Internet DRAFT - draft-buerkle-gsmp-move-branch-message
draft-buerkle-gsmp-move-branch-message
Internet-Draft Joachim Buerkle
25. November 1999 Bosch Telecom
Expiration Date: 24. May 2000
Extended move branch concept for GSMP
<draft-buerkle-gsmp-move-branch-message-01.txt>
Status of this Memo
This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC2026.
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Copyright Notice
Copyright (C) The Internet Society (1999). All Rights Reserved.
Abstract
Some multicast applications, such as Video distribution, need an
efficient support for moving between multicast groups.
This draft shows that the support of such application results in a
extended move branch concept of GSMP to be able to move the Output
branch of a connection not only to another port but also between
connections with the same QoS.
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Overview
Some GSMP applications, which are using zapping protocols to switch
between different content streams (multicast groups), need the
possibility to switch the output branch of connection to another
connection with the same QoS.
Since zapping between content streams is a highly time critical
action this draft proposes to generalized respectively extended
move branch concept of GSMP.
1. Current Situation
The Move Branch message of [1] is used to move a branch of an
Existing connection from its current output port label to a new
output port label in a single atomic transaction.
As defined in [1] the Move Branch message is a connection management
message used to move a single output branch of connection from its
current Output Port and Output Label, to a new Output Port and Output
Label on the same connection. None of the connection's other Output
Branches are modified. When the operation is complete the original
Output Label on the original Output Port will be deleted from the
Connection.
Furthermore [1] defines as an ATM specific procedure the ATM VPC
Move Branch. The ATM VPC Move Branch message is a connection
management message used to move a single Output Branch of a virtual
path connection from its current Output Port and Output VPI, to a
new Output Port and Output VPI on the same virtual channel
connection. None of the other Output Branches are modified. When
the operation is complete the original Output VPI on the original
Output Port will be deleted from the connection.
2. New Requirement
The new requirement of GSMP multicast applications, such as Video
distribution, is that GSMP provides a single atomic transaction to
move an Output Branch of a connection (e.g. a VCC) to another
existing connection (e.g. a VCC). Both connection must have the
same specified QoS.
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3. Possible Concepts
It is possible to consider a the move of Output branches between
existing connections (in case of a Port-Type=ATM VCCs) as a
variant of the GSMP move branch message, or as a distinct object in
its own right. The former would involve an extended definition of
the move branch message while the latter would involve a new
additional connection management message.
Which of these variants will be chosen is up to the GSMP WG
consensus.
3.1. Changes to GSMP with the first variant
The first variant means that there is no change of the message
Format but the Port and Label fields of the message are used in
Dependence of the message type.
The message will then defined 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Version | Message Type | Result | Code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Partition ID | Transaction Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Port Session Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Unchanged Port |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|x|x|x|E| Unchanged Label |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
** ~x x x|E| Unchanged Extended Label ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| To be changed Old Port |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|x x x|E| To be changed Old Label |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
** ~x x x|E| To be changed Extended Old Label ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| To be changed New Port |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|QMS|x|E| To be changed New Label |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
** ~x x x|E| To be changed Extended New Label ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Service Selector |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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** Note: There can be zero or more 32 bit words containing
Extended Labels (like those marked **) following an Input
or Output Label field. A 32 bit word containing an Extended
Label follows the previous label field if and only if the E
Flag immediately preceding the previous label is set.
The E, QMS and Service Selector fields are as defined in the Add
Branch message of [1].
The Port and Label Fields are then used for the different message
Types as defined as follows:
In the cases of GSMPs message types:
- #22
- #27
the port and label fields must be used for the existing as defined
in [1]. This means:
- Unchanged Port = Input Port
- Unchanged Label = Input Label
- Unchanged Extended Label = Extended Input Label
- To be changed Old Port = Output Port
- To be changed Old Label = Output Label
- To be changed Extended Old Label = Extended Output Label
- To be changed New Port = Output Port
- To be changed New Label = Output Label
- To be changed Extended New Label = Extended Output Label
In this case where the move branch message is used to move an Output
branch between existing connections (in case of a Port-Type=ATM VCCs)
a new message type must be defined and the port and label fields
must be used as defined as follows. This means:
- Unchanged Port = Output Port
- Unchanged Label = Output Label
- Unchanged Extended Label = Extended Output Label
- To be changed Old Port = Input Port
- To be changed Old Label = Input Label
- To be changed Extended Old Label = Extended Input Label
- To be changed New Port = Input Port
- To be changed New Label = Input Label
- To be changed Extended New Label = Extended Input Label
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3.2. Changes to GSMP with the second variant
The second variant means that there will be no changes for the
definition of the existing move branch message of [1] and that
there will be an additional request message which used to move
Output Branches between existing VCCs. This additional request
message is based on the frame format of the current move branch
message.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Version | Message Type | Result | Code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Partition ID | Transaction Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Port Session Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Output Port |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|x|x|x|E| Output Label |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~x x x|E| Extended Output Label ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Old Input Port |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|x|x|x|E| Old Input Label |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~x x x|E| Old Extended Input Label ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| New Input Port |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|QMS|x|E| New Input Label |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~x x x|E| New Extended Input Label ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Service Selector |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Version, Message Type, Result, Code, Partition ID, Transaction
Identifier, Port, QMS and Service Selector fields are as defined
in [1].
