draft-ietf-tsvwg-addip-sctp-00.txt   draft-ietf-tsvwg-addip-sctp-01.txt 
skipping to change at page 1, line 15 skipping to change at page 1, line 15
Cisco Systems Cisco Systems
Q. Xie Q. Xie
Motorola Motorola
M. Tuexen M. Tuexen
Siemens AG Siemens AG
I. Rytina I. Rytina
Ericsson Ericsson
P. Conrad P. Conrad
Temple University Temple University
expires in six months May 7, 2001 expires in six months June 6, 2001
SCTP Dynamic Addition of IP addresses SCTP Extensions for Dynamic Reconfiguration of IP Addresses
<draft-ietf-tsvwg-addip-sctp-00.txt> and Enforcement of Flow and Message Limits
<draft-ietf-tsvwg-addip-sctp-01.txt>
Status of This Memo Status of This Memo
This document is an Internet-Draft and is in full conformance with all This document is an Internet-Draft and is in full conformance with
provisions of Section 10 of RFC 2026 [RFC2026]. Internet-Drafts are all provisions of Section 10 of RFC 2026 [RFC2026]. Internet-Drafts
working documents of the Internet Engineering Task Force (IETF), its areas, are working documents of the Internet Engineering Task Force (IETF),
and its working groups. Note that other groups may also distribute its areas, and its working groups. Note that other groups may also
working documents as Internet-Drafts. distribute working documents as Internet-Drafts.
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.
Abstract Abstract
This document describes extensions to the Stream Control This document describes extensions to the Stream Control
Transmission Protocol (SCTP) [RFC2960] that provide a method to Transmission Protocol (SCTP) [RFC2960] that provide methods to (1)
reconfigure IP address information on an existing association or reconfigure IP address information on an existing association and
to request that a peer set a stream flow limit. (2) request that a peer set flow limits in units of bytes or
messages, either on a per-stream or per-association basis.
TABLE OF CONTENTS TABLE OF CONTENTS
1. Introduction............................................... 2 1. Introduction............................................... 2
2. Conventions................................................ 3 2. Conventions................................................ 3
3. Additional Chunks and Parameters........................... 3 3. Additional Chunks and Parameters........................... 3
3.1 New Chunk Types........................................... 3 3.1 New Chunk Types........................................... 4
3.1.1 Address Configuration Change Chunk (ASCONF)............ 3 3.1.1 Address Configuration Change Chunk (ASCONF)............ 4
3.1.2 Address Configuration Acknowledgment Chunk (ASCONF-ACK) 3.1.2 Address Configuration Acknowledgment Chunk (ASCONF-ACK). 5
3.2 New Parameter Types....................................... 4 3.2 New Parameter Types....................................... 6
3.2.1 Add IP Address.......................................... 6 3.2.1 Add IP Address.......................................... 7
3.2.2 Delete IP Address....................................... 6 3.2.2 Delete IP Address....................................... 7
3.2.3 Stream Flow Limit Change................................ 7 3.2.3 Stream Flow Limit Change................................ 8
3.2.4 Error Cause Indication.................................. 7 3.2.4 Error Cause Indication.................................. 9
3.2.5 Set Primary IP Address.................................. 8 3.2.5 Set Primary IP Address.................................. 9
3.2.6 Success Indication...................................... 8 3.2.6 Success Indication......................................10
3.3 New Error Causes.......................................... 9 3.2.7 Stream Message Limit Change.............................10
3.3.1 Error Cause: Request to Delete Last remaining IP Address 9 3.2.8 Association Message Limit Change........................11
3.3.2 Error Cause: Operation Refused due to Resource Shortage.10 3.3 New Error Causes..........................................11
3.3.3 Error Cause: Request to Delete Source IP Address........10 3.3.1 Error Cause: Request to Delete Last Remaining
4. Procedures.................................................11 IP Address..............................................12
4.1 ASCONF Chunk Procedures...................................11 3.3.2 Error Cause: Operation Refused Due to Resource Shortage.12
4.1.1 Congestion Control of ASCONF Chunks.....................12 3.3.3 Error Cause: Request to Delete Source IP Address........13
4.2 Upon reception of a ASCONF Chunk..........................13 4. Procedures.................................................13
4.3 General rules for address manipulation....................15 4.1 ASCONF Chunk Procedures...................................14
4.3.1 A special case for OOTB ABORT chunks....................17 4.1.1 Congestion Control of ASCONF Chunks.....................15
4.4 Setting of the primary address............................18 4.2 Upon reception of an ASCONF Chunk.........................16
4.5 Steam Flow Limit Procedures...............................18 4.3 General rules for address manipulation....................18
4.5.1 Stream Receiver side procedures.........................19 4.3.1 A special case for OOTB ABORT chunks....................20
4.5.2 Stream Sender side procedures...........................19 4.3.2 A special case for changing an address..................21
4.4 Setting of the primary address............................21
4.5 Stream Flow/Message Limit Procedures......................21
4.5.1 Stream receiver side procedures.........................22
4.5.2 Stream sender side procedures...........................23
4.5.3 ULP considerations on the use of SCTP flow limit 4.5.3 ULP considerations on the use of SCTP flow limit
facility................................................20 facility................................................24
5. Security Considerations....................................20 4.6 Association Message Limit Procedures......................24
6. IANA considerations........................................20 4.6.1 Receiver side procedures................................25
7. Authors' Addresses.........................................20 4.6.2 Sender side procedures..................................25
8. References.................................................21 5. Security Considerations....................................25
6. IANA considerations........................................26
7. Authors' Addresses.........................................26
8. References.................................................27
1. Introduction 1. Introduction
To extend the utility and application senarios of SCTP, this To extend the utility and application scenarios of SCTP, this
document introduces optional extensions that provide SCTP with the document introduces optional extensions that provide SCTP with the
ability to reconfigure IP address information on an existing ability to reconfigure IP address information on an existing
association or to request the peer set a stream flow limit. association or to request that the peer set flow limits in units
of bytes or messages, either on a per-stream or per-association
basis.
These extensions enable SCTP to be utilized in the following These extensions enable SCTP to be utilized in the following
applications: applications:
- Dynamic IP addresses added and subtracted extension: For - Dynamic IP address reconfiguration extension: For
computational or networking platforms that allow addition/removal of computational or networking platforms that allow addition/removal of
physical interface cards this feature can provide: physical interface cards this feature can provide:
A) a graceful method to add to the interfaces of an existing A) a graceful method to add to the interfaces of an existing
association. For the multi-homed IPv6 case this feature will association. For IPv6 this feature allows renumbering
allow renumbering of existing associations. of existing associations.
B) provides a method for an endpoint to request that its peer set B) a method for an endpoint to request that its peer set
its primary destination address: This can be useful its primary destination address. This can be useful
when an address is about to be deleted. Or when an endpoint when an address is about to be deleted, or when an endpoint
has some predetermined knowledge about which is the has some predetermined knowledge about which is the
preferred address to receive SCTP packets upon. preferred address to receive SCTP packets upon.
- The SCTP flow limit extension: This extension enables the - The SCTP flow limit extension: This extension enables
ability to request a sender to set a limit to the a receiver to request that a sender impose a byte limit on the
outstanding data sent to each stream. This in turn will outstanding data present on a per-stream basis.
provide:
The SCTP flow limit extension provides:
A) The ability to minimize the occurrence of a single stream A) The ability to minimize the occurrence of a single stream
monopolizing all transport level resources (e.g. a_rwnd monopolizing all transport level resources (e.g. a_rwnd
"deadlock"). "deadlock").
B) The ability to dynamically change the stream buffering B) The ability to dynamically change the stream buffering
limits as the application deems appropriate at any particular limits as the application deems appropriate at any particular
instant. instant.
- The SCTP message limit extension: This extension enables a
receiver to request that a sender impose a limit on the number
of outstanding messages present on:
A) each stream, and/or
B) the whole association.
The SCTP message limit extension provides a method for minimizing
the occurrence of a lack of resources needed for messages even
when resources for payload data are still available. This can
become important when handling a large number of short messages.
2. Conventions 2. Conventions
The keywords MUST, MUST NOT, REQUIRED, SHALL, SHALL NOT, SHOULD, The keywords MUST, MUST NOT, REQUIRED, SHALL, SHALL NOT, SHOULD,
SHOULD NOT, RECOMMENDED, NOT RECOMMENDED, MAY, and OPTIONAL, when SHOULD NOT, RECOMMENDED, NOT RECOMMENDED, MAY, and OPTIONAL, when
they appear in this document, are to be interpreted as described in they appear in this document, are to be interpreted as described in
RFC 2119 [RFC2119]. RFC 2119 [RFC2119].
3. Additional Chunks and Parameters 3. Additional Chunks and Parameters
This section describes the addition of two new chunks and, six This section describes the addition of two new chunks and, eight
new parameters to allow: new parameters to allow:
- Dynamic addition of IP Addresses to an association. - Dynamic addition of IP Addresses to an association.
- Dynamic deletion of IP Addresses to an association. - Dynamic deletion of IP Addresses to an association.
- A request to set the primary address the peer will - A request to set the primary address the peer will
use when sending to an endpoint. use when sending to an endpoint.
- The setting of stream flow limits. - The setting of stream byte limits.
