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Network Working Group W A Simpson
Internet Draft Daydreamer
expires in six months September 1994
IPv6 Neighbor Discovery -- ICMP Message Formats
draft-simpson-ipv6-discov-formats-00.txt
Status of this Memo
This document is a submission to the IPng Working Group of the
Internet Engineering Task Force (IETF). Comments should be submitted
to the ipng@sunroof.eng.sun.com mailing list.
Distribution of this memo is unlimited.
This document is an Internet-Draft. 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.
Internet Drafts are draft documents valid for a maximum of six
months, and may be updated, replaced, or obsoleted by other documents
at any time. It is not appropriate to use Internet Drafts as
reference material, or to cite them other than as a ``working draft''
or ``work in progress.''
To learn the current status of any Internet-Draft, please check the
``1id-abstracts.txt'' listing contained in the internet-drafts Shadow
Directories on ds.internic.net (US East Coast), nic.nordu.net
(Europe), ftp.isi.edu (US West Coast), or munnari.oz.au (Pacific
Rim).
Abstract
This document specifies ICMP messages for the identification and
location of adjacent IPv6 nodes.
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1. Additional ICMP Packets
The Packet format and basic facilities are already defined for ICMP
as modified for IPv6 [IPv6-ICMP].
Up-to-date values of the ICMP Type field are specified in the most
recent "Assigned Numbers" [RFC-1310]. This document concerns the
following values:
33 Solicitation
34 Advertisement
35 Mobile Registration Request
36 Mobile Registration Reply
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1.1. Solicitation
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Code | Checksum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Extensions ...
+-+-+-+-+-+-+-+-+-+-+-+-
Type 33
Code Up-to-date values are specified in the most recent
"Assigned Numbers" [RFC-1310]. Current values are
assigned as follows:
0 RESERVED
1 General
2 Router
3 Service
Checksum The ICMP Checksum.
Extensions This field is variable in length and contains zero
or more Extensions. These Extensions are described
in a later section.
The contents of the Reserved field MUST be zero on transmission, and
MUST be ignored on receipt. Future backward-compatible changes to
the protocol may specify the contents of the Reserved field or of
additional octets at the end of the message.
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1.1.1. General Solicitation
The General Solicitation MUST contain at least the following values:
IPv6 Header:
Destination an IPv6 Address of the target. It MUST NOT
contain a multicast address.
Source any IPv6 Address associated with the sending
node. It MUST NOT contain the Unspecified
Address.
ICMP fields:
Code 1 for General Solicitation.
Extensions:
Media-Access for interfaces which are not point-to-point
links.
System-Heard for each Router Advertisement that has been
heard, in order of preference.
In the unlikely event that not all extensions fit in a single
solicitation, as constrained by the MTU of the link, the remaining
extensions are removed.
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1.1.2. Router Solicitation
The Router Solicitation MUST contain at least the following values:
IPv6 Header:
Destination the all-routers multicast. The scope is set to
intra-link.
Source any IPv6 Address associated with the sending
node. It MAY contain the Unspecified Address,
when the node has not yet determined an IPv6
Address.
ICMP fields:
Code 2 for Router Solicitation.
There are no required extensions.
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1.1.3. Service Solicitation
The Service Solicitation MUST contain at least the following values:
IPv6 Header:
Destination the multicast group associated with the service.
The scope is set to intra-site.
Source any IPv6 Address associated with the sending
node. It MUST NOT contain the Unspecified
Address.
ICMP fields:
Code 3 for Service Solicitation.
Extensions:
Service-Information
One or more qualifiers, in order of importance.
In the unlikely event that not all extensions fit in a single
solicitation, as constrained by the MTU of the link, the remaining
extensions are removed.
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1.2. Advertisement
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Code | Checksum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence Number | LifeTime |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Extensions ...
+-+-+-+-+-+-+-+-+-+-+-+-
Type 34
Code Up-to-date values are specified in the most recent
"Assigned Numbers" [RFC-1310]. Current values are
assigned as follows:
0 RESERVED
1 General
2 Router
3 Service
4 Local Redirect
5 Remote Redirect
Checksum The ICMP Checksum.
Sequence Number Contains the number of Advertisement messages sent
since the node was initialized. This number MUST
include this advertisement. That is, the first
Advertisement contains the value one, and the value
zero indicates that the number has rolled over.
LifeTime Indicates the seconds remaining before the
advertised information is considered expired. The
maximum time is approximately 18.2 hours.
Extensions This field is variable in length and contains zero
or more Extensions. These Extensions are described
in a later section.
