draft-ietf-ippm-twamp-session-cntrl-00.txt   draft-ietf-ippm-twamp-session-cntrl-01.txt 
Network Working Group A. Morton Network Working Group A. Morton
Internet-Draft AT&T Labs Internet-Draft AT&T Labs
Intended status: Standards Track M. Chiba Intended status: Standards Track M. Chiba
Expires: April 29, 2009 Cisco Systems Expires: September 7, 2009 Cisco Systems
October 26, 2008 March 6, 2009
Individual Session Control Feature for TWAMP Individual Session Control Feature for TWAMP
draft-ietf-ippm-twamp-session-cntrl-00 draft-ietf-ippm-twamp-session-cntrl-01
Status of this Memo Status of this Memo
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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 a new
feature for TWAMP, that gives the controlling host the ability to feature for TWAMP, that gives the controlling host the ability to
start and stop one or more individual test sessions using their start and stop one or more individual test sessions using Session
Session Identifiers. The base capability of the TWAMP protocol Identifiers. The base capability of the TWAMP protocol requires all
requires all test sessions previously requested and accepted to start test sessions previously requested and accepted to start and stop at
and stop at the same time. the same time.
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 . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Purpose and Scope . . . . . . . . . . . . . . . . . . . . . . 3 2. Purpose and Scope . . . . . . . . . . . . . . . . . . . . . . 4
3. TWAMP Control Extensions . . . . . . . . . . . . . . . . . . . 4 3. TWAMP Control Extensions . . . . . . . . . . . . . . . . . . . 5
3.1. Connection Setup with Individual Session Control . . . . . 4 3.1. Connection Setup with Individual Session Control . . . . . 5
3.2. Start-Sessions Command with Session Control . . . . . . . 5 3.2. Start-N-Sessions Command with Individual Session
3.3. Stop-Sessions Command with Session Control . . . . . . . . 6 Control . . . . . . . . . . . . . . . . . . . . . . . . . 6
3.4. SERVWAIT Timeout Operation . . . . . . . . . . . . . . . . 7 3.3. Start-N-Ack Command with Individual Session Control . . . 8
3.5. Additional considerations . . . . . . . . . . . . . . . . 8 3.4. Stop-N-Sessions Command with Individual Session Control . 10
4. TWAMP Test with Individual Session Control . . . . . . . . . . 8 3.5. Stop-N-Ack Command with Individual Session Control . . . . 11
4.1. Sender Behavior . . . . . . . . . . . . . . . . . . . . . 9 3.6. SERVWAIT Timeout Operation . . . . . . . . . . . . . . . . 13
4.2. Reflector Behavior . . . . . . . . . . . . . . . . . . . . 9 3.7. Additional considerations . . . . . . . . . . . . . . . . 13
5. Security Considerations . . . . . . . . . . . . . . . . . . . 9 4. TWAMP Test with Individual Session Control . . . . . . . . . . 14
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9 4.1. Sender Behavior . . . . . . . . . . . . . . . . . . . . . 14
6.1. Registry Specification . . . . . . . . . . . . . . . . . . 9 4.2. Reflector Behavior . . . . . . . . . . . . . . . . . . . . 14
6.2. Registry Management . . . . . . . . . . . . . . . . . . . 10 5. Security Considerations . . . . . . . . . . . . . . . . . . . 14
6.3. Experimental Numbers . . . . . . . . . . . . . . . . . . . 10 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15
6.4. Registry Contents . . . . . . . . . . . . . . . . . . . . 10 6.1. Registry Specification . . . . . . . . . . . . . . . . . . 15
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 11 6.2. Registry Management . . . . . . . . . . . . . . . . . . . 15
8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 11 6.3. Experimental Numbers . . . . . . . . . . . . . . . . . . . 15
8.1. Normative References . . . . . . . . . . . . . . . . . . . 11 6.4. Registry Contents . . . . . . . . . . . . . . . . . . . . 16
8.2. Informative References . . . . . . . . . . . . . . . . . . 12 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 16
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 12 8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Intellectual Property and Copyright Statements . . . . . . . . . . 13 8.1. Normative References . . . . . . . . . . . . . . . . . . . 16
8.2. Informative References . . . . . . . . . . . . . . . . . . 17
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 17
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 of 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. TWAMP (and OWAMP) start This memo describes a new feature for TWAMP. TWAMP (and OWAMP) start
all previously requested and accepted test sessions at once. This all previously requested and accepted test sessions at once. This
feature allows the Control-Client to control individual test sessions feature allows the Control-Client to control individual test sessions
on the basis of their Session Identifier (SID). The feature permits on the basis of their Session Identifier (SID). This feature permits
a short duration TWAMP test to start (and/or stop) during a longer a short duration TWAMP test to start (and/or stop) during a longer
test. This feature permits a specific diagnostic test to begin if test. This feature permits a specific diagnostic test to begin if
intermediate results indicate that the test is warranted, for intermediate results indicate that the test is warranted, for
example. example.
