Mobile Ad hoc Networking (MANET) T. Clausen
Internet-Draft LIX, Ecole Polytechnique, France
Expires: December 21, 2006 C. Dearlove
BAE Systems Advanced Technology
Centre
J. Dean
Naval Research Laboratory
C. Adjih
INRIA Rocquencourt
June 19, 2006
Generalized MANET Packet/Message Format
draft-ietf-manet-packetbb-01
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Copyright Notice
Copyright (C) The Internet Society (2006).
Abstract
This document describes a generalized multi-message packet format
which may be used by mobile ad hoc network routing and other
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protocols.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Applicability Statement . . . . . . . . . . . . . . . . . . . 5
4. Protocol Overview and Functioning . . . . . . . . . . . . . . 6
5. Signaling Framework . . . . . . . . . . . . . . . . . . . . . 7
5.1. Packet Format . . . . . . . . . . . . . . . . . . . . . . 7
5.1.1. Padding . . . . . . . . . . . . . . . . . . . . . . . 8
5.2. Messages . . . . . . . . . . . . . . . . . . . . . . . . . 9
5.2.1. Address Blocks . . . . . . . . . . . . . . . . . . . . 12
5.3. TLVs and TLV Blocks . . . . . . . . . . . . . . . . . . . 14
5.3.1. TLVs . . . . . . . . . . . . . . . . . . . . . . . . . 14
5.3.2. Constraints . . . . . . . . . . . . . . . . . . . . . 17
5.4. Message Content Fragmentation . . . . . . . . . . . . . . 17
6. TLV specification . . . . . . . . . . . . . . . . . . . . . . 20
6.1. Message TLV Specification . . . . . . . . . . . . . . . . 20
6.2. Address Block TLV Specification . . . . . . . . . . . . . 21
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 22
8. Security Considerations . . . . . . . . . . . . . . . . . . . 24
9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 25
9.1. Normative References . . . . . . . . . . . . . . . . . . . 25
9.2. Informative References . . . . . . . . . . . . . . . . . . 25
Appendix A. Packet and Message Layout . . . . . . . . . . . . . 26
Appendix A.1. General Packet Format . . . . . . . . . . . . . . . 26
Appendix B. Contributors . . . . . . . . . . . . . . . . . . . . 38
Appendix C. Acknowledgements . . . . . . . . . . . . . . . . . . 39
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 40
Intellectual Property and Copyright Statements . . . . . . . . . . 41
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1. Introduction
Signaling in a mobile ad hoc network routing protocol consists,
mainly, of stating IP addresses and attributes associated to such IP
addresses. Since this is a task common to many such protocols, this
specification presents a generalized signaling framework, which may
be employed both by mobile ad hoc network routing protocols and other
protocols with similar signaling requirements.
The framework consists of a specification of:
o a mechanism whereby message types can be specified and (regardless
of type, whether known or unknown) can be correctly parsed and
forwarded;
o a generalized multi-message packet format, allowing multiple
messages to be contained within a single transmission;
o a message format, composed of a message header and a message body,
with the message header containing *all* necessary information to
allow a node to make forwarding and processing decisions without
resorting to inspecting the message body. The message header
information permits single- and multi-hop diffusion whilst
supporting scope controlled multicast and unicast use of the
format;
o a message body structure, encouraging uniform message parsing,
regardless of message body content;
o a mechanism whereby addresses can be represented in a compact way
(address compression);
o an extensibility mechanism whereby arbitrary attributes, through
TLVs (type-length-value triplets), can be included and associated
with a message, an address or a set of addresses, while being
correctly parseable by a generic message parser.
An important design criterion behind this specification is to allow
development of easy parsing logic, even in the face of a flexible
format. This implies that, given an incoming control message, a
single parser is able to process the message independent of type and
present, to a protocol using this specification, an abstraction of
addresses with associated attributes directly. The information
contained in the message header furthermore allows the recipient node
to recognize duplicates and make appropriate forwarding decisions.
Additionally, the signaling framework in this specification is
developed with the objective of minimizing the complexity of this
parser by providing a straightforward message layout.
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2. Terminology
The keywords "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC2119 [1].
Additionally, this document uses the following terminology:
Address - an address of the same type and length as the source IP
address in the IP datagram carrying the packet.
TLV - Type-Length-Value structure. This is a generic way in which an
attribute can be represented and correctly parsed, without knowing
the content, or understanding the type of the attribute by the
parser. This allows internal extensibility, i.e. for a protocol
extension to add arbitrary attributes within a control message.
? - zero or one occurrences of the preceding element.
* - zero or more occurrences of the preceding element.
+ - one or more occurrences of the preceding element.
<foo> - An element specified in the parsing of a packet, message or
other entity. If <foo> is an 8 or 16 bit field then <foo> is also
used to represent the value of that field.
bar - A variable, usually obtained through calculations based on the
value(s) of field(s). Variables are introduced in the
specification solely as a means to clarify the description.
address-length - A variable whose value is the length of an address
in octets, i.e. it is 4 if using IPv4, or 16 if using IPv6.
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3. Applicability Statement
This specification describes a generic multi-message packet format,
for carrying MANET routing protocol signals. The specification has
been developed from that used by OLSR [3].