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1.2.1. General Advertisement
The General Advertisement MUST contain at least the following values:
IPv6 Header:
Destination the Source specified in the solicitation.
Source the Destination specified in the solicitation.
ICMP fields:
Code 1 for General Advertisement.
Lifetime the interface's configured AdvertisementLifetime.
Extensions:
Media-Access for interfaces which are not point-to-point
links.
Other-Identifier for each of that node's known IPv6 Addresses
other than the IPv6 Address specified in the IPv6
Source field. The prefix size is set to zero.
System-Heard for each Router Advertisement that has been
heard, in order of preference.
In the unlikely event that not all extensions fit in a single
advertisement, as constrained by the MTU of the link, the
remaining extensions are removed.
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1.2.2. Router Advertisement
The Router Advertisement MUST contain at least the following values:
IPv6 Header:
Destination the all-nodes multicast. The scope is set to
intra-link.
Source the primary IPv6 Address of the node.
The same IPv6 Address is used for all interfaces.
When a router has more than one interface on the
same link, or a multi-homed host can hear the
same router on more than one link, it is
necessary to unambiguously know which router sent
this advertisement. The individual routing
prefixes for the links are distinguished in the
Routing Information extension.
ICMP fields:
Code 2 for Router Advertisement.
Lifetime the interface's configured AdvertisementLifetime.
Extensions:
Media-Access for interfaces which are not point-to-point
links.
Routing-Information
for each of that interface's associated IPv6
Addresses whose Advertise flags are TRUE.
Change-Identifier for each of that interface's recently changed
IPv6 Addresses.
Other-Identifier for each of that node's other IPv6 Addresses
which have not already been included through
prefix subsumption.
System-Heard for each Router Advertisement that has been
heard, in order of preference.
In the unlikely event that not all extensions fit in a single
advertisement, as constrained by the MTU of the link, multiple
advertisements are sent, with each except the last containing as
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many extensions as can fit.
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1.2.3. Service Advertisement
The Service Advertisement MUST contain at least the following values:
IPv6 Header:
Destination the all-nodes multicast. The scope is set by
administrative policy.
Source any IPv6 Address associated with the sending
node.
ICMP fields:
Code 3 for Service Advertisement.
Lifetime the interface's configured AdvertisementLifetime.
Extensions:
Media-Access for interfaces which are not point-to-point
links.
Other-Identifier for each of that node's known IPv6 Addresses
other than the IPv6 Address specified in the IPv6
Source field. The prefix size is set to zero.
Service-Information
One or more qualifiers, in order of importance.
System-Heard for each Router Advertisement that has been
heard, in order of preference.
In the unlikely event that not all extensions fit in a single
advertisement, as constrained by the MTU of the link, multiple
advertisements are sent, with each except the last containing as
many extensions as can fit.
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1.2.4. Local Redirect
The Local Redirect MUST contain at least the following values:
IPv6 Header:
Destination the Source specified in the packet being
redirected.
Source the primary IPv6 Address associated with the
sending node.
ICMP fields:
Code 4 for Local Redirect.
Sequence the last Sequence from the target node
Advertisement.
Lifetime the remaining Lifetime from the target node
Advertisement.
Extensions:
Media-Access for interfaces which are not point-to-point
links, the Media-Access extension from the target
node Advertisement.
Other-Identifier for each IPv6 Address associated with the target
node. The metric is set to zero.
When the redirect applies to an entire cluster,
the prefix size is set to the size of the cluster
prefix.
Transit-Information
one or more, when the redirect is limited to a
specific Quality of Service. The metric is set
to zero.
Redirected-Header The target header.
In the unlikely event that not all extensions fit in a single
redirect, as constrained by the MTU of the link, the remaining
extensions are removed. Only a single redirect is sent.
The Local Redirect is used by a router to redirect a host to another
router, or to another host on the same link. These uses are
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indistinguishable.
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1.2.5. Remote Redirect
The Remote Redirect MUST contain at least the following values:
IPv6 Header:
Destination the Source specified in the packet being
redirected.
Source the primary IPv6 Address associated with the
sending node.
An Authentication Header is required.
ICMP fields:
Code 5 for Remote Redirect.
Sequence the last Sequence from the target node
Advertisement.
Lifetime the remaining Lifetime from the target node
Advertisement.
Extensions:
Change-Identifier when the IPv6 Destination of the redirected
packet is changing. The Prefix Size is set to
zero.
Other-Identifier for each IPv6 Address associated with the target
node. The metric is set to zero, and the prefix
size is set to zero.