This feature requires a Mode bit position assignment and the This feature requires a Mode bit position assignment and the
assignment of two new TWAMP command numbers (for the augmented Start assignment of two new TWAMP command numbers (for the augmented Start
and Stop commands). This feature also specifies a new Stop-ACK and Stop commands). This feature also specifies a new Stop-ACK
Server response, to complete the symmetry of the session stopping Server response, to complete the symmetry of the session stopping
process in the same way as the Start-ACK response. process in the same way as the Start-ACK response.
Implementers of this feature may also wish to implement the "Reflect Implementers of this feature may also wish to implement the "Reflect
Octets" feature, described in [draft-ietf-ippm-twamp-reflect-octets, Octets" feature, described in [I-D.ietf-ippm-twamp-reflect-octets].
work in progress]. This feature allows a Control-Client to insert a This feature allows a Control-Client to insert a locally-specified
locally-specified request number into the Request-TW-Session command request number into the Request-TW-Session command (in octets
(in octets originally designated MBZ=Must Be Zero), and a compliant originally designated MBZ=Must Be Zero), and a compliant Server will
Server will return the request number in its reply (Accept message). return the request number in its reply (Accept message).
This memo is intended to be an update to the TWAMP RFC. This memo is intended to be an update to the TWAMP RFC.
Throughout this memo, the bits marked MBZ (Must Be Zero) MUST be set
to zero by senders and MUST be ignored by receivers.
2. Purpose and Scope 2. Purpose and Scope
The purpose of this memo is to describe an additional function and The purpose of this memo is to describe an additional function and
feature for TWAMP [RFC5357]. The feature needs a clear description feature for TWAMP [RFC5357]. The feature needs a clear description
so it can be discussed and (hopefully) adopted in the IP Performance so it can be discussed and (hopefully) adopted in the IP Performance
Metrics Charter. Metrics Charter.
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 features: following features:
1. Extension of the modes of operation through assignment of a new 1. Extension of the modes of operation through assignment of a new
value in the Mode field to communicate feature capability and value in the Mode field to communicate feature capability and
use, use,
2. the definition of augmented Start Session and Stop Session 2. the definitions of augmented start session and stop session
commands, and commands (with corresponding acknowledgements), and
3. the definition of related procedures for TWAMP entities. 3. the definition of related procedures for TWAMP entities.
The motivation for this added feature is the ability to start and The motivation for this feature is the ability to start and stop
stop individual test sessions at will, using a single TWAMP-control individual test sessions at will, using a single TWAMP-control
connection. connection.
3. TWAMP Control Extensions 3. TWAMP Control Extensions
TWAMP-Control protocol is a derivative of the OWAMP-Control protocol, TWAMP-Control protocol is a derivative of the OWAMP-Control protocol,
and provides two-way measurement capability. TWAMP [RFC5357] uses and provides two-way measurement capability. TWAMP [RFC5357] uses
the Modes Field to identify and select specific communication the Modes Field to identify and select specific communication
capabilities, and this field is a recognized extension mechanism. capabilities, and this field is a recognized extension mechanism.
