Internet DRAFT - draft-ietf-forces-packet-parallelization
draft-ietf-forces-packet-parallelization
Internet Engineering Task Force E. Haleplidis
Internet-Draft University of Patras
Intended status: Experimental J. Halpern
Expires: April 13, 2015 Ericsson
October 10, 2014
ForCES Packet Parallelization
draft-ietf-forces-packet-parallelization-03
Abstract
Forwarding and Control Element Separation (ForCES) defines an
architectural framework and associated protocols to standardize
information exchange between the control plane and the forwarding
plane in a ForCES Network Element (ForCES NE). RFC5812 has defined
the ForCES Model provides a formal way to represent the capabilities,
state, and configuration of forwarding elements within the context of
the ForCES protocol (RFC 5810), so that Control Elements (CEs) can
control the Forwarding Elements (FEs) accordingly. More
specifically, the model describes the logical functions that are
present in an FE, what capabilities these functions support, and how
these functions are or can be interconnected.
Many network devices support parallel packet processing. This
document describes how ForCES can model a network device's
parallelization datapath.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on April 13, 2015.
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Copyright Notice
Copyright (c) 2014 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
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the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
1.2. Definitions . . . . . . . . . . . . . . . . . . . . . . . 3
2. Packet Parallelization . . . . . . . . . . . . . . . . . . . 4
2.1. Core parallelization LFB . . . . . . . . . . . . . . . . 6
2.2. Parallelization metadata . . . . . . . . . . . . . . . . 9
3. Parallel Base Types . . . . . . . . . . . . . . . . . . . . . 9
3.1. Frame Types . . . . . . . . . . . . . . . . . . . . . . . 9
3.2. Data Types . . . . . . . . . . . . . . . . . . . . . . . 10
3.3. MetaData Types . . . . . . . . . . . . . . . . . . . . . 10
4. Parallel LFBs . . . . . . . . . . . . . . . . . . . . . . . . 11
4.1. Splitter . . . . . . . . . . . . . . . . . . . . . . . . 11
4.1.1. Data Handling . . . . . . . . . . . . . . . . . . . . 11
4.1.2. Components . . . . . . . . . . . . . . . . . . . . . 12
4.1.3. Capabilities . . . . . . . . . . . . . . . . . . . . 12
4.1.4. Events . . . . . . . . . . . . . . . . . . . . . . . 12
4.2. Merger . . . . . . . . . . . . . . . . . . . . . . . . . 12
4.2.1. Data Handling . . . . . . . . . . . . . . . . . . . . 13
4.2.2. Components . . . . . . . . . . . . . . . . . . . . . 14
4.2.3. Capabilities . . . . . . . . . . . . . . . . . . . . 14
4.2.4. Events . . . . . . . . . . . . . . . . . . . . . . . 14
4.3. CoreParallelization . . . . . . . . . . . . . . . . . . . 15
4.3.1. Data Handling . . . . . . . . . . . . . . . . . . . . 15
4.3.2. Components . . . . . . . . . . . . . . . . . . . . . 15
4.3.3. Capabilities . . . . . . . . . . . . . . . . . . . . 15
4.3.4. Events . . . . . . . . . . . . . . . . . . . . . . . 15
5. XML for Parallel LFB library . . . . . . . . . . . . . . . . 16
6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 23
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 24
7.1. LFB Class Names and LFB Class Identifiers . . . . . . . . 24
7.2. Metadata ID . . . . . . . . . . . . . . . . . . . . . . . 25
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8. Security Considerations . . . . . . . . . . . . . . . . . . . 25
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 25
9.1. Normative References . . . . . . . . . . . . . . . . . . 25
9.2. Informative References . . . . . . . . . . . . . . . . . 26
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 26
1. Introduction
A lot of network devices can process packets in a parallel manner.
The Forwarding and Control Element Separation (ForCES) Model
[RFC5812] presents a formal way to describe the Forwarding Plane's
datapath with Logical Function Blocks (LFBs) using XML. This
document describes how packet parallelization can be described with
the ForCES model.
The modeling concept has been influenced by Cilk [Cilk]. Cilk is a
programming language that has been developed since 1994 at the MIT
Laboratory to allow programmers to identify elements that can be
executed in parallel. The two Cilk concepts used in this document is
spawn and sync. Spawn being the place where parallel tasks can start
and sync being the place where the parallel task finishes and must
collect all parallel output.
As task, we define a grouping of packets or pieces of a packet
(chunks) that belong to the same original packet and are going to be
processed in parallel. All packets/chunks of the same task will be
distinguished by an identifier, in the specific case we use a 32-bit
identifier named task correlator.
