| 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
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.
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.
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 publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License.
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.
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].
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:
This document also introduces the following terms:
This document addresses the following two types of packet parallelization:
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:
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.
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.
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] 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:
<!-- 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>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
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:
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.
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 |
One data type has been defined in this library.
| DataType Name | Type | Synopsis |
|---|---|---|
| ParallelTypes | Atomic uchar. Special Values Flood (0), Split (1). | The type of parallelization this packet will go through |
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. |
| 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. |
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
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 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:
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.
This LFB has only one capability specified, the MinMaxChunkSize a struct of two uint32 to specify the minimum and maximum chunk size.
This LFB has no events specified.
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.
+-------------+
MergerIn | |
--------->| | MergerOut
| Merger LFB |----------->
InvalidIn | |
--------->| |
+-------------+
Figure 5: Merger LFB
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.
This LFB has the following components specified:
This LFB has no capabilities specified.
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
A core LFB that specifies that the FE supports parallelization, instead of updating the FEObject LFB
The CoreParallelization does not handle data.
This LFB has no components specified.
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:
This LFB specifies no events
<?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>
<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
</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>
</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>
<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>
<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
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>
<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
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 Nyström for his security review which refined this document to its final shape.
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 Class Identifier | LFB Class Name | LFB Version | Description | Reference |
|---|---|---|---|---|
| 65537 | Ext-Splitter | 1.0 | A splitter LFB will either send the same packet or chunks of one packet to multiple LFBs. | This document |
| 65538 | Ext-Merger | 1.0 | A merger LFB receives multiple packets or multiple chunks of the same packet and merge them into one. | This document |
| 65539 | Ext-CoreParallelization | 1.0 | A core LFB to signify the parallelization capability | This document |
The Metadata ID namespace is 32 bits long. Values assigned by this specification are:
| Value | Name | Definition |
|---|---|---|
| 0x00000010 | ParallelMetadataSet | This document |
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.
| [I-D.ietf-forces-model-extension] | Haleplidis, E., "ForCES Model Extension", Internet-Draft draft-ietf-forces-model-extension-05, 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. |
| [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. |
| [Cilk] | MIT, "Cilk language", . |