Internet Engineering Task Force W. Wang
Internet-Draft Zhejiang Gongshang University
Intended status: Informational E. Haleplidis
Expires: September 4, 2010 University of Patras
K. Ogawa
NTT Corporation
F. Jia
National Digital Switching
Center(NDSC)
J. Halpern
Ericsson
March 3, 2010
ForCES LFB Library
draft-ietf-forces-lfb-lib-01
Abstract
The forwarding and Control Element Separation (ForCES) protocol
defines a standard communication and control mechanism through which
a Control Element (CE) can control the behavior of a Forwarding
Element (FE). That control is accomplished through manipulating
components of Logical Function Blocks (LFBs), whose structure is
defined in a model RFC produced by the working group.In order to
build an actual solution using this protocol, there needs to be a set
of Logical Function Block definitions that can be instantiated by FEs
and controlled by CEs. This document provides a sample space of such
definitions. It is anticipated that additional defining documents
will be produced over time.
Status of this Memo
This Internet-Draft is submitted to IETF in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet-
Drafts.
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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."
The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt.
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The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html.
This Internet-Draft will expire on September 4, 2010.
Copyright Notice
Copyright (c) 2010 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
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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 BSD License.
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Table of Contents
1. Terminology and Conventions . . . . . . . . . . . . . . . . . 4
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 4
2. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . 5
3. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 7
4. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
5. Base Types . . . . . . . . . . . . . . . . . . . . . . . . . . 11
5.1. Data Types . . . . . . . . . . . . . . . . . . . . . . . . 11
5.2. Frame Types . . . . . . . . . . . . . . . . . . . . . . . 13
5.3. MetaData Types . . . . . . . . . . . . . . . . . . . . . . 14
5.4. XML Definition for Base Type Library . . . . . . . . . . . 15
6. LFB Classes Description . . . . . . . . . . . . . . . . . . . 39
6.1. Core LFBs . . . . . . . . . . . . . . . . . . . . . . . . 39
6.1.1. FE Protocol LFB . . . . . . . . . . . . . . . . . . . 39
6.1.2. FE Object LFB . . . . . . . . . . . . . . . . . . . . 39
6.2. Port LFBs . . . . . . . . . . . . . . . . . . . . . . . . 40
6.2.1. Generic Connectivity LFB . . . . . . . . . . . . . . . 40
6.2.2. Ethernet Port LFBs . . . . . . . . . . . . . . . . . . 41
6.2.3. POS Port LFBs . . . . . . . . . . . . . . . . . . . . 41
6.2.4. ATM Port LFBs . . . . . . . . . . . . . . . . . . . . 41
6.3. Address Resolution LFBs . . . . . . . . . . . . . . . . . 41
6.4. ICMP LFBs . . . . . . . . . . . . . . . . . . . . . . . . 42
6.5. IP Packet Validation LFBs . . . . . . . . . . . . . . . . 42
6.6. Classifier LFBs . . . . . . . . . . . . . . . . . . . . . 42
6.7. Forwarding LFBs . . . . . . . . . . . . . . . . . . . . . 43
6.7.1. Unicast Longest Prefix Match LFBs . . . . . . . . . . 43
6.7.2. Nexthop Applicator LFBs . . . . . . . . . . . . . . . 43
6.8. QoS Control LFBs . . . . . . . . . . . . . . . . . . . . . 43
6.8.1. Scheduler LFBs . . . . . . . . . . . . . . . . . . . . 44
6.8.2. Queue LFBs . . . . . . . . . . . . . . . . . . . . . . 45
6.9. Miscellaneous Packet Manipulation LFBs . . . . . . . . . . 45
6.10. Redirect LFB . . . . . . . . . . . . . . . . . . . . . . . 45
7. XML Definition for Base LFB Library . . . . . . . . . . . . . 46
8. Base LFB Library Use Case for Typical Router Functions . . . . 75
8.1. IP Forwardings . . . . . . . . . . . . . . . . . . . . . . 75
8.2. Address Resolution . . . . . . . . . . . . . . . . . . . . 76
8.3. ICMP . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
8.4. Running Routing Protocol . . . . . . . . . . . . . . . . . 76
8.5. Network Management . . . . . . . . . . . . . . . . . . . . 76
9. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 77
10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 78
11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 79
12. Security Considerations . . . . . . . . . . . . . . . . . . . 80
13. References . . . . . . . . . . . . . . . . . . . . . . . . . . 81
13.1. Normative References . . . . . . . . . . . . . . . . . . . 81
13.2. Informative References . . . . . . . . . . . . . . . . . . 81
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 82
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1. Terminology and Conventions
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].
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2. Definitions
This document follows the terminology defined by the ForCES
Requirements in [RFC3654]and by the ForCES framework in [RFC3746].
The definitions below are repeated below for clarity.
Control Element (CE) - A logical entity that implements the ForCES
protocol and uses it to instruct one or more FEs on how to process
packets. CEs handle functionality such as the execution of
control and signaling protocols.
Forwarding Element (FE) - A logical entity that implements the
ForCES protocol. FEs use the underlying hardware to provide per-
packet processing and handling as directed/controlled by one or
more CEs via the ForCES protocol.
ForCES Network Element (NE) - An entity composed of one or more
CEs and one or more FEs. To entities outside an NE, the NE
represents a single point of management. Similarly, an NE usually
hides its internal organization from external entities.
LFB (Logical Function Block) - The basic building block that is
operated on by the ForCES protocol. The LFB is a well defined,
logically separable functional block that resides in an FE and is
controlled by the CE via ForCES protocol. The LFB may reside at
the FE's datapath and process packets or may be purely an FE
control or configuration entity that is operated on by the CE.
Note that the LFB is a functionally accurate abstraction of the
FE's processing capabilities, but not a hardware-accurate
representation of the FE implementation.
FE Topology - A representation of how the multiple FEs within a
single NE are interconnected. Sometimes this is called inter-FE
topology, to be distinguished from intra-FE topology (i.e., LFB
topology).
LFB Class and LFB Instance - LFBs are categorized by LFB Classes.
An LFB Instance represents an LFB Class (or Type) existence.
There may be multiple instances of the same LFB Class (or Type) in
an FE. An LFB Class is represented by an LFB Class ID, and an LFB
Instance is represented by an LFB Instance ID. As a result, an
LFB Class ID associated with an LFB Instance ID uniquely specifies
an LFB existence.
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. It defines the functionality but not how
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metadata is encoded within an implementation.
LFB Component - Operational parameters of the LFBs that must be
visible to the CEs are conceptualized in the FE model as the LFB
components. The LFB components include, for example, flags,
single parameter arguments, complex arguments, and tables that the
CE can read and/or write via the ForCES protocol (see below).
LFB Topology - Representation of how the LFB instances are
logically interconnected and placed along the datapath within one
FE. Sometimes it is also called intra-FE topology, to be
distinguished from inter-FE topology.
ForCES Protocol - While there may be multiple protocols used
within the overall ForCES architecture, the term "ForCES protocol"
and "protocol" refer to the Fp reference points in the ForCES
Framework in [RFC3746]. This protocol does not apply to CE-to-CE
communication, FE-to-FE communication, or to communication between
FE and CE managers. Basically, the ForCES protocol works in a
master- slave mode in which FEs are slaves and CEs are masters.
This document defines the specifications for this ForCES protocol.
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3. Introduction
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). [RFC3654]has defined
the ForCES requirements, and [RFC3746] has defined the ForCES
framework.
The ForCES protocol Protocol FE-protocol FE-protocol
[I-D.ietf-forces-protocol] defines a protocol for communications
between Control Elements (CEs) Forwarding Elements (FEs) and for
Control Elements to manipulate resources in Forwarding Elements.