- The setting of stream message limits.
- The setting of association message limits.
Additionally, this section describes three new error causes that Additionally, this section describes three new error causes that
support these new chunks and parameters. support these new chunks and parameters.
3.1 New Chunk Types 3.1 New Chunk Types
This section defines two new Chunk types that will be used to This section defines two new chunk types that will be used to
transfer the control information reliably. Table 1 illustrates the two transfer the control information reliably. Table 1 illustrates the
new chunk types. two new chunk types.
Chunk Type Chunk Name Chunk Type Chunk Name
-------------------------------------------------------------- --------------------------------------------------------------
11000001 Address/Stream Configuration Change Chunk (ASCONF) 0xC1 Address/Stream Configuration Change Chunk (ASCONF)
10000000 Address Configuration Acknowledgment (ASCONF-ACK) 0x80 Address Configuration Acknowledgment (ASCONF-ACK)
Table 1: Address/Stream Configuration Chunks Table 1: Address/Stream Configuration Chunks
It should be noted that the ASCONF Chunk format requires the It should be noted that the ASCONF Chunk format requires the
receiver to report to the sender if it does not understand the receiver to report to the sender if it does not understand the
ASCONF chunk. This is accomplished by setting the upper bits in the ASCONF Chunk. This is accomplished by setting the upper bits in the
Chunk type as described in [RFC2960] section 3.2. Note that the chunk type as described in [RFC2960] section 3.2. Note that the
upper two bits in the ASCONF chunk are set to one. As defined in upper two bits in the ASCONF Chunk are set to one. As defined in
[RFC2960] section 3.2, setting these upper bits in this manner will [RFC2960] section 3.2, setting these upper bits in this manner will
cause the receiver that does not understand this chunk to skip the cause the receiver that does not understand this chunk to skip the
chunk and continue processing, but report in an Operation Error chunk and continue processing, but report in an Operation Error
Chunk using the 'Unrecognized Chunk Type' cause of error. Chunk using the 'Unrecognized Chunk Type' cause of error.
3.1.1 Address Configuration Change Chunk (ASCONF) 3.1.1 Address Configuration Change Chunk (ASCONF)
This chunk is used to communicate to the remote endpoint one of the This chunk is used to communicate to the remote endpoint one of the
configuration change requests that MUST be acknowledged. The configuration change requests that MUST be acknowledged. The
information carried in the ASCONF chunk is always in the form of a information carried in the ASCONF Chunk uses the form of a
Tag-Length-Value (TLV) as described in "3.2.1 Tag-Length-Value (TLV), as described in "3.2.1
Optional/Variable-length Parameter Format" in [RFC2960]. Optional/Variable-length Parameter Format" in [RFC2960], for
all variable parameters.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = 0xC1 | Chunk Flags | Chunk Length | | Type = 0xC1 | Chunk Flags | Chunk Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Serial Number | | Serial Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | Addr Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Address Bytes 0-3 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Address Bytes 4-7 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Address Bytes 8-11 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Address Bytes 12-15 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ASCONF-Request Correlation ID #1 | | ASCONF-Request Correlation ID #1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ASCONF Parameter #1 | | ASCONF Parameter #1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
\ \ \ \
/ .... / / .... /
\ \ \ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ASCONF-Request Correlation ID #N | | ASCONF-Request Correlation ID #N |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ASCONF Parameter #N | | ASCONF Parameter #N |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Serial Number : 32 bits (unsigned integer) Serial Number : 32 bits (unsigned integer)
This value represents a Serial Number for the ASCONF Chunk. The This value represents a Serial Number for the ASCONF Chunk. The
valid range of Serial Number is from 0 to 4294967295 (2**32 - 1). valid range of Serial Number is from 0 to 4294967295 (2**32 - 1).
Serial Numbers wrap back to 0 after reaching 4294967295. Serial Numbers wrap back to 0 after reaching 4294967295.
Reserved: 24 bits
Reserved, set to 0 by the sender and ignored by the
receiver.
Address Type : 8 bits (unsigned char)
This value determines the type of address found in the
Address Bytes field. If the value is 5 then the first
4 bytes of the Address Bytes field contain an IPv4 address,
in network byte order. If the value is 6 then the first
16 bytes of the Address Bytes field contain an IPv6 address,
in network byte order.
Address Bytes: 16 bytes (unsigned chars)
This field contains an address which is part of the association.
This field may be used by the receiver of the ASCONF to help
in finding the association.
ASCONF-Request Correlation ID: 32 bits (unsigned integer) ASCONF-Request Correlation ID: 32 bits (unsigned integer)
This is an opaque integer assigned by the sender to identify each This is an opaque integer assigned by the sender to identify each
request parameter. It is in host byte order and is only meaningful request parameter. It is in host byte order and is only meaningful
to the sender. The receiver of the ASCONF chunk will copy this 32 to the sender. The receiver of the ASCONF Chunk will copy this 32
bit value into the ASCONF Correlation ID field of the bit value into the ASCONF Correlation ID field of the
ASCONF-ACK. The sender of the ASCONF can use this same value in the ASCONF-ACK. The sender of the ASCONF can use this same value in the
ASCONF-ACK to find which request the response is for. ASCONF-ACK to find which request the response is for.
ASCONF Parameter: TLV format ASCONF Parameter: TLV format
Each Address configuration change is represented by a TLV Each Address configuration change is represented by a TLV
parameter has defined in Section 3.2. One or more request parameter as defined in Section 3.2. One or more requests
may be present in a ASCONF chunk. may be present in an ASCONF Chunk.
3.1.2 Address Configuration Acknowledgment Chunk (ASCONF-ACK) 3.1.2 Address Configuration Acknowledgment Chunk (ASCONF-ACK)
This chunk is used by the receiver of an ASCONF chunk to acknowledge This chunk is used by the receiver of an ASCONF Chunk to acknowledge
its reception. It carries zero or more results for any ASCONF the reception. It carries zero or more results for any ASCONF
Parameters that were processed by the receiver. Parameters that were processed by the receiver.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = 0x80 | Chunk Flags | Chunk Length | | Type = 0x80 | Chunk Flags | Chunk Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Serial Number | | Serial Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ASCONF-Request Correlation ID #1 | | ASCONF-Request Correlation ID #1 |
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/ .... / / .... /
\ \ \ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ASCONF-Request Correlation ID #N | | ASCONF-Request Correlation ID #N |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ASCONF Parameter Response#N | | ASCONF Parameter Response#N |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Serial Number : 32 bits (unsigned integer) Serial Number : 32 bits (unsigned integer)
This value represents the Serial Number for the ASCONF chunk that This value represents the Serial Number for the received ASCONF Chunk
was received to which this Chunk is acknowledgment of. This value is that is acknowledged by this chunk. This value is
copied from the received ASCONF chunk. copied from the received ASCONF Chunk.
ASCONF-Request Correlation ID: 32 bits (unsigned integer) ASCONF-Request Correlation ID: 32 bits (unsigned integer)
This value is copied from the ASCONF Correlation ID received in the This value is copied from the ASCONF Correlation ID received in the
ASCONF chunk. It is used by the receiver of the ASCONF-ACK to identify ASCONF Chunk. It is used by the receiver of the ASCONF-ACK to identify
which ASCONF parameter this response is associated with. which ASCONF parameter this response is associated with.
ASCONF Parameter Response : TLV format ASCONF Parameter Response : TLV format
The ASCONF Parameter Response is used in the ASCONF-ACK to report The ASCONF Parameter Response is used in the ASCONF-ACK to report
status of ASCONF processing. By default, if a responding endpoint status of ASCONF processing. By default, if a responding endpoint
does not include any Error cause a success is indicated. Thus a does not include any Error Cause, a success is indicated. Thus a
sender of a ASCONF-ACK MAY indicate complete success of all TLV's in sender of an ASCONF-ACK MAY indicate complete success of all TLVs in
a ASCONF by returning only the Chunk Type, Chunk Flags, Chunk Length an ASCONF by returning only the Chunk Type, Chunk Flags, Chunk Length
(set to 8) and the Serial Number. (set to 8) and the Serial Number.
3.2 New Parameter Types 3.2 New Parameter Types
The six new parameters added follow the format defined in section The eight new parameters added follow the format defined in section
3.2.1 of [RFC2960]. Table 2 describes the Parameters. 3.2.1 of [RFC2960]. Table 2 describes the parameters.
Address Configuration Parameters Parameter Type Address Configuration Parameters Parameter Type
------------------------------------------------- -------------------------------------------------
Add IP Address 49153 (0xC001) Add IP Address 0xC001
Delete IP Address 49154 (0xC002) Delete IP Address 0xC002
Stream Flow limit Request 49155 (0xC003) Stream Byte Limit Request 0xC003
Error Cause Indication 49156 (0xC004) Error Cause Indication 0xC004
Set Primary Address 49157 (0xC005) Set Primary Address 0xC005
Success report 49158 (0xC006) Success report 0xC006
Stream Message Limit Request 0xC007
Association Message Limit Request 0xC008
Table 2: Address Configuration Parameters Table 2: Address Configuration Parameters
3.2.1 Add IP Address 3.2.1 Add IP Address
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = 0xC001 | Length = Variable | | Type = 0xC001 | Length = Variable |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Address Parameter | | Address Parameter |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = 0xC001 | Length = Variable | | Type = 0xC001 | Length = Variable |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Address Parameter | | Address Parameter |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Address Parameter: TLV Address Parameter: TLV
This field contains an IPv4 or IPv6 address parameter as described This field contains an IPv4 or IPv6 address parameter as described
in 3.3.2.1 of RFC2960. The complete TLV is wrapped within this in 3.3.2.1 of RFC2960. The complete TLV is wrapped within this
parameter. It informs the receiver that the Address specified is to parameter. It informs the receiver that the address specified is to
be added to the existing association. be added to the existing association.
