draft-ietf-rddp-ddp-02.txt   draft-ietf-rddp-ddp-03.txt 
INTERNET-DRAFT Hemal Shah Remote Direct Data Placement Work Group Hemal Shah
draft-ietf-rddp-ddp-02.txt Intel Corporation INTERNET-DRAFT Intel Corporation
Expires: August, 2004 James Pinkerton Category: Standards Track James Pinkerton
Microsoft Corporation draft-ietf-rddp-ddp-03.txt Microsoft Corporation
Renato Recio Renato Recio
IBM Corporation IBM Corporation
Paul Culley Paul Culley
Hewlett-Packard Company Hewlett-Packard Company
February, 2004 Expires: February, 2005 August, 2004
Direct Data Placement over Reliable Transports Direct Data Placement over Reliable Transports
1 Status of this Memo Status of this Memo
By submitting this Internet-Draft, I certify that any applicable
patent or other IPR claims of which I am aware of have been
disclosed, and any of which I become aware will be disclosed, in
accordance with RFC 3668.
By submitting this Internet-Draft, I accept the provisions of
Section 4 of RFC 3667.
This document is an Internet-Draft and is subject to all provisions This document is an Internet-Draft and is subject to all provisions
of Section 10 of RFC2026. of Section 10 of RFC2026.
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2 Abstract Abstract
The Direct Data Placement protocol provides information to Place the The Direct Data Placement protocol provides information to Place the
incoming data directly into an upper layer protocol's receive buffer incoming data directly into an upper layer protocol's receive buffer
without intermediate buffers. This removes excess CPU and memory without intermediate buffers. This removes excess CPU and memory
utilization associated with transferring data through the utilization associated with transferring data through the
intermediate buffers. intermediate buffers.
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Table of Contents Table of Contents
1 Status of this Memo.........................................1 Status of this Memo...............................................1
2 Abstract....................................................1 Abstract..........................................................1
3 Introduction................................................4 1 Introduction................................................4
3.1 Architectural Goals.........................................4 1.1 Architectural Goals.........................................4
3.2 Protocol Overview...........................................5 1.2 Protocol Overview...........................................5
3.3 DDP Layering................................................6 1.3 DDP Layering................................................6
4 Glossary....................................................9 2 Glossary....................................................9
4.1 General.....................................................9 2.1 General.....................................................9
4.2 LLP........................................................10 2.2 LLP........................................................10
4.3 Direct Data Placement (DDP)................................10 2.3 Direct Data Placement (DDP)................................10
5 Reliable Delivery LLP Requirements.........................13 3 Reliable Delivery LLP Requirements.........................13
6 Header Format..............................................15 4 Header Format..............................................15
6.1 DDP Control Field..........................................15 4.1 DDP Control Field..........................................15
6.2 DDP Tagged Buffer Model Header.............................16 4.2 DDP Tagged Buffer Model Header.............................16
6.3 DDP Untagged Buffer Model Header...........................17 4.3 DDP Untagged Buffer Model Header...........................17
6.4 DDP Segment Format.........................................18 4.4 DDP Segment Format.........................................18
7 Data Transfer..............................................19 5 Data Transfer..............................................19
7.1 DDP Tagged or Untagged Buffer Models.......................19 5.1 DDP Tagged or Untagged Buffer Models.......................19
7.1.1 Tagged Buffer Model......................................19 5.1.1 Tagged Buffer Model.......................................19
7.1.2 Untagged Buffer Model....................................19 5.1.2 Untagged Buffer Model.....................................19
7.2 Segmentation and Reassembly of a DDP Message...............19 5.2 Segmentation and Reassembly of a DDP Message...............19
7.3 Ordering Among DDP Messages................................21 5.3 Ordering Among DDP Messages................................21
7.4 DDP Message Completion & Delivery..........................22 5.4 DDP Message Completion & Delivery..........................22
8 DDP Stream Setup & Teardown................................23 6 DDP Stream Setup & Teardown................................23
8.1 DDP Stream Setup...........................................23 6.1 DDP Stream Setup...........................................23
8.2 DDP Stream Teardown........................................23 6.2 DDP Stream Teardown........................................23
8.2.1 DDP Graceful Teardown....................................23 6.2.1 DDP Graceful Teardown.....................................23
8.2.2 DDP Abortive Teardown....................................24 6.2.2 DDP Abortive Teardown.....................................24
9 Error Semantics............................................25 7 Error Semantics............................................25
9.1 Errors detected at the Data Sink...........................25 7.1 Errors detected at the Data Sink...........................25
9.2 DDP Error Numbers..........................................26 7.2 DDP Error Numbers..........................................26
10 Security Considerations....................................27 8 Security Considerations....................................27
10.1 Protocol-specific Security Considerations................27 8.1 Protocol-specific Security Considerations..................27
10.2 Using IPSec with DDP.....................................27 8.2 Using IPSec with DDP.......................................27
10.3 Association of an STag and a DDP Stream..................27 8.3 Association of an STag and a DDP Stream....................27
10.4 Other Security Considerations............................28 8.4 Other Security Considerations..............................28
11 IANA Considerations........................................30 9 IANA Considerations........................................30
12 References.................................................31 10 References.................................................31
12.1 Normative References.....................................31 10.1 Normative References......................................31
12.2 Informative References...................................31 10.2 Informative References....................................31
13 Appendix...................................................32 11 Appendix...................................................32
13.1 Receive Window sizing....................................32 11.1 Receive Window sizing.....................................32
14 Author's Addresses.........................................33 12 Author's Addresses.........................................33
15 Acknowledgments............................................34 13 Acknowledgments............................................34
16 Full Copyright Statement...................................37 14 Full Copyright Statement...................................37
Table of Figures Table of Figures
Figure 1 DDP Layering.............................................7 Figure 1 DDP Layering.............................................7
Figure 2 MPA, DDP, and RDMAP Header Alignment.....................8 Figure 2 MPA, DDP, and RDMAP Header Alignment.....................8
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Figure 3 DDP Control Field.......................................15 Figure 3 DDP Control Field.......................................15
Figure 4 Tagged Buffer DDP Header................................16 Figure 4 Tagged Buffer DDP Header................................16
Figure 5 Untagged Buffer DDP Header..............................17 Figure 5 Untagged Buffer DDP Header..............................17
Figure 6 DDP Segment Format......................................18 Figure 6 DDP Segment Format......................................18
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3 Introduction 1 Introduction
Direct Data Placement Protocol (DDP) enables an Upper Layer Protocol Direct Data Placement Protocol (DDP) enables an Upper Layer Protocol
(ULP) to send data to a Data Sink without requiring the Data Sink to (ULP) to send data to a Data Sink without requiring the Data Sink to
Place the data in an intermediate buffer - thus when the data Place the data in an intermediate buffer - thus when the data
arrives at the Data Sink, the network interface can Place the data arrives at the Data Sink, the network interface can Place the data
directly into the ULP's buffer. This can enable the Data Sink to directly into the ULP's buffer. This can enable the Data Sink to
consume substantially less memory bandwidth than a buffered model consume substantially less memory bandwidth than a buffered model
because the Data Sink is not required to move the data from the because the Data Sink is not required to move the data from the
intermediate buffer to the final destination. Additionally, this can intermediate buffer to the final destination. Additionally, this can
also enable the network protocol to consume substantially fewer CPU also enable the network protocol to consume substantially fewer CPU
cycles than if the CPU was used to move the data, and removes the cycles than if the CPU was used to move the data, and removes the
bandwidth limitation of only being able to move data as fast as the bandwidth limitation of only being able to move data as fast as the
CPU can copy the data. CPU can copy the data.
DDP preserves ULP record boundaries (messages) while providing a DDP preserves ULP record boundaries (messages) while providing a
variety of data transfer mechanisms and completion mechanisms to be variety of data transfer mechanisms and completion mechanisms to be
used to transfer ULP messages. used to transfer ULP messages.
3.1 Architectural Goals 1.1 Architectural Goals
DDP has been designed with the following high-level architectural DDP has been designed with the following high-level architectural
goals: goals:
* Provide a buffer model that enables the Local Peer to Advertise * Provide a buffer model that enables the Local Peer to Advertise
a named buffer (i.e. a Tag for a buffer) to the Remote Peer, a named buffer (i.e. a Tag for a buffer) to the Remote Peer,
such that across the network the Remote Peer can Place data such that across the network the Remote Peer can Place data
into the buffer at Remote Peer specified locations. This is into the buffer at Remote Peer specified locations. This is
referred to as the Tagged Buffer Model. referred to as the Tagged Buffer Model.
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without a need for a copy, even if incoming DDP Segments arrive without a need for a copy, even if incoming DDP Segments arrive
out of order. This requires the protocol to separate Data out of order. This requires the protocol to separate Data
Placement of ULP Payload contained in an incoming DDP Segment Placement of ULP Payload contained in an incoming DDP Segment
from Data Delivery of completed ULP Messages. from Data Delivery of completed ULP Messages.
* If the LLP supports multiple LLP streams within a LLP * If the LLP supports multiple LLP streams within a LLP
Connection, provide the above capabilities independently on Connection, provide the above capabilities independently on
each LLP stream and enable the capability to be exported on a each LLP stream and enable the capability to be exported on a
per LLP stream basis to the ULP. per LLP stream basis to the ULP.
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3.2 Protocol Overview 1.2 Protocol Overview
DDP supports two basic data transfer models - a Tagged Buffer data DDP supports two basic data transfer models - a Tagged Buffer data
transfer model and an Untagged Buffer data transfer model. transfer model and an Untagged Buffer data transfer model.