Resources in Forwarding Elements are described by classes of Logical
Function Blocks (LFBs). The FE model documentFE-MODEL
[I-D.ietf-forces-model]. specifies the structure and abstract
semantics of LFBs, and provides XML schema for the definitions of
LFBs.
This document comforts to the specifications of the FE modelFE-MODEL
[I-D.ietf-forces-model] and specifies definitions of classes of LFBs
which can be combined to provide functions of a typical router. It
basically provides functions to implement IP forwarding. More
definitions of LFB classes with more functions may be developed in
future time and documented by IETF, and users may also develop
individual LFB classes for purposes of their specific functions
according to the FE modelFE-MODEL [I-D.ietf-forces-model].
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4. Overview
The LFB classes described in this document are designed to provide
the functions of a typical router [RFC1812] . They are expected to
provide functions for a typical router to:
o Interface to packet networks and implement the functions required
by that network. These functions typically include:
* Encapsulating and decapsulating the IP datagrams with the
connected network framing (e.g., an Ethernet header and
checksum),
* Sending and receiving IP datagrams up to the maximum size
supported by that network, this size is the network's Maximum
Transmission Unit or MTU,
* Translating the IP destination address into an appropriate
network-level address for the connected network (e.g., an
Ethernet hardware address), if needed, and.
* Responding to network flow control and error indications, if
any.
o Conform to specific Internet protocols including the Internet
Protocol (IPv4 and/or IPv6), Internet Control Message Protocol
(ICMP), and others as necessary.
o Receive and forwards Internet datagrams. Important issues in this
process are buffer management, congestion control, and fairness.
* Recognizes error conditions and generates ICMP error and
information messages as required.
* Drops datagrams whose time-to-live fields have reached zero.
* Fragments datagrams when necessary to fit into the MTU of the
next network.
o Choose a next-hop destination for each IP datagram, based on the
information in its routing database.
o Usually support an interior gateway protocol (IGP) to carry out
distributed routing and reachability algorithms with the other
routers in the same autonomous system. In addition, some routers
will need to support an exterior gateway protocol (EGP) to
exchange topological information with other autonomous systems.
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o Provide network management and system support facilities,
including loading, debugging, status reporting, exception
reporting and control.
According to ForCES architecture, all above typical router functions
should be implemented upon the concept of Logical Functional Blocks
(LFBs). It is critical to classify above functional requirements
into various classes of LFBs and construct a typical but also
flexible enough base LFB library for various IP forwarding
equipments. In the process, some principles may be applied:
o if a function can be designed by either one LFB or two or more
LFBs with the same cost, it will be designed by two or more LFBs
so as to provide more flexibility for implementers.
o when flexibility is not required, an LFB should take advantage of
its as much as possible independence and leave least couples with
other LFBs. The couples may be from LFB attributes definitions as
well as physical implementations.
o unless there is a difference in actual functionality, it should
not represent the same thing in two different fashions. Or else,
it may add extra burden on implementation.
The document intends to meet the above typical router function
requirements by defining groups of LFB classes like Core LFBs,Port
LFBs,etc.
For every group of LFB classes, a set of LFBs are defined for
individual function purposes. Section 6(LFB Descriptions Section)
describes individual LFBs in every group of LFBs in details.
Based on the classes of LFBs, the typical organization of the
processing path and their interconnections can be established by the
CE using the ForCES protocol, so as to achieve typical router
functions. Taking a typical forwarding function as an example, Port
LFBs receive packets and decapsulate the IP datagrams to form IP
level packets. Different port media have different manipulating
requirements from CE, therefore various port LFBs for various media
may have to be defined. IP packets from port LFBs are then validated
before being further forwarded. A kind of valildation LFBs like IPv4
validator and/or IPv6 valildator are applied for the purpose. After
validation, some packets for control purpose will be specifically
processed, like ARP packets will be processed by an Address
resolution LFB and ICMP packets by an ICMP LFB. To separate the
control packets, a metadata classifier LFB is applied in the process.
After validation process, Forwarding LFBs can then be applied. In
the Forwarding LFBs, a Longest Prefix Match LFB is used to look up
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the destination information in a packet, and select the next hop
index to be used for sending the packet onward. A next hop
applicator LFB uses the next hop index metadata to apply the proper
headers to the IP packets, and direct them to the proper egress.
Section 8 provides more detailed descriptions on how various typical
router functions are implemented based on the defined base LFB
classes.
To define various LFB classes, a set of base type definitions with
the data types, packet frame types, and metadata types have to be
specified in advance. Section 5 (Base Types Section) provide a
description on the base types used by this LFB library. In order to
provide an extensive use of these base types for other LFB
definitions, the base type definitions are provided by a specific xml
file as a base type library which is separate from the LFB definition
library.
LFB classes are finally defined by XML with specifications and schema
from the ForCES FE modelFE-MODEL [I-D.ietf-forces-model]. Section 6
(LFB Definitions Section) provide the complete XML definitions of the
base LFB classes library.
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5. Base Types
The FE modelFE-MODEL [I-D.ietf-forces-model] has specified the
following data types as predefined (built-in) atomic data-types:
char, uchar, int16, uint16, int32, uint32, int64, uint64, string[N],
string, byte[N], boolean, octetstring[N], float16, float32, float64.
Based on these atomic data types and with the use of type definition
elements in the FE model XML schema, new data types, packet frame
types, and metadata types can further be defined.
To define a base LFB library for typical router functions, a base
data types, frame types, and metadata types MUST be defined. This
section provides a description of these types and a detailed XML
definitions of the base types.
In order for extensive use of the base type definitions for other LFB
definitions than this base LFB library, the base type definitions are
provided with a separate xml library file labeled with
"BaseTypeLibrary". Users can refer to this library by the statement:
5.1. Data Types
The following data types are currently defined and put in the base
type library:
1. ifIndex - A Port Identifier.
2. IEEEMAC - IEEE MAC Address.
3. NetSpeedType - Network speed values.
4. IEEENegotiationType - IEEENegotiation types.
5. PortStatsType - Port statistics.
6. PortStatusValues - The possible values of status Used for both
administrative and operation status.
7. LocalIpAddrType - Local IP address belonging to FE.
8. LocalIpv6AddrType - The device local IPv6 address infomation.
9. IPv4Addr - IPv4 address.
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10. IPv6Addr - IPv6 address.
11. IPv4Prefix - IPv4 prefix defined by an address and a prefix
length.
12. IPv4NextHopInfoType - IPv4 nexthop information,include nexthop
ip address,output FE and interface etc.
13. IPv4FibEntryType - IPv4 forwarding table entry.
14. IPv4PrefixTableEntry - IPv4 prefix table entry.
15. IPv4UcastLPMStatisticsType - Statistics of IPv4UcastLPM LFB.
16. IPv4ValidatorStatisticsType - IPv4 validator LFB statistics
type.
17. IPv6Prefix - IPv6 prefix defined by an address and a prefix
length.
18. IPv6NextHopInfoType - IPv6 next hop information, include next
hop ip address,output FE and interfac eetc.
19. IPv6PrefixTableEntry - IPv6 prefix table entry.
20. IPv6LPMClassiferStatisticsType - Statistics of IPv6 LPM
ClassifierLFB.
21. IPv6ValidatorStatisticsType - IPv6 validator LFB statistics
type.
22. NextHopFlagsType - Flags used to define different next hop
behaviors.
23. WeightTableEntryType - Weight table for queues.
24. NbrState - IPv6 neighbour entry resolution state.
25. ArpTableEntryType - Arp Entry.
26. NbrTableEntryType - IPv6 neighbour table entry.
27. DCHostTableEntryTypev4 - Direct connected ARP table entry for
IPv4.