The specification is designed specifically with IP (IPv4/IPv6) in
mind. All addresses within a control message are assumed to be of
the same size, deduced from IP. In the case of mixed IPv6 and IPv4
addresses, IPv4 addresses are carried in IPv6 as specified in [2].
The packets defined by this specification may use any transport
protocol appropriate to the protocol using this specification. When
the diffusion mechanism enabled by this specification is employed,
UDP may be most appropriate.
The multi-message package format in this specification is
characterized by lending itself to low-complexity parsing logic, as
well as to an efficient parsing for low-capacity routers. The header
information in each message suffices to allow for each message to be
forwarded (if required) and delivered correctly with regards to the
message's delivery semantics, without parsing and inspecting the
message body.
The specification accommodates two types of extensibility: "external
extensibility", whereby new message types can be specified and
(regardless of type) still be correctly forwarded and parsed using
the simple parsing logic, and "internal extensibility", whereby new
attributes can be included in existing message types while these can
still be correctly forwarded and parsed using the simple parsing
logic.
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4. Protocol Overview and Functioning
This specification does not describe a protocol. It describes a
packet format, which MAY be used by any mobile ad hoc network routing
or other protocol.
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5. Signaling Framework
This section provides abstract descriptions of message and packet
formats.
5.1. Packet Format
Messages are carried in a general packet format, allowing
piggybacking of several independent messages in a single packet
transmission.
The packet format conforms to the following specification:
<packet> = {<packet-header><pad-octet>*}?
{<message><pad-octet>*}*
where <message> is defined in Section 5.2, and with <pad-octet>
conforming to the following specification:
<pad-octet> is an 8 bit field with all bits cleared ('0'). The use
of <pad-octet> is detailed in Section 5.1.1.
<packet-header> is defined by:
<packet-header> = <zero>
<packet-semantics>
<packet-seq-number>?
<tlv-block>?
with the elements of <packet-header> conforming to the following
specification:
<zero> is an 8 bit field with all bits cleared ('0'). This field
serves to identify if the packet starts with a packet header.
<packet-semantics> is an 8 bit field, which specifies the composition
of the packet header:
bit 0 (pseqnum) indicates, if cleared ('0'), that the packet
header contains a <packet-seq-number>. If set ('1'), the
packet header does not include a <packet-seq-number>.
bit 1 (ptlv) indicates, if cleared ('0'), that the packet header
does not include a TLV block. If set ('1'), the packet header
includes a TLV block.
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bits 2-7 are reserved, and SHOULD each be cleared ('0').
<packet-seq-number> is omitted if the pseqnum bit is set ('1'),
otherwise it is a 16 bit field, which specifies a packet sequence
number. If used, a separate packet sequence number MUST be
maintained for each transmitting interface. Each packet sequence
number MUST be incremented by one each time a packet, as defined
in this document and which includes the packet sequence number, is
transmitted over this interface.
<tlv-block> is omitted if the ptlv bit is cleared ('0'), otherwise it
is a TLV block as specified in Section 5.3.
Note that since the message type zero is reserved (see Section 7),
the presence or absence of a packet header can be determined by
inspecting the first octet of the packet.
5.1.1. Padding
Packet headers and messages can be padded to ensure 32 bit alignment
of each message contained within the packet.
5.1.1.1. Packet Header Padding
The packet header specification in Section 5.1 ensures that a packet
header consists of an integral number of octets, with all defined
syntactical entities (<zero>, <packet-semantics>, <packet-seq-
number>, <tlv-block>) being octet-aligned.
The first <message> in a packet can be 32 bit aligned by adding the
appropriate number of <pad-octet>s subsequent to the <packet-header>.
The number of <pad-octet>s required to achieve this 32 bit alignment
is calculated as the smallest number which, when added to the size of
the packet header <tlv-block> (if any) and the size of the <packet-
seq-number> (if any) and the size of the fixed part of the header
(the <zero> and <packet-semantics> fields, which are each one octet
long) produces an integer multiple of 4.
If the <packet-header> contains a <packet-seq-number> and no <tlv-
block>, (i.e. if both the pseqnum and ptlv bits are cleared) then
there SHOULD NOT be any <pad-octets> subsequent to the <packet-
header>, since then the <packet-header> has length exactly 4 octets
and the first <message> is then already 32 bit aligned.
There is no need to indicate if padding is included subsequent to the
packet header: the first octet of a message (see Section 5.2 cannot
be zero. Thus, if after processing the packet header a recipient
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reads an octet with all bits cleared ('0'), this read octet is
padding.
5.1.1.2. Message Padding
The message specification in Section 5.2 ensures that a message
consists of an integral number of octets, with all defined
syntactical entities (<msg-header>, <address-block>, <tlv> etc.)
being octet-aligned.
The first message can be 32 bit aligned by using packet header
padding, as described in Section 5.1.1.1. Subsequent messages (and,
hence, also the <originator-address>, if any), can be 32 bit aligned
by adding the appropriate number of <pad-octet>s subsequent to each
message. (When added to the last message this instead ensures that
the overall packet is a multiple of 32 bits in length.)
The number of <pad-octet>s required to achieve 32 bit alignment of
the end of message (and hence the start of the next, if any),
assuming that the start of the message is 32 bit aligned, is
calculated as the smallest number which when added to <msg-size>
produces a multiple of 4.