An example TLV requesting that the IPv4 address 10.1.1.1 should be An example TLV requesting that the IPv4 address 10.1.1.1 be
made the primary destination address would look as follows: added to the association would look as follows:
+--------------------------------+ +--------------------------------+
| Type=0xC001 | Length = 12 | | Type=0xC001 | Length = 12 |
+--------------------------------+ +--------------------------------+
| Type=5 | Length = 8 | | Type=5 | Length = 8 |
+----------------+---------------+ +----------------+---------------+
| Value=0x0a010101 | | Value=0x0a010101 |
+----------------+---------------+ +----------------+---------------+
Valid Chunk Appearance Valid Chunk Appearance
The Add IP Address parameter may only appear in the ASCONF chunk The Add IP Address parameter may only appear in the ASCONF Chunk
type. type.
3.2.2 Delete IP Address 3.2.2 Delete IP Address
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type =0xC002 | Length = Variable | | Type =0xC002 | Length = Variable |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Address Parameter | | Address Parameter |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Address Parameter: TLV Address Parameter: TLV
This field contains an IPv4 or IPv6 address parameter as described in This field contains an IPv4 or IPv6 address parameter as described in
3.3.2.1 of [RFC2960]. The complete TLV is wrapped within this 3.3.2.1 of [RFC2960]. The complete TLV is wrapped within this
parameter. It informs the receiver that the Address specified is to parameter. It informs the receiver that the address specified is to
be removed from the existing association. be removed from the existing association.
An example TLV deleting the IPv4 address 10.1.1.1 from an existing An example TLV deleting the IPv4 address 10.1.1.1 from an existing
association would look as follows: association would look as follows:
+--------------------------------+ +--------------------------------+
| Type=0xC002 | Length = 12 | | Type=0xC002 | Length = 12 |
+--------------------------------+ +--------------------------------+
| Type=5 | Length = 8 | | Type=5 | Length = 8 |
+----------------+---------------+ +----------------+---------------+
| Value=0x0a010101 | | Value=0x0a010101 |
+----------------+---------------+ +----------------+---------------+
Valid Chunk Appearance Valid Chunk Appearance
The Delete IP Address parameter may only appear in the ASCONF chunk The Delete IP Address parameter may only appear in the ASCONF Chunk
type. type.
3.2.3 Stream Flow Limit Change 3.2.3 Stream Flow Limit Change
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type =0xC003 | Length = Variable | | Type =0xC003 | Length = Variable |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Stream Number 1 | Flow Limit 1 | | Stream Number 1 | Byte Limit 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
\ / \ /
/ \ / \
\ / \ /
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Stream Number N | Flow Limit N | | Stream Number N | Byte Limit N |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Stream Number n : 16 bits (unsigned integer) Stream Number n : 16 bits (unsigned integer)
This is the stream number that is requesting a limit be placed This is the stream number for which a limit is to be enforced.
on the sender based on the applications receive buffer sizes.
Flow Limit n : 16 bits (unsigned integer) Byte Limit n : 16 bits (unsigned integer)
This is the limit the receiver is requesting (in bytes) as to the This is the limit (in bytes) that the receiver (sending the chunk)
maximum amount of data that the receiver may accept. Note that the is requesting that the sender (receiver of the chunk) enforce as
value 0 holds a special meaning described in Section 4.5. the maximum amount of outstanding data permitted at any time on
this stream, as per the rules in Section 4.5. Note that the value
'0' holds a special meaning described in Section 4.5.1
Valid Chunk Appearance Valid Chunk Appearance
The Stream Flow Limit Change parameter may only appear in the ASCONF The Stream Flow Limit Change parameter may appear in the ASCONF
chunk type. chunk, the INIT, or the INIT-ACK chunk type. The inclusion of this
parameter in the INIT or INIT-ACK can be used to indicate initial
byte limits.
3.2.4 Error Cause Indication 3.2.4 Error Cause Indication
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = 0xC004 | Length = Variable | | Type = 0xC004 | Length = Variable |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Error Cause(s) or Return Info on Success | | Error Cause(s) or Return Info on Success |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
skipping to change at page 8, line 49 skipping to change at page 10, line 4
+--------------------------------+ +--------------------------------+
| Type=0xC005 | Length = 12 | | Type=0xC005 | Length = 12 |
+--------------------------------+ +--------------------------------+
| Type=5 | Length = 8 | | Type=5 | Length = 8 |
+----------------+---------------+ +----------------+---------------+
| Value=0x0a010101 | | Value=0x0a010101 |
+----------------+---------------+ +----------------+---------------+
Valid Chunk Appearance Valid Chunk Appearance
The Set Primary IP Address parameter may appear in the ASCONF Chunk,
The Set Primary IP Address parameter may appear in the ASCONF chunk,
the INIT, or the INIT-ACK chunk type. The inclusion of this parameter the INIT, or the INIT-ACK chunk type. The inclusion of this parameter
in the INIT or INIT-ACK can be used to indicate an initial preference in the INIT or INIT-ACK can be used to indicate an initial preference
of primary address. of primary address.
3.2.6 Success Indication 3.2.6 Success Indication
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = 0xC006 | Length = 4 | | Type = 0xC006 | Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
By default if a responding endpoint does not report an error for any By default if a responding endpoint does not report an error for any
requested TLV, a success is implicitly indicated. Thus a sender of a requested TLV, a success is implicitly indicated. Thus a sender of a
ASCONF-ACK MAY indicate complete success of all TLV's in a ASCONF by ASCONF-ACK MAY indicate complete success of all TLVs in an ASCONF by
returning only the Chunk Type, Chunk Flags, Chunk Length (set to 8) returning only the Chunk Type, Chunk Flags, Chunk Length (set to 8)
and the Serial Number. and the Serial Number.
The responding endpoint MAY also choose to explicitly report a The responding endpoint MAY also choose to explicitly report a
success for a requested TLV, by returning a success report ASCONF success for a requested TLV, by returning a success report ASCONF
Parameter Response. Parameter Response.
Valid Chunk Appearance Valid Chunk Appearance
The Success Indication parameter may only appear in the ASCONF-ACK The Success Indication parameter may only appear in the ASCONF-ACK
chunk type. chunk type.
3.2.7 Stream Message Limit Change
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type =0xC007 | Length = Variable |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Stream Number 1 | Message Limit 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
\ /
/ \
\ /
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Stream Number N | Message Limit N |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Stream Number n : 16 bits (unsigned integer)
This is the stream number for which a limit is to be enforced.
Message Limit n : 16 bits (unsigned integer)
This is the limit (in messages) that the receiver (sending the
chunk) is requesting that the sender (receiver of the chunk)
enforce as the maximum number of outstanding messages permitted at
any time on this stream, as per the rules in Section 4.5. Note
that the value '0' holds a special meaning described in Section
4.5.1.
Valid Chunk Appearance
The Stream Message Limit Change parameter may appear in the ASCONF
chunk, the INIT, or the INIT-ACK chunk type. The inclusion of this
parameter in the INIT or INIT-ACK can be used to indicate initial
stream message limits.
3.2.8 Association Message Limit Change
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type =0xC008 | Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Association Message Limit |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Association Message Limit n : 32 bits (unsigned integer)
This is the limit (in messages) that the receiver (sending the
chunk) is requesting that the sender (receiver of the chunk)
enforce as the maximum number of outstanding messages permitted at
any time on the association, as per the rules in Section 4.6.
Note that the value 0 holds a special meaning described in Section
4.5.1
Valid Chunk Appearance
The Association Message Limit Change parameter may appear in the
ASCONF Chunk, the INIT, or the INIT-ACK chunk type. The inclusion
of this parameter in the INIT or INIT-ACK can be used to indicate
an initial association message limit.
3.3 New Error Causes 3.3 New Error Causes
Three new Error Causes are added to the SCTP Operational Errors, Three new Error Causes are added to the SCTP Operational Errors,
primarily for use in the ASCONF-ACK chunk. primarily for use in the ASCONF-ACK chunk.