28. DCHostTableEntryTypev6 - Direct connected ARP table entry for
IPv6.
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29. IPPacketType - The packet type code.
30. IPDispatchTableType - The dispatch table type.
31. MetaType - Metadata type definition.
32. MetadataClassTableType - The meta data classifying table.
33. LinkEncapType - Encapsulation type.
34. IPAddress - IP layer address.
35. ArpStateType - The arp entry state.
36. MatchTargetType - Indicator for the kind of field to be matched
by this entry in a classifier.
37. MatchTargetIdentifier - Identify the specific target of a match
condition.
38. MatchBitString - A bit string for use in a match condition.
39. MatchCondition - Structure for a single condition to be applied.
40. MatchConditiontType - Indicator for the kind of match condition
to be applied.
41. MatchMetaDataAction - An action to set a metadata item to either
a specific value or a field from the incoming meta data or
packet.
42. NextHopIndex - An index used by the next hop table Typically
stored in and generated as metadata by the longest-prefix-match
LFB.
5.2. Frame Types
According to FE modelFE-MODEL [I-D.ietf-forces-model], frame types
are used in LFB definitions to define the types of frames the LFB
expects at its input port(s) and emits at its output port(s). The
element in the FE model is used to define a new frame
type.
The following frame types are currently defined and put in the base
type library as base frame types for the LFB library:
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1. EthernetII - An Ethernet II frame type.
2. Ethernet802.3 - An Ethernet 802.3 frame type.
3. Ethernet802.2 - An Ethernet 802.2 frame type.
4. Ethernet802.2SNAP - An Ethernet 802.2 with SNAP frame.
5. IPv4Frame - An IPv4 packet.
6. IPv6Frame - An IPv6 packet.
7. TaggedFrame - A frame of any type with associated metadata.
8. MetadataFrame - Frame only contains meta data.
9. Arbitrary - Any kind of frame except Metadata Frame.
5.3. MetaData Types
LFB Metadata is used to communicate per-packet state from one LFB to
another. The element in the FE model is used to define
a new metadata type.
The following metadata types are currently defined and put in the
base type library as base metadata types for the LFB library
definitions:
1. NextHopID - An index into a Next Hop entry in Nexthop table.
2. ExceptionID - Exception Types.
3. IngressPort - At which interface the packet arrive.
4. EgressPort - The interface out which the packet will emmit.
5. NextHopIP - Nexthop IPv4 address.
6. NexthopIPv6 - Nexthop IPv6 address.
7. PacketLength - The length of the packet in octets.
8. IPPacketType - Type of the packet.
9. QueueID - The queue ID.
10. QueueOperationCmd - The type of operation on the queue,there are
two types defined here: enqueue and dequeue.
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11. SrcFEID - Source FE ID.
12. DstFEID - Destination FE ID.
13. NexthopIndex - Next hop index into the link layer address
resolution table.
14. NHEncapMethod - How should the following LFBs do to encapsulate
the packets.
15. ErrorId - Error Type.
5.4. XML Definition for Base Type Library
This library provides base types definitions for LFB library.
EthernetII
an Ethernet II frame type
Ethernet802.3
An Ethernet 802.3 frame type
Ethernet802.2
An Ethernet 802.2 frame type
Ethernet802.2SNAP
An Ethernet 802.2 with SNAP frame
IPv4
An IPv4 packet
IPv6
An IPv6 packet
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MetadataFrame
Frame only contains meta data
Arbitrary
Any kind of frame except Metadata Frame.
IEEEMAC
IEEE mac.
byte[6]
LANSpeedType
LAN speed values
uint32
LAN_SPEED_10M
10M Ethernet
LAN_SPEED_100M
100M Ethernet
LAN_SPEED_1G
1000M Ethernet
LAN_SPEED_10G
10G Ethernet
LAN_SPEED_AUTO
LAN speed auto
NegotiationType
Negotiation types
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uint32
Auto
Auto negotitation.
Half-duplex
port negotitation half duplex
Full-duplex
port negotitation full duplex
PortStatsType
port statistics
InUcastPkts
Number of unicast packets received
uint64
InMulticastPkts
Number of multicast packets received
uint64
InBroadcastPkts
Number of broadcast packets received
uint64
InOctets
number of octets received
uint64
OutUcastPkts
Number of unicast packets transmitted
uint64
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OutMulticastPkts
Number of multicast packets transmitted
uint64
OutBroadcastPkts
Number of broadcast packets transmitted
uint64
OutOcetes
Number of octets transmitted
uint64
InErrorPkts
Number of input error packets
uint64
OutErrorPkts
Number of output error packets
uint64
PortStatusValues
The possible values of status. Used for both
administrative and operation status
uchar
Disabled
the port is operatively disabled.
UP
the port is up.
Down
The port is down.
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IPAddr
IPv4 address
uint32
MacFilterTableEntryType
MAC filter table entry
IEEEMAC
LocalIpAddrType
The device local IP address infomation
FEID
The FE on which the port ip resides
uint32
IfIndex
port index on the specified FE
uint32
IPaddr
IP address of the port
IPAddr
netmask
netmask of this ip address
IPAddr
BcastAddr
The associated Broadcast address of the ip
address
IPAddr
LocalIpv6AddrType
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The device local IPv6 address infomation
FEID
The FE on which the port ip resides
uint32
IfIndex
port index on the specified FE
uint32
IPv6addr
IP address of the port
IPv6Addr
prefixlen
prefix length of this ip address
uint32
IPv4Addr
IPv4 address
uint32
IPv6Addr
IPv6 address
byte[16]
IPv4Prefix
prefix defined by an address and a prefix length
address
Address part
IPv4addr
prefixlen
Prefix length part
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uchar
IPv4NextHopInfoType
IPv4 nexthop information,include nexthop ip address,
output FE and interface etc.
NexthopID
nexthop id
uint32
FEID
output FE id
uint32
OutputPortID
output port index
uint32
MTU
The maximum transmition unit of the nexthop
link.
uint32
Flags
Associated flags of the nexthop,such as local
delivery,multicast etc.
NextHopFlagsType
NexthopIPaddr
IP address of the nexthop
IPv4Addr
L2Index
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index into the L2 link layer table,such as IPv4
ARP table or IPv6 NBR table.
uint32
EncapNeeded
The type of encapsulation needed on the packet.
EncapType
IPv4FibEntryType
IPv4 forwarding table entry.
prefix
IPv4 prefix.
IPv4Prefix
FEID
output FE id
uint32
OutputPortID
output port index
uint32
MTU
The maximum transmition unit of the nexthop link.
uint32
Flags
Associated flags of the nexthop,such as local
delivery,multicast etc.
NextHopFlagsType
NexthopIPaddr
IP address of the nexthop
IPv4Addr
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L2Index
index into the L2 link layer table,such as IPv4
ARP table or IPv6 NBR table.
uint32
EncapNeeded
The type of encapsulation needed on the packet.