Redirected-Header The target header.
In the unlikely event that not all extensions fit in a single
redirect, as constrained by the MTU of the link, the remaining
extensions are removed. Only a single redirect is sent.
The Remote Redirect is primarily used to support Mobility.
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1.3. Mobile Registration Request
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Code | Checksum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| unused | LifeTime |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ Identification +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Home Agent ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Care-Of-Address ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Extensions ...
+-+-+-+-+-+-+-+-+-+-+-+-
IPv6 Header:
Destination The IPv6 Address of the Agent, when known.
When the IPv6 Address is unknown (the agent was
discovered via a link-layer protocol), the "all
Mobile Agents" multicast address. The link-layer
unicast address is used to deliver the datagram
to the correct Agent.
Source An IPv6 Address belonging to the interface on
which this message is sent.
A Mobile Node MUST use the transient Care-Of-
Address when assigned; otherwise, the Home-
Address is used.
ICMP fields:
Type 35 <TBD>
Code Bitmask of optional capabilities:
1 - retain prior registrations
2 - registering through Foreign Agent
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LifeTime The seconds remaining before the registration is
considered expired. A value of zero indicates a
request for de-registration. A value of all ones
indicates infinity.
Home Agent The IPv6 Address of a Home Agent.
Care-Of-Address The IPv6 Address for the decapsulation end of a
tunnel.
Identification A sequence number assigned by the Mobile Node.
This is used to assist in matching Requests with
Replies.
A Network Time Protocol [RFC-1305] formatted
value is preferred. The low-order 32 bits of the
NTP format represent fractional seconds, and
those bits which are not available from a time
source SHOULD be generated from a good source of
randomness.
A battery-backed clock is the usual source of
this value. In more robust implementations,
Global Positioning System or authenticated NTP
values MAY be used. The elapsed time since
system startup or another such monotonically
increasing counter MAY be used, but is considered
less secure, as it could repeat each time the
machine is restarted, or when a poor source of
randomness is used for the low-order bits. See
[Eastlake, et alia] for a discussion of sources
of randomness.
It is possible to use an entirely random
"nonce" in this field, or to generate nonces
from previous registration exchanges. We have
not standardized this procedure because of
intellectual property concerns. It is also
incompatible with the expected venue of the
protocol, and presents difficulties with
interoperability and security validation.
The value MUST NOT be the same as an immediately
preceeding request, and SHOULD NOT repeat during
the lifetime of the Mobility Security Association
between the Mobile Node and the Home Agent.
Extensions:
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Other-Identifier required. Contains the Home-Address of the
Mobile Node. The metric is set to zero.
Mobile-Home Authentication
required. Immediately follows all non-
authentication extensions.
When forwarded by a Foreign Agent, extensions which are specific to
the Foreign Agent are removed. All others are copied without
modification.
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1.4. Mobile Registration Reply
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Code | Checksum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| unused | LifeTime |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ Identification +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Extensions ...
+-+-+-+-+-+-+-+-+-+-+-+-
IPv6 Header:
The Source and Destination of the Request message are swapped for
the Reply message.
Note that the Source of the original Mobile Registration Request
must be saved in order for a Foreign Agent to return the reply to
the correct Mobile Node.
ICMP fields:
Type 36 <TBD>
Code One of the following codes:
0 service will be provided.
denied by Foreign Agent,
16 reason unspecified.
17 administratively prohibited.
18 insufficient resources.
19 Mobile Node failed authentication.
20 Home Agent failed authentication.
21 Request LifeTime too long.
denied by Home Agent,
32 reason unspecified.
33 administratively prohibited.
34 insufficient resources.
35 Mobile Node failed authentication.
36 Foreign Agent failed authentication.
Up-to-date values of the Code field are specified
in the most recent "Assigned Numbers" [RFC-1310].
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LifeTime The seconds remaining before the registration is
considered expired. A value of zero confirms a
request for de-registration. A value of all ones
indicates infinity.
Identification Copied from the Request message.
Extensions:
Other-Identifier required. Contains the Home-Address of the
Mobile Node. The metric is set to zero.
Mobile-Home Authentication
required. Immediately follows all non-
authentication extensions.
Note that the Care-Of-Address and Home Agent are
not present in the message. This provides a
separate calculation value for mutual
authentication.
When forwarded by a Foreign Agent, extensions which are specific to
the Foreign Agent are removed. All others are copied without
modification.
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2. Extensions
Extensions allow variable amounts of information to be carried within
each Solicitation or Advertisement packet. Some extensions are
common to both packet types.
