipping to change at page 6, line 49 skipping to change at page 7, line 40
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
| HMAC (16 octets) | | HMAC (16 octets) |
| | | |
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The "Padding Length" Field *continues* to specify the number of The "Padding Length" Field *continues* to specify the number of
padding octets that the Session-Sender will append to ALL TWAMP-Test padding octets that the Session-Sender will append to ALL TWAMP-Test
packets associated with this test session. See below for packets associated with this test session. See below for
considerations on the minimum length of the padding octets, considerations on the minimum length of the padding octets, following
especially when complying with the options described in this memo, the definitions of the two new fields that follow the Type-P
following the definitions of the two new fields that follow the Descriptor.
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 OPTIONAL Truncate Reflector's test packet depends on support for the RECOMMENDED
Padding mode, or the RECOMMENDED truncation process in TWAMP section truncation process in TWAMP section 4.2.1 [RFC5357].
4.2.1 [RFC5357].
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 include in its TWAMP-Test that the Session-Reflector SHALL return in include in its TWAMP-Test
skipping to change at page 7, line 41 skipping to change at page 8, line 29
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 RECOMMENDED truncation process in TWAMP section 4.2.1
[RFC5357]. [RFC5357].
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.
The "Padding Length" SHALL be >= 27 + "Length of padding to reflect" The "Padding Length" SHALL be >= 27 + "Length of padding to reflect"
octets when specifying a test session using BOTH the OPTIONAL Reflect octets when specifying a test session using BOTH the OPTIONAL Reflect
Octets mode and OPTIONAL Truncate Padding mode with the Octets mode and the RECOMMENDED truncation process in TWAMP section
Unauthenticated TWAMP-Test mode. 4.2.1 [RFC5357].
The "Padding Length" SHALL be >= 56 + "Length of padding to reflect" The "Padding Length" SHALL be >= 56 + "Length of padding to reflect"
octets when specifying a test session using BOTH the OPTIONAL Reflect octets when specifying a test session using BOTH the OPTIONAL Reflect
Octets mode and OPTIONAL Truncate Padding mode with the Authenticated Octets mode and the RECOMMENDED truncation process in TWAMP section
or Encrypted TWAMP-Test modes. 4.2.1 [RFC5357].
3.3. 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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-|
| | | |
skipping to change at page 8, line 41 skipping to change at page 9, line 36
The "Reflected octets" field SHALL contain the octets from the The "Reflected octets" field SHALL contain the octets from the
Request-TW-Session "Octets to be reflected" Field, and be 2 octets Request-TW-Session "Octets to be reflected" Field, and be 2 octets
long, as shown. long, as shown.
The "Server octets" field SHALL contain information that the Server The "Server octets" field SHALL contain information that the Server
intends to be returned in the TWAMP-Test packet padding to-be- intends to be returned in the TWAMP-Test packet padding to-be-
reflected Field, OR SHALL be zero, and be 2 octets long, as shown. reflected Field, OR SHALL be zero, and be 2 octets long, as shown.
Although the Server determines the SID, this field is very long (16 Although the Server determines the SID, this field is very long (16
octets) and does not normally appear in TWAMP-Test packets. octets) and does not normally appear in TWAMP-Test packets.
In Truncate Padding mode, IF calculations on the Padding lengths When supporting the RECOMMENDED truncation process in TWAMP section
reveal that there are insufficient octets supplied to produce equal- 4.2.1 [RFC5357], IF calculations on the Padding lengths reveal that
length Session-Sender and Session-Reflector test packets, then the there are insufficient octets supplied to produce equal-length
Accept Field MUST be set to 3 = some aspect of the request is not Session-Sender and Session-Reflector test packets, then the Accept
supported. Field MUST be set to 3 = some aspect of the request is not supported.
3.4. Additional considerations 3.4. Additional considerations
The value of the Modes Field sent by the Server in the Server The value of the Modes Field sent by the Server in the Server
Greeting message is the bit-wise OR of the mode values that it is Greeting message is the bit-wise OR of the mode values that it is
willing to support during this session. willing to support during this session.