EncapType
IPv4PrefixTableEntry
IPv4 prefix table entry
Prefix
IPv4 address prefix
IPv4Prefix
NexthopID
Index into the nexthop table.
uint32
IPv4UcastLPMStatisticsType
statistics of IPv4UcastLPM LFB
InRcvdPkts
The total number of input packets received from
interfaces, including those received in error
uint64
FwdPkts
IPv4 packet forwarded by this LFB
uint64
NoRoutePkts
The number of IP datagrams discarded because no
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route could be found to transmit them to their
destination.
uint64
InDeliverPkts
The total number of input datagrams successfully
delivered to IP user-protocols (including ICMP).
uint64
IPv4ValidatorStatisticsType
IPv4 validator LFB statistics type
badHeaderPkts
The total number of input datagrams with bad ip
header
uint64
badTotalLengthPkts
The total number of input datagrams with bab
length
uint64
badTTLPkts
The total number of input datagrams with bad TTL
uint64
badChecksum
The total number of input datagrams with bad
checksum
uint64
IPv6Prefix
IPv6 prefix
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IPv6addr
address part of the prefix
IPv6Addr
prefixlen
length of the prefix
uint32
IPv6NextHopInfoType
IPv4 nexthop information,include nexthop ip address,
output FE and interface etc.
NexthopID
nexthop id
uint32
FEID
output FE id
uint32
OutputPortID
output port index
uint32
MTU
The maximum transmition unit of the nexthop link.
uint32
Flags
Associated flags of the nexthop,such as local
delivery,multicast etc.
NextHopFlagsType
NexthopIPv6addr
IP address of the nexthop
IPv6Addr
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L2Index
index into the L2 table
uint32
EncapNeeded
The type of encapsulation needed on the packet.
EncapType
IPv6PrefixTableEntry
IPv6 prefix table entry
Prefix
IPv6 address prefix
IPv6Prefix
NexthopID
index to the nexthop table.
uint32
IPv6LPMClassiferStatisticsType
statistics of IPv6LPMClassifier LFB
InRcvdPkts
The total number of input packets received
from interfaces,including those received in error
uint64
FwdPkts
IPv4 packet forwarded by this LFB
uint64
NoRoutePkts
The number of IP datagrams discarded because no
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route could be found to transmit them to their destination.
uint64
InDeliverPkts
The total number of input datagrams successfully
delivered to IP user-protocols (including ICMP).
uint64
IPv6ValidatorStatisticsType
IPv6 validator LFB statistics type
badHeaderPkts
The total number of input datagrams with bad ip
header
uint64
badTotalLengthPkts
The total number of input datagrams with bab
length
uint64
badTTLPkts
The total number of input datagrams with bad
TTL
uint64
badChecksum
The total number of input datagrams with bad
checksum
uint64
NextHopFlagsType
Flags used to define different nexthop behaviors
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uint32
local
Packets match the nexthop entry with this flag
are delivered
to the higher level protocols.
drop
Packets match the nexthop entry with this flag
are to be
dropped.
broadcast
The route associated with this nexthop is a
broadcast.
multicast
The route associated with this nexthop is
multicast.
WeightTableEntryType
Weight table for queues.
QueueID
queue id
uint32
weight
weight of the queue.
uint32
NbrState
IPv6 neighbour entry resolution state.
uchar
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INCOMPLETE
Address resolution is being performed on the
entry.Specifically, a Neighbor Solicitation has been
sent to the solicited-node multicast address of the
target,but the corresponding Neighbor Advertisement
has not yet been received.
REACHABLE
Positive confirmation was received within the
last ReachableTime milliseconds that the forward path
to the neighbor was functioning properly. While
REACHABLE,no special action takes place as packets are
sent.
STALE
More than ReachableTime milliseconds have
elapsed since the last positive confirmation was
received that the forward path was functioning properly.
While stale, no action takes place until a packet is
sent.The STALE state is entered upon receiving an
unsolicited Neighbor Discovery message that updates the
cached link-layer address. Receipt of such a message
does not confirm reachability, and entering the STALE
state insures reachability is verified quickly if the
entry is actually being used. However,reachability is
not actually verified until the entry is actually used.
DELAY
More than ReachableTime milliseconds have
elapsed since the last positive confirmation was
received that the forward path was functioning
properly,and a packet was sent within the last
DELAY_FIRST_PROBE_TIME seconds. If no reachability
confirmation is received within DELAY_FIRST_PROBE_TIME
seconds of entering the DELAY state, send a Neighbor
Solicitation and change the state to PROBE.
PROBE
A reachability confirmation is actively sought
by retransmitting Neighbor Solicitations every
RetransTimer milliseconds until a reachability
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confirmation is received.
ArpTableEntryType
Arp entry.
Index
Index of the arp table.
uint32
NeighborIP
IP address of the neighbour.
IPv4Addr
SrcMac
Source MAC.
IEEEMAC
NeighborMac
Mac of the Neighbor.
IEEEMAC
State
The state of the address resolution progress.
ArpStateType
NbrTableEntryType
IPv6 neighbour table entry.
Index
Index of the arp table.
uint32
NeighborIPv6
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IP address of the neighbour.
IPv6Addr
SrcMac
Source MAC.
IEEEMAC
NeighborMac
Mac of the Neighbor.
IEEEMAC
State
The state of the entry's resolution progress.
NbrState
DCHostTableEntryTypev4
Direct connected arp table entry for IPv4.
NeighbourIP
IP address of the neighbour.
IPv4Addr
SrcMac
Source MAC.
IEEEMAC
NeighborMac
Mac of the Neighbor.
IEEEMAC
DCHostTableEntryTypev6
Direct connected arp table entry for IPv4.
NeighbourIPv6
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IP address of the neighbour.
IPv4Addr
SrcMac
Source MAC.
IEEEMAC
NeighborMac
Mac of the Neighbor.
IEEEMAC
PacketType
The packet type code.
uchar
IPv4Ucast
IPv4 unicast packet.
IPv4Mcast
IPv4 multicast packet.
IPv6Ucast
IPv6 unicast packet.
IPv6Mcast
IPv6 multicast packet.
DispatchTableType
The dispatch table type.
PacketType
The type of the packet.IPv4Uncast,IPv6Ucast,
IPv4Mulcast,IPv6Mulcast etc.
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PacketType
index
The index of the output group to output the
packets.
uint32
MetaType
Metadata type definition.
MetadataID
The ID of the metadata,the value is
standardalized in the corresponding
LFB definition RFCs.
uint32
MetadataName
The name of the metadata.
String
MetadataClassyTableType
The meta data classifying table.
value
Value of the meta data.
uint32
index
The index of the port in the output group to use
for outputing the packets.
uint32
EncapType
Encapsulation type.
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uchar
Link
Link layer encapsulation such as Ethernet and
PPP.
InterFE
Inter FE communication encapsulation.
Tunnel
Tunnel encapsulation such as IP-in-IP.
IPAddress
IP layer address.
Ipv4
IPv4 address.
IPv4Addr
Ipv6
IPv6 address.
IPv6Addr
ArpStateType
The arp entry state.
uchar
Mannul
The entry is mannully set.
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InSolicit
The peer's level 2 address is still in
requesting.
Vaild
The address resolution have been completed
successfully,it now can be used in the data packets
forwarding.
NextHopID
An index into a Next Hop entry in Nexthop table
1
int32
ExceptionID
Exception Types
2
uint32
Options
Packets with options,for IPv6 Packet with
next-header set to hop-by-hop header(0).
LengthMismatch
The packet length reported by link layer is
less than the total length field.
BadTTL
The packet can't be forwarded as the TTL has
expired.
Multicast
The packet received is a multicast packet.
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FragRequired
The MTU for outgoing interface is less than the
packet size.
Redirect
The outgoing port is same as the one on which
the packet is received.
LocalDelivery
The packet is for a local interface.
LimitedBroadcast
The packet received as limited broadcast.
InputPortID
At which interface the packet arrive.
3
uint32
OutputPortID
The interface out which the packet will emmit.
4
uint32
NextHopIP
Nexthop IPv4 address.
5
IP4Addr
NexthopIPv6
Nexthop IPv6 address
6
IPv6Addr
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PacketLength
The length of the packet in octets.