This document is in the experimental track and thus the LFB Class IDs
will not be included in the standard action's values. Therefore the
LFB Class IDs must have a value larger than 65535 and the LFB names
must begin with the prefix 'Ext-'. However for brevity, when we
refer to the LFB Class names in the text of this document (not the
formal definitions), the 'Ext-' prefix will be omitted.
1.1. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119].
1.2. Definitions
This document follows the terminology defined by the ForCES Model in
[RFC5812]. In particular, the reader is expected to be familiar with
the following terms:
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FE
CE
FE Model
LFB (Logical Functional Block) Class (or type)
LFB Instance
LFB Model
Element
Attribute
LFB Metadata
ForCES Component
LFB Class Library
This document also introduces the following terms:
Chunk - Pieces of a packet
Task - Grouping of packets or chunks belong to the same packet
that are processed in parallel
Task Correlator - A 32-bit identifier that uniquely distinguishes
tasks
Split Type - A parallel type where the packets are split into
chunks to be processed in parallel. Each task in a split type is
composed only of chunks.
Flood Type - A parallel type where the packets are copied as is to
downstream LFBs to be processed in parallel. Each task in a flood
type is composed only of packets.
2. Packet Parallelization
This document addresses the following two types of packet
parallelization:
1. Flood - where a copy of a packet is sent to multiple LFBs to be
processed in parallel.
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2. Split - where the packet will be split in equal size chunks
specified by the CE and sent to multiple LFB instances probably
of the same LFB class to be processed in parallel.
It must be noted that the process of copying the packet in the Flood
parallel type is implementation dependent and is loosely defined
here. An implementer may either decide to physical copy the packet
and send all packets on the parallel paths, or may decide to
logically copy the packet by simply sending, for example, pointers of
the same packet provided that the necessary interlocks are taken into
account. The implementer has to take into account the device's
characteristics to decide which approach fits best to the device.
In the split parallel type, while harder, the implementer may also
decide to logically split the packet and send, for example, pointers
to parts of the packet, provided that the necessary interlocks are
managed. In addition, how chunks are distributed to the LFBs, e.g.,
which chunk to which LFB, is implementation dependent. For example
while usually chunks are sent to the same LFB class, the number of
LFB instances may not equal to the number of chunks. It is up to the
implementer to decide how these chunks will be sent, for example in a
round-robin fashion.
This document introduces two LFBs that are used in before and after
the parallelization occurs:
1. Splitter - similar to Cilk's spawn. An LFB that will split the
path of a packet which will be sent to multiple downstream LFBs
to be processed in parallel.
2. Merger - similar to Cilk's sync. An LFB that will receive
packets or chunks of the same initial packet and merge them and
the results into one packet.
Both parallel packet distribution types can currently be achieved
with the ForCES model. The splitter LFB has one group output that
produces either chunks or packets to be sent to LFBs for processing
and the merger LFB has one group input that expects either packets or
chunks to aggregate all the parallel packets or chunks and produce a
single packet. Figure 1 shows a simple example of a split parallel
datapath along with the splitter and merger LFB. Figure 2 shows an
example of a flood parallel datapath along with the splitter and
merger LFB.
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C1+M +------------+ C1+M
+---->| Regex LFB |----+
+----------+ | +------------+ | +----------+
| |---+ +------>| |
P | | C2+M +------------+ C2+M | | P
--->| Splitter |-------->| Regex LFB |----------->| Merger |--->
| LFB | CN+M +------------+ CN+M | LFB |
| |---+ +------>| |
+----------+ | +------------+ | +----------+
+---->| Regex LFB |----+
+------------+
Figure 1: Simple split parallel processing
+----------+ +------------+ +-------+ +----------+
| |P+M | Classifier |P+M | Meter |P+M | |
P | |--->| LFB |--->| LFB |--->| | P
--->| Splitter | +------------+ +-------+ | Merger |--->
| LFB | | LFB |
| |P+M +------------+ P+M | |
| |--------->| IPv4 TTL |---------->| |
+----------+ | Decrement | +----------+
| LFB |
+------------+
Figure 2: Simple flood parallel processing
This version of the modeling framework does not allow for nested
parallel datapath topologies. This decision was reached by the
authors and the ForCES working group as there was no strong use case
or need at decision time. This led to a simpler metadata definition,
which was needed to be transported between the splitter and the
corresponding merger. If there is a need for nested parallel
datapaths a new version of a splitter and merger will be needed to be
defined as well as an augmentation to the defined metadata.
2.1. Core parallelization LFB
One important element to a developer is the ability to define which
LFBs can be used in a parallel mode, which LFBs can be parallelized
with which as well as the order in which parallel LFBs can be
assembled.