There is no need to indicate if padding is included subsequent to a
message: the first octet of a message (see Section 5.2) cannot be
zero. Thus if after processing a message a recipient reads any
octets with all bits cleared ('0'), these read octets are padding.
The <msg-size> does not include padding.
The padding after a message may be freely changed when a message is
forwarded without affecting the message.
5.2. Messages
Information is carried through "messages". Messages may contain:
o zero or more TLVs, associated with the whole message;
o a set of addresses about which the originating node wishes to
convey information. These addresses MAY be divided into one or
more address blocks;
o zero or more TLVs following each address block. These are
explained in more detail in Section 5.3.1 and convey information
about the addresses in that address block.
A message also contains a message header, which can be parsed without
examining the remainder of the packet, and which contains information
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sufficient to allow the recipient to:
o recognize duplicate messages;
o determine considerations for forwarding;
o manage controlled-scope diffusion of messages.
Message content MAY (e.g. due to size limitations) be fragmented.
Each fragment is transmitted such that it makes up a syntactically
correct message (i.e. all headers are set as if each fragment is a
message in its own right, and each message contains all necessary
message TLVs). Content fragmentation is detailed in Section 5.4.
A message has the following general layout:
<message> = <msg-header>
<tlv-block>
{<addr-block><tlv-block>}*
<msg-header> = <msg-type>
<msg-semantics>
<msg-size>
<msg-header-info>
<msg-header-info> = <originator-address>?
<hop-limit>?
<hop-count>?
<msg-seq-number>?
The elements of <msg-header-info> are included according to the flags
in <msg-semantics> as described below.
The elements used above conform to the following specification:
<tlv-block> is as specified in Section 5.3
<addr-block> is a block of addresses, with which the originator of
the message has a special relationship, specific to the protocol
using this specification. Address blocks are specified in
Section 5.2.1;
<msg-type> is an 8 bit field, which specifies the type of message. A
type with all bits cleared ('0') MUST NOT be used. The two most
significant bits are allocated with the following semantics:
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bit 7 (msg-user): message types with this bit cleared ('0') are
defined in this specification or can be allocated via standards
action. Message types with this bit set ('1') are reserved for
private/local use.
bit 6 (msg-protocol): for message types with the msg-user bit
cleared ('0'), this bit specifies, if cleared ('0'), that the
message type is protocol independent, i.e. is not specific to
any one protocol, or, if set ('1'), that the message type is
specific to the protocol for which it is defined.
<msg-semantics> is an 8 bit field, which specifies the interpretation
of the remainder of the message header and the processing which
can be undertaken only parsing the message header:
bit 0 (noorig): indicates, if cleared ('0') that the elements
<originator-address> and <msg-seq-number> in the <msg-header-
info> be included, as specified in the above. If set ('1'), a
reduced header which does not include <originator-address> and
<msg-seq-number> is used; this reduced header does not provide
provisions for duplicate suppression;
bit 1 (nohops): indicates, if cleared ('0') that the elements
<hop-limit> and <hop-count> in the <msg-header-info> be
included, as specified in the above. If set ('1'), a reduced
header which does not include the elements <hop-limit> <hop-
count> from the <msg-header-info> is used; this reduced header
does not provide provisions for scope-delimited forwarding;
bit 2 (typedep): indicates, if cleared ('0'), that the message
sequence number in the message is type-independent. If set
('1'), the message sequence number contained in the message is
type dependent, i.e. the source of the message maintains a
sequence number separately for the type indicated in the <msg-
type> field; this bit SHALL be cleared ('0') if there is no
message sequence number, i.e. if the noorig bit is set;
bits 3-7: are RESERVED and SHALL each be cleared ('0') to be in
conformance with this version of the specification.
<msg-size> is a 16 bit field, which specifies the size of the <msg-
header> and the following <msg-body>, counted in octets;
<originator-address> is the address of an interface of the node,
which originated the message. Its length is equal to address-
length octets. Each node SHOULD select one of its interface
addresses as its "originator address" and MUST utilize this
address consistently as the <originator address> in all messages
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it generates which include this field. Note that the originator
address is distinct from the IP source address, and that the same
originator address MUST be used regardless of which interface a
message is transmitted on. Also note that if a message is
retransmitted the originator address MUST NOT be changed;
<hop-limit> is an 8 bit field, which contains the maximum number of
hops a message will be transmitted. Before a message is
retransmitted, the hop-limit MUST be decremented by 1. When a
node receives a message with a hop-limit equal to 0 or 1, the
message MUST NOT be retransmitted under any circumstances.
Normally, a node will not receive a message with a hop-limit of 0
(note that this hop-limit is distinct from the IPv6 hop-limit);
<hop-count> is an 8 bit field, which contains the number of hops a
message has traveled. Before a message is retransmitted, the hop-
count MUST be incremented by 1. Initially, this hop-count SHOULD
be set to 0 by the originator of the message;
<msg-seq-number> is a 16 bit field, which contains a unique number,
generated by the originator node. The originator-address, msg-
seq-number and, if the typedep bit in the <msg-semantics> field is
set, the <msg-type> of a message serves to uniquely identify the
message in the network (allowing, among other things, duplicate
elimination).
5.2.1. Address Blocks
An address block represents a set of addresses in a compact and
simple form. Assuming that an address can be specified as a sequence
of bits of the form 'head:mid:tail', then an address block is a set
of addresses sharing the same 'head' and 'tail' and having different
'mids'. (The case where the 'tail' is empty is treated specially, as
is the case where the 'tail' consists of zero-valued octets, the
latter is particularly appropriate when used with a TLV indicating a
prefix length, see Section 6.2.)