7
uint32
PacketType
Type of the packet
8
uint32
IPv4
IPv4 packet
IPv6
IPv6 packet
TaggedFrame
packet with metadata
MetaDataFrame
meta data only
QueueID
The queue ID
9
uint32
QueueOperationCmd
The type of operation on the queue,there are two
types defined here: enqueue and dequeue.
10
uchar
Enqueue
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Enqueue command.
Dequeue
Dequeue command.
SrcFEID
Source blade ID.
11
uchar
DstFEID
Destination blade ID.
12
uchar
NexthopIndex
Nexthop index into the link layer address resolution
table.
13
uint
EncapMethod
how should the following LFBs do to encapsulate the
packets,such as link encapsulation which means the packets need
to encapsulate link layer header before sending to media;inter
FE communication encapsulation which means the packets need to
first encapsulate inter FE communication header before
transimiting to other FEs;tunnel encapsulation which means the
packet need do extra tunnel encapsulation before sending out to
media.
14
EncapType
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6. LFB Classes Description
According to ForCES specifications, LFB (Logical Function Block) is a
well defined, logically separable functional block that resides in an
FE, and is a functionally accurate abstraction of the FE's processing
capabilities. An LFB Class (or type) is 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.
Only for better understanding purposes, LFB classes defined in this
document are further categorized into groups of LFBs, including Core
LFBs, Port LFBs, etc.
The following sections describe the LFB classes according to the
groups.
6.1. Core LFBs
The core LFBs provide basic ForCES functionality for FE in a ForCES
system. Two core LFBs are defined: the FE Protocol LFB and the FE
Object LFB.
6.1.1. FE Protocol LFB
The FE Protocol LFB is defined as a logical entity in each FE that is
used to control the ForCES protocol. It repsesents FE Protocol
attributes like supportable ForCES protocol versions, current running
version, FE restart policy, CE failover policy, etc. The ForCES
protocol specification document FE-MODEL [I-D.ietf-forces-model]
defines the LFB in details and specifes that every FE must have one
FE Protocol LFB.
The definition of the LFB is included in this base LFB library by
using "load" element:
6.1.2. FE Object LFB
The FE Object LFB is defined to make the FE information easily
accessible. Information like the FE Name, FE ID, FE State, LFB
Topology in the FE are represented in the class of LFB. The FE model
documentFE-MODEL [I-D.ietf-forces-model] defines the LFB in details
and specifies that every FE must have one FE Object LFB.
The definition of the LFB is included in this base LFB library by
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using "load" element:
6.2. Port LFBs
Classes of Port LFBs are LFBs that are related to the operation of FE
media interfaces linked to outer networks or other FEs in the same
ForCES system. According to different media types, different media
port LFBs may have to be defined. For every type of media port, it
usually needs to implement encapsulating and decapsulating the IP
datagrams with the connected network framing. For the sake of the
flexibility, the function of encapsulating and decapsulating are
usually categorized in LFB classes as separate LFBs.
Even if ports with different media may have different logical
abstracts for the attributes, a general description for different
ports still exist. A Generic Connectivity LFB is defined for this
sake. By use of an FE model XML schema element,
specific media port LFBs are then defined in a easier way.
6.2.1. Generic Connectivity LFB
This LFB Class provides a generic basis for representing connectivity
between the FE and the outside world. The LFB has one or more ports
for packets that the FE processing logic is forwrding for
transmission by this Connectivity LFB. It has one or more ports for
packets that the Connectivity LFB has received and is handing to the
FE processing logic. Multiple ports for handline packets are
supported so that protocol specific encapsulation and demultiplexing
can be provided by this LFB. This LFB also has ports for sending
packets to lower layer Connectivity LFBs and receiving packets from
such lower layer Connectivity LFBs. This enables support for the
processing components of interface stacks, such as PPP over Ethernet
or Ethernet over MPLS. For packets arriving from Media or lower
layer connectivity, this LFB will perform appropriate media
validation, then remove media specific headers, and place the
relevant information in meta-data. For ethernet, the Source MAC
would be in meta-data. For Frame Relay or ATM, a circuit identifier
would be in meta-data. For Ethernet with VLANs, this meta-data would
indicate which VLAN the packet came from. For packets to be
transmitted, meta-data indicating the destination (destination MAC or
outgoing circuit, etc.) is required. This LFB will also include
statistical components such as the number of octets and packets sent
and received, the number of various input and output errors, etc.
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6.2.2. Ethernet Port LFBs
(TBD)
1. EtherPort LFB
LFB for Ethernet ports
2. EtherDecap LFB
An LFB class for definition of Ethernet decapsulation and
Ethernet filtering functions.
3. EtherEncap LFB
An LFB classifier definition for completes ethernet encapsulation
fuctions.
6.2.3. POS Port LFBs
(TBD)
6.2.4. ATM Port LFBs
(TBD)
6.3. Address Resolution LFBs
(TBD)
This LFB class provides the function of address resolution for IPv4/
IPv6 nodes.
1. ARP
This LFB class provides the function of address resolution for
IPv4 node.
2. IPv6 Address Resolution
This LFB class provides the function of IPv6 address resolution
part of neighbor discovery protocol.It provides an offload of ND
protocol processing to FE.It process the following ND messages:
neighbour solicitation and neighbour advertisement.
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6.4. ICMP LFBs
(TBD)
1. ICMP Geneartor
This LFB class provide some basic ICMP function. It only
generate the following ICMP messages: ICMP destination
unreachable and time excceeded.
2. ICMPv6 Generator
This LFB class provide some basic ICMPv6 function, it only
generate the following ICMP messages for the packets that need
some basic ICMP processing: destination not reachable and time
excceeded.
6.5. IP Packet Validation LFBs
(TBD)
1. IPv4 Validator
An LFB Class definition for validates the IPv4 packet.
This LFB validates the IP version and header length fields,
including verifying that the packet length is at least as long as
the header indicates.
2. IPv6 Validator
An LFB Class definition for validates the IPv6 packet.
This LFB validates the IP version and header length fields,
including verifying that the packet length is at least as long as
the header indicates.
6.6. Classifier LFBs
(TBD)
1. Metadata Classifier LFB
This LFB class provides the function of classify packets
according to the meta data. Now it only works on one meta data.
2. Arbitrary Classifier LFB
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This is a class definition for an Arbitrary Classifier LFB. The
input is a port group, and the match conditions can include the
port in their test. This allows the topology to carry some
information if desired. The match conditions can select an
output from the SuccessOuput output port group. If no condition
matches, the packet will be sesnt to the FailOutput port.
6.7. Forwarding LFBs
(TBD)
Forwarding LFBs are specifically for implementing IP packet
forwarding tasks.
6.7.1. Unicast Longest Prefix Match LFBs
1. IPv4UcastLPM
IPv4 Longest Prefix Match Lookup LFB
2. IPv6UcastLPM
An LFB class definition for IPv6 longest prefix lookup function.
6.7.2. Nexthop Applicator LFBs
1. IPv4 NextHop Applicator
An LFB definition for applicating next hop action to IPv4
packets, the actions include:TTL operation,checksum
recalculation.
2. IPv6UcastNexthopApplicator
An LFB for applicating next hop action to IPv6 packets,actions
mainly inlcude TTL incrementation and checksum recalculation.
6.8. QoS Control LFBs
(TBD)
To build an actual forwarder, one must include some limited for of
queueing and scheduling. Queues are entities which store packets.
Schedulers are entities which react to the state of queues and cause
packets to be emitted from queues.
The actual interaction between queues and schedulers (and their real
world degree of separation) is quite complex. A very complex LFB
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model would be required to represent all the complexity.