The following sections describe one such extension. The following sections describe one such extension.
skipping to change at page 5, line 14 skipping to change at page 6, line 16
unauthenticated test packet format. unauthenticated test packet format.
If the Server sets the new bit position (bit position Z) in the If the Server sets the new bit position (bit position Z) in the
Server Greeting message to indicate its capabilities, then the Server Server Greeting message to indicate its capabilities, then the Server
and Session-Reflector MUST comply with the requirements of this memo and Session-Reflector MUST comply with the requirements of this memo
to control sessions on an individual basis if desired. to control sessions on an individual basis if desired.
If the Control-Client intends to control sessions on an individual If the Control-Client intends to control sessions on an individual
basis (according to the requirements in this memo), it MUST set the basis (according to the requirements in this memo), it MUST set the
mode bit (Z, corresponding to the new mode) in the Setup Response mode bit (Z, corresponding to the new mode) in the Setup Response
message. message. This means that:
IF the Control-Client has selected the Reflect Octets feature 1. The Control-Client and the Server MUST use the start and stop
[draft-ietf-ippm-twamp-reflect-octets, work in progress] in commands intended for individual session control and the
combination with the Individual Session Control feature (after the corresponding acknowledgements, as defined in the sections that
Server identified its capability), AND utilizes the feature to insert follow.
a locally-specified request number in the Request-TW-Session command,
THEN the Control Client MAY send more than one Request-TW-Session
command to a given Server without waiting for the corresponding
Accept-Session message.
3.2. Start-Sessions Command with Session Control 2. The Control-Client and the Server MUST NOT use the start and stop
commands (2 and 3) and the acknowledgement defined in [RFC5357].
Having requested one or more test sessions and received affirmative The Control-Client MUST also set one mode bit to indicate the chosen
Accept-Session responses, a TWAMP Client MAY start the execution of security mode (currently bits 0, 1, 2, or 3), consistent with the
the requested test sessions by sending a Start-Sessions message to modes offered by the Server. The Control-Client MAY also set Modes
the server. bit Z with other features and bit positions (such as the reflect
octets feature).
The format of this message is as follows: If the Control-Client has selected the Reflect Octets feature
[I-D.ietf-ippm-twamp-reflect-octets] in combination with the
Individual Session Control feature (after the Server identified its
capability), AND utilizes the feature to insert a locally-specified
request number in the Request-TW-Session command, THEN the Control
Client MAY send more than one Request-TW-Session command to a given
Server without waiting for the corresponding Accept-Session message.
In such a case the Access-Session response reflects the locally-
specified request number. Note that when the Reflect Octets feature
is being used all Request-TW-Session command and Accept-Session
responses MUST include the locally-specified request number.
3.2. Start-N-Sessions Command with Individual Session Control
Having
o initiated Individual Session Control mode in the Setup Response,
o requested one or more test sessions, and
o received affirmative Accept-Session response(s),
a TWAMP Client MAY start the execution of one or more test sessions
by sending a Start-N-Sessions message to the Server (note that "N"
indicates that this command is applicable to one or more sessions,
and does not change with the number of sessions identified in the
command).
The format of the Start-N-Sessions message is as follows:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+B +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+B
| 7 | | | 7 | |
+-+-+-+-+-+-+-+-+ + +-+-+-+-+-+-+-+-+ +
| MBZ (11 octets) | | MBZ (11 octets) |
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Number of Sessions | | Number of Sessions |
skipping to change at page 6, line 31 skipping to change at page 7, line 40
. remaining SIDs (16 octets each) . . remaining SIDs (16 octets each) .
. . . .