To access the parallelization details, we opted for defining a new
LFB class - the CoreParallelization LFB. This choice was an
alternative to making another change to the core FEObject LFB. The
CoreParallelization exists merely to define the capabilities for an
FE's LFB parallelization. A CE using the ForCES Protocol [RFC5810]
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can check the existence of this LFB class in the FEObject's
SupportedLFBs component. The existence of the CoreParallelization
LFB will indicate to the CE that the specific FE supports
parallelization. There MUST be only one instance of the
CoreParallelization LFB per FE.
The topology of the parallel datapath can be deferred and manipulated
from the FEObject LFB's LFBTopology.
The CoreParallelization requires only one capability in order to
specify each LFB that can be used in a parallel mode:
o The Name of the LFB.
o The Class ID of the LFB.
o The Version of the LFB.
o The number of instances that class can support in parallel.
o A list of LFB classes that can follow this LFB class in a pipeline
for a parallel path.
o A list of LFB classes that can exist before this LFB class in a
pipeline for a parallel path.
o A list of LFB classes that can process packets or chunks in
parallel with this LFB class.
<!-- Datatype -->
<dataTypeDef>
<name>ParallelLFBType</name>
<synopsis>Table entry for parallel LFBs</synopsis>
<struct>
<component componentID="1">
<name>LFBName</name>
<synopsis>The name of an LFB Class</synopsis>
<typeRef>string</typeRef>
</component>
<component componentID="2">
<name>LFBClassID</name>
<synopsis>The id of the LFB Class</synopsis>
<typeRef>uint32</typeRef>
</component>
<component componentID="3">
<name>LFBVersion</name>
<synopsis>The version of the LFB Class used by this FE
</synopsis>
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<typeRef>string</typeRef>
</component>
<component componentID="4">
<name>LFBParallelOccurrenceLimit</name>
<synopsis>The upper limit of instances of the same
parallel LFBs of this class</synopsis>
<optional />
<typeRef>uint32</typeRef>
</component>
<component componentID="5">
<name>AllowedParallelAfters</name>
<synopsis>List of LFB Classes that can follow this LFB
in a parallel pipeline</synopsis>
<optional />
<array>
<typeRef>uint32</typeRef>
</array>
</component>
<component componentID="6">
<name>AllowedParallelBefores</name>
<synopsis>List of LFB Classes that this LFB class can
follow in a parallel pipeline</synopsis>
<optional />
<array>
<typeRef>uint32</typeRef>
</array>
</component>
<component componentID="7">
<name>AllowedParallel</name>
<synopsis>List of LFB Classes that this LFB class be run
in parallel with</synopsis>
<array>
<typeRef>uint32</typeRef>
</array>
</component>
</struct>
</dataTypeDef>
<!-- Capability -->
<capability componentID="32">
<name>ParallelLFBs</name>
<synopsis>List of all supported parallel LFBs</synopsis>
<array type="Variable-size">
<typeRef>ParallelLFBType</typeRef>
</array>
</capability>
Figure 3: XML Definitions for CoreParallelization LFB
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2.2. Parallelization metadata
It is expected that the splitting and merging mechanisms are an
implementation issue. This document plays the role of defining the
operational parameters for the splitting and merging, namely, the
size of the chunks, what happens if a packet or chunk has been marked
as invalid and whether the merge LFB should wait for all packets or
chunks to arrive. The following metadata set is defined as a struct:
1. ParallelType - Flood or split
2. TaskCorrelator - Identify packets or chunks that belonged to the
initial packet that entered the Splitter LFB
3. ParallelNum - Sequence Number of the packet or the chunk for a
specific task.
4. ParralelPartsCount - Total number of packets or chunks for a
specific task.
This metadata is produced from the Splitter LFB and is opaque to LFBs
in parallel paths and is passed along to the merger LFB without being
consumed.
In the case in which an LFB decides that a packet/chunk has to be
dropped, the LFB MAY drop the packet/chunk but the metadata MUST be
sent to the Merger LFB's InvalidIn input port for merging purposes.
Additional metadata produced by LFBs inside a datapath MAY be
aggregated within the Merger LFB and sent on after the merging
process. In case of receiving the same metadata definition with
multiple values the merger LFB MUST keep the first received from a
valid packet or chunk.
3. Parallel Base Types
3.1. Frame Types
One frame type has been defined in this library.
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+---------------+---------------------------------------------------+
| Frame Type | Synopsis |
| Name | |
+---------------+---------------------------------------------------+
| Chunk | A chunk is a frame that is part of an original |
| | larger frame |
+---------------+---------------------------------------------------+
Parallel Frame Types
3.2. Data Types
One data type has been defined in this library.