Specifically, an address block conforms to the following
specification:
<address-block> = <num-addr>
<head-octet>
<head>?
<tail-octet>?
<tail>?
<mid>*
with the elements defined thus:
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<num-addr> is an 8 bit field containing the number of addresses
represented in the address block, which MUST NOT be zero. It is
equal to the number of <mid>s following (except when, as defined
below, mid-length == 0 and no <mid>s are required);
<head-octet> is an 8 bit field, where:
bits 0-6: contain the length of the <head>, if any. The
corresponding variable head-length is calculated by:
head-length = <head-octet> & 127
bit 7 (notail): indicates, if cleared ('0'), that the address
block contains a <tail-octet> (see below), if set ('1') that no
<tail-octet> is included;
<head> is omitted if head-length == 0, otherwise it is a field of
head-length octets which contains the leftmost octets which the
addresses in the block have in common (it SHOULD contain the
longest such sequence);
<tail-octet> is omitted if the notail bit is set ('1'), otherwise it
is an 8 bit field, where:
bits 0-6: contain the length of the <tail>, if any, or the
equivalent number of zero-valued tail octets. The
corresponding variable tail-length is calculated by:
tail-length = <tail-octet> & 127
bit 7 (zerotail): indicates, if cleared ('0'), that a <tail> (see
below) is included, if set ('1') that no <tail> is included,
and that the tail-length rightmost octets of each address in
the block are zero-valued;
If the <tail-octet> is omitted then tail-length = 0.
<tail> is omitted if tail-length == 0 or the zerotail bit is set
('1'), otherwise it is a field of length tail-length octets which
contains the rightmost octets which the addresses in the block
have in common (it SHOULD contain the longest such sequence in
this case);
If tail-length != 0 and the zerotail bit is set ('1') then all the
addresses in the block have tail-length zero-valued rightmost
octets (tail-length SHOULD be the largest such number in this
case);
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mid-length is a variable, calculated by:
mid-length = address-length - head-length - tail-length
mid-length MUST be non-negative.
<mid> is omitted if mid-length == 0 (in which case all addresses in
the block are the same), otherwise each <mid> is a field of length
mid-length octets, representing the 'mid' of the corresponding
address in the address block.
This representation aims at providing a flexible, yet compact, way of
representing sets of addresses.
5.3. TLVs and TLV Blocks
A TLV block has the following general layout:
<tlv-block> = <tlv-length>
<tlv>*
with the elements defined thus:
<tlv-length> is a 16 bit field, which contains the total length (in
octets) of the immediately following TLV(s). It does not include
its own length, thus if no TLVs follow, this field contains zero;
<tlv> is a TLV, providing information regarding the entire packet or
message or the address block which it follows. TLVs are specified
in Section 5.3.1;
5.3.1. TLVs
A TLV is a carrier of information, relative to a packet, to a message
or to addresses in an address block.
A TLV associated with an address block specifies some attribute(s),
which are associated with address(es) in the address-block. In order
to provide the largest amount of flexibility to benefit from address
aggregation as described in Section 5.2.1, a TLV associated to an
address block can apply to:
o all addresses in the address block;
o any continuous sequence of addresses in the address block;
o a single address in the address block.
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All TLVs conform to the following specification:
<tlv> = <tlv-type>
<tlv-semantics>
<index-start>?
<index-stop>?
<length>?
<value>?
where the elements are defined thus:
<tlv-type> is an 8 bit field, which specifies the type of the TLV.
The two most significant bits are allocated with the following
semantics:
bit 7 (tlv-user): TLV types with this bit cleared ('0') are
defined in this specification or can be allocated via standards
action. TLV types with this bit set ('1') are reserved for
private/local use.
bit 6 (msg-protocol): for TLV types with the tlv-user bit cleared
('0'), this bit specifies, if cleared ('0'), that the TLV type
is protocol independent, i.e. is not specific to any one
protocol, or, if set ('1'), that the TLV type is specific to
the protocol for which it is defined.
<tlv-semantics> is an 8 bit field which specifies the semantics of
the TLV according to the following:
bit 0 (novalue): if cleared ('0') contains <length> and <value>
elements. TLVs with this bit set ('1') contains no <length> or
<value> elements - the TLV type carries all the information
needed.
bit 1 (extended): if cleared ('0'), the size of the length field
is 8 bits. If set ('1'), the size of the length field is 16
bits. This bit MUST be cleared ('0') if the novalue bit is set
('1').
bit 2 (noindex): if cleared ('0'), the <index-start> and <index-
stop> elements are included. If set ('1'), the <index-start>
and <index-stop> elements are not included. This bit MUST be
set for packet or message TLVs. If this bit is set ('1') for
address block TLVs, the TLV applies to all addresses in the
address block.
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bit 3 (multivalue): if cleared ('0'), the TLV includes a single
value which applies to all addresses described by <index-start>
and <index-stop>. If set ('1'), the TLV includes separate
values for each of the addresses indicated by <index-start> and
<index-stop>. This bit MUST be cleared ('0') for packet or
message TLVs or if the novalue bit is set ('1').
bits 4-7: are RESERVED and SHALL each be cleared ('0').