Cause Code Cause Code
Value Cause Code Value Cause Code
--------- ---------------- --------- ----------------
12 Request to delete last remaining IP address. 0xC Request to Delete Last Remaining IP Address.
13 Operation Refused due to resource shortage. 0xD Operation Refused Due to Resource Shortage.
14 Request to delete source IP address. 0xE Request to Delete Source IP Address.
Table 3: New Error Causes Table 3: New Error Causes
3.3.1 Error Cause: Request to Delete Last Remaining IP Address
3.3.1 Error Cause: Request to Delete Last remaining IP Address
Cause of error Cause of error
--------------- ---------------
Request to delete last remaining IP address: The receiver of this Request to Delete Last Remaining IP address: The receiver of this
error sent a request to delete the last IP address from its error sent a request to delete the last IP address from its
association with its peer. This error indicates that the request is association with its peer. This error indicates that the request is
rejected. rejected.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Cause Code=12 | Cause Length=Variable | | Cause Code=0x000C | Cause Length=Variable |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
\ TLV-Copied-From-ASCONF / \ TLV-Copied-From-ASCONF /
/ \ / \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
An example of a failed delete in an Error Cause TLV would look as An example of a failed delete in an Error Cause TLV would look as
follows in the response ASCONF-ACK message: follows in the response ASCONF-ACK message:
+--------------------------------+ +--------------------------------+
| Type = 0xC004 | Length = 20 | | Type = 0xC004 | Length = 20 |
+--------------------------------+ +--------------------------------+
| Cause=12 | Length = 16 | | Cause=0x000C | Length = 16 |
+----------------+---------------+ +----------------+---------------+
| Type= 0xC002 | Length = 12 | | Type= 0xC002 | Length = 12 |
+----------------+---------------+ +----------------+---------------+
| Type=5 | Length = 8 | | Type=0x0005 | Length = 8 |
+----------------+---------------+ +----------------+---------------+
| Value=0x0a010101 | | Value=0x0A010101 |
+----------------+---------------+ +----------------+---------------+
3.3.2 Error Cause: Operation Refused due to Resource Shortage 3.3.2 Error Cause: Operation Refused Due to Resource Shortage
Cause of error Cause of error
--------------- ---------------
This error cause is used to report a failure by the receiver to This error cause is used to report a failure by the receiver to
perform the requested operation due to a lack of resources. The perform the requested operation due to a lack of resources. The
entire TLV that is refused is copied from the ASCONF-REQ into the entire TLV that is refused is copied from the ASCONF-REQ into the
error cause. error cause.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Cause Code=13 | Cause Length=Variable | | Cause Code=0x000D | Cause Length=Variable |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
\ TLV-Copied-From-ASCONF / \ TLV-Copied-From-ASCONF /
/ \ / \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
An example of a failed addition in an Error Cause TLV would look as An example of a failed addition in an Error Cause TLV would look as
follows in the response ASCONF-ACK message: follows in the response ASCONF-ACK message:
+--------------------------------+ +--------------------------------+
| Type = 0xC004 | Length = 20 | | Type = 0xC004 | Length = 20 |
+--------------------------------+ +--------------------------------+
| Cause=13 | Length = 16 | | Cause=0x000D | Length = 16 |
+----------------+---------------+ +----------------+---------------+
| Type=0xC001 | Length = 12 | | Type=0xC001 | Length = 12 |
+--------------------------------+ +--------------------------------+
| Type=5 | Length = 8 | | Type=0x0005 | Length = 8 |
+----------------+---------------+ +----------------+---------------+
| Value=0x0a010101 | | Value=0x0A010101 |
+----------------+---------------+ +----------------+---------------+
3.3.3 Error Cause: Request to Delete Source IP Address 3.3.3 Error Cause: Request to Delete Source IP Address
Cause of error Cause of error
--------------- ---------------
Request to delete source IP address: The receiver of this error sent Request to Delete Source IP Address: The receiver of this error sent
a request to delete the source IP address of the ASCONF a request to delete the source IP address of the ASCONF
message. This error indicates that the request is rejected. message. This error indicates that the request is rejected.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Cause Code=14 | Cause Length=Variable | | Cause Code=0x000E | Cause Length=Variable |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
\ TLV-Copied-From-ASCONF / \ TLV-Copied-From-ASCONF /
/ \ / \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
An example of a failed delete in an Error Cause TLV would look as An example of a failed delete in an Error Cause TLV would look as
follows in the response ASCONF-ACK message: follows in the response ASCONF-ACK message:
+--------------------------------+ +--------------------------------+
| Type = 0xC004 | Length = 20 | | Type = 0xC004 | Length = 20 |
+--------------------------------+ +--------------------------------+
| Cause=14 | Length = 16 | | Cause=0x000E | Length = 16 |
+----------------+---------------+ +----------------+---------------+
| Type=0xC002 | Length = 12 | | Type=0xC002 | Length = 12 |
+----------------+---------------+ +----------------+---------------+
| Type=5 | Length = 8 | | Type=0x0005 | Length = 8 |
+----------------+---------------+ +----------------+---------------+
| Value=0x0a010101 | | Value=0x0A010101 |
+----------------+---------------+ +----------------+---------------+
IMPLEMENTATION NOTE: It is unlikely that an endpoint would source IMPLEMENTATION NOTE: It is unlikely that an endpoint would source
a packet from the address being deleted, unless the endpoint a packet from the address being deleted, unless the endpoint
does not do proper source address selection. does not do proper source address selection.
4. Procedures 4. Procedures
This section will lay out the specific procedures for address/stream This section will lay out the specific procedures for address/stream
configuration change chunk type and its processing. configuration change chunk type and its processing.
4.1 ASCONF Chunk Procedures 4.1 ASCONF Chunk Procedures
When an endpoint has an ASCONF signaled change to be sent to the When an endpoint has an ASCONF signaled change to be sent to the
remote endpoint it should do the following: remote endpoint it should do the following:
A1) Create a ASCONF Chunk as defined in section 3.1.1. The chunk A1) Create an ASCONF Chunk as defined in section 3.1.1. The chunk
should contain all of the TLV('s) of information necessary to be should contain all of the TLV(s) of information necessary to be
sent to the remote endpoint, and unique correlation identities for sent to the remote endpoint, and unique correlation identities for
each request. each request.
A2) A serial number should be assigned to the Chunk. The serial A2) A serial number should be assigned to the Chunk. The serial
number should be a monotonically increasing number. All serial number should be a monotonically increasing number. All serial
numbers are defined to be initialized at the start of the numbers are defined to be initialized at the start of the
association to the same value as the Initial TSN. association to the same value as the Initial TSN.
A3) If no ASCONF chunk is outstanding (un-acknowledged) with the A3) If no ASCONF Chunk is outstanding (un-acknowledged) with the
remote peer AND there is less than cwnd bytes of user data remote peer, AND there is less than cwnd bytes of user data
outstanding send the chunk. outstanding, send the chunk.
A4) Start a T-4 RTO timer, using the RTO value of the selected A4) Start a T-4 RTO timer, using the RTO value of the selected
destination address (normally the primary path see [RFC2960] section destination address (normally the primary path; see [RFC2960] section
6.4 for details). 6.4 for details).
A5) When the ASCONF-ACK which acknowledges the serial number last A5) When the ASCONF-ACK that acknowledges the serial number last
sent arrives, stop the T-4 RTO timer and clear the appropriate sent arrives, stop the T-4 RTO timer, and clear the appropriate
association and destination error counters as defined in [RFC2960] association and destination error counters as defined in [RFC2960]
section 8.1 and 8.2. section 8.1 and 8.2.
A6) Process all of the TLV's within the ASCONF-ACK to find out A6) Process all of the TLVs within the ASCONF-ACK to find out
particular status information returned to the various requests that particular status information returned to the various requests that
were sent. Use the Correlation IDs to correlate the request and the were sent. Use the Correlation IDs to correlate the request and the
responses. responses.
A7) If an error response is received to a TLV whose parameter type A7) If an error response is received for a TLV parameter,
all TLVs with no response before the failed TLV are considered all TLVs with no response before the failed TLV are considered
successful if not reported. All TLVs after the failed response are successful if not reported. All TLVs after the failed response are
considered unsuccessful unless a specific success indication is considered unsuccessful unless a specific success indication is
present for the parameter. present for the parameter.
A8) If there are no responses to TLVs whose parameter type begins A8) If there is no response(s) to specific TLV parameter(s), and no
all TLVs not responded to are considered successful. failures are indicated, then all request(s) are considered
successful.
If the T-4 RTO timer expires the endpoint should do the following: If the T-4 RTO timer expires the endpoint should do the following:
B1) Increment the error counter and perform path failure detection B1) Increment the error counter and perform path failure detection
on the appropriate destination address as defined in [RFC2960] on the appropriate destination address as defined in [RFC2960]
section 8.2. section 8.2.
B2) Increment the association error counter and perform endpoint B2) Increment the association error counter and perform endpoint
failure detection on the association as defined in [RFC2960] section failure detection on the association as defined in [RFC2960] section
8.1. 8.1.
B3) Back-off the destination address RTO timer to which the ASCONF B3) Back-off the destination address RTO timer to which the ASCONF
chunk was sent. chunk was sent by doubling the RTO timer value.
B4) Re-transmit the ASCONF chunk last sent and if possible choose an B4) Re-transmit the ASCONF Chunk last sent and if possible choose an
alternate destination address (please refer to [RFC2960] section alternate destination address (please refer to [RFC2960] section
6.4.1). An endpoint MUST NOT add new parameters to this chunk, it 6.4.1). An endpoint MUST NOT add new parameters to this chunk, it
MUST be the same (including its serial number) as the last ASCONF MUST be the same (including its serial number) as the last ASCONF
sent. sent.