Thus, the last six bits of the Modes 32-bit Field are used. A client Thus, the last six bits of the Modes 32-bit Field are used. A client
conforming to this extension of [RFC5357] MAY ignore the values in conforming to this extension of [RFC5357] MAY ignore the values in
the first 24 bits of the Modes Field, or it MAY support other the first 24 bits of the Modes Field, or it MAY support other
features that are communicated in these bit positions. (The first 24 features that are communicated in these bit positions. (The first 24
bits are available for future protocol extensions.) bits are available for future protocol extensions.)
Other ways in which TWAMP extends OWAMP are described in [RFC5357].
4. Extended TWAMP Test 4. Extended TWAMP Test
The TWAMP test protocol is similar to the OWAMP [RFC4656] test The TWAMP test protocol is similar to the OWAMP [RFC4656] test
protocol with the exception that the Session-Reflector transmits test protocol with the exception that the Session-Reflector transmits test
packets to the Session-Sender in response to each test packet it packets to the Session-Sender in response to each test packet it
receives. TWAMP section 4[RFC5357] defines two additional test receives. TWAMP section 4[RFC5357] defines two additional test
packet formats for packets transmitted by the Session-Reflector. The packet formats for packets transmitted by the Session-Reflector. The
appropriate format depends on the security mode chosen. The new appropriate format depends on the security mode chosen. The new
modes specified here utilize some of the padding octets within each modes specified here utilize some of the padding octets within each
test packet format, or require truncation of those octets depending test packet format, or require truncation of those octets depending
skipping to change at page 9, line 35 skipping to change at page 10, line 28
4.1. Sender Behavior 4.1. Sender Behavior
This section describes extensions to the behavior of the TWAMP This section describes extensions to the behavior of the TWAMP
Session-Sender. Session-Sender.
4.1.1. Packet Timings 4.1.1. Packet Timings
The Send Schedule is not utilized in TWAMP, and this is unchanged in The Send Schedule is not utilized in TWAMP, and this is unchanged in
this memo. this memo.
4.1.2. Packet Formats and Contents 4.1.2. Reflect Octets: Packet Formats and Contents
The Session-Sender packet format and content follow the same The Session-Sender packet format and content follow the same
procedure and guidelines as defined in section 4.1.2 of [RFC4656] (as procedure and guidelines as defined in section 4.1.2 of [RFC4656] (as
indicated in section 4.1.2 of TWAMP [RFC5357]). indicated in section 4.1.2 of TWAMP [RFC5357]).
The Reflect octets mode re-designates the original TWAMP-Test (and The Reflect octets mode re-designates the original TWAMP-Test (and
OWAMP-Test) Packet Padding Field (see section 4.1.2 of [RFC4656]), as OWAMP-Test) Packet Padding Field (see section 4.1.2 of [RFC4656]), as
shown below for unauthenticated mode: shown below for unauthenticated mode:
0 1 2 3 0 1 2 3
skipping to change at page 11, line 21 skipping to change at page 12, line 21
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
| Packet Padding (to be reflected) | | Packet Padding (to be reflected) |
. (length in octets specified elsewhere) . . (length in octets specified elsewhere) .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
In this example, the "Client octets" and the "Server octets" fields In this example, the "Client octets" and the "Server octets" fields
contain the same information that the Client and Server exchanged in contain the same information that the Client and Server exchanged in
the Request-TW-Session and Accept-Session messages corresponding to the Request-TW-Session and Accept-Session messages corresponding to
this specific test session. These octets would be reflected the same this specific test session. These octets would be reflected the same
as the rest of the "Packet Padding (to be reflected)" Field. as the rest of the "Packet Padding (to be reflected)" Field.