<index-start> is omitted if the noindex bit is set ('1'), otherwise
it is an 8 bit field. In the former case, the variable index-
start is defined by:
index-start = <index-start>
in the latter case, the variable index-start is defined by:
index-start = 0
If this TLV is associated with an address block then index-start
specifies the index of the first address in the address block
(starting at zero) for which this TLV applies;
<index-stop> is omitted if the noindex bit is set ('1'), otherwise it
is an 8 bit field. In the former case, the variable index-stop is
defined by:
index-stop = <index-stop>
in the latter case, for a TLV associated with an address block
with <num-addr> addresses the variable index-stop is defined by:
index-stop = <num-addr> - 1
otherwise (a TLV associated with a packet or a message) the
variable index-stop is defined by:
index-stop = 0
If this TLV is associated with an address block then index-stop
specifies the index of the last address in the address block
(starting at zero) for which this TLV applies.
number-values is a variable, defined by
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number-values = <index-stop> - <index-start> + 1
If this TLV is associated with an address block then number-values
is the number of addresses in that block to which this TLV
applies, otherwise it is 1.
<length> is omitted if the novalue bit is set ('1'), otherwise it is
an 8 bit or 16 bit field, according to whether the extended bit is
cleared ('0') or set ('1'), respectively. If present this field
specifies the length, counted in octets, of the data contained in
<value>. If the multivalue bit is set ('1') then <length> MUST be
an integral multiple of number-values and the variable single-
length is defined by
single-length = <length> / number-values
otherwise, if the multivalue bit is cleared ('0'), the variable
single-length is defined by
single-length = <length>
<value> is omitted if the novalue bit is set ('1'), Otherwise it is a
field of length <length> octets. If the multivalue bit is cleared
('0') then this field is associated with the packet, message or
the relevant addresses (from index-start to index-stop) in the
address block with which this TLV is associated, as appropriate.
If the multivalue bit is set ('1') then this field is divided
equally into number-values fields, each of length single-length
octets and these are associated, in order, to the relevant
addresses (from index-start to index-stop) in the address block
with which this TLV is associated. The association is interpreted
according to the <tlv-type> field.
5.3.2. Constraints
TLVs in the same <tlv-block> SHALL be sorted in ascending TLV type
order.
Two or more TLVs of the same type associated with the same <addr-
block> SHALL NOT both cover any index (address).
TLVs of the same type associated with the same <addr-block> SHALL be
sorted in ascending <index-start> order.
5.4. Message Content Fragmentation
A message may be larger than is desirable to include, with the
packet, message and other headers (transport, IP), in a MAC frame.
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In this case the message SHOULD be fragmented. Only the originator
of a message may decide to fragment a message. When a message is
fragmented it MUST be assigned a content sequence number by the
originator. A content sequence number may also be assigned for
reasons other than fragmentation.
A content sequence number may be specific to the type of the message
or not. If the content sequence number is to be used for
fragmentation then this is indicated as specified in Section 6.1.
Two messages with the same originator and, when the content sequence
number is type-specific, with the same type, with different message
bodies SHALL NOT be assigned the same content sequence number. Two
messages with the same originator and the same message body MAY be
assigned the same content sequence number, with the same type-
dependence, in which case they MUST be fragmented identically.
A fragment of a message may have one of two forms:
o the fragment is a "partially or wholly self-contained message" and
may, thus, be parsed and processed immediately by the recipient.
Additional processing MAY be necessary when all fragments are
received;
o the fragment is not a "partially or wholly self-contained message"
and may, thus, not be processed until all fragments of the message
have been received.
Regardless of under which of the above forms a message is fragmented,
each fragment MUST be a complete message as defined in this
specification, i.e. MUST contain syntactically correct address
blocks and TLVs. Furthermore, all fragments of a given message MUST
be of the same type, and have the same fragmentation semantics, see
Section 6.1.
If a message is fragmented, each fragment MUST contain the following
TLVs, defined in Section 6.1:
o a message TLV with type FRAGMENTATION, specifying the number of
fragments, the fragment number (counting from zero), if the
fragment is a partially or wholly self-contained message, and if
the CONTENT-SEQ-NUMBER generated by the originator of the
fragmented message is specific to the type of the fragmented
message or not;
o a message TLV with type CONTENT-SEQ-NUMBER, specifying the content
sequence number associated with the information in the fragment.
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If the content sequence number included in the CONTENT-SEQ-NUMBER TLV
of a message is specific to the type of the message then the
originating node MUST maintain a content sequence number for that
message type and MUST increment it when it originates a new message
of that type, but not of any other type. A node MAY maintain such
type-specific content sequence numbers for any number of types.
If the content sequence number included in the CONTENT-SEQ-NUMBER TLV
of a message is not specific to the type of the message then the
originating node MUST maintain a single content sequence number for
those message type for which a content sequence number is required,
but for which the node does not maintain a type-specific content
sequence number. The node MUST increment this single content
sequence number when it originates a new message of any relevant
type, but not of any other types (either those for which a content
sequence number is not appropriate, or for which a type-specific
content sequence number is maintained.)