B5) Restart the T-4 RTO timer. Note if a different destination is B5) Restart the T-4 RTO timer. Note that if a different destination is
selected, then the RTO used will be that of the new destination selected, then the RTO used will be that of the new destination
address. address.
Note: That the the total number of re-transmissions is limited by B2 Note: the total number of re-transmissions is limited by B2
above. If the maximum is reached the association will fail and enter above. If the maximum is reached, the association will fail and enter
a CLOSED state (see [RFC2960] section 6.4.1 for details). a CLOSED state (see [RFC2960] section 6.4.1 for details).
4.1.1 Congestion Control of ASCONF Chunks 4.1.1 Congestion Control of ASCONF Chunks
In defining the ASCONF chunk transfer procedures it is essential
In defining the ASCONF Chunk transfer procedures, it is essential
that these transfers MUST NOT cause congestion within the network. that these transfers MUST NOT cause congestion within the network.
To achieve this we place these restrictions on the transfer of To achieve this, we place these restrictions on the transfer of
ASCONF chunks: ASCONF Chunks:
R1) One and only one ASCONF Chunk MAY be in transit and R1) One and only one ASCONF Chunk MAY be in transit and
unacknowledged at any one time. If a sender, after sending a ASCONF unacknowledged at any one time. If a sender, after sending an ASCONF
chunk, decides it needs to transfer another ASCONF Chunk, it MUST chunk, decides it needs to transfer another ASCONF Chunk, it MUST
wait until the ASCONF-ACK Chunk returns from the previous ASCONF wait until the ASCONF-ACK Chunk returns from the previous ASCONF
Chunk before sending a subsequent ASCONF. Note this restriction Chunk before sending a subsequent ASCONF. Note this restriction
binds each side, so at any time two ASCONF may be in-transit on any binds each side, so at any time two ASCONF may be in-transit on any
given association (one sent from each endpoint). given association (one sent from each endpoint).
R2) A ASCONF MUST NOT be sent if there is no room in the current R2) A ASCONF MUST NOT be sent if there is no room in the current
cwnd. If there is room in the cwnd of the destination network the cwnd. If there is room in the cwnd of the destination network, the
Chunk may be sent regardless of the value of rwnd. Chunk may be sent regardless of the value of rwnd.
R3) A ASCONF may be bundled with any other Chunk type except other R3) A ASCONF may be bundled with any other chunk type (except other
ASCONF chunks. ASCONF Chunks) as long as the source address in the IP header of
the packet is already a part of the association. If the ASCONF
chunk is using an alternate source address as the source in
the IP header, then NO other chunks may be bundled with the ASCONF
chunk.
R4) A ASCONF-ACK may be bundled with any other Chunk type except R4) A ASCONF-ACK may be bundled with any other chunk type except
other ASCONF-ACK's. other ASCONF-ACKs.
R5) Both ASCONF and ASCONF-ACK chunks MUST NOT be sent in any SCTP R5) Both ASCONF and ASCONF-ACK chunks MUST NOT be sent in any SCTP
state except ESTABLISHED. state except ESTABLISHED.
R6) An ASCONF and respective ASCONF-ACK MUST NOT be larger than the R6) An ASCONF and respective ASCONF-ACK MUST NOT be larger than the
path MTU of the destination. path MTU of the destination.
If the sender of a ASCONF chunk receives a Operational Error If the sender of an ASCONF Chunk receives a Operational Error
indicating that the ASCONF chunk type is not understood, then the indicating that the ASCONF chunk type is not understood, then the
sender MUST not send subsequent ASCONF chunks to the peer. The sender MUST not send subsequent ASCONF Chunks to the peer. The
endpoint should also inform the upper level application that the endpoint should also inform the upper layer application that the
peer endpoint does not support any of the extensions detailed in this peer endpoint does not support any of the extensions detailed in this
document. document.
4.2 Upon reception of a ASCONF Chunk. 4.2 Upon reception of an ASCONF Chunk.
When an endpoint receives a ASCONF chunk from the remote peer it When an endpoint receives an ASCONF Chunk from the remote peer
should perform the following: special procedures MAY be needed to identify the association
the ASCONF Chunk is associated with. To properly find the
association the following procedures should be followed:
L1) Use the source address and port number of the sender to
attempt to identify the association (i.e. use the same method
defined in [RFC2960] used for all other SCTP chunks ). If found
proceed to rule L5.
L2) If the association is not found, use the address found
in the Address Bytes field combined with the port number
found in the SCTP common header. If found proceed to rule
L4.
L3) If neither L1 or L2 locates the association, treat
the chunk as an Out Of The Blue chunk as defined in
[RFC2960].
L4) Verify that no other chunk is bundled with the ASCONF
chunk. If other chunks are bundled with the ASCONF Chunk
then the receiver MUST silently discard the ASCONF chunk.
L5) Follow the normal rules to validate the SCTP verification
tag found in [RFC2960].
After identification and verification of the association,
the following should be performed to properly process the ASCONF Chunk:
C1) Compare the value of the serial number to the value the endpoint C1) Compare the value of the serial number to the value the endpoint
stored in a new association variable 'Peer-Serial-Number'. This stored in a new association variable 'Peer-Serial-Number'. This
value MUST be initialized to the Initial TSN value minus 1. value MUST be initialized to the Initial TSN value minus 1.
C2) If the value found in the serial number is equal to the the C2) If the value found in the serial number is equal to the the
('Peer-Serial-Number' + 1), the endpoint should: ('Peer-Serial-Number' + 1), the endpoint should:
V1) Process the TLV's contained within the Chunk performing the V1) Process the TLVs contained within the Chunk performing the
appropriate actions as indicated by each TLV type. The TLV's MUST appropriate actions as indicated by each TLV type. The TLVs MUST
be processed in order within the Chunk. In other words if the sender be processed in order within the Chunk. For example, if the sender
puts 3 TLV's in one chunk the first TLV (the one closest to the puts 3 TLVs in one chunk, the first TLV (the one closest to the
Chunk Header) in the Chunk MUST be processed first. The next TLV in Chunk Header) in the Chunk MUST be processed first. The next TLV in
the chunk (the middle one) would be processed second and finally the the chunk (the middle one) MUST be processed second and finally the
last TLV in the Chunk would be processed last. last TLV in the Chunk MUST be processed last.
V2) In processing the chunk, the receiver should build a response V2) In processing the chunk, the receiver should build a response
message with the appropriate error TLV's, as specified in the message with the appropriate error TLVs, as specified in the
Parameter type bits for any ASCONF Parameter it does not understand. Parameter type bits for any ASCONF Parameter it does not understand.
To indicate an unrecognized parameter, parameter type 8 as defined To indicate an unrecognized parameter, parameter type 8 as defined
in in the INIT-ACK in 3.3.3 of [RFC2960] should be used. It may also in in the INIT-ACK in 3.3.3 of [RFC2960] should be used. The
use the response to carry rejections for other reasons such as endpoint may also use the response to carry rejections for other
resource shortages etc using the Error Cause TLV and an appropriate reasons such as resource shortages etc using the Error Cause TLV and
error condition. an appropriate error condition.
Note: a positive response is implied if no error is indicated by the Note: a positive response is implied if no error is indicated by the
sender. sender.
V3) All error responses must copy the ASCONF-Request Correlation ID V3) All error responses MUST copy the ASCONF-Request Correlation ID
field received in the ASCONF, from the TLV being responded to, into field received in the ASCONF, from the TLV being responded to, into
the ASCONF-Request Correlation ID field. The ASCONF-Request the ASCONF-Request Correlation ID field. The ASCONF-Request
Correlation ID always precedes the request TLV. Correlation ID always precedes the request TLV.
V4) After processing the entire Chunk, it MUST send all TLV's for V4) After processing the entire Chunk, it MUST send all TLVs for
both unrecognized parameters and any other status TLV's inside the both unrecognized parameters and any other status TLVs inside the
ASCONF-ACK chunk that acknowledges the arrival and processing of the ASCONF-ACK chunk that acknowledges the arrival and processing of the
ASCONF Chunk. ASCONF Chunk.
V5) Update the 'Peer-Serial-Number' to the value found in the serial V5) Update the 'Peer-Serial-Number' to the value found in the serial
number field. number field.
C3) If the value found in the serial number is equal to the value C3) If the value found in the serial number is equal to the value
stored in the 'Peer-Serial-Number', the endpoint should: stored in the 'Peer-Serial-Number', the endpoint should:
X1) Parse the ASCONF Chunk TLV's but the endpoint MUST not take any X1) Parse the ASCONF Chunk TLVs but the endpoint MUST NOT take any
action on the TLV's parsed (since it has already performed these action on the TLVs parsed (since it has already performed these
actions). actions).
X2) Build a response message with the appropriate response TLV's X2) Build a response message with the appropriate response TLVs
as specified in the ASCONF Parameter type bits, for any as specified in the ASCONF Parameter type bits, for any
parameter it does not understand or could not process. parameter it does not understand or could not process.
X3) After parsing the entire Chunk, it MUST send any response X3) After parsing the entire Chunk, it MUST send any response
TLV errors and status with a ASCONF-ACK chunk acknowledging the TLV errors and status with an ASCONF-ACK chunk acknowledging the
arrival and processing of the ASCONF Chunk. arrival and processing of the ASCONF Chunk.