The Tagged Buffer data transfer model requires the Data Sink to send The Tagged Buffer data transfer model requires the Data Sink to send
the Data Source an identifier for the ULP buffer, referred to as a the Data Source an identifier for the ULP buffer, referred to as a
Steering Tag (STag). The STag is transferred to the Data Source Steering Tag (STag). The STag is transferred to the Data Source
using a ULP defined method. Once the Data Source ULP has an STag for using a ULP defined method. Once the Data Source ULP has an STag for
a destination ULP buffer, it can request that DDP send the ULP data a destination ULP buffer, it can request that DDP send the ULP data
to the destination ULP buffer by specifying the STag to DDP. Note to the destination ULP buffer by specifying the STag to DDP. Note
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Buffer Model, a DDP Message can only start at offset 0. Buffer Model, a DDP Message can only start at offset 0.
* The Tagged Buffer Model allows multiple DDP Messages targeted * The Tagged Buffer Model allows multiple DDP Messages targeted
to a Tagged Buffer with a single ULP buffer Advertisement. The to a Tagged Buffer with a single ULP buffer Advertisement. The
Untagged Buffer Model requires associating a receive ULP buffer Untagged Buffer Model requires associating a receive ULP buffer
for each DDP Message targeted to an Untagged Buffer. for each DDP Message targeted to an Untagged Buffer.
Either data transfer model Places a ULP Message into a DDP Message. Either data transfer model Places a ULP Message into a DDP Message.
Each DDP Message is then sliced into DDP Segments that are intended Each DDP Message is then sliced into DDP Segments that are intended
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to fit within a lower-layer-protocol's (LLP) Maximum Upper Layer to fit within a lower-layer-protocol's (LLP) Maximum Upper Layer
Protocol Data Unit (MULPDU). Thus the ULP can post arbitrary size Protocol Data Unit (MULPDU). Thus the ULP can post arbitrary size
ULP Messages, containing up to 2^32 - 1 octets of ULP Payload, and ULP Messages, containing up to 2^32 - 1 octets of ULP Payload, and
DDP slices the ULP message into DDP Segments which are reassembled DDP slices the ULP message into DDP Segments which are reassembled
transparently at the Data Sink. transparently at the Data Sink.
DDP provides in-order Delivery for the ULP. However, DDP DDP provides in-order Delivery for the ULP. However, DDP
differentiates between Data Delivery and Data Placement. DDP differentiates between Data Delivery and Data Placement. DDP
provides enough information in each DDP Segment to allow the ULP provides enough information in each DDP Segment to allow the ULP
Payload in each inbound DDP Segment payloads to be directly Placed Payload in each inbound DDP Segment payloads to be directly Placed
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(e.g. SCTP). But in either case, DDP is specified such that each DDP (e.g. SCTP). But in either case, DDP is specified such that each DDP
Stream is independent and maps to a single LLP stream. Within a Stream is independent and maps to a single LLP stream. Within a
specific DDP Stream, the LLP Stream is required to provide in-order, specific DDP Stream, the LLP Stream is required to provide in-order,
reliable Delivery. Note that DDP has no ordering guarantees between reliable Delivery. Note that DDP has no ordering guarantees between
DDP Streams. DDP Streams.
A DDP protocol could potentially run over reliable Delivery LLPs or A DDP protocol could potentially run over reliable Delivery LLPs or
unreliable Delivery LLPs. This specification requires reliable, in unreliable Delivery LLPs. This specification requires reliable, in
order Delivery LLPs. order Delivery LLPs.
3.3 DDP Layering 1.3 DDP Layering
DDP is intended to be LLP independent, subject to the requirements DDP is intended to be LLP independent, subject to the requirements
defined in section 5. However, DDP was specifically defined to be defined in section 3. However, DDP was specifically defined to be
part of a family of protocols that were created to work well part of a family of protocols that were created to work well
together, as shown in Figure 1 DDP Layering. For LLP protocol together, as shown in Figure 1 DDP Layering. For LLP protocol
definitions of each LLP, see [MPA], [TCP], and [SCTP]. definitions of each LLP, see [MPA], [TCP], and [SCTP].
DDP enables direct data Placement capability for any ULP, but it has DDP enables direct data Placement capability for any ULP, but it has
been specifically designed to work well with RDMAP (see [RDMA]), and been specifically designed to work well with RDMAP (see [RDMA]), and
is part of the iWARP protocol suite. is part of the iWARP protocol suite.
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+-------------------+ +-------------------+
| | | |
| RDMA ULP | | RDMA ULP |
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | | | |
| ULP | RDMAP | | ULP | RDMAP |
| | | | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
skipping to change at line 294 skipping to change at line 302
| | | | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1 DDP Layering Figure 1 DDP Layering
If DDP is layered below RDMAP and on top of MPA and TCP, then the If DDP is layered below RDMAP and on top of MPA and TCP, then the
respective headers and payload are arranged as follows (Note: For respective headers and payload are arranged as follows (Note: For
clarity, MPA header and CRC are included but framing markers are not clarity, MPA header and CRC are included but framing markers are not
shown.): shown.):
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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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
// TCP Header // // TCP Header //
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MPA Header | | | MPA Header | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
| | | |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
// RDMAP ULP Payload // // RDMAP ULP Payload //
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MPA CRC | | MPA CRC |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2 MPA, DDP, and RDMAP Header Alignment Figure 2 MPA, DDP, and RDMAP Header Alignment
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4 Glossary 2 Glossary
4.1 General 2.1 General
Advertisement (Advertised, Advertise, Advertisements, Advertises) - Advertisement (Advertised, Advertise, Advertisements, Advertises) -
The act of informing a Remote Peer that a local RDMA Buffer is The act of informing a Remote Peer that a local RDMA Buffer is
available to it. A Node makes available an RDMA Buffer for available to it. A Node makes available an RDMA Buffer for
incoming RDMA Read or RDMA Write access by informing its incoming RDMA Read or RDMA Write access by informing its
RDMA/DDP peer of the Tagged Buffer identifiers (STag, base RDMA/DDP peer of the Tagged Buffer identifiers (STag, base
address, length). This advertisement of Tagged Buffer address, length). This advertisement of Tagged Buffer
information is not defined by RDMA/DDP and is left to the ULP. A information is not defined by RDMA/DDP and is left to the ULP. A
typical method would be for the Local Peer to embed the Tagged typical method would be for the Local Peer to embed the Tagged
Buffer's Steering Tag, address, and length in a Send message Buffer's Steering Tag, address, and length in a Send message
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Remote Peer - The RDMA/DDP protocol implementation on the opposite Remote Peer - The RDMA/DDP protocol implementation on the opposite
end of the connection. Used to refer to the remote entity when end of the connection. Used to refer to the remote entity when
describing protocol exchanges or other interactions between two describing protocol exchanges or other interactions between two
Nodes. Nodes.
ULP - Upper Layer Protocol. The protocol layer above the protocol ULP - Upper Layer Protocol. The protocol layer above the protocol
layer currently being referenced. The ULP for RDMA/DDP is layer currently being referenced. The ULP for RDMA/DDP is
expected to be an OS, application, adaptation layer, or expected to be an OS, application, adaptation layer, or
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proprietary device. The RDMA/DDP documents do not specify a ULP proprietary device. The RDMA/DDP documents do not specify a ULP
- they provide a set of semantics that allow a ULP to be - they provide a set of semantics that allow a ULP to be
designed to utilize RDMA/DDP. designed to utilize RDMA/DDP.
ULP Message - The ULP data that is handed to a specific protocol ULP Message - The ULP data that is handed to a specific protocol
layer for transmission. Data boundaries are preserved as they layer for transmission. Data boundaries are preserved as they
are transmitted through iWARP. are transmitted through iWARP.
ULP Payload - The ULP data that is contained within a single ULP Payload - The ULP data that is contained within a single
protocol segment or packet (e.g. a DDP Segment). protocol segment or packet (e.g. a DDP Segment).
4.2 LLP 2.2 LLP
LLP - Lower Layer Protocol. The protocol layer beneath the protocol LLP - Lower Layer Protocol. The protocol layer beneath the protocol
layer currently being referenced. For example, for DDP the LLP layer currently being referenced. For example, for DDP the LLP
is SCTP, MPA, or other transport protocols. For RDMA, the LLP is is SCTP, MPA, or other transport protocols. For RDMA, the LLP is
DDP. DDP.
LLP Connection - Corresponds to an LLP transport-level connection LLP Connection - Corresponds to an LLP transport-level connection
between the peer LLP layers on two nodes. between the peer LLP layers on two nodes.
LLP Stream - Corresponds to a single LLP transport-level stream LLP Stream - Corresponds to a single LLP transport-level stream
between the peer LLP layers on two Nodes. One or more LLP between the peer LLP layers on two Nodes. One or more LLP
Streams may map to a single transport-level LLP Connection. For Streams may map to a single transport-level LLP Connection. For
transport protocols that support multiple streams per connection transport protocols that support multiple streams per connection
(e.g. SCTP), a LLP Stream corresponds to one transport-level (e.g. SCTP), a LLP Stream corresponds to one transport-level
stream. stream.
MULPDU - Maximum Upper Layer Protocol Data Unit. The current maximum MULPDU - Maximum Upper Layer Protocol Data Unit. The current maximum
size of the record that is acceptable for DDP to pass to the LLP size of the record that is acceptable for DDP to pass to the LLP
for transmission. for transmission.
4.3 Direct Data Placement (DDP) 2.3 Direct Data Placement (DDP)
DDP Graceful Teardown - The act of closing a DDP Stream such that DDP Graceful Teardown - The act of closing a DDP Stream such that
all in-progress and pending DDP Messages are allowed to complete all in-progress and pending DDP Messages are allowed to complete
successfully. successfully.
DDP Abortive Teardown - The act of closing a DDP Stream without DDP Abortive Teardown - The act of closing a DDP Stream without
attempting to complete in-progress and pending DDP Messages. attempting to complete in-progress and pending DDP Messages.