If in this case the message is used just for ports with attribute
PortType=ATM the port's labels must be interpreted as ATM Labels as
defined in [1]:
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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
+ - - -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | VPI | VCI |
+ - - -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Since ATM ports do not support Extension Labels so the VPI and
VCI values always occupy the 28 bits following the flags in
a connection management message.
The Message Type for this new message is to be defined by the
GSMP WG for the general and the ATM specific case.
4. Behavior in case of the new move branch message
No matter which variant will be chosen by the GSMP WG the behavior
of the new message will be defines as follows.
If the connection specified by the Old Input Port and Old Input
Label (e.g. VPI/VCI) and the branch specified by the New Input Port
and New Input Label (e.g. VPI/VCI) fields already exists, and the
Output Branch specified by the Output Port and Output Label (e.g.
VPI/VCI) fields exists as a branch on the connection specified by
the Old Input Port and Old Input Label (VPI/VCI), the Output Branch
is added to the connection respectively branch specified by the New
Input Port and the New Input Label. When the operation is complete
the original Output Label (e.g. VPI/VCI) on the original Output Port
will be deleted from the connection (e.g. VCC). If the Result field
of the request message is "AckAll" a success response message must
be sent upon successful completion of the operation. The success
response message must not be sent until the Move Branch operation
has been completed.
This means that with this message a single output branch of
Connection (e.g. VCC) is moved from its current Input Port and
Input Label (e.g. VPI/VCI), to a New Input Port and Input Label
(e.g. VPI/VCI) on another connection (e.g. VCC) which has the same
QoS specified in the Service Selection field. None of the
connection's (e.g. VCCs) other Output Branches are modified.
If the connection specified by the Old Input Port and Old Input
Label fields does not exist, a failure response must be returned
with the Code field indicating, "The connection specified by the Old
Input Port does not exist."
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If the connection specified by the Old Input Port and Old Input Label
fields already exists, but the Output Branch specified by the Output
Port and Output Label fields does not exist as a branch on that
connection, a failure response must be returned with the Code field
indicating, "The specified Output branch does not exist."
If the connection specified by the Old Input Port, Old Input Label,
Output Port and Output Label fields does exist, but the connection
specified by the New Input Port and New Input Label does not exists
a failure response must be returned with the Code field indicating,
"The specified New Input branch does not exist."
4.1. ATM specific Part (Port-Type=ATM)
As it is current practice in [1] for ATM, there shall be a separate
message type for the ATM specific case of this operation.
In the ATM case this operation makes only sense for virtual channel
Connections, so the movement of VPC shall not be supported. A failure
response message must be returned in the VPC case indicating ,
"This operation is not supported for VPCs."
The Move Branch message is in this ATM case a connection management
message used to move a single output branch of a virtual channel
connection from its current input port and current Input VPI/VCI,
to a New Input Port and New Input VPI/VCI on a different virtual
channel connection.
None of the other Output Branches are modified. When the operation
is complete the original Output VPI/VCI on the original connection
specified by the Old Input Port and Old Input VPI/VCI will be
deleted from the connection.
If the virtual channel connection specified by the Old Input
Port and Old Input VPI/VCI field does not exist, a failure response
must be returned with the Code field indicating, "The virtual
channel connection specified by the Old Input Port does not exist."
If the virtual channel connection specified by the Old Input Port
and Old Input VPI/VCI field already exists, but the output branch
specified by the Output Port and Output VPI/VCI field does not exist
as a branch on that connection, a failure response must be returned
with the Code field indicating, "The specified Output branch does
not exist."
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If the virtual channel connection specified by the New Input Port
and New Input Label fields does not exist, a failure response must
be returned with the Code field indicating, "The virtual channel
connection specified by the New Input Port does not exist."
If the Output Branch specified by the New Input Port, New Input VPI,
and New Input VCI fields for a virtual channel connection; is
already in use by any connection other than that specified by the
Output Port and Output Label fields then the resulting new input
branch will have multiple Output Branches. If multiple point-to-
point connections share the same Output Branch the result will be
a multipoint-to-point connection. If multiple point-to-multipoint
trees share the same Output Branches the result will be a
multipoint-to-multipoint connection.
5. Modifications
If the GSMP WG decides to go along with another header format,
like it is proposed in [2], the proposal of this draft can be
easily mapped also to this new message format.
6. References
[1] Tom Worster, et. al., "General Switch Management Protocol",
<draft-ietf-gsmp-02.txt>, Oct. 1999.
[2] Matt Peters, Balaji Srinivasan, Jaroslaw Sydir, "GSMP enhancements"
<draft-sydir-cplane-gsmp-enhancements-00.txt>, Oct. 1999.
Authors' Contact
Joachim Buerkle
@ Bosch Telecom GmbH Phone: +49 7191 13 4602
Gerberstrasse 33 Telefax: +49 7191 13 64602
71522 Backnang Email: joachim.buerkle@de.bosch.com (Germany)
Germany jbuerkle@rtp-bosch.com (USA)
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