X4) The endpoint MUST NOT update its 'Peer-Serial-Number'. X4) The endpoint MUST NOT update its 'Peer-Serial-Number'.
IMPLEMENTATION NOTE: As an optimization a receiver may wish to save IMPLEMENTATION NOTE: As an optimization a receiver may wish to save
the last ASCONF-ACK for some predetermined period of time and the last ASCONF-ACK for some predetermined period of time and
instead of re-processing the ASCONF (with the same serial number) it instead of re-processing the ASCONF (with the same serial number) it
may just re-transmit the ASCONF-ACK. It may wish to use the arrival may just re-transmit the ASCONF-ACK. It may wish to use the arrival
of a new serial number to discard the previously saved ASCONF-ACK or of a new serial number to discard the previously saved ASCONF-ACK or
any other means it may choose to expire the saved ASCONF-ACK. any other means it may choose to expire the saved ASCONF-ACK.
C4) Otherwise, the ASCONF chunk is discarded since it must be either C4) Otherwise, the ASCONF Chunk is discarded since it must be either
a stale packet or from an attacker. A receiver of such a packet MAY a stale packet or from an attacker. A receiver of such a packet MAY
log the event for security purposes. log the event for security purposes.
C5) In both cases C2 and C3 the ASCONF-ACK MUST be sent back to the C5) In both cases C2 and C3 the ASCONF-ACK MUST be sent back to the
source address contained in the IP header of the ASCONF being source address contained in the IP header of the ASCONF being
responded to. responded to.
4.3 General rules for address manipulation 4.3 General rules for address manipulation
When building TLV parameters for the ASCONF Chunk that When building TLV parameters for the ASCONF Chunk that
will add or delete IP addresses the following rules should be will add or delete IP addresses the following rules should be
applied: applied:
D1) When adding an IP address to an association, the IP address is D1) When adding an IP address to an association, the IP address is
NOT considered fully added to the association until the ASCONF-ACK NOT considered fully added to the association until the ASCONF-ACK
arrives. This means that until such time as the ASCONF containing arrives. This means that until such time as the ASCONF containing
the add is acknowledged the sender MUST NOT use the new IP address the add is acknowledged the sender MUST NOT use the new IP address
as a source for ANY SCTP packet. The receiver of the add IP address as a source for ANY SCTP chunks besides an ASCONF Chunk.
request may use the address has a destination immediately. The receiver of the add IP address request may use the
address as a destination immediately.
D2) After the ASCONF-ACK of an IP address add arrives, the endpoint D2) After the ASCONF-ACK of an IP address add arrives, the
MAY begin using the added IP address as a source address. endpoint MAY begin using the added IP address as a source
address for any type of SCTP chunk.
D3) If an endpoint receives an Error Cause TLV indicating that the D3) If an endpoint receives an Error Cause TLV indicating that the
IP address Add, IP address Deletion, or Set Primary IP Address IP address Add, IP address Deletion, or Set Primary IP Address
parameters was not understood, the endpoint MUST consider the parameters was not understood, the endpoint MUST consider the
operation failed and MUST NOT attempt to send any subsequent Add, operation failed and MUST NOT attempt to send any subsequent Add,
Delete or Set Primary requests to the peer. Delete or Set Primary requests to the peer.
D4) When deleting an IP address from an association, the IP address D4) When deleting an IP address from an association, the IP address
MUST be considered a valid destination address for the reception of MUST be considered a valid destination address for the reception of
SCTP packets until the ASCONF-ACK arrives and MUST NOT be used has a SCTP packets until the ASCONF-ACK arrives and MUST NOT be used as a
source address for any subsequent packets. This means that any source address for any subsequent packets. This means that any
datagrams that arrive before the ASCONF-ACK destined to the IP address datagrams that arrive before the ASCONF-ACK destined to the IP address
being deleted MUST be considered part of the current being deleted MUST be considered part of the current
association. One special consideration is that ABORT chunks arriving association. One special consideration is that ABORT chunks arriving
destined to the IP address being deleted MUST be ignored (see destined to the IP address being deleted MUST be ignored (see
Section 4.3.1 for further details). Section 4.3.1 for further details).
D5) An endpoint MUST NOT delete its last remaining IP address from an D5) An endpoint MUST NOT delete its last remaining IP address from an
association. In other words if an endpoint is NOT multi-homed it association. In other words if an endpoint is NOT multi-homed it
MUST NOT use the delete IP address. Or if an endpoint sends multiple MUST NOT use the delete IP address. Or if an endpoint sends multiple
requests to delete IP addresses it MUST NOT delete all of the IP requests to delete IP addresses it MUST NOT delete all of the IP
addresses that the peer has listed for the requester. addresses that the peer has listed for the requester.
D6) An endpoint MUST NOT set a source address for an SCTP packet D6) An endpoint MUST NOT set a IP header source address for an SCTP
holding the ASCONF chunk to be the same as an address being deleted packet holding the ASCONF Chunk to be the same as an address being
by the ASCONF chunk. deleted by the ASCONF Chunk.
D7) If a request is received to delete the last remaining IP address D7) If a request is received to delete the last remaining IP address
of a peer endpoint, the receiver MUST send an Error Cause TLV with of a peer endpoint, the receiver MUST send an Error Cause TLV with
the error cause set to the new error code 'Request to delete last IP the error cause set to the new error code 'Request to Delete Last
remaingin address'. The requested delete MUST NOT be performed or Remaining IP Address'. The requested delete MUST NOT be performed or
acted upon, other than to send the ASCONF-ACK. acted upon, other than to send the ASCONF-ACK.
D8) If a request is received to delete an IP address which is also D8) If a request is received to delete an IP address which is also
the source address of the IP packet which contained the ASCONF the source address of the IP packet which contained the ASCONF
chunk, the receiver MUST reject this request. To reject the request chunk, the receiver MUST reject this request. To reject the request
the receiver MUST send an Error Cause TLV set to the new error code the receiver MUST send an Error Cause TLV set to the new error code
"Request to Delete Source IP Address" (unless Rule D5 has also been 'Request to Delete Source IP Address' (unless Rule D5 has also been
violated, in which case the error code 'Request to delete last violated, in which case the error code 'Request to Delete Last
remaining IP address' is sent). Remaining IP Address' is sent).
D9) If an endpoint receives an ADD IP address request and does not D9) If an endpoint receives an ADD IP address request and does not
have the local resources to add this new address to the association, have the local resources to add this new address to the association,
it MUST return an Error Cause TLV set to the new error code it MUST return an Error Cause TLV set to the new error code
"Operation Refused due to Resource Shortage". 'Operation Refused Due to Resource Shortage'.
D10) If an endpoint receives an 'Out of Resource' error in response D10) If an endpoint receives an 'Out of Resource' error in response
to its request to ADD an IP address to an association, it must to its request to ADD an IP address to an association, it must
either ABORT the association or not consider the address part of the either ABORT the association or not consider the address part of the
association. In other words if the endpoint does not ABORT the association. In other words if the endpoint does not ABORT the
association, it must consider the add attempt failed and NOT use association, it must consider the add attempt failed and NOT use
this address and treat SCTP packets destined to the address as Out this address and treat SCTP packets destined to the address as Out
Of The Blue packets. Of The Blue packets.
D11) When an endpoint receiving a ASCONF to add an IP address sends D11) When an endpoint receiving an ASCONF to add an IP address sends
an 'Out of Resource' in its response, it MUST also fail any an 'Out of Resource' in its response, it MUST also fail any
subsequent add or delete requests bundled in the ASCONF. The subsequent add or delete requests bundled in the ASCONF. The
receiver MUST NOT reject an ADD and then accept a subsequent DELETE receiver MUST NOT reject an ADD and then accept a subsequent DELETE
of an IP address in the same ASCONF chunk. In other words, once a of an IP address in the same ASCONF Chunk. In other words, once a
receiver begins failing any ADD or DELETE request, it must fail all receiver begins failing any ADD or DELETE request, it must fail all
subsequent ADD or DELETE requests contained in that single ASCONF. subsequent ADD or DELETE requests contained in that single ASCONF.
D12) When an endpoint receives a request to delete an IP address D12) When an endpoint receives a request to delete an IP address
that is the current primary address, it is an implementation that is the current primary address, it is an implementation
decision as to how that endpoint chooses the new primary address. decision as to how that endpoint chooses the new primary address.
D13) When an endpoint receives a valid request to DELETE an IP D13) When an endpoint receives a valid request to DELETE an IP
address the endpoint MUST consider the address no longer as part of address the endpoint MUST consider the address no longer as part of
the association. It MUST NOT send SCTP packets for the association the association. It MUST NOT send SCTP packets for the association
skipping to change at page 18, line 10 skipping to change at page 21, line 5
ASCONF-REQ[DEL-IP:X]----\------------------> ASCONF-REQ[DEL-IP:X]----\------------------>
\ /---------ASCONF-ACK \ /---------ASCONF-ACK
\ / \ /
\----/-----------> OOTB \----/-----------> OOTB
(Ignored <---------------------/-------------ABORT (Ignored <---------------------/-------------ABORT
by rule D4) / by rule D4) /
<---------------------/ <---------------------/
For this case, during the deletion of an IP address, an For this case, during the deletion of an IP address, an
Abort MUST be ignored if the destination address of the Abort MUST be ignored if the destination address of the
Abort message is that of the destination being deleted. Abort message is that of a destination being deleted.