+---------------+------------------------+--------------------------+
| DataType Name | Type | Synopsis |
+---------------+------------------------+--------------------------+
| ParallelTypes | Atomic uchar. Special | The type of |
| | Values Flood (0), | parallelization this |
| | Split (1). | packet will go through |
+---------------+------------------------+--------------------------+
Parallel Data Types
3.3. MetaData Types
The following metadata structure with ID 16, using the ForCES model
extension [I-D.ietf-forces-model-extension], is defined for the
parallelization library:
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+--------------------+--------+----+--------------------------------+
| Metadata Name | Type | ID | Synopsis |
+--------------------+--------+----+--------------------------------+
| ParallelType | uchar | 1 | The type of parallelization |
| | | | this packet will go through. 0 |
| | | | for flood, 1 for split. |
| | | | |
| TaskCorrelator | uint32 | 2 | An identification number to |
| | | | specify that a packet or a |
| | | | chunks belongs to the same |
| | | | parallel task. |
| | | | |
| ParallelNum | uint32 | 3 | Defines the number of a |
| | | | specific packet or chunk of a |
| | | | specific task. |
| | | | |
| ParallelPartsCount | uint32 | 4 | Defines the total number of |
| | | | packets or chunks for a |
| | | | specific task. |
+--------------------+--------+----+--------------------------------+
Metadata Structure for Merging
4. Parallel LFBs
4.1. Splitter
The splitter LFB takes part in parallelizing the processing datapath
by sending either the same packet Figure 2 or chunks Figure 1 of the
same packet to multiple LFBs.
+---------------+
SplitterIn | | SplitterOut
---------->| Splitter LFB |------------->
| |
+---------------+
Figure 4: Splitter LFB
4.1.1. Data Handling
The splitter LFB receives any kind of packet via the singleton input,
Input. Depending upon the CE's configuration of the ParallelType
component, if the parallel type is of type flood (0), the same packet
MUST be sent through all of the group output SplitterOut's instances.
If the parallel type is of type split (1), the packet will be split
into same size chunks except the last which MAY be smaller, with the
max size being defined by the ChunkSize component. Chunks MAY be
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sent out in a round-robin fashion through the group output
ParallelOut's instances or in any other way defined by the
implementer. Each packet or chunk will be accompanied by the
following metadata set as a struct:
o ParallelType - The parallel type, split or flood.
o ParallelID - generated by the splitter LFB to identify that chunks
or packets belong to the same parallel task.
o ParallelNum - each chunk or packet of a parallel id will be
assigned a number in order for the merger LFB to know when it has
gathered them all along with the ParallelPartsCount metadata.
o ParallelPartsCount - the number of chunks or packets for the
specific task.
4.1.2. Components
The splitter LFB has only two components. The first is the
ParallelType, an uint32 that defines how the packet will be processed
by the Splitter LFB. The second is the ChunkSize, an uint32 that
specifies the size of each chunk when a packet is split into multiple
same size chunks. The last chunk MAY be smaller than the value of
the ChunkSize.
4.1.3. Capabilities
This LFB has only one capability specified, the MinMaxChunkSize a
struct of two uint32 to specify the minimum and maximum chunk size.
4.1.4. Events
This LFB has no events specified.
4.2. Merger
The merger LFB is the synchronization point for multiple packets or
packet chunks of the same task, emanating out of the parallel path as
illustrated in Figure 2 and Figure 1.
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+-------------+
MergerIn | |
--------->| | MergerOut
| Merger LFB |----------->
InvalidIn | |
--------->| |
+-------------+
Figure 5: Merger LFB
4.2.1. Data Handling
The merger LFB receives either a packet or a chunk via the group
input ParallelIn, along with the ParallelType metadata that, the
TaskCorrelator, the ParallelNum and the ParallelPartsCount.
In case that an upstream LFB has dropped a packet or a chunk the
merger LFB MAY receive only the metadata or both metadata and packet
or chunk through the InvalidIn group input port. It SHOULD receive a
metadata specifying the error code. Currently defined metadata's in
the Base LFB Library [RFC6956] are the ExceptionID and the
ValidateErrorID.
If the MergeWaitType is set to false the Merger LFB will initiate the
merge process upon receiving the first packet. If false, for each
task identified by the task correlator, it will wait for all packets/
chunks to arrive unless the MergeWaitTimeoutTimer timer expires. If
the MergeWaitTimeoutTimer has expired, the Merger MUST consider the
rest of the packets/chuncks, that have not been received, as invalid
and MUST handle the packets according to the InvalidAction value.