Additionally, there is the issue of representing the relationship
between the queue and the scheduler. A simple approach has been
taken in these class definitions.
A queue element consists of an input port (called InData) on which it
receives data packets, and output port (called OutData) on which it
will send packets when permitted by its definition or the scheduler.
Its relationship to scheduluers is represented by a set of output
ports (the group OutCountrol) and an input port (called InControl).
These ports are defined to carry packets consisting only of meta-
data. In fact, these ports are an abstraction, and what one might
call a legal fiction. An element of the OutControl group represents
the fact that a scheduler is aware of the state of that queue
element. The InControl port represents the fact that one or more
schedulers connected to that port are controlling that queue. There
is no meta-data defined for actual exchange on these ports, as their
real world realization is highly implementation dependent. To
complete this picture, a schedule has a group of input ports
(Watchers) representing the connectivity to queues it is aware of,
and a group of output ports (Controllers) representing control over
queues. This allows for the simple case of a controller who monitors
and controls a single set of queues, and more interesting cases where
the control of certain queues may depend upon the state of queues
whihc are not under the control of the scheduler.
The Queues and schedulers LFBs that are defined in this library are:
1. Scheduler
2. Queue
3. WRRSched
6.8.1. Scheduler LFBs
1. Generic Scheduler
This defines a base LFB class for schedulers. Schedulers have an
Input Port group called Watchers for representing the queues they
watch, and an Output Port group called Controllers fro
representing the queues they control.
2. WRRSched
Weighted round robin scheduler.
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6.8.2. Queue LFBs
Queues have a packet input, a packet output, a control input, and a
group of control outputs. The control ports represent the control
relationships with scheduluers.
6.9. Miscellaneous Packet Manipulation LFBs
(TBD)
1. Packet Trimmer LFB
LFB removes data from the front of a packet.
2. Duplicator LFB
An LFB Class definition for packet duplicator LFB. Any packet
received on an input port is logically copied and sent to all
output ports.
3. IPv4 Option Proccessing LFB
This LFB class process the IPv4 packet with options, it can
process on the following options: Router-alert option.
4. IPv6 Extend Header Processing LFB
This LFB class process the IPv6 packet with extended header, For
the moment, the packets to this LFB are redirect to RedirectSink
LFB by default.
6.10. Redirect LFB
(TBD)
An LFB Class definition for exchanging data packets between the FE
and the CE.
This LFB represents a point of exchagne of data packets between the
CE and the FE. Packets with meta-data are exchanged. It is expected
that the output port of a RedirectLFB, if it is connected at all,
will be connected to a meta-data redirector.
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7. XML Definition for Base LFB Library
This library provides base LFB class definitions.
EtherPort
LFB for Ethernet ports
1.0
PacketsFromProcessingUnit
Ports for receiving packets from processing unit
such as NP,that will be sent to media.
[EthernetII]
[OutputPort]
PacketsFromMedia
Ports for receiving packets from ethernet media.
[EthernetII]
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PacketsToProcessingUnit
Ports for sending packets to processing unit such
as NP for further processing.
[EthernetII]
[InputPort]
PacketsToMedia
Ports for sending packets to media.
[EthernetII]
IfIndex
A unique value for each interface. Its value ranges
between 1 and the value of total number of interfaces in the
system. The value for each interface must remain constant at
least from one re-initialization of the entity's network
management system to the next re-initialization.
uint32
IfName
Name of this port
string[16]
LinkSpeed
Speed of this port
LANSpeedType
MTU
Maximum transmition unit
uint32
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OperaStatus
Operate state of this port.
PortStatusValues
"down"
AdminStatus
Administrator's state of this port
PortStatusValues
"down"
PromiscuousMode
Whether the interface is in promiscuous mode
booleanType
"no"
CarrierStatus
whether the port is linked with an connector.
booleanType
"no"
OperMode
The port operation mode,must be one of the
following values:Auto,Half-duplex,Full-duplex
NegotiationType
"auto"
SrcMACAddr
source MAC
IEEEMAC
MacAliasTable
A series of MACs that the port can receive frame
on.
IEEEMAC
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StatsEnable
whether enable the statistics in this LFB.
booleanType
"no"
PortStats
port statistics.
PortStatsType
Ipaddr
IP layer Address.
IPAddress
PortStatusChanged
Port status has changed since last time reporting.
OperaStatus
OperaStatus
EtherDecap
An LFB class for definition of Ethernet decapsulation
and Ethernet filtering functions
1.0
PacketsIn
Packets from other LFB.
[EthernetII]
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DecapOut
Ethernet decapsulation output.
[Arbitrary]
DispatchTable
This table is used for selecting output in the
ouput group for the incoming packet stream.
DispatchTableType
IPv4Validor
An LFB Class definition for validates the IPv4 packets.
1.0
ValidatePktsIn
Port used to receive IPv4 packet for validation.
[IPv4]
SuccessOut
Out port for the packets passing the validation.
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[IPv4]
ExceptionOut
Output port for the packets needed to be dealt by
higher level protcol stacks.The following packets are
identified as exception packets:1 Packet with header
length>5;2 Packet with destination address equal to
255.255.255.255;3 Packet with expired TTL (checked after a
forwarding decision is made);4 Packet length error.
[ExceptionID]
FailOutput
Output for packets failed to pass the validation.
[ IPv4 ]
StatsEnable
whether to gather statistics in this LFB.
booleanType
"no"
IPv4ValidatorStats
ipv4 validator LFB statistics
IPv4ValidatorStatisticsType
Detailed validation process please refer to RFC1812
and RFC2644.
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IPv4UcastLPM
IPv4 Longest Prefix Match Lookup LFB
1.0
PktIn
The port to receive IPv4 packets from other LFBs
[IPv4]
SuccessOut
Successful output when all is fine.
[IPv4]
[NextHopID]
[FEID]
[OutputPortID]
[MTU]
[Flags]
[NexthopIPAddr]
[EncapMethod]
ExceptionOut
Exception output
[IPv4]
[InputPortID ]
[ExceptionID]
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FailOutput
Dropper
[ IPv4 ]
PrefixTable
IPv4 prefix table
IPv4PrefixTableEntry
IPv4PrefixTableEntry.prefix
Fib
IPv4 unicast forwarding table.
IPv4FibEntryType
IPv4FibEntryType.prefix
LocalIpAddrTable
The table of interfaces's ip address infomation
on the local device
LocalIpAddrType
IPv4Stats
The IPv4 associated statistics
IPv4UcastLPMStatisticsType
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PrefixTableLimit
maxium number of prefix supported by this LFB
uint32
LocalIpAddrTableLimit
maxium number of IP address entrys supported by
this LFB
uint32
This LFB represents the IPv4 longest prefix match
lookup operation.
IPv4NextHopApplicator
An LFB definition for applicating next hop action to
IPv4 packets,the actions include:TTL operation,checksum
recalculation.
1.0
PktIn
Port used to receive IPv4 packets from other LFBs
[ IPv4 ]
[
NextHopID]
[
FEID]
[
OutputPortID]
[
MTU]
[
Flags]
[
NexthopIPAddr]
[
EncapMethod]
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SuccessOut
Output port for packet successfully fulfill the
nexthop application.
[ IPv4 ]
[DstFEID]
[OutputPortID]
[L2Index]
[NextHopIP]
[EncapMethod]
ExceptionOut
Output for packets need deep dealt by higher level
protocol stacks.
[ IPv4 ]
[InputPortID]
[ExceptionID]
FailOutput
Output for packets failed the nexthop application
operation.