4.3.2 A special case for changing an address.
In some instances the sender may only have one IP address in an
association that is being renumbered. When this occurs, the sender
may not be able to send to the peer the appropriate ADD/DELETE pair
and use the old address as a source in the IP header. For this
reason the sender MUST fill in the Address Bytes field with an
address that is part of the association (in this case the one being
deleted). This will allow the receiver to locate the association
without using the source address found in the IP header. Such
an SCTP packet MUST NOT be bundled with any other chunk.
The receiver of such an ASCONF chunk MUST NOT process the
SCTP packet if any other chunks are contained inside the SCTP
packet. The receiver MUST always first use the source address
found in the IP header in looking up the association. The
receiver should attempt to use the address found in the Address
Bytes field only if the lookup fails using the source address from
the IP header. The receiver MUST NOT reply to the source address
of the packet in this special case, but to the new address that
was added by the ASCONF (since the old address is no longer a part
of the association after processing).
4.4 Setting of the primary address 4.4 Setting of the primary address
A sender of this option may elect to send this combined with A sender of this option may elect to send this combined with
a deletion or addition of an address. A sender SHOULD only send a deletion or addition of an address. A sender SHOULD only send
a set primary request to an address that is already considered a set primary request to an address that is already considered
part of the association. In other words if a sender combines part of the association. In other words if a sender combines
a set primary with an add of a new IP address the set primary a set primary with an add of a new IP address the set primary
will be discarded unless the add request is to be processed will be discarded unless the add request is to be processed
BEFORE the set primary (i.e. it preceeds the set primary). BEFORE the set primary (i.e. it precedes the set primary).
A request to set primary MAY also appear in a INIT or INIT-ACK A request to set primary MAY also appear in a INIT or INIT-ACK
chunk. This can give a hint to the peer endpoint as to which chunk. This can give advice to the peer endpoint as to which
of its addresses the sender of the INIT or INIT-ACK would like of its addresses the sender of the INIT or INIT-ACK would like
to be used as the primary address. to be used as the primary address.
The request to set an address as the primary path is an option the The request to set an address as the primary path is an option the
receiver MAY perform. It is considered a hint to the receiver of the receiver SHOULD perform. It is considered advice to the receiver of
best destination address to use in sending SCTP packets (in the the best destination address to use in sending SCTP packets (in the
requester's view). It is possible that the receiver may have other requester's view). If a request arrives that asks the receiver to
knowledge that it may act upon and NOT set the specified address as set an address as primary that does not exist, the receiver should
primary. If a request arrives that asks the receiver to set an NOT honor the request, leaving its existing primary address
address as primary that does not exist, the receiver should NOT unchanged.
honor the request, leaving its existing primary address unchanged.
4.5 Steam Flow Limit Procedures 4.5 Stream Flow Limit and Message Limit Procedures
A stream in SCTP is an uni-directional logical channel established A stream in SCTP is an uni-directional logical channel established
from one to another associated SCTP endpoint, within which all user from one to another associated SCTP endpoint, within which all user
messages are delivered in sequence except for those submitted to the messages are delivered in sequence except for those submitted to the
un-ordered delivery service which may arrive out of sequence. Since un-ordered delivery service which may arrive out of sequence. Since
each stream is uni-directional and no feedback mechanism exists to each stream is uni-directional and no feedback mechanism exists to
limit a sender, it is possible for one unique stream to monopolize limit a sender, it is possible for one unique stream to monopolize
all of the transport level receiver window space. The mechanism all of the transport level receiver window space. The mechanism
defined here attempts to alleviate this problem by allowing the defined here attempts to alleviate this problem by allowing the
receiver side to communicate to the sender a limit on how much receiver side to communicate to the sender a limit on how much
outstanding data may be sent within a particular stream. outstanding data may be sent within a particular stream.
The procedures defined here are broken down into two sides: The procedures defined here are broken down into two sides:
o The stream receiver side or peer requesting the limit. And, o The stream receiver side or peer requesting the limit. And,
o the stream sender side or peer that MUST honor the limit request. o the stream sender side or peer that MUST honor the limit request.
The receivers side is mainly involved with sending the request to The receiver's side is mainly involved with sending the request to
the peer. The senders side is where the actual limitations and flow the peer. The sender's side is where the actual flow or message
limit will occur. Note in section 4.5.1 the stream receiver is the limit will be enforced. Note that the stream receiver is the
endpoint that sends the ASCONF message, in section 4.5.2 the sender endpoint that sends the ASCONF, INIT or INIT-ACK message (see
side is the endpoint that receives the ASCONF message. Section 4.5.1), whereas the stream sender is the endpoint that
receives the ASCONF, INIT or INIT-ACK message (see Section 4.5.2).
4.5.1 Stream Receiver side procedures 4.5.1 Stream receiver side procedures
The receiver side SCTP makes decisions on stream flow limit based on The receiver side SCTP requests byte or message limits in response
upper layer input. Normally the upper layer makes a request to limit to an upper layer request. An upper layer may request, via an API
all or a subset of the active streams that send data to it via an interface, that a byte or message limit be imposed on all or a
API interface. How this decision is made is outside the scope of subset of the active streams that send data to the upper layer
this document. receiver, or that a message limit be imposed on the association.
The basis on which the upper layer determines these limits is
outside the scope of this document.
Anytime flow limits are made known to the SCTP endpoint by the Any time during an association that limits are requested of the SCTP
application, the receiver side SHOULD create a ASCONF Chunk and endpoint by the upper layer, the receiver side SHOULD create an
attach to it one or more stream flow limits with there respective ASCONF Chunk and attach to a Stream Flow Limit Change, Stream
stream number. If the receiver wishes to remove all limits Message Limit Change, or Association Message Limit Change parameter
(previously placed on a particular stream) it may do so by placing as appropriate. These parameter types MAY also be placed in an INIT
the special value '0' in the 'Flow Limit' field. Once acknowledged or INIT-ACK chunk at the beginning of an association to request
initial values for the appropriate limits.
The Stream Flow Limit Change and Stream Message Limit Changes
parameters contain a sequence of one or more pairs, each of which
consists of a specific stream number, and a byte or message limit
to be applied to that stream.
If the receiver wishes to remove the flow limit or message limit
for a specific stream, it may do so by placing the special value
'0' in the Flow Limit or Message Limit field. Once acknowledged
by the peer endpoint the receiver should consider the limit in by the peer endpoint the receiver should consider the limit in
place. place.
In the case of flow or message limits contained within an INIT
chunk, any such limit is considered acknowledged with the arrival of
the INIT-ACK, provided that the peer indicates that it understands
the requested limit by NOT placing an 'unrecognized parameter' error
in the INIT-ACK.
Similarly, for flow or message limits contained within an INIT-ACK
chunk, any such limit is considered acknowledged with the arrival of
the cookie, provided that the peer indicates that it understands the
requested limit by NOT placing an 'unrecognized parameter' error in
the cookie.
To send initial limits, ASCONF chunks are NOT bundled with the INIT
or INIT-ACK. Instead the TLV is added to the variable parameters
section of the INIT or INIT-ACK.
Note that the parameter type field upper two bits dictates that any Note that the parameter type field upper two bits dictates that any
parameter not understood should be skipped and reported to the parameter not understood should be skipped and reported to the
sender with an Operational Error. If an Operational Error is sender with an Operational Error. If an Operational Error is
received that indicates that the 'Stream Flow Limit Request' is not received that indicates that the 'Stream Byte Limit Request' or
understood, the sender of the limit request MUST not send subsequent 'Stream Message Limit Request' is not understood, the sender of the
limit requests. The endpoint SHOULD also inform the upper level limit request MUST not send subsequent limit requests. The endpoint
application that the peer endpoint does not support this feature. SHOULD also inform the upper layer application that the peer
endpoint does not support this feature.
4.5.2 Stream Sender side procedures 4.5.2 Stream Sender side procedures
When a 'Stream Flow Limit Request' is received the sender MUST When a 'Stream Byte Limit Request' or 'Stream Message Limit
record each flow limit with its appropriate stream. Request' is received the sender MUST record each limit with its
appropriate stream.
After a limit is set on a stream the sender MUST obey the following After a limit is set on a stream the sender MUST obey the following
rules when sending to the peer on that stream: rules when sending to the peer on that stream:
S1) When the upper layer application attempts to send to the peer on S1) When the upper layer application attempts to send to the peer on
a stream, check the number of outstanding bytes sent to that stream a stream, check
(those TSN's in queue to be sent, which the cumulative TSN - the number of outstanding bytes sent to that stream
(those TSNs in queue to be sent, which the Cumulative TSN
Acknowledgment has not passed, on this stream) versus the limit set Acknowledgment has not passed, on this stream) versus the limit set
for that stream (The last received limit for this stream is for that stream (The last received limit for this stream is
henceforth termed the current limit). henceforth termed the current limit).
- the number of outstanding messages sent on that stream (for which
not all TSNs are passed by the Cumulative TSN Acknowledgment)
versus the limit for this stream.