Data Placement (Placement, Placed, Places) - For DDP, this term is Data Placement (Placement, Placed, Places) - For DDP, this term is
specifically used to indicate the process of writing to a data specifically used to indicate the process of writing to a data
buffer by a DDP implementation. DDP Segments carry Placement buffer by a DDP implementation. DDP Segments carry Placement
information, which may be used by the receiving DDP information, which may be used by the receiving DDP
implementation to perform Data Placement of the DDP Segment ULP implementation to perform Data Placement of the DDP Segment ULP
Payload. See "Data Delivery" and “Direct Data Placement”. Payload. See "Data Delivery" and ôDirect Data Placementö.
DDP Control Field - A fixed 8-bit field in the DDP Header. DDP Control Field - A fixed 8-bit field in the DDP Header.
DDP Header - The header present in all DDP Segments. The DDP Header DDP Header - The header present in all DDP Segments. The DDP Header
contains control and Placement fields that are used to define contains control and Placement fields that are used to define
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the final Placement location for the ULP Payload carried in a the final Placement location for the ULP Payload carried in a
DDP Segment. DDP Segment.
DDP Message - A ULP defined unit of data interchange, which is DDP Message - A ULP defined unit of data interchange, which is
subdivided into one or more DDP Segments. This segmentation may subdivided into one or more DDP Segments. This segmentation may
occur for a variety of reasons, including segmentation to occur for a variety of reasons, including segmentation to
respect the maximum segment size of the underlying transport respect the maximum segment size of the underlying transport
protocol. protocol.
DDP Segment - The smallest unit of data transfer for the DDP DDP Segment - The smallest unit of data transfer for the DDP
protocol. It includes a DDP Header and ULP Payload (if present). protocol. It includes a DDP Header and ULP Payload (if present).
A DDP Segment should be sized to fit within the Lower Layer A DDP Segment should be sized to fit within the Lower Layer
Protocol MULPDU. Protocol MULPDU.
DDP Stream - a sequence of DDP messages whose ordering is defined by DDP Stream - a sequence of DDP messages whose ordering is defined by
the LLP. For SCTP, a DDP Stream maps directly to an SCTP stream. the LLP. For SCTP, a DDP Stream maps directly to an SCTP stream.
For MPA, a DDP Stream maps directly to a TCP connection and a For MPA, a DDP Stream maps directly to a TCP connection and a
single DDP Stream is supported. Note that DDP has no ordering single DDP Stream is supported. Note that DDP has no ordering
guarantees between DDP Streams. guarantees between DDP Streams.
DDP Stream Identifier (ID) An identifier for a DDP Stream. DDP Stream Identifier (ID) û An identifier for a DDP Stream.
Direct Data Placement - A mechanism whereby ULP data contained Direct Data Placement - A mechanism whereby ULP data contained
within DDP Segments may be Placed directly into its final within DDP Segments may be Placed directly into its final
destination in memory without processing of the ULP. This may destination in memory without processing of the ULP. This may
occur even when the DDP Segments arrive out of order. Out of occur even when the DDP Segments arrive out of order. Out of
order Placement support may require the Data Sink to implement order Placement support may require the Data Sink to implement
the LLP and DDP as one functional block. the LLP and DDP as one functional block.
Direct Data Placement Protocol (DDP) - Also, a wire protocol that Direct Data Placement Protocol (DDP) - Also, a wire protocol that
supports Direct Data Placement by associating explicit memory supports Direct Data Placement by associating explicit memory
buffer placement information with the LLP payload units. buffer placement information with the LLP payload units.
Message Offset (MO) - For the DDP Untagged Buffer Model, specifies Message Offset (MO) - For the DDP Untagged Buffer Model, specifies
the offset, in octets, from the start of a DDP Message. the offset, in octets, from the start of a DDP Message.
Message Sequence Number (MSN) - For the DDP Untagged Buffer Model, Message Sequence Number (MSN) - For the DDP Untagged Buffer Model,
specifies a sequence number that is increasing with each DDP specifies a sequence number that is increasing with each DDP
Message. Message.
Protection Domain (PD) A Mechanism used to associate a DDP Stream Protection Domain (PD) û A Mechanism used to associate a DDP Stream
and an STag. Under this mechanism, the use of an STag is valid and an STag. Under this mechanism, the use of an STag is valid
on a DDP Stream if the STag has the same Protection Domain on a DDP Stream if the STag has the same Protection Domain
Identifier (PD ID) as the DDP Stream. Identifier (PD ID) as the DDP Stream.
Protection Domain Identifier (PD ID) An identifier for the Protection Domain Identifier (PD ID) û An identifier for the
Protection Domain. Protection Domain.
Queue Number (QN) - For the DDP Untagged Buffer Model, identifies a Queue Number (QN) - For the DDP Untagged Buffer Model, identifies a
destination Data Sink queue for a DDP Segment. destination Data Sink queue for a DDP Segment.
Steering Tag - An identifier of a Tagged Buffer on a Node, valid as Steering Tag - An identifier of a Tagged Buffer on a Node, valid as
defined within a protocol specification. defined within a protocol specification.
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STag - Steering Tag STag - Steering Tag
Tagged Buffer - A buffer that is explicitly Advertised to the Remote Tagged Buffer - A buffer that is explicitly Advertised to the Remote
Peer through exchange of an STag, Tagged Offset, and length. Peer through exchange of an STag, Tagged Offset, and length.
Tagged Buffer Model - A DDP data transfer model used to transfer Tagged Buffer Model - A DDP data transfer model used to transfer
Tagged Buffers from the Local Peer to the Remote Peer. Tagged Buffers from the Local Peer to the Remote Peer.
Tagged DDP Message - A DDP Message that targets a Tagged Buffer. Tagged DDP Message - A DDP Message that targets a Tagged Buffer.
skipping to change at line 515 skipping to change at line 523
Untagged Buffer - A buffer that is not explicitly Advertised to the Untagged Buffer - A buffer that is not explicitly Advertised to the
Remote Peer. Remote Peer.
Untagged Buffer Model - A DDP data transfer model used to transfer Untagged Buffer Model - A DDP data transfer model used to transfer
Untagged Buffers from the Local Peer to the Remote Peer. Untagged Buffers from the Local Peer to the Remote Peer.
Untagged DDP Message - A DDP Message that targets an Untagged Untagged DDP Message - A DDP Message that targets an Untagged
Buffer. Buffer.
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5 Reliable Delivery LLP Requirements 3 Reliable Delivery LLP Requirements
1. LLPs MUST expose MULPDU & MULPDU Changes. This is required so 1. LLPs MUST expose MULPDU & MULPDU Changes. This is required so
that the DDP layer can perform segmentation aligned with the that the DDP layer can perform segmentation aligned with the
MULPDU and can adapt as MULPDU changes come about. The corner MULPDU and can adapt as MULPDU changes come about. The corner
case of how to handle outstanding requests during a MULPDU case of how to handle outstanding requests during a MULPDU
change is covered by the requirements below. change is covered by the requirements below.
2. In the event of a MULPDU change, DDP MUST NOT be required by the 2. In the event of a MULPDU change, DDP MUST NOT be required by the
LLP to re-segment DDP Segments that have been previously posted LLP to re-segment DDP Segments that have been previously posted
to the LLP. Note that under pathological conditions the LLP may to the LLP. Note that under pathological conditions the LLP may
skipping to change at line 571 skipping to change at line 579
DDP Stream to be torn down. DDP Stream to be torn down.
9. For a specific LLP Stream, the LLP MUST provide a mechanism to 9. For a specific LLP Stream, the LLP MUST provide a mechanism to
indicate that the LLP Stream has been gracefully torn down. For indicate that the LLP Stream has been gracefully torn down. For
a specific LLP Connection, the LLP MUST provide a mechanism to a specific LLP Connection, the LLP MUST provide a mechanism to
indicate that the LLP Connection has been gracefully torn down. indicate that the LLP Connection has been gracefully torn down.
Note that if the LLP does not allow an LLP Stream to be torn Note that if the LLP does not allow an LLP Stream to be torn
down independently of the LLP Connection, the above requirements down independently of the LLP Connection, the above requirements
allow the LLP to notify DDP of both events at the same time. allow the LLP to notify DDP of both events at the same time.
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10. For a specific LLP Connection, when all LLP Streams are either 10. For a specific LLP Connection, when all LLP Streams are either
gracefully torn down or are labeled as erroneous LLP streams, gracefully torn down or are labeled as erroneous LLP streams,
the LLP Connection MUST be torn down. the LLP Connection MUST be torn down.
11. The LLP MUST NOT pass a duplicate DDP Segment to the DDP Layer 11. The LLP MUST NOT pass a duplicate DDP Segment to the DDP Layer
after it has passed all the previous DDP Segments to the DDP after it has passed all the previous DDP Segments to the DDP
Layer and the associated ordering information for the previous Layer and the associated ordering information for the previous
DDP Segments and the current DDP Segment. DDP Segments and the current DDP Segment.
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6 Header Format 4 Header Format
DDP has two different header formats: one for Data Placement into DDP has two different header formats: one for Data Placement into
Tagged Buffers, and the other for Data Placement into Untagged Tagged Buffers, and the other for Data Placement into Untagged
Buffers. See Section 7.1 for a description of the two models. Buffers. See Section 5.1 for a description of the two models.
6.1 DDP Control Field 4.1 DDP Control Field
The first 8 bits of the DDP Header carry a DDP Control Field that is The first 8 bits of the DDP Header carry a DDP Control Field that is
common between the two formats. It is shown below in Figure 3, common between the two formats. It is shown below in Figure 3,
offset by 16 bits to accommodate the MPA header defined in [MPA]. offset by 16 bits to accommodate the MPA header defined in [MPA].
The MPA header is only present if DDP is layered on top of MPA. The MPA header is only present if DDP is layered on top of MPA.
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
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
|T|L| Rsvd |DV | |T|L| Rsvd |DV |
skipping to change at line 635 skipping to change at line 643
Delivered to the ULP after: Delivered to the ULP after:
. Placement of all DDP Segments of this DDP Message and all . Placement of all DDP Segments of this DDP Message and all
prior DDP Messages, and prior DDP Messages, and
. Delivery of each prior DDP Message. . Delivery of each prior DDP Message.