Since FRAGMENTATION is defined to be TLV type zero (see Section 6.1),
it can be determined if a message is fragmented by inspecting the
first three octets of the message body (the first three octets after
the message header):
o if the first two octets (the message TLV block length) are both
zero then the message is not a fragment;
o otherwise if the third octet (the first message TLV type) is zero
then the message is a fragment;
o otherwise the message is not a fragment.
A message SHOULD NOT be sent with a message TLV with type
FRAGMENTATION indicating "fragment zero of one".
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6. TLV specification
This document specifies two message TLVs, which are required in the
case of message fragmentation, and one address block TLV. The
address block TLV is included to allow a standardized way of
representing network addresses, with a prefix length, in control
messages.
6.1. Message TLV Specification
Message TLV Specification Overview
+----------------------+------+--------+----------------------------+
| Name | Type | Length | Value |
+----------------------+------+--------+----------------------------+
| FRAGMENTATION | 0 | 24 | See Table 2 below. |
| | | bits | |
| | | | |
| CONT_SEQ_NUM | 1 | 16 | A sequence number, |
| | | bits | associated with the |
| | | | content of the message |
+----------------------+------+--------+----------------------------+
Table 1
The fragmentation TLV contains the following fields in the following
order:
FRAGMENTATION TLV Value Specification Overview
+-------------+----------------------------------------------------+
| Field Width | Value |
+-------------+----------------------------------------------------+
| 8 bits | Number of fragments |
| | |
| 8 bits | Fragment number |
| | |
| 8 bits | Fragmentation semantics bit vector. |
+-------------+----------------------------------------------------+
Table 2
The bits in the fragmentation semantics bit vector are defined as
follows:
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bit 0 (notselfcont): indicates, if cleared ('0') that the message TLV
is a partially or wholly self-contained message, or if set ('1')
that the message TLV is not a partially or wholly self-contained
message.
bit 1 (typedepseq): indicates, if cleared ('0') that the originator
maintains a single sequence number for fragmented messages of
types including the type of this message, and that this is
included in the CONTENT-SEQ-NUMBER TLV. If set ('1'), the
originator node maintains a separate sequence number for the type
of this message, and that the sequence number in the CONTENT-SEQ-
NUMBER TLV is the sequence number corresponding to the type of
this message.
bits 2-7: are RESERVED and SHALL each be cleared ('0').
6.2. Address Block TLV Specification
The following address block TLV is provided for general use, and is
included in this specification since it complements the address
representation by providing a way of representing a network address
in a message.
Address Block TLV Specification Overview
+----------------------+------+--------+----------------------------+
| Name | Type | Length | Value |
+----------------------+------+--------+----------------------------+
| PREFIX_LENGTH | 0 | 8 bits | Indicates that the address |
| | | | is a network address, |
| | | | rather than a host |
| | | | address. The value is the |
| | | | length of the |
| | | | netmask/prefix. |
+----------------------+------+--------+----------------------------+
Table 3
An address in an address block without an associated PREFIX_LENGTH
TLV may be considered to have a prefix length equal to the address
length (in bits).
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7. IANA Considerations
The message format in this specification defines a message "type"
field, as well as two TLV types for message TLVs and address block
TLVs respectively.
A new registry for message types must be created with initial
assignments as specified in Table 4.
A new registry for packet TLV types must be created, with no initial
assignments.
A new registry for message TLV types must be created with initial
assignments as specified in Table 5.
A new registry for address block TLV types must be created with
initial assignments as specified in Table 6.
Assigned Message Types
+--------------------+-------+--------------------------------------+
| Mnemonic | Value | Description |
+--------------------+-------+--------------------------------------+
| RESERVED | 0 | At start of packet signals that what |
| | | follows is a packet header, rather |
| | | than a message header, and to allow |
| | | packet header and message padding |
| | | with zero octets |
| | | |
| RESERVED | 1 | |
| | | |
| RESERVED | 2 | |
| | | |
| RESERVED | 3 | |
| | | |
| RESERVED | 4 | |
+--------------------+-------+--------------------------------------+
Table 4
Message types 1 to 4 are reserved because they are used by OLSRv1 [3]
which uses a compatible packet/message header format.
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Assigned Message TLV Types
+--------------------+-------+--------------------------------------+
| Mnemonic | Value | Description |
+--------------------+-------+--------------------------------------+
| FRAGMENTATION | 0 | Specifies behavior in case of |
| | | content fragmentation |
| | | |
| CONT_SEQ_NUM | 1 | A sequence number, associated with |
| | | the content of the message |
+--------------------+-------+--------------------------------------+
Table 5
Assigned Address Block TLV Types
+--------------------+-------+--------------------------------------+
| Mnemonic | Value | Description |
+--------------------+-------+--------------------------------------+
| PREFIX_LENGTH | 0 | Indicates that associated addresses |
| | | are network addresses, with given |
| | | prefix length |
+--------------------+-------+--------------------------------------+
Table 6
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8. Security Considerations
Packets are designed to be transmitted only one hop, and not
forwarded. Thus, hop-by-hop packet level security MAY be
implemented, between nodes with an existing security association,
through including suitable packet TLV(s) containing a cryptographic
signature to the packet. Since packets are received as transmitted,
signatures can be calculated based on the entire packet content
(including message and packet headers), or on parts thereof as
appropriate.
The messages contained in a packet are available at each hop, and
MAY, according to the information in the message header, and the
protocol employing this specification, be forwarded and/or processed.