S2) If the number of outstanding bytes is greater than or equal to S2a) If the number of outstanding bytes is greater than or equal to
the current limit, the SCTP endpoint MUST reject the request and NOT the current limit, the SCTP endpoint MUST reject the request and NOT
queue the data for transmit. Instead it SHOULD return an error to queue the data for transmit. Instead it SHOULD return an error
the sending application. to the sending application.
S3) If the number of outstanding bytes is less than the current S2b) If the number of outstanding messages is greater or equal to
the current limit, the SCTP endpoint MUST reject the request and NOT
queue the data for transmit. Instead it SHOULD return an error
to the sending application.
S3a) If the number of outstanding bytes is less than the current
limit, validate that the data to be sent plus the number of limit, validate that the data to be sent plus the number of
outstanding bytes is smaller than or equal to this limit. If the outstanding bytes is smaller than or equal to this limit. If the
user data plus the number of outstanding bytes is smaller than or user data plus the number of outstanding bytes is smaller than or
equal to the current limit accept the data for transmit and queue equal to the current limit accept the data for transmit and queue
the user data (increasing the number of outstanding data bytes on the user data (increasing the number of outstanding data bytes on
this stream). If the user data plus the number of outstanding bytes this stream). If the user data plus the number of outstanding bytes
is larger than the current limit for this stream, the SCTP endpoint is larger than the current limit for this stream, the SCTP endpoint
MUST reject the request and NOT queue the data for transmit and MUST reject the request and NOT queue the data for transmit and
instead SHOULD return an error to the application. instead SHOULD return an error to the application.
S3b) If the number of outstanding messages is less than the current
limit, accept the data for transmit and queue the user data
(increasing the number of outstanding messages on this stream).
S4) Any time a stream limit is updated to the value of 0, consider S4) Any time a stream limit is updated to the value of 0, consider
this indication to mean no limit is in effect for this stream. this indication to mean no limit is in effect for this stream.
NOTE: Stream limits do NOT change the underlying SCTP rwnd and
its usage as defined in [RFC2960]. The association MUST still
honor the rwnd when sending to the peer endpoint as defined in
[RFC2960].
4.5.3 ULP considerations on the use of SCTP flow limit facility 4.5.3 ULP considerations on the use of SCTP flow limit facility
The effect of rule S3 in section 4.5.2 places a maximum size upon a A side-effect of rule S3 in section 4.5.2 is that an upper limit
sender. Once a limit is in effect, if the sending Upper Layer is imposed on the size of messages that may be sent to any stream
Protocol (ULP) wishes to send a message that is larger than that where a flow limit is in place. Once a flow limit is in effect,
permitted by the imposed stream limit, the ULP will need to provide if the sending Upper Layer Protocol (ULP) wishes to send a message
a mechanism for fragmentation and re-assembly. that is larger than that permitted by the imposed stream limit,
the ULP will need to provide a mechanism for fragmentation and
re-assembly.
This ULP mechanism is in addition to any fragmentation and This ULP mechanism is in addition to any fragmentation and
re-assembly that may be provided by SCTP. It is the sole re-assembly that may be provided by SCTP. It is the sole
responsibility of the ULP to handle the case of a single responsibility of the ULP to handle the case of a single user
user message being larger than the stream flow limit, if message being larger than the stream byte limit, if applicable.
applicable.
4.6 Association Message Limit Procedures
Using the stream flow/message limit functionality described
in 4.5 it is possible for a receiver to limit the sender in
a way the receiver thinks is appropriate. For an overall
(per association) byte based limit the receiver can make use
of the rwnd field in SACK-chunks.
An overall message based limit is provided by the 'Association
Message Limit Request'. This can be useful to make better use of
message oriented pools (e.g. mbufs) and to limit the delivery time
for messages.
The procedures defined here are broken down into two sides:
o The receiver side or peer requesting the limit. And,
o the sender side or peer that MUST honor the limit request.
The receiver's side is mainly involved with sending the request to
the peer. The sender's side is where the actual limitations and flow
message limit will occur. Note in section 4.6.1 the receiver
is the endpoint that sends the ASCONF, INIT or INIT-ACK message, in
section 4.6.2 the sender side is the endpoint that receives
the ASCONF, INIT or INIT-ACK message.
4.6.1 Receiver side procedures
The same rules as given in 4.5.1 for the stream limits apply to the
association limit.
4.6.2 Sender side procedures
When an 'Association Message Limit Request' is received the sender MUST
record this limit for the association.
After a limit is set for the association the sender MUST obey the
following rules when sending to the peer on that stream:
S1) When the upper layer application attempts to send to the peer on
a stream, check the number of outstanding messages sent on the
association (for which not all TSNs are passed by the Cumulative TSN
Acknowledgment) versus the limit for this association.
S2) If the number of outstanding messages is greater or equal to
the current limit, the SCTP endpoint MUST reject the request and NOT
queue the data for transmit. Instead it SHOULD return an error
to the sending application.
S3) If the number of outstanding messages is less than the current
limit, accept the data for transmit and queue the user data
(increasing the number of outstanding messages on this association).
S4) Any time the association limit is updated to the value of 0,
consider this indication to mean no limit is in effect for the
Association.
5. Security Considerations 5. Security Considerations
The ADD/DELETE of an IP address to an existing association does The ADD/DELETE of an IP address to an existing association does
provide an additional mechanism by which existing associations can provide an additional mechanism by which existing associations can
be hijacked. Where the attacker is able to intercept and or alter be hijacked. Where the attacker is able to intercept and or alter
the packets sent and received in an association the use of this the packets sent and received in an association, the use of this
feature MAY increase the ease at which an association may be feature MAY increase the ease with which an association may be
overtaken. This threat SHOULD be considered when deploying a version overtaken. This threat SHOULD be considered when deploying a version
of SCTP that use this feature. The IP Authentication Header of SCTP that makes use of this feature. The IP Authentication Header
[RFC2402] SHOULD be used when the threat environment requires [RFC2402] SHOULD be used when the threat environment requires
stronger integrity protections, but does not require stronger integrity protections, but does not require
confidentiality. It should be noted that in the base SCTP confidentiality. It should be noted that in the base SCTP
specification [RFC2960], if an attacker is able to intercept and or specification [RFC2960], if an attacker is able to intercept and or
alter packets, even without this feature it is possible to hijack an alter packets, even without this feature it is possible to hijack an
existing association, please refer to Section 11 of RFC2960. existing association; please refer to Section 11 of RFC2960.
6. IANA considerations 6. IANA considerations
This document defines the following new SCTP parameters, chunks This document defines the following new SCTP parameters, chunks
and errors: and errors:
- Two new Chunk Types, - Two new chunk types,
- Six Parameter Types, and - Eight parameter types, and
- Three new SCTP Error Causes. - Three new SCTP error causes.
7. Acknowledgements 7. Acknowledgments
The authors wish to thank Jon Berger, John Loughney, Ivan Rodriguez, The authors wish to thank Jon Berger, John Loughney, Ivan Arias
Marshall Rose, and Chip Sharp for their invaluable comments. Rodriguez, Marshall Rose, and Chip Sharp for their invaluable
comments.
8. Authors' Addresses 8. Authors' Addresses
Randall R. Stewart Tel: +1-815-477-2127 Randall R. Stewart Tel: +1-815-477-2127
Cisco Systems, Inc. EMail: rrs@cisco.com Cisco Systems, Inc. EMail: rrs@cisco.com
8745 W. Higgins Road, Suite 200 8745 W. Higgins Road, Suite 200
Chicago, Ill 60631 Chicago, Ill 60631
USA USA
Micheal A. Ramalho Tel: +1-732-809-0188 Micheal A. Ramalho Tel: +1-732-809-0188
Cisco Systems, Inc. EMail: mramalho@cisco.com Cisco Systems, Inc. EMail: mramalho@cisco.com
1802 Rue de la Porte 1802 Rue de la Porte
Wall Township, NJ 0719-3784 Wall Township, NJ 0719-3784
skipping to change at page 21, line 33 skipping to change at page 26, line 51
Hofmannstr. 51 Hofmannstr. 51
81359 Munich 81359 Munich
Germany Germany
Ian Rytina Tel: +61-3-9301-6164 Ian Rytina Tel: +61-3-9301-6164
Ericsson Australia EMail:ian.rytina@ericsson.com Ericsson Australia EMail:ian.rytina@ericsson.com
37/360 Elizabeth Street 37/360 Elizabeth Street
Melbourne, Victoria 3000 Melbourne, Victoria 3000
Australia Australia
Phil Conrad Tel: +1-XXX-XXX-XXXX Phil Conrad Tel: +1-215-204-7910
Netlab Research Group Email conrad@joda.cis.temple.edu Netlab Research Group Email conrad@acm.org
Dept. Of Computer & Dept. Of Computer &
Information Sciences Information Sciences
Temple University Temple University
1805 N Broad St. 1805 N Broad St.
Philadelphia, PA 19122 Philadelphia, PA 19122
USA USA
9. References 9. References
[RFC2960] R. R. Stewart, Q. Xie, K. Morneault, C. Sharp, [RFC2960] R. R. Stewart, Q. Xie, K. Morneault, C. Sharp,
 End of changes. 

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