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+B +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+B
| | | |
| HMAC (16 octets) | | HMAC (16 octets) |
| | | |
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+B +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+B
The Number of sessions field indicates the count of sessions that The Command Number value of 7 indicates that this is a Start-N-
this Start command applies to. The SID is as defined in OWAMP (and Sessions command. The Control-Client MUST compose this command, and
TWAMP) section 3.5 [RFC4656]. the Server MUST interpret this command, according to the field
descriptions below.
The Server MUST respond with a Start-Ack message (which SHOULD be The Number of Sessions field indicates the count of sessions that
sent as quickly as possible). Start-Ack messages have the format this Start command applies to, and must be one or greater. The
defined in section 3.7 of [RFC4656]. number of SID fields that follow MUST be equal to the value in the
Number of Sessions field (otherwise, the command MUST NOT be affirmed
with a zero Accept field in the Start-N-Ack response).
The Control Client MUST NOT send a subsequent Start Sessions command All SID fields are constructed as defined in the last paragraph of
until an outstanding message is acknowledged with a Start-Ack OWAMP section 3.5 [RFC4656] (and referenced in TWAMP). Note that the
message. SID is assigned by the Server during the session request exchange.
3.3. Stop-Sessions Command with Session Control The message is terminated with a single block HMAC, as illustrated
above.
The Stop-Sessions command can only be issued by the Control-Client. The Server MUST respond with one or more Start-N-Ack messages (which
The message MUST contain at least one SID. The message is terminated SHOULD be sent as quickly as possible). Start-N-Ack messages SHALL
with a single block HMAC, to complete the Stop-Sessions Command. have the format defined in the next session.
Thus, the TWAMP Stop-Sessions command for individual session control <<<<< Comment: Al thinks we don't need the limitation below now,
is constructed as follows: unless it refers to the EXISTING Start-Sessions command. The real
question is, Do we require (MUST) the use of the -N- commands in
Indiv.Sess.Cntrl mode, or allow both types??? I'm leaning toward -N-
commands ONLY. >>>> The Control Client MUST NOT send a subsequent
Start Sessions command until an outstanding message is acknowledged
with a Start-Ack message.
When using Individual Session Control mode and its Start-N-Ack
command as described in the next section, multiple Start-N-Sessions
commands MAY be sent without waiting for acknowledgement, and the
Start-N-sessions commands MAY arrive in any order.
3.3. Start-N-Ack Command with Individual Session Control
The Server responds to the Start-N-Sessions command (for one or more
specific sessions referenced by their SIDs) with one or more Start-N-
Ack commands with Accept fields corresponding to one or more of the
SIDs. This allows for the possibility that a Server cannot
immediately start one or more the sessions referenced in a particular
Start-N-Sessions command, but can start one or more of the sessions.
The format of the message is as follows.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+B +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+B
| 8 | Accept | MBZ | | 8 | Accept | MBZ |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MBZ (8 octets) |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Number of Sessions | | Number of Sessions |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+B
| |
| First SID (16 octets) |
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+B
| |
. remaining SIDs (16 octets each) .
. .
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+B
| |
| HMAC (16 octets) |
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MBZ (8 octets) |
The Command Number value of 8 indicates that this is a Start-N-Ack
message. The Server MUST compose this command, and the Control-
Client MUST interpret this command, according to the field
descriptions below.
The Accept Field values are defined in OWAMP section 3.3 [RFC4656].
The Number of Sessions field indicates the count of sessions that
this Start-N-Ack command applies to, and must be one or greater. The
number of SID fields that follow MUST be equal to the value in the
Number of Sessions field.
All SID fields are constructed as defined in the last paragraph of
OWAMP section 3.5 [RFC4656] (and referenced in TWAMP). Note that the
SID is assigned by the Server during the session request exchange.
The message is terminated with a single block HMAC, as illustrated
above.
Note that the SIDs for all Sessions with the same 'Accept' code can
be acknowledged using the same Start-N-Ack message.