4.1.3. Padding Truncation 4.1.3. Reflect Octets: Interaction with Padding Truncation
When the Truncate Padding mode is selected and communicated in the When the Reflect Octets mode is selected, and the RECOMMENDED
Setup Response message, the Session-Sender MUST anticipate a minimum truncation process in TWAMP section 4.2.1 [RFC5357] is supported, the
padding required to achieve equal size test packets in both Session-Sender MUST anticipate a minimum padding required to achieve
directions. The amount of padding needed depends on BOTH the equal size test packets in both directions. The amount of padding
needed to achieve symmetrical packet size depends on BOTH the
security mode (Unauthenticated/Authenticated/Encrypted) and whether security mode (Unauthenticated/Authenticated/Encrypted) and whether
the Reflect Octets mode is selected simultaneously. the Reflect Octets mode is selected simultaneously.
When using the Truncate Padding mode, the Session-Sender MUST append When using the RECOMMENDED truncation process in TWAMP section 4.2.1
sufficient Packet Padding octets to allow the same IP packet payload [RFC5357] alone, the Session-Sender MUST append sufficient Packet
lengths to be used in each direction of transmission (this is usually Padding octets to allow the same IP packet payload lengths to be used
desirable). To compensate for the Session-Reflector's larger test in each direction of transmission (this is usually desirable). To
packet format, the Session-Sender MUST append at least 27 octets of compensate for the Session-Reflector's larger test packet format, the
padding in Unauthenticated mode, and at least 56 octets in Session-Sender MUST append at least 27 octets of padding in
Authenticated and Encrypted modes. The sizes of TWAMP Test protocol Unauthenticated mode, and at least 56 octets in Authenticated and
packets and the resulting truncated padding to achieve equal packet Encrypted modes. The sizes of TWAMP Test protocol packets and the
sizes in both directions are shown in the table below: resulting truncated padding to achieve equal packet sizes in both
directions are shown in the table below:
+-------------------+----------------------+---------------------+ +-------------------+----------------------+---------------------+
| Octets in: | Unauthenticated Mode | Auth/Encrypted Mode | | Octets in: | Unauthenticated Mode | Auth/Encrypted Mode |
+-------------------+----------------------+---------------------+ +-------------------+----------------------+---------------------+
| Reflector Header | 41 | 104 | | Reflector Header | 41 | 104 |
| Sender Header | 14 | 48 | | Sender Header | 14 | 48 |
| Truncated Padding | 27 | 56 | | Truncated Padding | 27 | 56 |
+-------------------+----------------------+---------------------+ +-------------------+----------------------+---------------------+
TWAMP-Test Padding Trucation TWAMP-Test Padding Trucation
When using the Reflect Octets mode simultaneously with the Truncate When using the Reflect Octets mode simultaneously with the
Padding mode, the Session-Sender MUST append at least 27 octets of RECOMMENDED truncation process in TWAMP section 4.2.1 [RFC5357], the
padding plus the "Length of the padding to reflect" octets when Session-Sender MUST append at least 27 octets of padding plus the
operating in Unauthenticated mode. The Session-Sender MUST append at "Length of the padding to reflect" octets when operating in
least 56 octets of padding plus the "Length of the padding to Unauthenticated mode. The Session-Sender MUST append at least 56
reflect" octets when operating in Authenticated and Encrypted modes. octets of padding plus the "Length of the padding to reflect" octets
when operating in Authenticated and Encrypted modes.
4.1.4. Symmetrical Size: Session-Sender Packet Format
When the Symmetrical Size mode is selected, the Session-Sender SHALL
use the following TWAMP-Test Packet Format in Unauthenticated mode:
Unauthenticated Mode
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Timestamp |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Error Estimate | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
| |
| |
| MBZ (27 octets) |
| |
| |
| |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | |
+-+-+-+-+-+-+-+-+ +
. .
. Packet Padding .
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
4.1.5. Symmetrical Size AND Reflect Octets: Session-Sender Packet
Format
When BOTH the Symmetrical Size mode and the Reflect Octets mode are
selected, the Session-Sender SHALL use the following TWAMP-Test
Packet Format in Unauthenticated mode:
Unauthenticated Mode
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Timestamp |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Error Estimate | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
| |
| |
| MBZ (27 octets) |
| |
| |
| |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | |
+-+-+-+-+-+-+-+-+ +
| Packet Padding (to be reflected) |
. (length in octets specified in command) .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. .