If a message is to be forwarded, the <hop-count> and <hop-limit>
fields in the message header, if present, SHOULD be modified. All
other message header fields, and the message body, MAY, depending on
the protocol employing this specification, be left intact.
Such a protocol (using immutable messages, other than the indicated
fields) using this message format MAY, between nodes with an existing
security association, implement end-to-end message security by
including suitable message TLV(s) containing a cryptographic
signature to the message. This signature can be calculated based on
the entire message, including the message header, with the provision
that the <hop-count> and <hop-limit> fields MUST, if present, both be
set to zero ('0') for both calculation and verification of the
signature.
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9. References
9.1. Normative References
[1] Bradner, S., "Key words for use in RFCs to Indicate Requirement
Levels", RFC 2119, BCP 14, March 1997.
[2] Hinden, R. and S. Deering, "Internet Protocol Version 6 (IPv6)
Addressing Architecture", RFC 3513, April 2003.
9.2. Informative References
[3] Clausen, T. and P. Jacquet, "The Optimized Link State Routing
Protocol", RFC 3626, October 2003.
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Appendix A. Packet and Message Layout
This section specifies the translation from the abstract descriptions
of packets employed in the protocol specification, and the bit-layout
packets actually exchanged between the nodes.
Appendix A.1. General Packet Format
The basic layout of a packet (excluding transport and IP headers)
SHALL be one of the following five options.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 0 0 0 0 0| Reserved |0|0| Packet Sequence Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| Message + Padding |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
: ... :
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| Message + Padding |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
or
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 0 0 0 0 0| Reserved |0|1| Padding |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| Message + Padding |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
: ... :
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| Message + Padding |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
or
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 0 0 0 0 0| Reserved |1|0| Packet Sequence Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| Packet TLV Block |
| |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | Padding |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| Message + Padding |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
: ... :
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| Message + Padding |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
or
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 0 0 0 0 0| Reserved |1|1| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| |
| Packet TLV Block |
| |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | Padding |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| Message + Padding |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
: ... :
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| Message + Padding |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
or
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| Message + Padding |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
: ... :
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| Message + Padding |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Note that in the first four cases the Reserved bits SHOULD be zero,
whilst in the last case the first octet MUST NOT be zero (this is
used to recognise this case). In all cases where they are present,
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the octets indicated as Padding are optional and MAY be omitted. If
not omitted they SHOULD be used to pad to a 32 bit boundary and MUST
all be zero.
The basic layout of a message, plus padding, SHALL be one of the
following four options.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Message Type | Resv |N|0|0| Message Size |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Originator Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Hop Limit | Hop Count | Message Sequence Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| Message Body |
| |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | Padding |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
or
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Message Type | Resv |N|0|1| Message Size |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Hop Limit | Hop Count | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| |
| Message Body |
| |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | Padding |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
or
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Message Type | Resv |N|1|0| Message Size |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Originator Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Message Sequence Number | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| |
| Message Body |
| |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | Padding |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
or
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Message Type | Resv |N|1|1| Message Size |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| Message Body |
| |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | Padding |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The reserved bits marked Resv SHOULD be zero. The N bit is set ('1')
if the message sequence number is type-dependent, or cleared ('0') if
the message sequence number is type-independent. The octets
indicated as Padding are optional and MAY be omitted. If not omitted
they SHOULD be used to pad to a 32 bit boundary and MUST all be zero;
they are not included in the message size.
The basic layout of a message body SHALL be as follows.
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| Message TLV Block |
| +-+-+-+-+-+-+-+-+
| | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| |
| Address Block |
| |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | |
+-+-+-+-+-+-+-+-+ |
| Address TLV Block |
| |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| |
: ... :
| |
| +-+-+-+-+-+-+-+-+
| | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| |
| Address Block |
| |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| |
| Address TLV Block |
| |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The basic layout of an address block SHALL be one of the following
three options.
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Number Addrs |0| Head Length | Head |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Mid | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| |
: ... :
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Mid |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
or
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Number Addrs |1| Head Length | Head |0| Tail Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tail | Mid | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| |
: ... :
| |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | Mid |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
or
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Number Addrs |1| Head Length | Head |1| Tail Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Mid | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| |
: ... :
| |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | Mid |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The length of each Mid section is equal to the address length minus
the Head Length and the Tail Length. In the first case there is no
Tail section, the Mid sections are actually tail sections. In the
third case the tail section is not included, it is all octets zero.
The basic layout of a TLV block (packet TLV block, message TLV block
or address TLV block) SHALL be as follows.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Length | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| |
| TLV |
| +-+-+-+-+-+-+-+-+
| | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| |
: ... :
| |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| |
| TLV |
| +-+-+-+-+-+-+-+-+
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Length is of the TLV block contents, it does not include itself
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(hence if there are no TLVs then Length is zero).
The basic layout of a TLV SHALL be one of the following six options.