For example, say that the Server receives a Start-N-Sessions command
for SIDs 1, 2, 3, and 4. The Server determines that the resources
for SID=3 are temporarily unavailable. The Server responds with two
Start-N-Ack commands with fields as follows:
Accept = 0 Number of Sessions = 3 SIDs 1, 2, 4
Accept = 5 Number of Sessions = 1 SID 3
3.4. Stop-N-Sessions Command with Individual Session Control
The Stop-N-Sessions command can only be issued by the Control-Client.
The command MUST contain at least one SID.
The TWAMP Stop-N-Sessions command for use in Individual Session
Control mode is formatted 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+B
| 9 | |
+-+-+-+-+-+-+-+-+ +
| MBZ (11 octets) |
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Number of Sessions |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+B +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+B
| | | |
| First SID (16 octets) | | First SID (16 octets) |
| | | |
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+B +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+B
| | | |
. remaining SIDs (16 octets each) . . remaining SIDs (16 octets each) .
. . . .
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+B +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+B
| | | |
| HMAC (16 octets) | | HMAC (16 octets) |
| | | |
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+B +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+B
The Command Number value of 9 indicates that this is a Stop-N-
Sessions command. The Control-Client MUST compose this command, and
the Server MUST interpret this command, according to the field
descriptions below.
The Number of sessions field indicates the count of sessions that The Number of sessions field indicates the count of sessions that
this Stop command applies to. The SID is as defined in OWAMP (and this Stop-N-Sessions command applies to. The SID is as defined in
TWAMP) section 3.5 [RFC4656]. OWAMP (and TWAMP) section 3.5 [RFC4656] and the value must be one or
greater. The number of SID fields that follow MUST be equal to the
value in the Number of Sessions field.
3.4. SERVWAIT Timeout Operation The message is terminated with a single block HMAC, as illustrated
above.
The Server MUST respond with one or more Stop-N-Ack messages (which
SHOULD be sent as quickly as possible). Stop-N-Ack messages SHALL
have the format defined in the next session.
3.5. Stop-N-Ack Command with Individual Session Control
In response to the Stop-N-Sessions command (for one or more specific
sessions referenced by their SIDs), the Server MUST reply with one or
more Stop-N-Ack commands with Accept fields corresponding to one or
more of the SIDs. This allows for the possibility that a Server
cannot immediately stop one or more the sessions referenced in a
particular Stop-N-Sessions command, but can stop one or more of the
sessions.
The format for the Stop-N-Ack command 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+B
| 10 | Accept | MBZ |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MBZ (8 octets) |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Number of Sessions |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+B
| |
| First SID (16 octets) |
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+B
| |
. remaining SIDs (16 octets each) .
. .
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+B
| |
| HMAC (16 octets) |
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Command Number value of 10 indicates that this is a Stop-N-Ack
message. The Server MUST compose this command, and the Control-
Client MUST interpret this command, according to the field
descriptions below.
The Accept Field values are defined in OWAMP section 3.3 [RFC4656].
The Number of Sessions field indicates the count of sessions that
this Stop-N-Ack command applies to, and must be one or greater. The
number of SID fields that follow MUST be equal to the value in the
Number of Sessions field.
All SID fields are constructed as defined in the last paragraph of
OWAMP section 3.5 [RFC4656] (and referenced in TWAMP). Note that the
SID is assigned by the Server during the session request exchange.
The message is terminated with a single block HMAC, as illustrated
above.
Note that the SIDs for all Sessions with the same 'Accept' code can
be acknowledged using the same Stop-N-Ack message.
3.6. SERVWAIT Timeout Operation
Section 3.1 of [RFC5357] describes the operation of the optional Section 3.1 of [RFC5357] describes the operation of the optional
SERVWAIT timer. In normal TWAMP operation, the Server suspends SERVWAIT timer. In normal TWAMP operation, the Server suspends
monitoring the SERVWAIT timer while test sessions are in progress. monitoring the SERVWAIT timer while test sessions are in progress.
