Internet DRAFT - draft-haleplidis-forces-packet-parallelization
draft-haleplidis-forces-packet-parallelization
Internet Engineering Task Force E. Haleplidis
Internet-Draft University of Patras
Intended status: Standards Track J. Halpern
Expires: May 20, 2014 Ericsson
November 16, 2013
ForCES Packet Parallelization
draft-haleplidis-forces-packet-parallelization-04
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, so that control elements (CEs) can control the
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 May 20, 2014.
Copyright Notice
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Copyright (c) 2013 IETF Trust and the persons identified as the
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Table of Contents
1. Terminology and Conventions . . . . . . . . . . . . . . . . . 2
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
1.2. Definitions . . . . . . . . . . . . . . . . . . . . . . . 3
2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Packet Parallelization . . . . . . . . . . . . . . . . . . . 4
4. Parallel Base Types . . . . . . . . . . . . . . . . . . . . . 9
4.1. Frame Types . . . . . . . . . . . . . . . . . . . . . . . 9
4.2. Data Types . . . . . . . . . . . . . . . . . . . . . . . 9
4.3. MetaData Types . . . . . . . . . . . . . . . . . . . . . 10
5. Parallel LFBs . . . . . . . . . . . . . . . . . . . . . . . . 10
5.1. Splitter . . . . . . . . . . . . . . . . . . . . . . . . 10
5.1.1. Data Handling . . . . . . . . . . . . . . . . . . . . 10
5.1.2. Components . . . . . . . . . . . . . . . . . . . . . 11
5.1.3. Capabilities . . . . . . . . . . . . . . . . . . . . 11
5.1.4. Events . . . . . . . . . . . . . . . . . . . . . . . 11
5.2. Merger . . . . . . . . . . . . . . . . . . . . . . . . . 11
5.2.1. Data Handling . . . . . . . . . . . . . . . . . . . . 11
5.2.2. Components . . . . . . . . . . . . . . . . . . . . . 12
5.2.3. Capabilities . . . . . . . . . . . . . . . . . . . . 13
5.2.4. Events . . . . . . . . . . . . . . . . . . . . . . . 13
6. XML for Parallel LFB library . . . . . . . . . . . . . . . . 13
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 19
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 20
8.1. LFB Class Names and LFB Class Identifiers . . . . . . . . 20
8.2. Metadata ID . . . . . . . . . . . . . . . . . . . . . . . 20
9. Security Considerations . . . . . . . . . . . . . . . . . . . 21
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 21
10.1. Normative References . . . . . . . . . . . . . . . . . . 21
10.2. Informative References . . . . . . . . . . . . . . . . . 21
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 21
1. Terminology and Conventions
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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]. The required definitions are repeated below for clarity.
FE Model - The FE model is designed to model the logical
processing functions of an FE. The FE model proposed in this
document includes three components; the LFB modeling of individual
Logical Functional Block (LFB model), the logical interconnection
between LFBs (LFB topology), and the FE-level attributes,
including FE capabilities. The FE model provides the basis to
define the information elements exchanged between the CE and the
FE in the ForCES protocol [RFC5810].
LFB (Logical Functional Block) Class (or type) - A template that
represents a fine-grained, logically separable aspect of FE
processing. Most LFBs relate to packet processing in the data
path. LFB classes are the basic building blocks of the FE model.
LFB Instance - As a packet flows through an FE along a data path,
it flows through one or multiple LFB instances, where each LFB is
an instance of a specific LFB class. Multiple instances of the
same LFB class can be present in an FE's data path. Note that we
often refer to LFBs without distinguishing between an LFB class
and LFB instance when we believe the implied reference is obvious
for the given context.
LFB Model - The LFB model describes the content and structures in
an LFB, plus the associated data definition. XML is used to
provide a formal definition of the necessary structures for the
modeling. Four types of information are defined in the LFB model.
The core part of the LFB model is the LFB class definitions; the
other three types of information define constructs associated with
and used by the class definition. These are reusable data types,
supported frame (packet) formats, and metadata.
Element - Element is generally used in this document in accordance
with the XML usage of the term. It refers to an XML tagged part
of an XML document. For a precise definition, please see the full
set of XML specifications from the W3C. This term is included in
this list for completeness because the ForCES formal model uses
XML.
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Attribute - Attribute is used in the ForCES formal modeling in
accordance with standard XML usage of the term, i.e., to provide
attribute information included in an XML tag.