If the Last flag is set to zero, the DDP Segment is an If the Last flag is set to zero, the DDP Segment is an
intermediate DDP Segment. intermediate DDP Segment.
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Rsvd - Reserved: 4 bits. Rsvd - Reserved: 4 bits.
Reserved for future use by the DDP protocol. This field MUST be Reserved for future use by the DDP protocol. This field MUST be
set to zero on transmit, and not checked on receive. set to zero on transmit, and not checked on receive.
DV - Direct Data Placement Protocol Version: 2 bits. DV - Direct Data Placement Protocol Version: 2 bits.
The version of the DDP Protocol in use. This field MUST be set The version of the DDP Protocol in use. This field MUST be set
to one to indicate the version of the specification described to one to indicate the version of the specification described
in this document. The value of DV MUST be the same for all the in this document. The value of DV MUST be the same for all the
DDP Segments transmitted or received on a DDP Stream. DDP Segments transmitted or received on a DDP Stream.
6.2 DDP Tagged Buffer Model Header 4.2 DDP Tagged Buffer Model Header
Figure 4 shows the DDP Header format that MUST be used in all DDP Figure 4 shows the DDP Header format that MUST be used in all DDP
Segments that target Tagged Buffers. It includes the DDP Control Segments that target Tagged Buffers. It includes the DDP Control
Field previously defined in Section 6.1. (Note: In Figure 4, the DDP Field previously defined in Section 4.1. (Note: In Figure 4, the DDP
Header is offset by 16 bits to accommodate the MPA header defined in Header is offset by 16 bits to accommodate the MPA header defined in
[MPA]. The MPA header is only present if DDP is layered on top of [MPA]. The MPA header is only present if DDP is layered on top of
MPA.) MPA.)
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|T|L| Rsvd | DV| RsvdULP | |T|L| Rsvd | DV| RsvdULP |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| STag | | STag |
skipping to change at line 690 skipping to change at line 698
specific DDP Message MUST contain the same value for this specific DDP Message MUST contain the same value for this
field. The Data Source MUST ensure that each DDP Segment within field. The Data Source MUST ensure that each DDP Segment within
a specific DDP Message contains the same value for this field. a specific DDP Message contains the same value for this field.
STag - Steering Tag: 32 bits. STag - Steering Tag: 32 bits.
The Steering Tag identifies the Data Sink's Tagged Buffer. The The Steering Tag identifies the Data Sink's Tagged Buffer. The
STag MUST be valid for this DDP Stream. The STag is associated STag MUST be valid for this DDP Stream. The STag is associated
with the DDP Stream through a mechanism that is outside the with the DDP Stream through a mechanism that is outside the
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scope of the DDP Protocol specification. At the Data Source, scope of the DDP Protocol specification. At the Data Source,
DDP MUST set the STag field to the value specified by the ULP. DDP MUST set the STag field to the value specified by the ULP.
At the Data Sink, the DDP MUST provide the STag field when the At the Data Sink, the DDP MUST provide the STag field when the
ULP Message is delivered. Each DDP Segment within a specific ULP Message is delivered. Each DDP Segment within a specific
DDP Message MUST contain the same value for this field and MUST DDP Message MUST contain the same value for this field and MUST
be the value supplied by the ULP. The Data Source MUST ensure be the value supplied by the ULP. The Data Source MUST ensure
that each DDP Segment within a specific DDP Message contains that each DDP Segment within a specific DDP Message contains
the same value for this field. the same value for this field.
TO - Tagged Offset: 64 bits. TO - Tagged Offset: 64 bits.
The Tagged Offset specifies the offset, in octets, within the The Tagged Offset specifies the offset, in octets, within the
Data Sink's Tagged Buffer, where the Placement of ULP Payload Data Sink's Tagged Buffer, where the Placement of ULP Payload
contained in the DDP Segment starts. A DDP Message MAY start at contained in the DDP Segment starts. A DDP Message MAY start at
an arbitrary TO within a Tagged Buffer. an arbitrary TO within a Tagged Buffer.
6.3 DDP Untagged Buffer Model Header 4.3 DDP Untagged Buffer Model Header
Figure 5 shows the DDP Header format that MUST be used in all DDP Figure 5 shows the DDP Header format that MUST be used in all DDP
Segments that target Untagged Buffers. It includes the DDP Control Segments that target Untagged Buffers. It includes the DDP Control
Field previously defined in Section 6.1. (Note: In Figure 5, the DDP Field previously defined in Section 4.1. (Note: In Figure 5, the DDP
Header is offset by 16 bits to accommodate the MPA header defined in Header is offset by 16 bits to accommodate the MPA header defined in
[MPA]. The MPA header is only present if DDP is layered on top of [MPA]. The MPA header is only present if DDP is layered on top of
MPA.) MPA.)
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|T|L| Rsvd | DV| RsvdULP[0:7] | |T|L| Rsvd | DV| RsvdULP[0:7] |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| RsvdULP[8:39] | | RsvdULP[8:39] |
skipping to change at line 743 skipping to change at line 751
RsvdULP - Reserved for use by the ULP: 40 bits. RsvdULP - Reserved for use by the ULP: 40 bits.
The RsvdULP field is opaque to the DDP protocol and can be The RsvdULP field is opaque to the DDP protocol and can be
structured in any way by the ULP. At the Data Source, DDP MUST structured in any way by the ULP. At the Data Source, DDP MUST
set RsvdULP Field to the value specified by the ULP. It is set RsvdULP Field to the value specified by the ULP. It is
transferred unmodified from the Data Source to the Data Sink. transferred unmodified from the Data Source to the Data Sink.
At the Data Sink, DDP MUST provide RsvdULP field to the ULP At the Data Sink, DDP MUST provide RsvdULP field to the ULP
when the ULP Message is Delivered. Each DDP Segment within a when the ULP Message is Delivered. Each DDP Segment within a
specific DDP Message MUST contain the same value for the specific DDP Message MUST contain the same value for the
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RsvdULP field. At the Data Sink, the DDP implementation is NOT RsvdULP field. At the Data Sink, the DDP implementation is NOT
REQUIRED to verify that the same value is present in the REQUIRED to verify that the same value is present in the
RsvdULP field of each DDP Segment within a specific DDP Message RsvdULP field of each DDP Segment within a specific DDP Message
and MAY provide the value from any one of the received DDP and MAY provide the value from any one of the received DDP
Segment to the ULP when the ULP Message is Delivered. Segment to the ULP when the ULP Message is Delivered.
QN - Queue Number: 32 bits. QN - Queue Number: 32 bits.
The Queue Number identifies the Data Sink's Untagged Buffer The Queue Number identifies the Data Sink's Untagged Buffer
queue referenced by this header. Each DDP segment within a queue referenced by this header. Each DDP segment within a
skipping to change at line 779 skipping to change at line 787
contains the same value for this field. contains the same value for this field.
MO - Message Offset: 32 bits. MO - Message Offset: 32 bits.
The Message Offset specifies the offset, in octets, from the The Message Offset specifies the offset, in octets, from the
start of the DDP Message represented by the MSN and Queue start of the DDP Message represented by the MSN and Queue
Number on the DDP Stream associated with this DDP Segment. The Number on the DDP Stream associated with this DDP Segment. The
MO referencing the first octet of the DDP Message MUST be set MO referencing the first octet of the DDP Message MUST be set
to zero by the DDP layer. to zero by the DDP layer.
6.4 DDP Segment Format 4.4 DDP Segment Format
Each DDP Segment MUST contain a DDP Header. Each DDP Segment may Each DDP Segment MUST contain a DDP Header. Each DDP Segment may
also contain ULP Payload. Following is the DDP Segment format: also contain ULP Payload. Following is the DDP Segment format:
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| DDP | | | DDP | |
| Header| ULP Payload (if any) | | Header| ULP Payload (if any) |
| | | | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 6 DDP Segment Format Figure 6 DDP Segment Format
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7 Data Transfer 5 Data Transfer
DDP supports multi-segment DDP Messages. Each DDP Message is DDP supports multi-segment DDP Messages. Each DDP Message is
composed of one or more DDP Segments. Each DDP Segment contains a composed of one or more DDP Segments. Each DDP Segment contains a
DDP Header. The DDP Header contains the information required by the DDP Header. The DDP Header contains the information required by the
receiver to Place any ULP Payload included in the DDP Segment. receiver to Place any ULP Payload included in the DDP Segment.
7.1 DDP Tagged or Untagged Buffer Models 5.1 DDP Tagged or Untagged Buffer Models
DDP uses two basic Buffer Models for the Placement of the ULP DDP uses two basic Buffer Models for the Placement of the ULP
Payload: Tagged Buffer Model and Untagged Buffer Model. Payload: Tagged Buffer Model and Untagged Buffer Model.
7.1.1 Tagged Buffer Model 5.1.1 Tagged Buffer Model
The Tagged Buffer Model is used by the Data Source to transfer a DDP The Tagged Buffer Model is used by the Data Source to transfer a DDP
Message into a Tagged Buffer at the Data Sink that has been Message into a Tagged Buffer at the Data Sink that has been
previously Advertised to the Data Source. An STag identifies a previously Advertised to the Data Source. An STag identifies a
Tagged Buffer. For the Placement of a DDP Message using the Tagged Tagged Buffer. For the Placement of a DDP Message using the Tagged
Buffer model, the STag is used to identify the buffer, and the TO is Buffer model, the STag is used to identify the buffer, and the TO is
used to identify the offset within the Tagged Buffer into which the used to identify the offset within the Tagged Buffer into which the
ULP Payload is transferred. The protocol used to Advertise the ULP Payload is transferred. The protocol used to Advertise the
Tagged Buffer is outside the scope of this specification (i.e. ULP Tagged Buffer is outside the scope of this specification (i.e. ULP
specific). A DDP Message can start at an arbitrary TO within a specific). A DDP Message can start at an arbitrary TO within a
Tagged Buffer. Tagged Buffer.