If one packet or chunk has been received through the InvalidIn port
then the merging procedure will handle the packets/chuncks according
to the InvalidAction value. If the InvalidAction component has been
set to 0 then if one packet or chunk is not valid all will dropped,
else the process will initiate. Once the merging process has been
completed the resulting packet will be sent via the singleton output
port MergerOut.
If the Merger LFB receives different values for the same metadata
from different packets or chunks that has the same task correlator
then the Merger LFB will use the first metadata from a packet or
chunk that entered the LFB through the MergerIn input port.
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4.2.2. Components
This LFB has the following components specified:
1. InvalidAction - a uchar defining what the Merge LFB will do if an
invalid chunk or packet is received. If set to 0 (DropAll) the
merge will be considered invalid and all chunks or packets will
be dropped. If set to 1 (Continue) the merge will continue.
2. MergeWaitTimeoutTimer - a uint32 defining the amount of time, in
milliseconds, that the Merger will wait for all packets or
chuncks within the same task to arrive before considering them
invalid. The MergeWaitTimeoutTimer starts as soon as the first
chunk or packet of a parallel task arrives.
3. MergeWaitType - a boolean. If true the Merger LFB will wait for
all packets or chunks to be received prior to performing the
merge. If false, when one packet or a chunk with a response is
received by the merge LFB it will start with the merge process.
4. InvalidMergesCounter - a uint32 that counts the number of merges
where there is at least one packet or chunk that entered the
merger LFB through the InvalidIn input port.
5. InvalidTotalCounter - a uint32 that counts the number of merges
where all packets/chunks entered the merger LFB through the
InvalidIn input port.
6. InvalidIDCounters - a struct of two arrays. Each array has a
uint32 per row. Each array counts number of invalid merges where
at least one packet or chunk entered through InvalidID per error
ID. The first array is the InvalidExceptionID and the second is
the InvalidValidateErrorID.
4.2.3. Capabilities
This LFB has no capabilities specified.
4.2.4. Events
This LFB specifies only two event. The first detects whether the
InvalidMergesCounter has exceeded a specific value and the second
detects whether the InvalidAllCounter has exceeded a specific value.
Both error reports will send the respective counter value. Event
Filters can be used to limit the number of messages
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4.3. CoreParallelization
A core LFB that specifies that the FE supports parallelization,
instead of updating the FEObject LFB
4.3.1. Data Handling
The CoreParallelization does not handle data.
4.3.2. Components
This LFB has no components specified.
4.3.3. Capabilities
This LFB has only one capability specified. The ParallelLFBs is a
table which lists all the LFBs that can be parallelized. Each row of
the table contains:
1. LFBName - a string. The Name of the parallel LFB.
2. LFBClassID - a uint32. The Class ID of the parallel LFB.
3. LFBVersion - a string. The Version of the parallel LFB.
4. LFBParallelOccurrenceLimit - a uint32. The upper limit of
instances of the same parallel LFBs of this class.
5. AllowedParallelAfters - a table of uint32s (LFB Class IDs). A
list of LFB classes that can follow this LFB class in a pipeline
for a parallel path.
6. AllowedParallelBefores - a table of uint32s (LFB Class IDs). A
list of LFB classes that can exist before this LFB class in a
pipeline for a parallel path.
7. AllowedParallel - a table of uint32s (LFB Class IDs). A list of
LFB classes that can process packets or chunks in parallel with
this LFB class.