. Additional Packet Padding .
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
In this combined mode, the Packet Padding to be reflected follows the
27 MBZ octets. In Authenticated or Encrypted modes, the Packet
Padding to be reflected follows the 56 MBZ octets.
4.2. Reflector Behavior 4.2. Reflector Behavior
The TWAMP Reflector follows the procedures and guidelines in section The TWAMP Reflector follows the procedures and guidelines in section
4.2 of [RFC5357], with the following additional functions: 4.2 of [RFC5357], with the following additional functions:
o Reflect Octets mode: Designated octets in the "Packet Padding (to o Reflect Octets mode: Designated octets in the "Packet Padding (to
be reflected)" field of the Session-Sender's test packet MUST be be reflected)" field of the Session-Sender's test packet MUST be
included in the Session-Reflector's test packet. included in the Session-Reflector's test packet.
o Truncate Padding mode: Octets in the packet padding field of the o Symmetrical Size mode: The Session-Reflector MUST operate using
Session-Sender's test packet MUST be truncated so that the length the Session_Reflector Packet Format defined in section 4.1.4,
of the Session-Reflector's test packet equals the length of the where the Padding Octets are separated from the information
Session-Sender's test packet. fields.
4.2.1. Packet Format and Contents 4.2.1. Reflect Octets: Session-Reflector Packet Format and Contents
The Reflect Padding feature re-designates the packet padding field, The Reflect Padding feature re-designates the packet padding field,
as shown below for unauthenticated mode: as shown below. When the Reflect Octets mode is selected, the
Session-Sender SHALL use the following TWAMP-Test Packet Format in
Unauthenticated mode:
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 |
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Error Estimate | MBZ | | Error Estimate | MBZ |
skipping to change at page 13, line 40 skipping to change at page 15, line 47
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
| | | |
| | | |
. Additional Packet Padding . . Additional Packet Padding .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The "Packet Padding (from Session-Sender)" field MUST be the same The "Packet Padding (from Session-Sender)" field MUST be the same
octets as the "Packet Padding (to be reflected)" field in the octets as the "Packet Padding (to be reflected)" field in the
Session-Sender's test packet, and therefore MUST conform to the Session-Sender's test packet, and therefore MUST conform to the
length specified in the Request-TW-Session message. length specified in the Request-TW-Session message.
IF the test packet length is truncated within the padding fields in When simultaneously using the RECOMMENDED truncation process in TWAMP
conformance with the RECOMMENDED truncation process in TWAMP section section 4.2.1 [RFC5357] AND Reflect octets mode, the Session-
4.2.1 [RFC5357], THEN ALL padding designated to be reflected MUST be Reflector MUST reflect the designated octets from the Session-
reflected by Session-Reflectors using this feature. Sender's test packet in the "Packet Padding (from Session-Sender)"
Field, and MAY re-use additional Packet Padding from the Session-
4.2.2. Padding Truncation Sender. The Session-Reflector MUST truncate the padding such that
the highest number octets are discarded, and the test packet length
Note that the Session-Reflector Test Packet Formats are larger than equals the Session-Sender's packet length. When using the
the Sender's formats. When the Truncate Padding mode is selected and RECOMMENDED truncation process, the Session-Reflector MUST truncate
communicated in the Setup Response message, the Session-Reflector exactly 27 octets of padding in Unauthenticated mode, and exactly 56
must truncate a specific number of padding octets to achieve equal octets in Authenticated and Encrypted modes.
size test packets in both directions. The number of octets truncated
depends on BOTH the security mode (Unauthenticated/Authenticated/
Encrypted) and whether the Reflect octets mode is selected
simultaneously.
When using the Truncate Padding mode, the Session-Reflector MUST
truncate exactly 27 octets of padding in Unauthenticated mode, and
exactly 56 octets in Authenticated and Encrypted modes. The Session-
Reflector MAY re-use the Sender's Packet Padding (since the
requirements for padding generation are the same for each), and in
this case the Session-Reflector MUST truncate the padding such that
the highest number octets are discarded.