Additionally, a Tagged Buffer can potentially be written multiple Additionally, a Tagged Buffer can potentially be written multiple
times. This might be done for error recovery or because a buffer is times. This might be done for error recovery or because a buffer is
being re-used after some ULP specific synchronization mechanism. being re-used after some ULP specific synchronization mechanism.
7.1.2 Untagged Buffer Model 5.1.2 Untagged Buffer Model
The Untagged Buffer Model is used by the Data Source to transfer a The Untagged Buffer Model is used by the Data Source to transfer a
DDP Message to the Data Sink into a queued buffer. DDP Message to the Data Sink into a queued buffer.
The DDP Queue Number is used by the ULP to separate ULP messages The DDP Queue Number is used by the ULP to separate ULP messages
into different queues of receive buffers. For example, if two queues into different queues of receive buffers. For example, if two queues
were supported, the ULP could use one queue to post buffers handed were supported, the ULP could use one queue to post buffers handed
to it by the application above the ULP, and it could use the other to it by the application above the ULP, and it could use the other
queue for buffers which are only consumed by ULP specific control queue for buffers which are only consumed by ULP specific control
messages. This enables the separation of ULP control messages from messages. This enables the separation of ULP control messages from
opaque ULP Payload when using Untagged Buffers. opaque ULP Payload when using Untagged Buffers.
The DDP Message Sequence Number can be used by the Data Sink to The DDP Message Sequence Number can be used by the Data Sink to
identify the specific Untagged Buffer. The protocol used to identify the specific Untagged Buffer. The protocol used to
communicate how many buffers have been queued is outside the scope communicate how many buffers have been queued is outside the scope
of this specification. Similarly, the exact implementation of the of this specification. Similarly, the exact implementation of the
buffer queue is outside the scope of this specification. buffer queue is outside the scope of this specification.
7.2 Segmentation and Reassembly of a DDP Message 5.2 Segmentation and Reassembly of a DDP Message
At the Data Source, the DDP layer MUST segment the data contained in At the Data Source, the DDP layer MUST segment the data contained in
a ULP message into a series of DDP Segments, where each DDP Segment a ULP message into a series of DDP Segments, where each DDP Segment
contains a DDP Header and ULP Payload, and MUST be no larger than contains a DDP Header and ULP Payload, and MUST be no larger than
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the MULPDU value advertised by the LLP. The ULP Message Length MUST the MULPDU value advertised by the LLP. The ULP Message Length MUST
be less than 2^32. At the Data Source, the DDP layer MUST send all be less than 2^32. At the Data Source, the DDP layer MUST send all
the data contained in the ULP message. At the Data Sink, the DDP the data contained in the ULP message. At the Data Sink, the DDP
layer MUST Place the ULP Payload contained in all valid incoming DDP layer MUST Place the ULP Payload contained in all valid incoming DDP
Segments associated with a DDP Message into the ULP Buffer. Segments associated with a DDP Message into the ULP Buffer.
DDP Message segmentation at the Data Source is accomplished by DDP Message segmentation at the Data Source is accomplished by
identifying a DDP Message (which corresponds one-to-one with a ULP identifying a DDP Message (which corresponds one-to-one with a ULP
Message) uniquely and then, for each associated DDP Segment of a DDP Message) uniquely and then, for each associated DDP Segment of a DDP
Message, by specifying an octet offset for the portion of the ULP Message, by specifying an octet offset for the portion of the ULP
skipping to change at line 902 skipping to change at line 910
of the STag effectively enables the ULP to implement of the STag effectively enables the ULP to implement
segmentation and reassembly due to ULP specific constraints. segmentation and reassembly due to ULP specific constraints.
See [RDMAP] for details of how this is done. See [RDMAP] for details of how this is done.
A different implementation of a ULP could use an Untagged DDP A different implementation of a ULP could use an Untagged DDP
Message sent after the Tagged DDP Message which details the Message sent after the Tagged DDP Message which details the
initial TO for the STag that was used in the Tagged DDP initial TO for the STag that was used in the Tagged DDP
Message. And finally, another implementation of a ULP could Message. And finally, another implementation of a ULP could
choose to always use an initial TO of zero such that no choose to always use an initial TO of zero such that no
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additional message is required to convey the initial TO used in additional message is required to convey the initial TO used in
a Tagged DDP Message. a Tagged DDP Message.
Regardless of whether the ULP chooses to recover the original ULP Regardless of whether the ULP chooses to recover the original ULP
Message boundary at the Data Sink for a Tagged DDP Message, DDP Message boundary at the Data Sink for a Tagged DDP Message, DDP
supports segmentation and reassembly of the Tagged DDP Message. The supports segmentation and reassembly of the Tagged DDP Message. The
STag is used to identify the ULP Buffer at the Data Sink and the TO STag is used to identify the ULP Buffer at the Data Sink and the TO
is used to identify the octet-offset within the ULP Buffer is used to identify the octet-offset within the ULP Buffer
referenced by the STag. The ULP at the Data Source MUST specify the referenced by the STag. The ULP at the Data Source MUST specify the
STag and the initial TO when the ULP Message is handed to DDP. STag and the initial TO when the ULP Message is handed to DDP.
skipping to change at line 937 skipping to change at line 945
1486 = 1500 (MULPDU) - 14 (for the DDP Header) 1486 = 1500 (MULPDU) - 14 (for the DDP Header)
A zero-length DDP Message is allowed and MUST consume exactly one A zero-length DDP Message is allowed and MUST consume exactly one
DDP Segment. Only the DDP Control and RsvdULP Fields MUST be valid DDP Segment. Only the DDP Control and RsvdULP Fields MUST be valid
for a zero length Tagged DDP Segment. The STag and TO fields MUST for a zero length Tagged DDP Segment. The STag and TO fields MUST
NOT be checked for a zero-length Tagged DDP Message. NOT be checked for a zero-length Tagged DDP Message.
For either Untagged or Tagged DDP Messages, the Data Sink is not For either Untagged or Tagged DDP Messages, the Data Sink is not
required to verify that the entire ULP Message has been received. required to verify that the entire ULP Message has been received.
7.3 Ordering Among DDP Messages 5.3 Ordering Among DDP Messages
Messages passed through the DDP MUST conform to the ordering rules Messages passed through the DDP MUST conform to the ordering rules
defined in this section. defined in this section.
At the Data Source, DDP: At the Data Source, DDP:
* MUST transmit DDP Messages in the order they were submitted to * MUST transmit DDP Messages in the order they were submitted to
the DDP layer, the DDP layer,
* SHOULD transmit DDP Segments within a DDP Message in increasing * SHOULD transmit DDP Segments within a DDP Message in increasing
MO order for Untagged DDP Messages and in increasing TO order MO order for Untagged DDP Messages and in increasing TO order
for Tagged DDP Messages. for Tagged DDP Messages.
At the Data Sink, DDP (Note: The following rules are motivated by At the Data Sink, DDP (Note: The following rules are motivated by
LLP implementations that separate Placement and Delivery.): LLP implementations that separate Placement and Delivery.):
* MAY perform Placement of DDP Segments out of order, * MAY perform Placement of DDP Segments out of order,
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* MAY perform Placement of a DDP Segment more than once, * MAY perform Placement of a DDP Segment more than once,
* MUST Deliver a DDP Message to the ULP at most once, * MUST Deliver a DDP Message to the ULP at most once,
* MUST Deliver DDP Messages to the ULP in the order they were * MUST Deliver DDP Messages to the ULP in the order they were
sent by the Data Source. sent by the Data Source.
7.4 DDP Message Completion & Delivery 5.4 DDP Message Completion & Delivery
At the Data Source, DDP Message transfer is considered completed At the Data Source, DDP Message transfer is considered completed
when the reliable, in-order transport LLP has indicated that the when the reliable, in-order transport LLP has indicated that the
transfer will occur reliably. Note that this in no way restricts the transfer will occur reliably. Note that this in no way restricts the
LLP from buffering the data at either the Data Source or Data Sink. LLP from buffering the data at either the Data Source or Data Sink.
Thus at the Data Source, completion of a DDP Message does not Thus at the Data Source, completion of a DDP Message does not
necessarily mean that the Data Sink has received the message. necessarily mean that the Data Sink has received the message.
At the Data Sink, DDP MUST Deliver a DDP Message if and only if all At the Data Sink, DDP MUST Deliver a DDP Message if and only if all
of the following are true: of the following are true:
skipping to change at line 993 skipping to change at line 1001
At the Data Sink, DDP MUST provide the ULP Message Length to the ULP At the Data Sink, DDP MUST provide the ULP Message Length to the ULP
when an Untagged DDP Message is Delivered. The ULP Message Length when an Untagged DDP Message is Delivered. The ULP Message Length
may be calculated by adding the MO and the ULP Payload length in the may be calculated by adding the MO and the ULP Payload length in the
last DDP Segment (with the Last flag set) of an Untagged DDP last DDP Segment (with the Last flag set) of an Untagged DDP
Message. Message.
At the Data Sink, DDP MUST provide the RsvdULP Field of the DDP At the Data Sink, DDP MUST provide the RsvdULP Field of the DDP
Message to the ULP when the DDP Message is delivered. Message to the ULP when the DDP Message is delivered.
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8 DDP Stream Setup & Teardown 6 DDP Stream Setup & Teardown
This section describes LLP independent issues related to DDP Stream This section describes LLP independent issues related to DDP Stream
setup and teardown. setup and teardown.
8.1 DDP Stream Setup 6.1 DDP Stream Setup
It is expected that the ULP will use a mechanism outside the scope It is expected that the ULP will use a mechanism outside the scope
of this specification to establish an LLP Connection, and that the of this specification to establish an LLP Connection, and that the
LLP Connection will support one or more LLP Streams (e.g. MPA/TCP or LLP Connection will support one or more LLP Streams (e.g. MPA/TCP or
SCTP). After the LLP sets up the LLP Stream, it will enable a DDP SCTP). After the LLP sets up the LLP Stream, it will enable a DDP
Stream on a specific LLP Stream at an appropriate point. Stream on a specific LLP Stream at an appropriate point.