4.3.4. Events
This LFB specifies no events
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5. XML for Parallel LFB library
<?xml version="1.0" encoding="UTF-8"?>
<LFBLibrary xmlns="urn:ietf:params:xml:ns:forces:lfbmodel:1.1"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="urn:ietf:params:xml:ns:forces:lfbmodel:1.1"
provides="Parallel">
<load library="BaseTypeLibrary" location="BaseTypeLibrary.LFB"/>
<frameDefs>
<frameDef>
<name>Chunk</name>
<synopsis>A chunk is a frame that is part of an original
larger frame</synopsis>
</frameDef>
</frameDefs>
<dataTypeDefs>
<dataTypeDef>
<name>ParallelTypes</name>
<synopsis>The type of parallelization this packet will go
through</synopsis>
<atomic>
<baseType>uchar</baseType>
<specialValues>
<specialValue value="0">
<name>Flood</name>
<synopsis>The packet/chunk has been sent as a whole
to multiple recipients</synopsis>
</specialValue>
<specialValue value="1">
<name>Split</name>
<synopsis>The packet/chunk has been split into
multiple chunks and sent to recipients</synopsis>
</specialValue>
</specialValues>
</atomic>
</dataTypeDef>
<dataTypeDef>
<name>ParallelLFBType</name>
<synopsis>Table entry for parallel LFBs</synopsis>
<struct>
<component componentID="1">
<name>LFBName</name>
<synopsis>The name of an LFB Class</synopsis>
<typeRef>string</typeRef>
</component>
<component componentID="2">
<name>LFBClassID</name>
<synopsis>The id of the LFB Class</synopsis>
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<typeRef>uint32</typeRef>
</component>
<component componentID="3">
<name>LFBVersion</name>
<synopsis>The version of the LFB Class used by this FE
</synopsis>
<typeRef>string</typeRef>
</component>
<component componentID="4">
<name>LFBParallelOccurrenceLimit</name>
<synopsis>The upper limit of instances of the same
parallel LFBs of this class</synopsis>
<optional/>
<typeRef>uint32</typeRef>
</component>
<component componentID="5">
<name>AllowedParallelAfters</name>
<synopsis>List of LFB Classes that can follow this LFB
in a parallel pipeline</synopsis>
<optional/>
<array>
<typeRef>uint32</typeRef>
</array>
</component>
<component componentID="6">
<name>AllowedParallelBefores</name>
<synopsis>List of LFB Classes that this LFB class can
follow in a parallel pipeline</synopsis>
<optional/>
<array>
<typeRef>uint32</typeRef>
</array>
</component>
<component componentID="7">
<name>AllowedParallel</name>
<synopsis>List of LFB Classes that this LFB class be run
in parallel with</synopsis>
<array>
<typeRef>uint32</typeRef>
</array>
</component>
</struct>
</dataTypeDef>
</dataTypeDefs>
<metadataDefs>
<metadataDef>
<name>ParallelMetadataSet</name>
<synopsis>A metadata Set for parallelization related LFBs
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</synopsis>
<metadataID>32</metadataID>
<struct>
<component componentID="1">
<name>ParallelType</name>
<synopsis>The type of parallelization this packet/chunk
has gone through</synopsis>
<typeRef>ParallelTypes</typeRef>
</component>
<component componentID="2">
<name>TaskCorrelator</name>
<synopsis>An identification number to specify that
packets or chunks originate from the same packet.
</synopsis>
<typeRef>uint32</typeRef>
</component>
<component componentID="3">
<name>ParallelNum</name>
<synopsis>Defines the number of the specific packet or
chunk of the specific parallel ID.</synopsis>
<typeRef>uint32</typeRef>
</component>
<component componentID="4">
<name>ParallelPartsCount</name>
<synopsis>Defines the total number of packets or chunks
for the specific parallel ID.</synopsis>
<typeRef>uint32</typeRef>
</component>
</struct>
</metadataDef>
</metadataDefs>
<LFBClassDefs>
<LFBClassDef LFBClassID="65537">
<name>Ext-Splitter</name>
<synopsis>A splitter LFB takes part in parallelizing the
processing datapath. It will either send the same packet
or chunks of one packet to multiple LFBs</synopsis>
<version>1.0</version>
<inputPorts>
<inputPort>
<name>SplitterIn</name>
<synopsis>An input port expecting any kind of frame
</synopsis>
<expectation>
<frameExpected>
<ref>Arbitrary</ref>
</frameExpected>
</expectation>
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</inputPort>
</inputPorts>
<outputPorts>
<outputPort group="true">
<name>SplitterOut</name>
<synopsis>A parallel output port that sends the same
packet to all output instances or chunks of the same
packet different chunk on each instance.</synopsis>
<product>
<frameProduced>
<ref>Arbitrary</ref>
<ref>Chunk</ref>
</frameProduced>
<metadataProduced>
<ref>ParallelMetadataSet</ref>
</metadataProduced>
</product>
</outputPort>
</outputPorts>
<components>
<component componentID="1" access="read-write">
<name>ParallelType</name>
<synopsis>The type of parallelization this packet will
go through</synopsis>
<typeRef>ParallelTypes</typeRef>
</component>
<component componentID="2" access="read-write">
<name>ChunkSize</name>
<synopsis>The size of a chunk when a packet is split
into multiple same size chunks</synopsis>
<typeRef>uint32</typeRef>
</component>
</components>
<capabilities>
<capability componentID="31">
<name>MinMaxChunkSize</name>
<synopsis>The minimum and maximum size of a chunk
capable of split by this LFB</synopsis>
<struct>
<component componentID="1">
<name>MinChunkSize</name>
<synopsis>Minimum chunk size</synopsis>