When the Individual Session Control feature is utilized, this When the Individual Session Control feature is utilized, this
suspension is extended to cover the time when ANY test session is in suspension is extended to cover the time when ANY test session is in
progress. progress.
Thus, the Server SHALL suspend monitoring control connection activity Thus, the Server SHALL suspend monitoring control connection activity
after receiving any Start-Sessions command, and after receiving a after receiving any Start-N-Sessions command, and after receiving a
Stop-Sessions command for all corresponding SIDs (and no test Stop-N-Sessions command for all corresponding SIDs (and no test
sessions are in-progress), OR when REFWAIT expires on ALL test sessions are in-progress), OR when REFWAIT expires on ALL test
sessions initiated by a TWAMP-Control connection, then the SERVWAIT sessions initiated by a TWAMP-Control connection, then the SERVWAIT
monitoring SHALL resume (as though a Stop-Sessions command had been monitoring SHALL resume (as though a Stop-N-Sessions command had been
received). An implementation which supports the SERVWAIT timeout received). An implementation which supports the SERVWAIT timeout
option SHOULD also implement the REFWAIT timeout option. option SHOULD also implement the REFWAIT timeout option.
The diagram below illustrates the operation of timers SERVWAIT and The diagram below illustrates the operation of timers SERVWAIT and
REFWAIT. REFWAIT.
SERVWAIT REFWAIT SERVWAIT SERVWAIT REFWAIT SERVWAIT
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+
(no sessions (no sessions
in-progress) in-progress)
skipping to change at page 8, line 23 skipping to change at page 13, line 41
SID="1" SID="1"
+-+-+-+-+ +-+-+-+-+
SID="2" SID="2"
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
SID="3" SID="3"
>>>>>>>>>> Time >>>>>>>>>>>>>>>>>>> Time >>>>>>>>>>>>>>>> Time >>>>> >>>>>>>>>> Time >>>>>>>>>>>>>>>>>>> Time >>>>>>>>>>>>>>>> Time >>>>>
3.5. Additional considerations 3.7. 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.
If this feature is adopted, the last ???? bits of the Modes 32-bit If this feature is adopted, the last ???? bits of the Modes 32-bit
field are used. A Control-Client MAY ignore other bit positions field are used. A Control-Client MAY ignore other bit positions
greater than 2 in the Modes Field, or it MAY support other features greater than 2 in the Modes Field, or it MAY support other features
that are communicated in these bit positions. (The unassigned bits that are communicated in these bit positions. (The unassigned bits
are available for future protocol extensions.) are available for future protocol extensions.)
skipping to change at page 9, line 9 skipping to change at page 14, line 22
one for packets transmitted by the Session-Sender and one for packets one for packets transmitted by the Session-Sender and one for packets
transmitted by the Session-Reflector. As with OWAMP-Test protocol transmitted by the Session-Reflector. As with OWAMP-Test protocol
there are three security modes: unauthenticated, authenticated, and there are three security modes: unauthenticated, authenticated, and
encrypted. Unauthenticated mode has one test packet format, while encrypted. Unauthenticated mode has one test packet format, while
authenticated and encrypted modes use another (common) format. authenticated and encrypted modes use another (common) format.
4.1. Sender Behavior 4.1. Sender Behavior
The individual session control feature requires that the sender MUST The individual session control feature requires that the sender MUST
manage test sessions according to their SID. Otherwise, the sender manage test sessions according to their SID. Otherwise, the sender
behavior is as describe in section 4.1 of [RFC5357]. behavior is as described in section 4.1 of [RFC5357].