The ULP is required to enable both endpoints of an LLP Stream for The ULP is required to enable both endpoints of an LLP Stream for
DDP data transfer at the same time, in both directions; this is DDP data transfer at the same time, in both directions; this is
necessary so that the Data Sink can properly recognize the DDP necessary so that the Data Sink can properly recognize the DDP
Segments. Segments.
8.2 DDP Stream Teardown 6.2 DDP Stream Teardown
DDP MUST NOT independently initiate Stream Teardown. DDP either DDP MUST NOT independently initiate Stream Teardown. DDP either
responds to a stream being torn down by the LLP or processes a responds to a stream being torn down by the LLP or processes a
request from the ULP to teardown a stream. DDP Stream teardown request from the ULP to teardown a stream. DDP Stream teardown
disables DDP capabilities on both endpoints. For connection-oriented disables DDP capabilities on both endpoints. For connection-oriented
LLPs, DDP Stream teardown MAY result in underlying LLP Connection LLPs, DDP Stream teardown MAY result in underlying LLP Connection
teardown. teardown.
8.2.1 DDP Graceful Teardown 6.2.1 DDP Graceful Teardown
It is up to the ULP to ensure that DDP teardown happens on both It is up to the ULP to ensure that DDP teardown happens on both
endpoints of the DDP Stream at the same time; this is necessary so endpoints of the DDP Stream at the same time; this is necessary so
that the Data Sink stops trying to interpret the DDP Segments. that the Data Sink stops trying to interpret the DDP Segments.
If the Local Peer ULP indicates graceful teardown, the DDP layer on If the Local Peer ULP indicates graceful teardown, the DDP layer on
the Local Peer SHOULD ensure that all ULP data would be transferred the Local Peer SHOULD ensure that all ULP data would be transferred
before the underlying LLP Stream & Connection are torn down, and any before the underlying LLP Stream & Connection are torn down, and any
further data transfer requests by the Local Peer ULP MUST return an further data transfer requests by the Local Peer ULP MUST return an
error. error.
skipping to change at line 1047 skipping to change at line 1055
torn down. torn down.
If the Local Peer LLP supports a half-closed LLP Stream, on the If the Local Peer LLP supports a half-closed LLP Stream, on the
receipt of a LLP graceful teardown request of the DDP Stream, DDP receipt of a LLP graceful teardown request of the DDP Stream, DDP
SHOULD indicate the half-closed state to the ULP, and continue to SHOULD indicate the half-closed state to the ULP, and continue to
process outbound data transfer requests normally. Following this process outbound data transfer requests normally. Following this
event, when the Local Peer ULP requests graceful teardown, DDP MUST event, when the Local Peer ULP requests graceful teardown, DDP MUST
indicate to the LLP that it SHOULD perform a graceful close of the indicate to the LLP that it SHOULD perform a graceful close of the
other half of the LLP Stream. other half of the LLP Stream.
Shah, et. al. Expires August 2004 23 Shah, et. al. Expires February 2005 23
If the Local Peer LLP supports a half-closed LLP Stream, on the If the Local Peer LLP supports a half-closed LLP Stream, on the
receipt of a ULP graceful half-close teardown request of the DDP receipt of a ULP graceful half-close teardown request of the DDP
Stream, DDP SHOULD keep data reception enabled on the other half of Stream, DDP SHOULD keep data reception enabled on the other half of
the LLP stream. the LLP stream.
8.2.2 DDP Abortive Teardown 6.2.2 DDP Abortive Teardown
As previously mentioned, DDP does not independently terminate a DDP As previously mentioned, DDP does not independently terminate a DDP
Stream. Thus any of the following fatal errors on a DDP Stream MUST Stream. Thus any of the following fatal errors on a DDP Stream MUST
cause DDP to indicate to the ULP that a fatal error has occurred: cause DDP to indicate to the ULP that a fatal error has occurred:
* Underlying LLP Connection or LLP Stream is lost. * Underlying LLP Connection or LLP Stream is lost.
* Underlying LLP reports a catastrophic error. * Underlying LLP reports a catastrophic error.
* DDP Header has one or more invalid fields. * DDP Header has one or more invalid fields.
If the LLP indicates to the ULP that a fatal error has occurred, the If the LLP indicates to the ULP that a fatal error has occurred, the
DDP layer SHOULD report the error to the ULP (see Section 9.2, DDP DDP layer SHOULD report the error to the ULP (see Section 7.2, DDP
Error Numbers) and complete all outstanding ULP requests with an Error Numbers) and complete all outstanding ULP requests with an
error. If the underlying LLP Stream is still intact, DDP SHOULD error. If the underlying LLP Stream is still intact, DDP SHOULD
continue to allow the ULP to transfer additional DDP Messages on the continue to allow the ULP to transfer additional DDP Messages on the
outgoing half connection after the fatal error was indicated to the outgoing half connection after the fatal error was indicated to the
ULP. This enables the ULP to transfer an error syndrome to the ULP. This enables the ULP to transfer an error syndrome to the
Remote Peer. After indicating to the ULP a fatal error has occurred, Remote Peer. After indicating to the ULP a fatal error has occurred,
the DDP Stream MUST NOT be terminated until the Local Peer ULP the DDP Stream MUST NOT be terminated until the Local Peer ULP
indicates to the DDP layer that the DDP Stream should be abortively indicates to the DDP layer that the DDP Stream should be abortively
torndown. torndown.
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9 Error Semantics 7 Error Semantics
All LLP errors reported to DDP SHOULD be passed up to the ULP. All LLP errors reported to DDP SHOULD be passed up to the ULP.
9.1 Errors detected at the Data Sink 7.1 Errors detected at the Data Sink
For non-zero length Untagged DDP Segments, the DDP Segment MUST be For non-zero length Untagged DDP Segments, the DDP Segment MUST be
validated before Placement by verifying: validated before Placement by verifying:
1. The QN is valid for this stream. 1. The QN is valid for this stream.
2. The QN and MSN have an associated buffer that allows Placement 2. The QN and MSN have an associated buffer that allows Placement
of the payload. of the payload.
Implementers note: DDP implementations SHOULD consider lack of Implementers note: DDP implementations SHOULD consider lack of
skipping to change at line 1131 skipping to change at line 1139
available to handle the incoming DDP Segments. available to handle the incoming DDP Segments.
For non-zero length Tagged DDP Segments, the segment MUST be For non-zero length Tagged DDP Segments, the segment MUST be
validated before Placement by verifying: validated before Placement by verifying:
1. The STag is valid for this stream. 1. The STag is valid for this stream.
2. The STag has an associated buffer that allows Placement of the 2. The STag has an associated buffer that allows Placement of the
payload. payload.
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3. The TO falls in the range of legal offsets registered for the 3. The TO falls in the range of legal offsets registered for the
STag. STag.
4. The sum of the DDP Segment payload length and the TO falls in 4. The sum of the DDP Segment payload length and the TO falls in
the range of legal offsets registered for the STag. the range of legal offsets registered for the STag.
5. A 64-bit unsigned sum of the DDP Segment payload length and the 5. A 64-bit unsigned sum of the DDP Segment payload length and the
TO does not wrap. TO does not wrap.
If the DDP layer detects any of the receive errors listed in this If the DDP layer detects any of the receive errors listed in this
section, it MUST cease placing the remainder of the DDP Segment and section, it MUST cease placing the remainder of the DDP Segment and
report the error(s) to the ULP. The DDP layer SHOULD include in the report the error(s) to the ULP. The DDP layer SHOULD include in the
error report the DDP Header, the type of error, and the length of error report the DDP Header, the type of error, and the length of
the DDP segment, if available. DDP MUST silently drop any subsequent the DDP segment, if available. DDP MUST silently drop any subsequent
incoming DDP Segments. Since each of these errors represents a incoming DDP Segments. Since each of these errors represents a
failure of the sending ULP or protocol, DDP SHOULD enable the ULP to failure of the sending ULP or protocol, DDP SHOULD enable the ULP to
send one additional DDP Message before terminating the DDP Stream. send one additional DDP Message before terminating the DDP Stream.
9.2 DDP Error Numbers 7.2 DDP Error Numbers
The following error numbers MUST be used when reporting errors to The following error numbers MUST be used when reporting errors to
the ULP. They correspond to the checks enumerated in section 9.1. the ULP. They correspond to the checks enumerated in section 7.1.
Each error is subdivided into a 4-bit Error Type and an 8 bit Error Each error is subdivided into a 4-bit Error Type and an 8 bit Error
Code. Code.
Error Error Error Error
Type Code Description Type Code Description
---------------------------------------------------------- ----------------------------------------------------------
0x0 0x00 Local Catastrophic 0x0 0x00 Local Catastrophic
0x1 Tagged Buffer Error 0x1 Tagged Buffer Error
0x00 Invalid STag 0x00 Invalid STag
skipping to change at line 1179 skipping to change at line 1187
0x2 Untagged Buffer Error 0x2 Untagged Buffer Error
0x01 Invalid QN 0x01 Invalid QN
0x02 Invalid MSN - no buffer available 0x02 Invalid MSN - no buffer available
0x03 Invalid MSN - MSN range is not valid 0x03 Invalid MSN - MSN range is not valid
0x04 Invalid MO 0x04 Invalid MO
0x05 DDP Message too long for available buffer 0x05 DDP Message too long for available buffer
0x06 Invalid DDP version 0x06 Invalid DDP version
0x3 Rsvd Reserved for the use by the LLP 0x3 Rsvd Reserved for the use by the LLP
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10 Security Considerations 8 Security Considerations
This section discusses both protocol-specific considerations and the This section discusses both protocol-specific considerations and the
implications of using DDP with existing security mechanisms. A more implications of using DDP with existing security mechanisms. A more
detailed analysis of the security issues around the implementation detailed analysis of the security issues around the implementation
and the use of the DDP can be found in [RDMASEC]. and the use of the DDP can be found in [RDMASEC].