LFB Metadata - Metadata is used to communicate per-packet state
from one LFB to another, but is not sent across the network. The
FE model defines how such metadata is identified, produced, and
consumed by the LFBs, but not how the per-packet state is
implemented within actual hardware. Metadata is sent between the
FE and the CE on redirect packets.
ForCES Component - A ForCES Component is a well-defined, uniquely
identifiable and addressable ForCES model building block. A
component has a 32-bit ID, name, type, and an optional synopsis
description. These are often referred to simply as components.
LFB Component - An LFB component is a ForCES component that
defines the Operational parameters of the LFBs that must be
visible to the CEs.
LFB Class Library - The LFB class library is a set of LFB classes
that has been identified as the most common functions found in
most FEs and hence should be defined first by the ForCES Working
Group.
2. Introduction
A lot of network devices can process packets in a parallel manner.
The 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 modelling concept has been influenced by Cilc [Cilc]. Cilc 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 Cilc concepts used in this document is
spawn and sync. Spawn being the place where parallel work can start
and sync being the place where the parallel work finishes and must
collect all parallel output.
3. 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 depended and is loosely defined here.
An implementor 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
implementor has to take into account the device's characteristics to
decide which approach fits bets to the hardware.
Additionally in the split parallel type, while harder, the
implementor 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.
This document introduces two LFBs that are used in before and after
the parallelization occurs:
1. Splitter - similar to Cilc's spawn. An LFB that will split the
path of a packet and be sent to multiple LFBs to be processed in
parallel.
2. Merger - similar to Cilc's sync. An LFB that will receive
packets or chunks of the same initial packet and merge them into
one.
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 an 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.
+------------+
+---->| Regex LFB |----+
+----------+ | +------------+ | +----------+
| |---+ +------>| |
| | +------------+ | |
--->| Splitter |-------->| Regex LFB |----------->| Merger |--->
| LFB | +------------+ | LFB |
| |---+ +------>| |
+----------+ | +------------+ | +----------+
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+---->| Regex LFB |----+
+------------+
Figure 1: Simple split parallel processing
+----------+ +------------+ +-------+ +----------+
| | | Classifier | | Meter | | |
| |--->| LFB |--->| LFB |--->| |
--->| Splitter | +------------+ +-------+ | Merger |--->
| LFB | | LFB |
| | +------------+ | |
| |--------->| IPv4 TTL |---------->| |
+----------+ | Decrement | +----------+
| LFB |
+------------+
Figure 2: Simple flood parallel processing
This version of the modelling 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 the time. This led to a more simple metadata definition
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.
One important element to a developer is the ability to define which
LFBs can be used in a parallel mode, with which other LFBs can they
be parallelized with and the order of the LFBs can be assembled.
This information must be accessible in the core LFBs and therefore
this document needs to append one more capability in the FEObject
LFB. The topology of the parallel datapath can be deferred and
manipulated from the FEObject LFB's LFBTopology.
The FEObject LFB currently specifies the LFBtopology and supported
LFBs in an FE. In order to support parallelization the following
component is needed 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.
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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>
<typeRef>string</typeRef>
</component>
<component componentID="4">
<name>LFBParallelOccurenceLimit</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>
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<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 Definition for FEObjectLFB extension
While the ForCES model cannot describe how the splitting or the
merging is actually done as that is an implementation issue of the
actual LFB, however this document defines operational parameters to
control 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. Additionally this document defines metadata, which contain
necessary information to assist the merging procedure. The following
metadata set as a struct is defined:
1. ParallelType - Flood or split
2. Correlator - Identify packets or chunks that belonged to the
initial packet that entered the Splitter LFB
3. ParallelNum - Number of packet or chunk for specific Correlator.
4. ParralelPartsCount - Total number of packets or chunks for
specific Correlator.
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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 case of a packet/chunk being branded invalid by an LFB in a
parallel path, it MUST be sent by an output port of said LFB
An LFB inside a parallel path decides that a packet or a chunk has to
be dropped it MAY drop it 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.
4. Parallel Base Types
4.1. Frame Types
One frame type has been defined in this library.
+-----------------+-------------------------------------------------+
| Frame Type Name | Synopsis |
+-----------------+-------------------------------------------------+
| Chunk | A chunk is a frame that is part of an original |
| | larger frame |
+-----------------+-------------------------------------------------+
Parallel Frame Types
4.2. Data Types
One data type has been defined in this library.