The end of the list of Extensions is indicated by the Payload Length
of the IPv6 packet.
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
| Extension | Length | Data ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
Extension This document concerns the following values:
0 Single Pad (no length field)
1 Multiple Pads (with length field)
2 Change-Identifier
3 Other-Identifier
4 System-Heard
5 Routing-Information
6 Service-Information
7 Transit-Information
8 Redirected-Header
14 Maximum-Receive-Unit
15 Media-Access
16 Mobility (obsolete)
17 Home-Address (obsolete)
32 Mobile-Home Authentication
64 Minimal Encapsulation
65 GRE Encapsulation
Up-to-date values are specified in the most recent
"Assigned Numbers" [RFC-1310].
Length Indicates the length of the Data field which has
been used. The Length does not include the
Extension and Length octets. The Single Pad
(extension 0) is a special case, which has no Length
field.
Data This field is zero or more octets and contains the
value(s) for this Extension. The format and length
of the Data field is determined by the Extension and
Length fields.
When an extension is encountered which is not recognized, it is
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ignored. The length field is used to skip the data field in
searching for the next extension.
Every extension is aligned such that internal fields fall on natural
boundaries, except that fields larger than 64-bits need only be
aligned to 64-bit boundaries.
Any unused portion of the datagram between such Extensions is padded
as appropriate. The final Extension in a datagram does not require
trailing padding.
2.1. Single Pad
+-+-+-+-+-+-+-+-+
| Extension |
+-+-+-+-+-+-+-+-+
Extension 0
2.2. Multiple Pads
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
| Extension | Length | Data ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
Extension 1
Length Indicates the length of the Data field.
Data This field is zero or more bytes of zeroes.
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2.3. Change-Identifier
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Extension | Length | unused | Prefix Size |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| unused |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Old IPv6 Address ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ New IPv6 Address ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Extension 2
Length 22
Prefix Size Indicates the number of bits in both IPv6 Addresses
which define the cluster prefix width for the link.
The value ranges from 0 to 126.
Old IPv6 Address Depending on the Prefix Size, it may indicate a
cluster, or a single IPv6 Address.
New IPv6 Address Depending on the Prefix Size, it may indicate a
cluster, or a single IPv6 Address.
For advertisements, this allows changing a prefix for every node on a
router's interface.
For redirects, this allows changing a single target IPv6 Address.
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2.4. Other-Identifier
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Extension | Length | | Prefix Size |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Metric |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ IPv6 Address ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Extension 3
Length 14
Prefix Size Indicates the number of bits in the IPv6 Address
which define the cluster prefix width for the link.
The value ranges from 0 to 126.
If the IPv6 Address does not indicate a valid
prefix, the value is zero.
Non-routers MUST set this field to zero.
Metric Indicates the preference level for use of this node
to forward packets to the IPv6 Address. Lower
values indicate greater preference.
Non-routers MUST set this field to zero.
IPv6 Address Contains one of the IPv6 Addresses for this node.
This may be another IPv6 Address for the same
interface that sent the message, or may identify
another interface on the same node which sent the
message.
This supports multiple IPv6 Addresses per interface, as well as
multi-homed nodes.
When a number of interfaces, such as point-to-point interfaces, may
be aggregated with the same prefix, only one extension need be
included.
For advertisements, this enables the recipient node to determine the
best next-hop without sending a Solicitation when the next-hop is on
another interface attached to the same advertising node.
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For redirects, this enables the recipient node to determine the best
next-hop without multiple redirects for each cluster.
2.5. System-Heard
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Extension | Length | | Prefix Size |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence Number | Remaining LifeTime |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ IPv6 Address ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MRU | | Speed |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Quality |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Advertisement Count |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Error Count |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Extension 4
Length 30
Prefix Size Indicates the number of bits in the IPv6 Address
which define the cluster prefix width for the link.
The value ranges from 0 to 126.
If the IPv6 Address does not indicate a valid
prefix, the value is zero.
Sequence Number Contains the last heard sequence number from the
node.
Remaining LifeTime
Indicates the seconds remaining before the entry is
considered expired.
IPv6 Address Contains the primary IPv6 Address for the node,
taken from the Source field of the Advertisement
heard.
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MRU Indicates the maximum size packet that the node will
receive over the link.
Speed Indicates the speed of the link over which the
advertisement or solicitation was heard. Higher
values indicate greater speed. The speed value is
related to int( 10 * ln( speed / 100 ) ) in bits per
second.