10.1 Protocol-specific Security Considerations 8.1 Protocol-specific Security Considerations
The vulnerabilities of DDP to active third-party interference are no The vulnerabilities of DDP to active third-party interference are no
greater than any other protocol running over TCP. A third party, by greater than any other protocol running over TCP. A third party, by
injecting spoofed packets into the network that are Delivered to a injecting spoofed packets into the network that are Delivered to a
DDP Data Sink, could launch a variety of attacks that exploit DDP- DDP Data Sink, could launch a variety of attacks that exploit DDP-
specific behavior. Since DDP directly or indirectly exposes memory specific behavior. Since DDP directly or indirectly exposes memory
addresses on the wire, the Placement information carried in each DDP addresses on the wire, the Placement information carried in each DDP
Segment must be validated, including invalid STag and octet level Segment must be validated, including invalid STag and octet level
granularity base and bounds check, before any data is Placed. For granularity base and bounds check, before any data is Placed. For
example, a third-party adversary could inject random packets that example, a third-party adversary could inject random packets that
appear to be valid DDP Segments and corrupt the memory on a DDP Data appear to be valid DDP Segments and corrupt the memory on a DDP Data
Sink. Since DDP is IP transport protocol independent, communication Sink. Since DDP is IP transport protocol independent, communication
security mechanisms such as IPsec [IPSEC] or TLS [TLS] may be used security mechanisms such as IPsec [IPSEC] or TLS [TLS] may be used
to prevent such attacks. to prevent such attacks.
10.2 Using IPSec with DDP 8.2 Using IPSec with DDP
IPsec can be used to protect against the packet injection attacks IPsec can be used to protect against the packet injection attacks
outlined above. Because IPsec is designed to secure arbitrary IP outlined above. Because IPsec is designed to secure arbitrary IP
packet streams, including streams where packets are lost, DDP can packet streams, including streams where packets are lost, DDP can
run on top of IPsec without any change. IPsec packets are processed run on top of IPsec without any change. IPsec packets are processed
(e.g., integrity checked and possibly decrypted) in the order they (e.g., integrity checked and possibly decrypted) in the order they
are received, and a DDP Data Sink will process the decrypted DDP are received, and a DDP Data Sink will process the decrypted DDP
Segments contained in these packets in the same manner as DDP Segments contained in these packets in the same manner as DDP
Segments contained in unsecured IP packets. Segments contained in unsecured IP packets.
10.3 Association of an STag and a DDP Stream 8.3 Association of an STag and a DDP Stream
There are several mechanisms for associating an STag and a DDP There are several mechanisms for associating an STag and a DDP
Stream. Two required mechanisms for this association are a Stream. Two required mechanisms for this association are a
Protection Domain (PD) association and a DDP Stream association. Protection Domain (PD) association and a DDP Stream association.
Under the Protection Domain (PD) association, a unique Protection Under the Protection Domain (PD) association, a unique Protection
Domain Identifier (PD ID) is created and used locally to associate Domain Identifier (PD ID) is created and used locally to associate
an STag with a set of DDP Streams. Under this mechanism, the use of an STag with a set of DDP Streams. Under this mechanism, the use of
the STag is only permitted on the DDP Streams that have the same PD the STag is only permitted on the DDP Streams that have the same PD
ID as the STag. For an incoming DDP Segment of a Tagged DDP Message ID as the STag. For an incoming DDP Segment of a Tagged DDP Message
on a DDP Stream, if the PD ID of the DDP Stream is not the same as on a DDP Stream, if the PD ID of the DDP Stream is not the same as
the PD ID of the STag targeted by the Tagged DDP Message, then the the PD ID of the STag targeted by the Tagged DDP Message, then the
DDP Segment is not placed and the DDP layer MUST surface a local DDP Segment is not placed and the DDP layer MUST surface a local
error to the ULP. Note that the PD ID is locally defined, and cannot error to the ULP. Note that the PD ID is locally defined, and cannot
be directly manipulated by the Remote Peer. be directly manipulated by the Remote Peer.
Under the DDP Stream association, a DDP Stream is identified locally Under the DDP Stream association, a DDP Stream is identified locally
by a unique DDP Stream identifier (ID). An STag is associated with a by a unique DDP Stream identifier (ID). An STag is associated with a
Shah, et. al. Expires August 2004 27 Shah, et. al. Expires February 2005 27
DDP Stream by using a DDP Stream ID. In this case, for an incoming DDP Stream by using a DDP Stream ID. In this case, for an incoming
DDP Segment of a Tagged DDP Message on a DDP Stream, if the DDP DDP Segment of a Tagged DDP Message on a DDP Stream, if the DDP
Stream ID of the DDP Stream is not the same as the DDP Stream ID of Stream ID of the DDP Stream is not the same as the DDP Stream ID of
the STag targeted by the Tagged DDP Message, then the DDP Segment is the STag targeted by the Tagged DDP Message, then the DDP Segment is
not placed and the DDP layer MUST surface a local error to the ULP. not placed and the DDP layer MUST surface a local error to the ULP.
Note that the DDP Stream ID is locally defined, and cannot be Note that the DDP Stream ID is locally defined, and cannot be
directly manipulated by the Remote Peer. directly manipulated by the Remote Peer.
A ULP SHOULD associate an STag and a DDP Stream. DDP MUST support A ULP SHOULD associate an STag and a DDP Stream. DDP MUST support
Protection Domain association and DDP Stream association mechanisms Protection Domain association and DDP Stream association mechanisms
for associating an STag and a DDP Stream. for associating an STag and a DDP Stream.
10.4 Other Security Considerations 8.4 Other Security Considerations
DDP has several mechanisms that deal with a number of attacks. DDP has several mechanisms that deal with a number of attacks.
These attacks include, but are not limited to: These attacks include, but are not limited to:
1. Connection to/from an unauthorized or unauthenticated endpoint. 1. Connection to/from an unauthorized or unauthenticated endpoint.
2. Hijacking of a DDP Stream. 2. Hijacking of a DDP Stream.
3. Attempts to read or write from unauthorized memory regions. 3. Attempts to read or write from unauthorized memory regions.
4. Injection of RDMA Messages within a Stream on a multi-user 4. Injection of RDMA Messages within a Stream on a multi-user
operating system by another application. operating system by another application.
skipping to change at line 1274 skipping to change at line 1282
Hijacking of an DDP Stream would require that the underlying LLP Hijacking of an DDP Stream would require that the underlying LLP
Stream is hijacked. This would require knowledge of Advertised Stream is hijacked. This would require knowledge of Advertised
buffers in order to directly Place data into a user buffer and is buffers in order to directly Place data into a user buffer and is
therefore constrained by the same techniques mentioned to guard therefore constrained by the same techniques mentioned to guard
against attempts to read or write from unauthorized memory regions. against attempts to read or write from unauthorized memory regions.
DDP does not require a node to open its buffers to arbitrary attacks DDP does not require a node to open its buffers to arbitrary attacks
over the DDP Stream. It may access ULP memory only to the extent over the DDP Stream. It may access ULP memory only to the extent
that the ULP has enabled and authorized it to do so. The STag that the ULP has enabled and authorized it to do so. The STag
access control model is defined by a (forthcoming) document. access control model is defined in [RDMASEC]. Specific security
Specific security operations include: operations include:
1. STags are only valid over the exact byte range established by the 1. STags are only valid over the exact byte range established by the
ULP. DDP MUST provide a mechanism for the ULP to establish and ULP. DDP MUST provide a mechanism for the ULP to establish and
revoke the TO range associated with the ULP Buffer referenced by revoke the TO range associated with the ULP Buffer referenced by
the STag. the STag.
2. STags are only valid for the duration established by the ULP. The 2. STags are only valid for the duration established by the ULP. The
ULP may revoke them at any time, in accordance with its own upper ULP may revoke them at any time, in accordance with its own upper
layer protocol requirements. DDP MUST provide a mechanism for the layer protocol requirements. DDP MUST provide a mechanism for the
ULP to establish and revoke STag validity. ULP to establish and revoke STag validity.
Shah, et. al. Expires August 2004 28 Shah, et. al. Expires February 2005 28
3. DDP MUST provide a mechanism for the ULP to communicate the 3. DDP MUST provide a mechanism for the ULP to communicate the
association between a STag and a specific DDP Stream. association between a STag and a specific DDP Stream.
4. A ULP may only expose memory to remote access to the extent that 4. A ULP may only expose memory to remote access to the extent that
it already had access to that memory itself. it already had access to that memory itself.
5. If an STag is not valid on a DDP Stream, DDP MUST pass the invalid 5. If an STag is not valid on a DDP Stream, DDP MUST pass the invalid
access attempt to the ULP. The ULP may provide a mechanism for access attempt to the ULP. The ULP may provide a mechanism for
terminating the DDP Stream. terminating the DDP Stream.
Further, DDP provides a mechanism that directly Places incoming Further, DDP provides a mechanism that directly Places incoming
payloads in user-mode ULP Buffers. This avoids the risks of prior payloads in user-mode ULP Buffers. This avoids the risks of prior
solutions that relied upon exposing system buffers for incoming solutions that relied upon exposing system buffers for incoming
payloads. payloads.
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11 IANA Considerations 9 IANA Considerations
If DDP was enabled a priori for a ULP by connecting to a well-known If DDP was enabled a priori for a ULP by connecting to a well-known
port, this well-known port would be registered for the DDP with port, this well-known port would be registered for the DDP with
IANA. IANA.