When simultaneously using the Truncate Padding mode AND Reflect
octets mode, the Session-Reflector MUST reflect the designated octets
from the Session-Sender's test packet in the "Packet Padding (from
Session-Sender)" Field, and MAY re-use additional Packet Padding from
the Session-Sender. The Session-Reflector MUST truncate the padding
such that the highest number octets are discarded, and the test
packet length equals the Session-Sender's packet length.
5. Possible Alternative
If new TWAMP-Test packet formats are defined, the Reflect Octets and
Truncate Padding modes could be folded into one new mode.
It would be possible to obtain even 4 octet boundaries in the revised
format.
It is also possible to simplfy test packet reflection by leaving the
Session-Sender's fields exactly as received, and replacing the
Discard Fill Field with the new time stamps and sequence number
determined by the Session-Reflector.
No calculations on padding are needed, and symmetrical packet size is The Session-Reflector MAY re-use the Sender's Packet Padding (since
ensured for both directions of transmssion. the requirements for padding generation are the same for each).
The "Packet Padding (to be reflected)" Field could contain 4.2.2. Symmetrical Size: Session-Reflector Packet Format
information that is TLV encoded, but in general the padding is opaque
to the Session-Reflector.
This Alternative is illustrated for discussion purposes. When Symmetrical Size mode is selected, the Session-Sender packet
formats for unauthenticated and authenticated/encrypted modes are
identical to the core TWAMP specification, section 4.2.1 of
[RFC5357].
New Session-Sender Test Packet Format: The Session-Reflector MUST construct its test packet using the
information in the Session-Sender's test packet. The length of the
Session-Reflector's test packet SHALL equal the length of the
Session-Sender's test packet.
0 1 2 3 4.2.3. Symmetrical Size AND Reflect Octets: Session-Sender Packet
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 Format
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Timestamp |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Error Estimate | MBZ (2 octets) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| |
| |
| Discard Fill |
| |
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| Packet Padding (to be reflected) |
. (length in octets specified elsewhere) .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. .
. Additional Packet Padding .
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The "Discard Fill" octets are discarded at the Session-Reflector.
New Session-Reflector Test Packet format: When BOTH the Symmetrical Size mode and the Reflect Octets mode are
selected, the Session-Reflector MUST operate using the
Session_Reflector Packet Format defined in section 4.1.5, where the
Padding Octets are separated from the information fields, and the
Padding to be Reflected field precedes the Additional Padding.
0 1 2 3 The Session-Reflector SHALL use the same TWAMP-Test Packet Format as
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 specified in section 4.2.1 above.
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sender Sequence Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sender Timestamp |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sender Error Estimate | MBZ |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reflector Receive Timestamp |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reflector Sequence Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reflector's Sending Timestamp |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sender Error Estimate | MBZ |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sender TTL | MBZ (3 octets) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. .
. Packet Padding (from Session-Sender) .
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. Additional Packet Padding .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
6. Security Considerations 5. Security Considerations
These extended modes of operation do not appear to permit any new These extended modes of operation do not appear to permit any new
attacks on hosts communicating with core TWAMP [RFC5357] ??? attacks on hosts communicating with core TWAMP [RFC5357].
The security considerations that apply to any active measurement of The security considerations that apply to any active measurement of
live networks are relevant here as well. See [RFC4656] and live networks are relevant here as well. See [RFC4656] and
[RFC5357]. [RFC5357].
7. IANA Considerations 6. IANA Considerations
This memo adds two mode combinations to the IANA registry for the This memo adds two modes to the IANA registry for the TWAMP Modes
TWAMP Modes Field, and describes behavior when the new modes are Field, and describes behavior when the new modes are used. This
used. This field is a recognized extension mechanism for TWAMP. field is a recognized extension mechanism for TWAMP.
7.1. Registry Specification 6.1. Registry Specification
IANA has created a TWAMP-Modes registry (as requested in IANA has created a TWAMP-Modes registry (as requested in [RFC5618]).