[ IPv4 ]
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NextHopTable
Nexthop table
IPv4NextHopInfoType
NextHopTableLimit
Maxium number of nexthops this LFB supports
uint32
IPv6Validator
A LFB class definition for validating correctness
of IPv6 packets
1.0
ValidateIn
Input port for packets to be validated.
[IPv6]
SuccessOut
Output port for packets passing the validation.
[IPv6]
ExceptionOut
Output port for exception packet.The following
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packets are identified as Exception packet:1 Packet with
next header set to Hop-by-Hop.2 The packet length reported
by link layer is less than the total length field.3 Packet
with a link local destination address;4 The packet received
as limited broadcast.5 Packet with multicast destination
address (the MSB of the destination address is 0xFF);
[IPv6]
[ExceptionID]
FailOut
Output port for packet failing the validation.
[IPv6]
IPv6ValidatorStats
IPv6 validator LFB statistics
IPv6ValidatorStatisticsType
Detailed validation process could refer to RFC2460
and RFC2373.
IPv6UcastLPM
An LFB class definition for IPv6 longest prefix lookup
function.
1.0
PktIn
The port to receive IPv6 packets needed to do IPv4
LPM.
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[IPv6]
SuccessOut
Output for packets that have find the correct
route.
[IPv6]
[NextHopID]
FailOutput
LPM failed.
[ IPv6 ]
PrefixTable
IPv6 prefix table
IPv6PrefixTableEntry
IPv6PrefixTableEntry.prefix
LocalIpv6AddrTable
The table of interfaces's ip address infomation on
the local device
LocalIpv6AddrType
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IPv6Stats
The IPv6 associated statistics
IPv6LPMClassiferStatisticsType
PrefixTableLimit
maxium number of prefix supported by this LFB
uint32
LocalIpv6AddrTableLimit
maxium number of IPv6 address entrys supported
by this LFB
uint32
IPv6UcastNexthopApplicator
An LFB for applicating next hop action to IPv6 packets,
actions mainly inlcude TTL incrementation and checksum
recalculation.
1.0
PktIn
Input port for packets to be applicate nexthop.
[ IPv6 ]
[NextHopID]
SuccessOut
Output port for packet successfully fulfill the
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nexthop application.
[ IPv6 ]
[FEID]
[OutputPortID]
[L2Index]
[NextHopIPv6]
[EncapMethod]
ExceptionOut
Output port for exception packet.The following
packets are identified as Exception packet:1 Packet with
Hop Limit zero.2 The MTU for outgoing interface is less
than the packet size.3 The outgoing port is same as the
one on which the packet is received.4 The packet is for
a local interface.
[ IPv6 ]
[InputPortID]
[ExceptionID]
FailOutput
Output for packets failed the nexthop application
operation.
[ IPv6 ]
NextHopTable
Nexthop table
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IPv6NextHopInfoType
NextHopTableLimit
Maxium number of nexthops this LFB supports
uint32
EtherEncap
An LFB classifier definition for completes ethernet
encapsulation fuctions
1.0
EncapIn
Port for receiving packets needed to build Ethernet
encapsulation.
[IPv4]
[IPv6]
[L2Index]
[NextHopIP]
[NextHopIPv6]
[PacketType]
SuccessOut
[EthernetII]
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ExceptionOut
packet can't find the associated L2 information
[IPv4]
[IPv6]
ArpTable
Ethernet arp table.
ArpTableEntryType
NbrTable
IPv6 neighbour table.
NbrTableEntryType
DCHostTablev4
Direct connected host arp table for IPv4.
DCHostTableEntryTypev4
DCHostTablev6
Direct connected host arp table for IPv6.
DCHostTableEntryTypev6
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ArpTableLimit
Max number of arp entries in arp table.
uint32
NbrTableLimit
Max number of neighbours in neighbour table.
uint32
DCHostTablev4Limit
The limit on Direct connected host table for IPv4.
uint32
DCHostTablev6Limit
The limit on Direct connected host table for IPv6.
uint32
Scheduler
Base scheduler LFB.
1.0
Watcher
Input for watching the queues to be scheduled.
Queues to be scheduled can transmit packet enqueue and
dequeue infomation to scheduler through these port.
[MetadataFrame]
[QueueID]
[PacketLength]
[QueueOperationCmd]
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OutControl
Control output,this output is used by scheduler
to communicate commands to it's controlled queues such as
dequeue a packet.
[MetadataFrame]
[QueueOperationCmd]
QueueScheduledLimit
Max number of queues that can be scheduled by this
scheduler.
uint32
Queue
Queue LFB.
1.0
InControl
Input from scheduler
[QueueOperationCmd]
InData
Input port for data packet.
[Arbitrary]
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[PacketLength]
OutToController
Output to queue controller
[MetadataFrame]
[QueueID]
[PacketLength]
[QueueOperationCmd]
OutData
Data packet output
[Arbitrary]
CurLen
Current length of the queue in number of packets.
uint32
QueueLenLimit
Maximum length of the queue in number of packets.
uint32
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RedirectSink
This class definition provides for the function of
sinking data packets that needed to be sent to CE.
1.0
InFromOtherLFBs
Packets input from other LFBs and needed to sent
to CE.
[IPv4]
[IPv6]
[InputPortID]
[PacketLength]
[PacketType]
RedirectTap
This class provides the function of sinking data
packets that comes from CE and needed to be sent out by this
FE.
1.0
OutputToOtherLFBs
Packets input received from CE.
[IPv4]
[IPv6]
[PacketType]
[OutputPortID]
[PacketLength]
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DispatchTable
The table to dispatch the packets to different LFB.
DispatchTableType
outGroupNumOfPorts
The number of ports in output group.
uint32
MaxNumOfoutGroupPorts
The maxium number of ports in the output group.
uint32
WRRSched
Weighted round robin scheduler.
1.0
Scheduler
WeightTable
Weight table for queues to be scheduled.
WeightTableEntryType
IPv6AddrResolution
This LFB class provides the function of IPv6 address
resolution part of neighbor discovery protocol.It provides an
offload of ND protocol processing to FE.It process the following
ND messages:neighbour solicitation and neighbour advertisement.
1.0
AddrResDataPktIn
The IPv6 data packet that need to do the address
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resolution.
[IPv6]
AddrResProtoPktIn
The neighbour discovery packet related to
addresolution.
[IPv6]
AddrResDataPktOut
The IPv6 packet that have encapsulated with the
correct ethernet L2 info and need to be sent out to link.
[EthernetII]
AddrResProtoPktOut
The IPv6 neighbour discovey packet wich has been
encapsulation with the correct ethernet L2 info.
[EthernetII]
Nbrtable
This table is an alias to the IPv6 neighbour table
in the EtherEncap LFB.
NbrTable
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ICMPv6Generator
This LFB class provide some basic ICMPv6 function,it
only generate the following ICMP messages for the packets that
need some basic icmp processing:destination not reachable and
time excceeded.
1.0
PktIn
The IPv6 packet that need icmp processing.
[IPv6]
[ExceptionID]
ICMPv6PktOut
The output for the ICMPv6 packets generated
according to the input IPv6 packet and the ExceptionID.
[IPv6]
ExtendHeaderProc
This LFB class process the IPv6 packet with extended
header,For the moment,the packets to this LFB are redirect to
RedirectSink LFB by default.
1.0
PktIn
The IPv6 packet with extended header in.
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[IPv6]
PktOut
According to the Extended header type the packet
may have different next proccesing LFB.Now by default we
send all the packet with extended header to CE.
[IPv6]
arp
This LFB class provides the function of address
resolution for IPv4 nodes.
1.0
AddrResDataPktIn
The IPv4 data packet that need to do the address
resolution.