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12 References 10 References
12.1 Normative References 10.1 Normative References
[RFC2026] Bradner, S., "The Internet Standards Process -- Revision [RFC2026] Bradner, S., "The Internet Standards Process -- Revision
3", BCP 9, RFC 2026, October 1996. 3", BCP 9, RFC 2026, October 1996.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[MPA] Culley, P., Elzur, U., Recio, R., Bailey, S., Carrier, J., [MPA] Culley, P., Elzur, U., Recio, R., Bailey, S., Carrier, J.,
"Marker PDU Aligned Framing for TCP Specification", Internet "Marker PDU Aligned Framing for TCP Specification", Internet
Draft draft-ietf-rddp-mpa-00.txt (work in progress), September Draft draft-ietf-rddp-mpa-01.txt (work in progress), July 2004
2003
[RDMAP] Recio, R., Culley, P., Garcia, D., Hilland, J., "An RDMA [RDMAP] Recio, R., Culley, P., Garcia, D., Hilland, J., "An RDMA
Protocol Specification", Internet Draft draft-ietf-rddp-rdmap- Protocol Specification", Internet Draft draft-ietf-rddp-rdmap-
01.txt (work in progress), October 2003 01.txt (work in progress), October 2003
[SCTP] Stewart, R. et al., "Stream Control Transmission Protocol", [SCTP] Stewart, R. et al., "Stream Control Transmission Protocol",
RFC 2960, October 2000. RFC 2960, October 2000.
[TCP] Postel, J., "Transmission Control Protocol", STD 7, RFC 793, [TCP] Postel, J., "Transmission Control Protocol", STD 7, RFC 793,
September 1981. September 1981.
12.2 Informative References 10.2 Informative References
[TLS] Dierks, T. and C. Allen, "The TLS Protocol Version 1.0", RFC [TLS] Dierks, T. and C. Allen, "The TLS Protocol Version 1.0", RFC
2246, November 1998. 2246, November 1998.
[IPSEC] Atkinson, R., Kent, S., "Security Architecture for the [IPSEC] Atkinson, R., Kent, S., "Security Architecture for the
Internet Protocol", RFC 2401, November 1998. Internet Protocol", RFC 2401, November 1998.
[RDMASEC] Pinkerton J., Deleganes E., Romanow A., Bitan S., [RDMASEC] Pinkerton J., Deleganes E., Romanow A., Bitan S.,
"DDP/RDMAP Security", draft-ietf-rddp-security-01.txt (work in "DDP/RDMAP Security", draft-ietf-rddp-security-05.txt (work in
progress), February 2004. progress), August 2004.
Shah, et. al. Expires August 2004 31 Shah, et. al. Expires February 2005 31
13 Appendix 11 Appendix
13.1 Receive Window sizing 11.1 Receive Window sizing
Reliable, sequenced, LLPs include a mechanism to advertise the Reliable, sequenced, LLPs include a mechanism to advertise the
amount of receive buffer space a sender may consume. This is amount of receive buffer space a sender may consume. This is
generally called a "receive window". generally called a "receive window".
DDP allows data to be transferred directly to predefined buffers at DDP allows data to be transferred directly to predefined buffers at
the Data Sink. Accordingly, the LLP receive window size need not be the Data Sink. Accordingly, the LLP receive window size need not be
affected by the reception of a DDP Segment, if that segment is affected by the reception of a DDP Segment, if that segment is
placed before additional segments arrive. placed before additional segments arrive.
skipping to change at line 1380 skipping to change at line 1387
the rate that DDP Segments can be retired; there may be some cases the rate that DDP Segments can be retired; there may be some cases
where segment processing cannot keep up with the incoming packet where segment processing cannot keep up with the incoming packet
rate. If this occurs, one reasonable way to slow the incoming packet rate. If this occurs, one reasonable way to slow the incoming packet
rate is to reduce the receive window. rate is to reduce the receive window.
Note that the LLP should take care to comply with the applicable Note that the LLP should take care to comply with the applicable
RFCs; for instance, for TCP, receivers are highly discouraged from RFCs; for instance, for TCP, receivers are highly discouraged from
"shrinking" the receive window (reducing the right edge of the "shrinking" the receive window (reducing the right edge of the
window after it has been advertised). window after it has been advertised).
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14 Author's Addresses 12 Author's Addresses
Hemal Shah Hemal Shah
Intel Corporation Intel Corporation
MS AN1-PTL1 MS AN1-PTL1
1501 South Mopac Expressway, #400 1501 South Mopac Expressway, #400
Austin, TX 78746 USA Austin, TX 78746 USA
Phone: +1 (512) 732-3963 Phone: +1 (512) 732-3963
Email: hemal.shah@intel.com Email: hemal.shah@intel.com
James Pinkerton James Pinkerton
skipping to change at line 1413 skipping to change at line 1420
Phone: +1 (512) 838-1365 Phone: +1 (512) 838-1365
Email: recio@us.ibm.com Email: recio@us.ibm.com
Paul R. Culley Paul R. Culley
Hewlett-Packard Company Hewlett-Packard Company
20555 SH 249 20555 SH 249
Houston, TX 77070-2698 USA Houston, TX 77070-2698 USA
Phone: +1 (281) 514-5543 Phone: +1 (281) 514-5543
Email: paul.culley@hp.com Email: paul.culley@hp.com
Shah, et. al. Expires August 2004 33 Shah, et. al. Expires February 2005 33
15 Acknowledgments 13 Acknowledgments
John Carrier John Carrier
Adaptec, Inc. Adaptec, Inc.
691 S. Milpitas Blvd. 691 S. Milpitas Blvd.
Milpitas, CA 95035 USA Milpitas, CA 95035 USA
Phone: +1 (360) 378-8526 Phone: +1 (360) 378-8526
Email: john_carrier@adaptec.com Email: john_carrier@adaptec.com
Hari Ghadia Hari Ghadia
Adaptec, Inc. Adaptec, Inc.
skipping to change at line 1469 skipping to change at line 1476
Jim Wendt Jim Wendt
Hewlett-Packard Company Hewlett-Packard Company
8000 Foothills Boulevard 8000 Foothills Boulevard
Roseville, CA 95747-5668 USA Roseville, CA 95747-5668 USA
Phone: +1 (916) 785-5198 Phone: +1 (916) 785-5198
Email: jim_wendt@hp.com Email: jim_wendt@hp.com
Mike Krause Mike Krause
Hewlett-Packard Company, 43LN Hewlett-Packard Company, 43LN
Shah, et. al. Expires August 2004 34 Shah, et. al. Expires February 2005 34
19410 Homestead Road 19410 Homestead Road
Cupertino, CA 95014 USA Cupertino, CA 95014 USA
Phone: +1 (408) 447-3191 Phone: +1 (408) 447-3191
Email: krause@cup.hp.com Email: krause@cup.hp.com
Dave Minturn Dave Minturn
Intel Corporation Intel Corporation
MS JF1-210 MS JF1-210
5200 North East Elam Young Parkway 5200 North East Elam Young Parkway
Hillsboro, OR 97124 USA Hillsboro, OR 97124 USA
skipping to change at line 1519 skipping to change at line 1526
Phone: +1 (408) 285-6116 Phone: +1 (408) 285-6116
Email: dave.garcia@hp.com Email: dave.garcia@hp.com
Jeff Hilland Jeff Hilland
Hewlett-Packard Company Hewlett-Packard Company
20555 SH 249 20555 SH 249
Houston, Tx. 77070-2698 USA Houston, Tx. 77070-2698 USA
Phone: +1 (281) 514-9489 Phone: +1 (281) 514-9489
Email: jeff.hilland@hp.com Email: jeff.hilland@hp.com
Shah, et. al. Expires August 2004 35 Shah, et. al. Expires February 2005 35
Barry Reinhold Barry Reinhold
Lamprey Networks Lamprey Networks
Durham, NH 03824 USA Durham, NH 03824 USA
Phone: +1 (603) 868-8411 Phone: +1 (603) 868-8411
Email: bbr@LampreyNetworks.com Email: bbr@LampreyNetworks.com
Shah, et. al. Expires August 2004 36 Shah, et. al. Expires February 2005 36
16 Full Copyright Statement 14 Full Copyright Statement
This document and the information contained herein is provided on an This document and the information contained herein is provided on an
"AS IS" basis and ADAPTEC INC., AGILENT TECHNOLOGIES INC., BROADCOM "AS IS" basis and ADAPTEC INC., AGILENT TECHNOLOGIES INC., BROADCOM
CORPORATION, CISCO SYSTEMS INC., EMC CORPORATION, HEWLETT-PACKARD CORPORATION, CISCO SYSTEMS INC., EMC CORPORATION, HEWLETT-PACKARD
COMPANY, INTERNATIONAL BUSINESS MACHINES CORPORATION, INTEL COMPANY, INTERNATIONAL BUSINESS MACHINES CORPORATION, INTEL
CORPORATION, MICROSOFT CORPORATION, NETWORK APPLIANCE INC., THE CORPORATION, MICROSOFT CORPORATION, NETWORK APPLIANCE INC., THE
INTERNET SOCIETY, AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM INTERNET SOCIETY, AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM
ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY
WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE
ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS
FOR A PARTICULAR PURPOSE. FOR A PARTICULAR PURPOSE.
Copyright (c) The Internet Society (2004). This document is subject
to the rights, licenses and restrictions contained in BCP 78, and
except as set forth therein, the authors retain all their rights.
Copyright (c) 2002 ADAPTEC INC., BROADCOM CORPORATION, CISCO SYSTEMS Copyright (c) 2002 ADAPTEC INC., BROADCOM CORPORATION, CISCO SYSTEMS
INC., EMC CORPORATION, HEWLETT-PACKARD COMPANY, INTERNATIONAL INC., EMC CORPORATION, HEWLETT-PACKARD COMPANY, INTERNATIONAL
BUSINESS MACHINES CORPORATION, INTEL CORPORATION, MICROSOFT BUSINESS MACHINES CORPORATION, INTEL CORPORATION, MICROSOFT
CORPORATION, NETWORK APPLIANCE INC., All Rights Reserved. CORPORATION, NETWORK APPLIANCE INC., All Rights Reserved.
Shah, et. al. Expires August 2004 37 Shah, et. al. Expires February 2005 37
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