+-----------------+-------------------+-----------------------------+
| DataType Name | Type | Synopsis |
+-----------------+-------------------+-----------------------------+
| ParallelTypes | Atomic uchar. | The type of parallelization |
| | Special Values | this packet will go through |
| | Flood (0), Split | |
| | (1). | |
+-----------------+-------------------+-----------------------------+
Parallel Data Types
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4.3. 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:
+----------------------+--------+-----+-----------------------------+
| Metadata Name | Type | ID | Synopsis |
+----------------------+--------+-----+-----------------------------+
| ParallelType | uchar | 1 | The type of parallelization |
| | | | this packet will go |
| | | | through. 0 for flood, 1 for |
| | | | split. |
| | | | |
| Correlator | uint32 | 2 | An identification number to |
| | | | specify that packets or |
| | | | chunks belong to the same |
| | | | parallel work. |
| | | | |
| ParallelNum | uint32 | 3 | Defines the number of the |
| | | | specific packet or chunk of |
| | | | the specific parallel ID. |
| | | | |
| ParallelPartsCount | uint32 | 4 | Defines the total number of |
| | | | packets or chunks for the |
| | | | specific parallel ID. |
+----------------------+--------+-----+-----------------------------+
Metadata Structure for Merging
5. Parallel LFBs
5.1. Splitter
A splitter LFB takes part in parallelizing the processing datapath by
sending either the same packet or chunks of the same packet to
multiple LFBs.
5.1.1. 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 ParallelOut'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. All chunks will
be sent out in a round-robin fashion through the group output
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ParallelOut's instances. Each packet or chunk will be accompanied by
the following metadata set as a struct :
o ParallelType - The paralleltype split or flood.
o Parallel ID - generated by the splitter LFB to identify that
chunks or packets belong to the same parallel work.
o Parallel Num - 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 parallel id.
5.1.2. Components
This LFB has only two components specified. 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 maximum size of a chunk when a packet is split into
multiple same size chunks.
5.1.3. Capabilities
This LFB has only one capability specified, the MinMaxChunkSize a
struct of a uint32 to specify the minimum chunk size and a uint32 to
specify the maximum chunk size.
5.1.4. Events
This LFB has no events specified.
5.2. Merger
A merger LFB receives multiple packets or multiple chunks of the same
packet and merge them into one merged packet.
5.2.1. Data Handling
The Merger LFB receives either a packet or a chunk via the group
input ParallelIn, along with the ParallelType metadata to identify
whether what was received was a packet or a chunk, the Correlator,
the ParallelNum and the ParallelPartsCount.
In case that an LFB has dropped a packet or a chunk within a parallel
path the merger LFB MAY receive only the metadata or both metadata
and packet or chunk through the InvalidIn group input port. It
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SHOULD receive a metadata specifying the error code. Current defined
metadata's in the Base LFB Library [RFC6956] are the ExceptionID and
the ValidateErrorID. The Merger LFB MAY store the parallel metadata
along with the exception metadata as a string in the optional
InvalideMetadataSets as a means for the CE to debug errors in the
parallel path.
If the MergeWaitType is set to false the Merger LFB will initiate the
merge process upon receiving the first packet. If false it will wait
for all packet in the Correlator to arrive.
If one packet or chunk has been received through the InvalidIn port
then the merging procedure will be operate as configured by the
InvalidAction component. 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
finished the resulting packet will be sent via the singleton output
port PacketOutput.
If the Merger LFB receives different values for the same metadata
from different packets or chunks that has the same correlator then
the Merger LFB will use the first metadata from a packet or chunk
that entered the LFB through the ParallelIn input port.
5.2.2. 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. MergeWaitType - a boolean. If true the Merger LFB will wait for
all packets or chunks to be received prior to sending out a
response. If false, when one packet or a chunk with a response
is received by the merge LFB it will start with the merge
process.
3. 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.
4. InvalidAllCounter - a uint 32 that counts the number of merges
where all packets/chunks entered the merger LFB through the
InvalidIn input port.
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5. 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.
6. InvalideMetadataSets - an array of strings. An optional
component that stores metadata sets along with the error id as a
string. This could provide a debug information to the CE
regarding errors in the parallel paths.
5.2.3. Capabilities
This LFB has no capabilities specified.
5.2.4. 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.