[IPv4]
ArpPktIn
The neighbour discovery packet related to
addresolution.
[IPv4]
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AddrResDataPktOut
The IPv4 packet that have been encapsulated with
the correct ethernet L2 info and need to be sent out to
link.
[EthernetII]
ArpOut
The arp packet out.
[EthernetII]
Arptable
This table is an alias of the arp table in the
EtherEncap LFB.
ArpTable
ICMPGenerator
This LFB class provide some basic ICMP function,it
only generate the following ICMP messages:ICMP destination
unreachable and time excceeded.
1.0
PktIn
The IPv4 packet that need icmp processing.
[IPv4]
[ExceptionID]
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ICMPPktOut
The output for the ICMP packets generated according
to the input packet and the ExceptionID.
[IPv4]
MetadataClassifier
This LFB class provides the function of classify
packets according to the meta data.Now it only works on one
meta data.
1.0
PktIn
Packets need to do the classification.
[Arbitrary]
[Arbitrary]
ClassifiedOut
The output group for the classified packets.
[Arbitrary]
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MetaDataID
The metadata id that this classifier works on.
uint32
MetaDataName
The name of the meta data that this classifier
works on.
string
MetadataClassifyTable
The meta data classifying table.
MetadataClassyTableType
OutNumOfPorts
The number of ports in the output group.
uint32
MaxOutNumOfPorts
Maxium number of ports in the output group.
uint32
OptionProc
This LFB class process the IPv4 packet with options,
it can process on the following options:Router-alert option.
1.0
PktIn
The IPv4 packet with options in.
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[IPv4]
PktOut
According to the Option type the packet may have
different next proccesing LFB.Now by default we send all
the packet with extended header to CE.
[IPv4]
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8. Base LFB Library Use Case for Typical Router Functions
This section demonstrates examples on how the LFB classes defined by
the Base LFB library in Section 7 are applied to the achievements of
typical router functions.
As mentioned in the overview section, typical router functions can be
categorized in short into the following functions:
o IP forwarding
o address resolution
o ICMP
o network management
o running routing protocol
To achieve the functions, processing paths organized by the LFB
classes with their interconnections should be established in FE. In
general, CE controls and manages the processing paths by use of the
ForCES protocol.
Note that LFB class use cases shown in this section are only as
examples to demonstrate how typical router functions can be
implemented with the defined base LFB library. Users and
implementors of the base LFB library should not be limited by the
examples.
8.1. IP Forwardings
IP packets to be forwarded are from interfaces conneted via a kind of
media to outer networks. A Port LFB receives link layer packets. CE
may control the port LFB status by the LFB components defined in the
library. Link layer packets are delivered to a decapsulation LFB to
decapsulate to IP packets. The LFB also provides IP packet
distinguishing by classifying IP packet according to its types like
IPv4 or IPv6, unicast or multicast, and ARP packet. The packet type
information is included in a IPPacketType metadata and the metadata
is associated with every decapsulated IP packet.
Followed decapsulation LFBs are usually IP validation LFBs which
further validate IP packets according to IP protocol. The LFB also
distinguishes if the IP packets are exceptional packets like ICMP
packets other than IP packets to be further forwarded. The
exceptional packets are then associated with metadata indicating the
packet types and delivered to metadata classifier for specific
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classification and further processing.
Validated IP unicast packets for forwarding are delivered to unicast
Longes Prifix Match(UcastLPM) LFB, which produce nexthop information
for forwarding. The nexthop information is represented by a
nexthopID metadata.
IP packets with associated nexthop metadata are delivered to the
NextHopApplicator LFB. The LFB decides output ports for the IP
packets. Note that when IP packets need to traverse FEs for
forwarding, the LFB may also only decides the local FE output port to
the other FE and makes the packet to carry the nexthop information to
that FE.
IP packets with nexthop applied are then encapsulated by a link layer
encapsulation LFB according to the egress media and put on to the
appropriate output ports. In this process, address resolution LFBs
may have to be applied to decide the link layer output addresses for
the packets. Moreover, the queue management LFBs and scheduler LFBs
may be applied in the process to achieve individual QoS requirements.
Figure 1 shows the typical LFB processing path for the IPv4 unicast
forwarding case.
Figure 1. (TBD)
Figure 2 shows the typical LFB processing path for the IPv6 unicast
forwarding case.
Figure 2. (TBD)
8.2. Address Resolution
TBD
8.3. ICMP
TBD
8.4. Running Routing Protocol
TBD
8.5. Network Management
TBD
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9. Contributors
The authors would like to thank Jamal Hadi Salim and Ligang Dong who
made a major contribution to the development of this document.
Jamal Hadi Salim
Mojatatu Networks
Ottawa, Ontario
Canada
Email: hadi@mojatatu.com
Ligang Dong
Zhejiang Gongshang University
149 Jiaogong Road
Hangzhou 310035
P.R.China
Phone: +86-571-28877751
EMail: donglg@mail.zjgsu.edu.cn
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10. Acknowledgements
This document is based on earlier documents from Joel Halpern, Ligang
Dong, Fenggen Jia and Weiming Wang.
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11. IANA Considerations
(TBD)
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12. Security Considerations
These definitions if used by an FE to support ForCES create
manipulable entities on the FE. Manipulation of such objects can
produce almost unlimited effects on the FE. FEs should ensure that
only properly authenticated ForCES protocol participants are
performing such manipulations. Thus the security issues with this
protocol are defined in the FE-protocol [I-D.ietf-forces-protocol].
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13. References
13.1. Normative References
[I-D.ietf-forces-model]
Halpern, J. and J. Salim, "ForCES Forwarding Element
Model", draft-ietf-forces-model-16 (work in progress),
October 2008.
[I-D.ietf-forces-protocol]
Dong, L., Doria, A., Gopal, R., HAAS, R., Salim, J.,
Khosravi, H., and W. Wang, "ForCES Protocol
Specification", draft-ietf-forces-protocol-22 (work in
progress), March 2009.
13.2. Informative References
[RFC1812] Baker, F., "Requirements for IP Version 4 Routers",
RFC 1812, June 1995.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2629] Rose, M., "Writing I-Ds and RFCs using XML", RFC 2629,
June 1999.
[RFC3552] Rescorla, E. and B. Korver, "Guidelines for Writing RFC
Text on Security Considerations", BCP 72, RFC 3552,
July 2003.
[RFC3654] Khosravi, H. and T. Anderson, "Requirements for Separation
of IP Control and Forwarding", RFC 3654, November 2003.
[RFC3746] Yang, L., Dantu, R., Anderson, T., and R. Gopal,
"Forwarding and Control Element Separation (ForCES)
Framework", RFC 3746, April 2004.
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 5226,
May 2008.
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Authors' Addresses
Weiming Wang
Zhejiang Gongshang University
18, Xuezheng Str., Xiasha University Town
Hangzhou, 310018
P.R.China
Phone: +86-571-28877721
Email: wmwang@mail.zjgsu.edu.cn
Evangelos Haleplidis
University of Patras
Patras,
Greece
Email: ehalep@ece.upatras.gr
Kentaro Ogawa
NTT Corporation
Tokyo,
Japan
Email: ogawa.kentaro@lab.ntt.co.jp
Fenggen Jia
National Digital Switching Center(NDSC)
Jianxue Road
Zhengzhou, 452000
P.R.China
Phone: +86-571-28877751
Email: jfg@mail.ndsc.com.cn,fgjia@mail.zjgsu.edu.cn
Halpern Joel
Ericsson
P.O. Box 6049
Leesburg, 20178
VA
Phone: +1 703 371 3043
Email: jhalpern@redback.com
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