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 required by 4.2 of [RFC5357], with the following additional functions required by
this feature: this feature:
o The Session-Reflector MUST manage all test sessions accepted o The Session-Reflector MUST manage all test sessions accepted
according to their SID. according to their SID.
o Packets for a specific session/SID not received within the Timeout o Upon receipt of a TWAMP-Control Stop-N-Sessions command
(following the Stop-Session command) MUST be ignored by the referencing a specific session/SID, the Session-Reflector MUST
Session-Reflector. The Session-Reflector MUST NOT generate a test ignore TWAMP-Test packets (in the same session/SID) that arrive at
packet to the Session-Sender for packets that are ignored. the current time plus the Timeout (in the Request-TW-Session
command and assuming subsequent acknowledgement). The Session-
Reflector MUST NOT generate a test packet to the Session-Sender
for packets that are ignored.
o If the RECOMMENDED REFWAIT timer is implemented, it SHOULD be o If the RECOMMENDED REFWAIT timer is implemented, it SHOULD be
enforced when any test session is in-progress (started and not enforced when any test session is in-progress (started and not
stopped). stopped).
5. Security Considerations 5. Security Considerations
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 the security live networks are relevant here as well. See the security
considerations in[RFC4656] and [RFC5357]. considerations in[RFC4656] and [RFC5357].
6. IANA Considerations 6. IANA Considerations
This memo requests assignment of one mode bit position/value to the This memo requests assignment of one mode bit position/value to the
IANA registry for the TWAMP Mode field, and describes behavior when IANA registry for the TWAMP Mode field, and describes behavior when
the new mode is used. This field is a recognized extension mechanism the new mode is used. This field is a recognized extension mechanism
for TWAMP. for TWAMP.
This memo also requests assignment of two command numbers in the This memo also requests assignment of four command numbers in the
TWAMP-Control Command Number registry, and describes the use of the TWAMP-Control Command Number registry, and describes the use of the
new commands. The command number field is a recognized extension new commands. The command number field is a recognized extension
mechanism for TWAMP. mechanism for TWAMP.
6.1. 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
[I-D.ietf-ippm-more-twamp]). TWAMP-Modes are specified in TWAMP [I-D.ietf-ippm-more-twamp]). TWAMP-Modes are specified in TWAMP
Server Greeting messages and Set-up Response messages, as described Server Greeting messages and Set-up Response messages, as described
in section 3.1 of [RFC5357], consistent with section 3.1 of in section 3.1 of [RFC5357], consistent with section 3.1 of
[RFC4656], and extended by this memo. Modes are indicated by setting [RFC4656], and extended by this memo. Modes are indicated by setting
bits in the 32-bit Modes field. Thus, this registry can contain a bits in the 32-bit Modes field. Thus, this registry can contain a
total of 32 possible values. total of 32 possible values.
IANA has also created a TWAMP-Control Command Number registry. IANA has also created a TWAMP-Control Command Number registry.
TWAMP-Control commands are specified by the first octet in TWAMP- TWAMP-Control commands are specified by the first octet in TWAMP-
Control messages as specified in section 3.5 of [RFC5357], and Control messages as specified in section 3.5 of [RFC5357], and
augmented by this memo. This registry may contain sixteen possible augmented by this memo. This registry may contain 256 possible
values. values.
6.2. Registry Management 6.2. Registry Management
Because the TWAMP-Control Command Number registry can contain only Because the TWAMP-Control Command Number registry can contain only
sixteen values, TWAMP-Modes can only contain thirty-two values, and 256 values and TWAMP-Modes can only contain thirty-two values, and
because TWAMP is an IETF protocol, these registries must be updated because TWAMP is an IETF protocol, these registries must be updated
only by "IETF Consensus" as specified in [RFC2434](an RFC documenting only by "IETF Consensus" as specified in [RFC2434](an RFC documenting
registry use that is approved by the IESG). Management of these registry use that is approved by the IESG). Management of these
registries is described in section 8.2 of [RFC5357] and registries is described in section 8.2 of [RFC5357] and
[I-D.ietf-ippm-more-twamp]. [I-D.ietf-ippm-more-twamp].