A packet TLV or message TLV SHALL be one of the last three options
only.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Resv |M|0|0|0| Index Start | Index Stop |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Length | |
+-+-+-+-+-+-+-+-+ |
| Value |
| |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+-+-+-+-+-+-+-+-+
or
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Resv |0|0|0|1| Index Start | Index Stop |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
or
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Resv |M|0|1|0| Index Start | Index Stop |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Length | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| |
| |
| Value |
| |
| |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+-+-+-+-+-+-+-+-+
or
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Resv |M|1|0|0| Length | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| |
| Value |
| |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+-+-+-+-+-+-+-+-+
or
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Resv |0|1|0|1|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
or
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Resv |M|1|1|0| Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| |
| Value |
| |
| |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+-+-+-+-+-+-+-+-+
M denotes the multivalue bit in those cases when it may be set ('1')
or cleared ('0'). In the cases where it MUST be cleared ('0') it is
shown thus; it MUST also be cleared ('0') in a packet TLV or message
TLV.) The reserved bits marked Resv SHOULD also be zero.
An example packet, using IPv4 addresses (length four octets) is
shown. This packet has a header, with a packet sequence number but
no packet TLV block, and contains a single unfragmented message. The
message has a complete message header, a message TLV block of content
length 9 octets containing a single TLV (with the noindex bit of its
semantics set and value length 6 octets) and then two address blocks
each with a following TLV block. The first address block contains 3
addresses (head length 2 octets, no tail, hence mid length two
octets) and is followed by a TLV block of content length 9 octets
containing two TLVs. The first of these TLVs has the noindex bit of
its semantics set and has a single value of length 2 octets, which
applies to all of the addresses in the preceding address block. The
second of these TLVs has the novalue bit of its semantics set and
hence has no length or value fields (it does have index fields, which
indicate which of the addresses this TLV applies to). The second
address block contains 2 addresses (head length 0 octets, hence no
head octets, tail length 2 octets, zero-valued tail not included,
hence mid length two octets) and is followed by a TLV block of
content length 5 octets. This TLV block contains a single TLV of
type PREFIX_LENGTH which has the multivalue and no index bits of its
semantics set and a value field length of 2 octets, indicating two
values each of one octet length. There are two final padding octets
which are not included in the message length of 62 octets.
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 0 0 0 0 0| Reserved |0|0| Packet Sequence Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Message Type | Resv |N|0|0|0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 0|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Originator Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Hop Limit | Hop Count | Message Sequence Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 1| TLV Type | Resv |0|1|0|0|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 0 0 1 1 0| Value |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Value (cont) |0 0 0 0 0 0 1 1|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 0 0 0 1 0| Head | Mid |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Mid (cont) | Mid | Mid |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Mid (cont) |0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 1| TLV Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Resv |0|1|0|0|0 0 0 0 0 0 1 0| Value |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Type | Resv |0|0|0|1| Index Start | Index Stop |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 0 0 0 1 0|1 0 0 0 0 0 0 0|1 0 0 0 0 0 1 0| Mid |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Mid (cont) | Mid |0 0 0 0 0 0 0 0|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 0 0 1 0 1| PREFIX_LENGTH | Resv |1|1|0|0|0 0 0 0 0 0 1 0|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Value0 | Value1 |0 0 0 0 0 0 0 0|0 0 0 0 0 0 0 0|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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Appendix B. Contributors
This specification is the result of the joint efforts of the
following contributers from the OLSRv2 Design Team -- listed
alphabetically.
o Cedric Adjih, INRIA, France, <Cedric.Adjih@inria.fr>
o Emmanuel Baccelli, Hitachi Labs Europe, France,
<Emmanuel.Baccelli@inria.fr>
o Thomas Heide Clausen, LIX, Ecole Polytechnique, France,
<T.Clausen@computer.org>
o Justin W. Dean, NRL, USA<jdean@itd.nrl.navy.mil>
o Christopher Dearlove, BAE Systems, UK,
<chris.dearlove@baesystems.com>
o Satoh Hiroki, Hitachi SDL, Japan, <h-satoh@sdl.hitachi.co.jp>
o Philippe Jacquet, INRIA, France, <Philippe.Jacquet@inria.fr>
o Monden Kazuya, Hitachi SDL, Japan, <monden@sdl.hitachi.co.jp>
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Appendix C. Acknowledgements
The authors would like to acknowledge the team behind OLSRv1, as
specified in RFC3626, including Anis Laouiti, Pascale Minet, Laurent
Viennot (all at INRIA, France), and Amir Qayuum (Center for Advanced
Research in Engineering, Pakistan) for their contributions.
The authors would like to gratefully acknowledge the following people
for intense technical discussions, early reviews and comments on the
specification and its components: Joe Macker (NRL), Alan Cullen (BAE
Systems), Ian Chakeres (Boeing), Charlie E. Perkins (Nokia), Andreas
Schjonhaug (LIX), Florent Brunneau (LIX), and the entire IETF MANET
working group.
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Authors' Addresses
Thomas Heide Clausen
LIX, Ecole Polytechnique, France
Phone: +33 6 6058 9349
Email: T.Clausen@computer.org
URI: http://www.lix.polytechnique.fr/Labo/Thomas.Clausen/
Christopher M. Dearlove
BAE Systems Advanced Technology Centre
Phone: +44 1245 242194
Email: chris.dearlove@baesystems.com
URI: http://www.baesystems.com/ocs/sharedservices/atc/
Justin W. Dean
Naval Research Laboratory
Phone: +1 202 767 3397
Email: jdean@itd.nrl.navy.mil
URI: http://pf.itd.nrl.navy.mil/
Cedric Adjih
INRIA Rocquencourt
Phone: +33 1 3963 5215
Email: Cedric.Adjih@inria.fr
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Clausen, et al. Expires December 21, 2006 [Page 41]