<optional/>
<typeRef>uint32</typeRef>
</component>
<component componentID="2">
<name>MaxChunkSize</name>
<synopsis>Maximum chunk size</synopsis>
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<typeRef>uint32</typeRef>
</component>
</struct>
</capability>
</capabilities>
</LFBClassDef>
<LFBClassDef LFBClassID="65538">
<name>Ext-Merger</name>
<synopsis>A merger LFB receives multiple packets or multiple
chunks of the same packet and merge them into one merged
packet</synopsis>
<version>1.0</version>
<inputPorts>
<inputPort group="true">
<name>MergerIn</name>
<synopsis>A parallel input port that accepts packets
or chunks from all output instances</synopsis>
<expectation>
<frameExpected>
<ref>Arbitrary</ref>
<ref>Chunk</ref>
</frameExpected>
<metadataExpected>
<ref>ParallelMetadataSet</ref>
</metadataExpected>
</expectation>
</inputPort>
<inputPort group="true">
<name>InvalidIn</name>
<synopsis>When a packet is sent out of an error port of
an LFB in a parallel path will be sent to this
output port in the Merger LFB</synopsis>
<expectation>
<frameExpected>
<ref>Arbitrary</ref>
<ref>Chunk</ref>
</frameExpected>
<metadataExpected>
<one-of>
<ref>ExceptionID</ref>
<ref>ValidateErrorID</ref>
</one-of>
</metadataExpected>
</expectation>
</inputPort>
</inputPorts>
<outputPorts>
<outputPort>
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<name>MergerOut</name>
<synopsis>An output port expecting any kind of frame
</synopsis>
<product>
<frameProduced>
<ref>Arbitrary</ref>
</frameProduced>
</product>
</outputPort>
</outputPorts>
<components>
<component componentID="1" access="read-write">
<name>InvalidAction</name>
<synopsis>What the Merge LFB will do if an invalid
chunk or packet is received</synopsis>
<atomic>
<baseType>uchar</baseType>
<specialValues>
<specialValue value="0">
<name>DropAll</name>
<synopsis>Drop all packets or chunks
</synopsis>
</specialValue>
<specialValue value="1">
<name>Continue</name>
<synopsis>Continue with the merge</synopsis>
</specialValue>
</specialValues>
</atomic>
</component>
<component componentID="2" access="read-write">
<name>MergeWaitType</name>
<synopsis>Whether the Merge LFB will wait for all
packets or chunks to be received prior to sending
out a response</synopsis>
<typeRef>boolean</typeRef>
</component>
<component componentID="3" access="read-write">
<name>MergeWaitTimeoutTimer</name>
<synopsis>The time that the Merger will wait
for all packets or chuncks within the same task to arrive
before considering them invalid.</synopsis>
<typeRef>uint32</typeRef>
</component>
<component componentID="4" access="read-reset">
<name>InvalidMergesCounter</name>
<synopsis>Counts the number of merges where there is at
least one packet/chunk that entered the merger LFB
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through the InvalidIn input port</synopsis>
<typeRef>uint32</typeRef>
</component>
<component componentID="5" access="read-reset">
<name>InvalidTotalCounter</name>
<synopsis>Counts the number of merges where all
packets/chunks entered the merger LFB through the
InvalidIn input port</synopsis>
<typeRef>uint32</typeRef>
</component>
<component componentID="6" access="read-reset">
<name>InvalidIDCounters</name>
<synopsis>Counts number of invalid merges where at
least one packet/chunk entered through InvalidID per
error ID</synopsis>
<struct>
<component componentID="1">
<name>InvalidExceptionID</name>
<synopsis>Per Exception ID</synopsis>
<array>
<typeRef>uint32</typeRef>
</array>
</component>
<component componentID="2">
<name>InvalidValidateErrorID</name>
<synopsis>Per Validate Error ID</synopsis>
<array>
<typeRef>uint32</typeRef>
</array>
</component>
</struct>
</component>
</components>
<events baseID="30">
<event eventID="1">
<name>ManyInvalids</name>
<synopsis>An event that specifies if there are too many
invalids</synopsis>
<eventTarget>
<eventField>InvalidCounter</eventField>
</eventTarget>
<eventGreaterThan/>
<eventReports>
<eventReport>
<eventField>InvalidMergesCounter</eventField>
</eventReport>
</eventReports>
</event>
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<event eventID="2">
<name>ManyTotalInvalids</name>
<synopsis>An event that specifies if there are too many
invalids</synopsis>
<eventTarget>
<eventField>InvalidTotalCounter</eventField>
</eventTarget>
<eventGreaterThan/>
<eventReports>
<eventReport>
<eventField>InvalidTotalCounter</eventField>
</eventReport>
</eventReports>
</event>
</events>
</LFBClassDef>
<LFBClassDef LFBClassID="65539">
<name>Ext-CoreParallelization</name>
<synopsis>A core LFB that specifies that the FE supports
parallelization, instead of updating the FEObject
LFB</synopsis>
<version>1.0</version>
<capabilities>
<capability componentID="10">
<name>ParallelLFBs</name>
<synopsis>A table which lists all the LFBs that can be
parallelized</synopsis>
<array>
<typeRef>ParallelLFBType</typeRef>
</array>
</capability>
</capabilities>
</LFBClassDef>
</LFBClassDefs>
</LFBLibrary>
Figure 6: Parallel LFB library
6. Acknowledgments
The authors would like to thank Edward Crabbe for the initial
discussion that led to the creation of this document and Jamal Hadi
Salim and Dave Hood for comments and discussions that made this
document better. Additionally Adrian Farrel for his AD review.