This memo proposes assignment of values 7 and 8. This memo proposes assignment of values 7, 8, 9 and 10 in the Command
number Registry, and the next available bit position (indicated by
"Z") and corresponding value (indicated by "zzz") in section 3.1
above. Note that these values should be replaced by IANA or the RFC
Editor when assigned.
6.3. Experimental Numbers 6.3. Experimental Numbers
One experimental value has been assigned in the TWAMP-Control Command One experimental value has been assigned in the TWAMP-Control Command
Number registry. Number registry.
No additional experimental values are assigned in the TWAMP-Modes No additional experimental values are assigned in the TWAMP-Modes
registry. registry.
6.4. Registry Contents 6.4. Registry Contents
skipping to change at page 11, line 4 skipping to change at page 16, line 11
One experimental value has been assigned in the TWAMP-Control Command One experimental value has been assigned in the TWAMP-Control Command
Number registry. Number registry.
No additional experimental values are assigned in the TWAMP-Modes No additional experimental values are assigned in the TWAMP-Modes
registry. registry.
6.4. Registry Contents 6.4. Registry Contents
TWAMP-Control Command Number Registry TWAMP-Control Command Number Registry
Value Description Semantics Definition Value Description Semantics Definition
0 Reserved 0 Reserved
1 Forbidden 1 Forbidden
2 Start-Sessions RFC4656, Section 3.7 2 Start-Sessions RFC4656, Section 3.7
3 Stop-Sessions RFC4656, Section 3.8 3 Stop-Sessions RFC4656, Section 3.8
4 Reserved 4 Reserved
5 Request-TW-Session draft-ietf-ippm-twamp, Section 3.5 5 Request-TW-Session RFC5357, Section 3.5
6 Experimentation draft-ietf-ippm-twamp, Section 8.3 6 Experimentation RFC5357, Section 8.3
------------------------------------------------------------------ ------------------------------------------------------------------
7 Start-Sessions with this memo, Section 3.2 7 Start-N-Sessions this memo, Section 3.2
Individ. Session Cntrl. 8 Start-N-Ack this memo, Section 3.3
8 Stop-Sessions with this memo, Section 3.3 9 Stop-N-Sessions this memo, Section 3.4
Individ. Session Cntrl. 10 Stop-N-Ack this memo, Section 3.5
TWAMP-Modes Registry TWAMP-Modes Registry
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-...-more-twamp (3) 8 Unauth. TEST protocol, draft-...-more-twamp (3)
Auth. CONTROL Auth. CONTROL
skipping to change at page 11, line 45 skipping to change at page 17, line 7
8. References 8. References
8.1. Normative References 8.1. Normative References
[I-D.ietf-ippm-more-twamp] [I-D.ietf-ippm-more-twamp]
Morton, A. and K. Hedayat, "More Features for TWAMP", Morton, A. and K. Hedayat, "More Features for TWAMP",
draft-ietf-ippm-more-twamp-00 (work in progress), draft-ietf-ippm-more-twamp-00 (work in progress),
October 2008. October 2008.
[I-D.ietf-ippm-twamp-reflect-octets]
Morton, A. and L. Ciavattone, "TWAMP Reflect Octets
Feature", draft-ietf-ippm-twamp-reflect-octets-00 (work in
progress), October 2008.
[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.
skipping to change at page 12, line 31 skipping to change at page 18, line 4
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
Phone: +1 732 420 1571 Phone: +1 732 420 1571
Fax: +1 732 368 1192 Fax: +1 732 368 1192
Email: acmorton@att.com Email: acmorton@att.com
URI: http://home.comcast.net/~acmacm/ URI: http://home.comcast.net/~acmacm/
Murtaza Chiba Murtaza Chiba
Cisco Systems Cisco Systems
170 W. Tasman Drive
San Jose, 95134
USA USA
Phone: +1 Phone: +1 800 553 NETS
Fax: +1 Fax: +1
Email: mchiba@cisco.com Email: mchiba@cisco.com
URI: URI:
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