6. XML for Parallel LFB library
<?xml version="1.0" encoding="UTF-8"?>
<LFBLibrary xmlns="urn:ietf:params:xml:ns:forces:lfbmodel:1.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="urn:ietf:params:xml:ns:forces:lfbmodel:1.0"
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
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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>
</dataTypeDefs>
<metadataDefs>
<metadataDef>
<name>ParallelMetadataSet</name>
<synopsis>A metadata Set for parallelization related LFBs
</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>Correlator</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="18">
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<name>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>PacketIn</name>
<synopsis>An input port expecting any kind of frame
</synopsis>
<expectation>
<frameExpected>
<ref>Arbitrary</ref>
</frameExpected>
</expectation>
</inputPort>
</inputPorts>
<outputPorts>
<outputPort group="true">
<name>ParallelOut</name>
<synopsis>An 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>
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<capabilities>
<capability componentID="31">
<name>MinMaxChunkSize</name>
<synopsis>The minimum and maximum size of a chunk
capable of splitted 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>
<typeRef>uint32</typeRef>
</component>
</struct>
</capability>
</capabilities>
</LFBClassDef>
<LFBClassDef LFBClassID="19">
<name>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>ParallelIn</name>
<synopsis>An 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>
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<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>
<name>PacketOutput</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
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packets or chunks to be received prior to sending
out a response</synopsis>
<typeRef>boolean</typeRef>
</component>
<component componentID="3" 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
through the InvalidIn input port</synopsis>
<typeRef>uint32</typeRef>
</component>
<component componentID="4" access="read-reset">
<name>InvalidAllCounter</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="5" 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>
<component componentID="6" access="read-reset">
<name>InvalideMetadataSets</name>
<synopsis>Buffers metadata sets along with the error id
as a string.</synopsis>
<optional/>
<array>
<typeRef>string</typeRef>
</array>
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</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></eventGreaterThan>
<eventReports>
<eventReport>
<eventField>InvalidMergesCounter</eventField>
</eventReport>
</eventReports>
</event>
<event eventID="2">
<name>ManyAllInvalids</name>
<synopsis>An event that specifies if there are too many
invalids</synopsis>
<eventTarget>
<eventField>InvalidCounter</eventField>
</eventTarget>
<eventGreaterThan></eventGreaterThan>
<eventReports>
<eventReport>
<eventField>InvalidAllCounter</eventField>
</eventReport>
</eventReports>
</event>
</events>
</LFBClassDef>
</LFBClassDefs>
</LFBLibrary>
Figure 4: Parallel LFB library
7. Acknowledgements
The authors would like to thank Jamal Hadi Salim and Dave Hood for
comments and discussions that made this document better.
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8. IANA Considerations
8.1. LFB Class Names and LFB Class Identifiers
LFB classes defined by this document belong to LFBs defined by
Standards Track RFCs. According to IANA, the registration procedure
is Standards Action for the range 0 to 65535 and First Come First
Served with any publicly available specification for over 65535.
This specification includes the following LFB class names and LFB
class identifiers:
+--------------+----------+---------+-------------------+-----------+
| LFB Class | LFB | LFB | Description | Reference |
| Identifier | Class | Version | | |
| | Name | | | |
+--------------+----------+---------+-------------------+-----------+
| 18 | Splitter | 1.0 | A splitter LFB | This |
| | | | will either send | document |
| | | | the same packet | |
| | | | or chunks of one | |
| | | | packet to | |
| | | | multiple LFBs. | |
| | | | | |
| 19 | Merger | 1.0 | A merger LFB | This |
| | | | receives multiple | document |
| | | | packets or | |
| | | | multiple chunks | |
| | | | of the same | |
| | | | packet and merge | |
| | | | them into one. | |
+--------------+----------+---------+-------------------+-----------+
Logical Functional Block (LFB) Class Names and Class Identifiers
8.2. Metadata ID
The Metadata ID namespace is 32 bits long. Values assigned by this
specification:
+------------+---------------------+---------------+
| Value | Name | Definition |
+------------+---------------------+---------------+
| 0x00000010 | ParallelMetadataSet | This document |
+------------+---------------------+---------------+
Metadata ID assigned by this specification
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9. Security Considerations
10. References
10.1. Normative References
[I-D.ietf-forces-model-extension]
Haleplidis, E., "ForCES Model Extension", draft-ietf-
forces-model-extension-00 (work in progress), September
2013.
[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.
[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.
10.2. Informative References
[Cilc] MIT, "Cilk language", ,
<http://supertech.csail.mit.edu/cilk/>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
Authors' Addresses
Evangelos Haleplidis
University of Patras
Department of Electrical and Computer Engineering
Patras 26500
Greece
Email: ehalep@ece.upatras.gr
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Joel Halpern
Ericsson
P.O. Box 6049
Leesburg 20178
VA
Phone: +1 703 371 3043
Email: joel.halpern@ericsson.com
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