Finally Francis Dupont for his Gen-Art review and Magnus Nystroem for
his security review which refined this document to its final shape.
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7. IANA Considerations
7.1. LFB Class Names and LFB Class Identifiers
LFB classes defined by this document do not belong to LFBs defined by
Standards Track RFCs in the http://www.iana.org/assignments/forces
registry. As such the values defined in this document are in the
above 65535 value range.
This specification includes the following LFB class names and LFB
class identifiers:
+----------+--------------------+--------+---------------+----------+
| LFB | LFB Class Name | LFB Ve | Description | Referenc |
| Class Id | | rsion | | e |
| entifier | | | | |
+----------+--------------------+--------+---------------+----------+
| 65537 | Ext-Splitter | 1.0 | A splitter | This |
| | | | LFB will | document |
| | | | either send | |
| | | | the same | |
| | | | packet or | |
| | | | chunks of one | |
| | | | packet to | |
| | | | multiple | |
| | | | LFBs. | |
| | | | | |
| 65538 | Ext-Merger | 1.0 | A merger LFB | This |
| | | | receives | document |
| | | | multiple | |
| | | | packets or | |
| | | | multiple | |
| | | | chunks of the | |
| | | | same packet | |
| | | | and merge | |
| | | | them into | |
| | | | one. | |
| | | | | |
| 65539 | Ext-CoreParalleliz | 1.0 | A core LFB to | This |
| | ation | | signify the p | document |
| | | | arallelizatio | |
| | | | n capability | |
+----------+--------------------+--------+---------------+----------+
Logical Functional Block (LFB) Class Names and Class Identifiers
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7.2. Metadata ID
The Metadata ID namespace is 32 bits long. Values assigned by this
specification are:
+------------+---------------------+---------------+
| Value | Name | Definition |
+------------+---------------------+---------------+
| 0x00000010 | ParallelMetadataSet | This document |
+------------+---------------------+---------------+
Metadata ID assigned by this specification
8. Security Considerations
This document does not alter either the ForCES model [RFC5812] or the
ForCES protocol [RFC5810] and as such has no impact on their security
considerations. This document simply defines the operational
parameters and capabilities of LFBs that perform parallelization and
not how parallelization is implemented. Finally, this document does
not attempt to analyze the presence or possibility of security
interactions created by allowing parallel operations on packets. Any
such issues, if they exist, are for the designers of the particular
data path, not the general mechanism.
9. References
9.1. Normative References
[I-D.ietf-forces-model-extension]
Haleplidis, E., "ForCES Model Extension", draft-ietf-
forces-model-extension-05 (work in progress), September
2014.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC5810] Doria, A., Hadi Salim, J., Haas, R., Khosravi, H., Wang,
W., Dong, L., Gopal, R., and J. Halpern, "Forwarding and
Control Element Separation (ForCES) Protocol
Specification", RFC 5810, March 2010.
[RFC5812] Halpern, J. and J. Hadi Salim, "Forwarding and Control
Element Separation (ForCES) Forwarding Element Model", RFC
5812, March 2010.
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[RFC6956] Wang, W., Haleplidis, E., Ogawa, K., Li, C., and J.
Halpern, "Forwarding and Control Element Separation
(ForCES) Logical Function Block (LFB) Library", RFC 6956,
June 2013.
9.2. Informative References
[Cilk] MIT, "Cilk language",
<http://supertech.csail.mit.edu/cilk/>.
Authors' Addresses
Evangelos Haleplidis
University of Patras
Department of Electrical and Computer Engineering
Patras 26500
Greece
Email: ehalep@ece.upatras.gr
Joel Halpern
Ericsson
P.O. Box 6049
Leesburg VA 20178
USA
Phone: +1 703 371 3043
Email: joel.halpern@ericsson.com
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