[I-D.ietf-ippm-more-twamp]). TWAMP-Modes are specified in TWAMP TWAMP-Modes are specified in TWAMP Server Greeting messages and
Server Greeting messages and Set-up Response messages, as described Set-up Response messages, as described in section 3.1 of [RFC5357],
in section 3.1 of [RFC5357], consistent with section 3.1 of consistent with section 3.1 of [RFC4656], and extended by this memo.
[RFC4656], and extended by this memo. Modes are indicated by setting Modes are indicated by setting bits in the 32-bit Modes field. Thus,
bits in the 32-bit Modes field. Thus, this registry can contain a this registry can contain a total of 32 possible values.
total of 32 possible values.
7.2. Registry Management 6.2. Registry Management
Because the Modes registry can contain only thirty-two values, and This registry must be updated only by "IETF Consensus" as specified
because TWAMP is an IETF protocol, this registry must be updated only in [RFC2434](an RFC documenting registry use that is approved by the
by "IETF Consensus" as specified in [RFC2434](an RFC documenting IESG).
registry use that is approved by the IESG). For the Modes registry,
we expect that new features will be assigned using monotonically
increasing bit positions and in the range [0-31] and the
corresponding values, unless there is a good reason to do otherwise.
7.3. Experimental Numbers 6.3. Experimental Numbers
No experimental values are currently assigned for the Modes Registry. No experimental values are currently assigned for the Modes Registry.
7.4. Registry Contents 6.4. Registry Contents
TWAMP Modes Registry is recommended to be augmented as follows: TWAMP Modes Registry is recommended to be augmented as follows:
Value Description Semantics Definition Value Description Semantics Definition
0 Reserved 0 Reserved
1 Unauthenticated RFC4656, Section 3.1 1 Unauthenticated RFC4656, Section 3.1
2 Authenticated RFC4656, Section 3.1 2 Authenticated RFC4656, Section 3.1
4 Encrypted RFC4656, Section 3.1 4 Encrypted RFC4656, Section 3.1
8 Unauth. TEST protocol, draft-ietf-more-twamp (3) 8 Unauth. TEST protocol, RFC5618, Section 3.1 (3)
Auth. CONTROL Auth. CONTROL
-------------------------------------------------------- --------------------------------------------------------
xxx Reflect Octets this memo, section 3.1 xxx Reflect Octets this memo, section 3.1
Capability new bit position (X) Capability new bit position (X)
yyy Truncate Padding this memo, section 3.1 yyy Symmetrical Size this memo, section 3.1
Capability new bit position (Y) Sender Test Packet Format new bit position (Y)
The suggested values are The suggested values are
X=4, xxx=16 X=5, xxx=32
Y=5, yyy=32
8. Acknowledgements Y=6, yyy=64
7. Acknowledgements
The authors would like to thank Walt Steverson for helpful review and The authors would like to thank Walt Steverson for helpful review and
comments. comments.
9. References 8. References
9.1. Normative References
[I-D.ietf-ippm-more-twamp] 8.1. Normative References
Morton, A. and K. Hedayat, "More Features for the Two-Way
Active Measurement Protocol - TWAMP",
draft-ietf-ippm-more-twamp-02 (work in progress),
May 2009.
[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.
[RFC2434] Narten, T. and H. Alvestrand, "Guidelines for Writing an [RFC2434] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 2434, IANA Considerations Section in RFCs", BCP 26, RFC 2434,
October 1998. October 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.
9.2. Informative References [RFC5618] Morton, A. and K. Hedayat, "Mixed Security Mode for the
Two-Way Active Measurement Protocol (TWAMP)", RFC 5618,
August 2009.
8.2. Informative References
[x] "". [x] "".
Authors' Addresses Authors' Addresses
Al Morton Al Morton
AT&T Labs AT&T Labs
200 Laurel Avenue South 200 Laurel Avenue South
Middletown,, NJ 07748 Middletown,, NJ 07748
USA USA
 End of changes. 60 change blocks. 
268 lines changed or deleted 283 lines changed or added

This html diff was produced by rfcdiff 1.37a. The latest version is available from http://tools.ietf.org/tools/rfcdiff/