0 link is down
1 - 9 reserved
10 300 or less
24 1,200 96 1,544,000 T1
31 2,400 99 2,048,000 E1
38 4,800 106 4,000,000 Token Ring
42 7,200 110 6,312,000 T2
45 9,600 115 10,000,000 Ethernet
49 14,400 119 16,000,000 Token Ring
52 19,200
56 28,800 130 44,736,000 T3
59 38,400 142 155,520,000 STS-3,STM-1
63 57,600 202 622,080,000 STS-12,STM-4
64 64,000 216 2,488,320,000 STS-48,STM-16
71 128,000
73 153,600
78 256,000
Quality Contains an indication of the signal quality
received from this node. Higher values indicate
greater quality.
Advertisement Count
Indicates the number of advertisements that have
been heard from the identified node.
Error Count Indicates the number of errors which have been
detected on the link with the identified node.
This extension is included in the Advertisement message to indicate a
node which has been heard.
The MRU, Speed, Quality, Advertisement Count, and Error Count are
primarily used for selecting among multiple paths in a wireless
environment.
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2.6. Routing-Information
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Extension | Length |C|F| | Prefix Size |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | Preference |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ IPv6 Address ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Extension 5
Length 14
C Cluster bit. When this bit is set to 1, the IPv6
Cluster is entirely confined to the link. When
forwarding, a node MAY use the prefix to determine
whether a target node is on the link.
F Foreign Agent bit. When this bit is set to 1,
Mobile Registration through the Foreign Agent is
required, even when the Mobile Node has acquired a
transient Care-Of-Address.
Prefix Size Indicates the number of bits in the IPv6 Address
which define the cluster prefix width for the link.
The value ranges from 0 to 126.
If the IPv6 Address does not indicate a valid
prefix, the value is zero.
Preference Indicates the preference level for use of this node
to forward packets to the IPv6 Address. Higher
values indicate greater preference.
IPv6 Address Contains one of the IPv6 Addresses for this
interface.
This extension is sent only by Routers.
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2.7. Service-Information
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Extension | Length | Service |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data ...
+-+-+-+-+-+-+-+-+-+-+-+-
Extension 6
Length >= 2
Service The value of this field is usually the same as the
well-known port number. Up-to-date values are
specified in the most recent "Assigned Numbers"
[RFC-1310].
Data This field is variable in length and contains
Attribute information specific to the service.
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2.8. Transit-Information
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Extension | Length | | QoS |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Metric |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Extension 7
Length 6
QoS Indicates a quality of service for which transit
will be accepted.
Metric Indicates the preference level for use of this link
to forward packets of the indicated Quality of
Service. Lower values indicate greater preference.
For advertisements, this indicates that a router will accept transit
traffic for the service. If this extension is not included, other
routers will treat the link as a stub cluster.
For redirects, this indicates that the redirect is limited to only
the particular service. If this extension is not included, the
redirect includes all services.
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2.9. Redirected-Header
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Extension | Length | IPv6 Header ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Extension 8
Length 54
IPv6 Header 48 octets.
This extension is included in the Local or Remote Redirect to verify
the traffic that is being redirected.
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2.10. Maximum-Receive-Unit
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Extension | Length | MRU |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Extension 14
Length 2
MRU Indicates the maximum size packet that the node will
receive over the link.
The Maximum-Receive-Unit extension MUST be included in those messages
sent from an interface for which there is no dependable MTU, such as
Frame-Relay or Asynchronous Transfer Mode.
It MUST NOT be included in messages such as the Remote Redirect which
pass through intermediate nodes.
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2.11. Media-Access
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Extension | Length | Media Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Media Address ...
+-+-+-+-+-+-+-+-+-+-+-+-
Extension 15
Length >= 2
Media Type The value of this field is the same as the Hardware
Type used in ARP. Up-to-date values are specified
in the most recent "Assigned Numbers" [RFC-1310].
Media Address This field is variable in length and contains the
media address which is used to access this node.
The Media Address is always specified in Canonical
order.
The Media-Access extension MUST be included in those messages sent
from an interface on a multi-access media.
It MUST NOT be included in a message sent from a point-to-point
interface, or in messages such as the Remote Redirect which pass
through intermediate nodes.
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2.12. Mobile-Home Authentication Extension
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Extension | Length | Authenticator ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Extension 32
Length The number of data bytes in the Extension (16 when
MD5 is used).
Authenticator Variable length (128 bits for MD5).
A hash value taken over a stream of bytes consisting
of the shared secret, followed by (concatenated
with) the fields in the Mobile Registration message
beginning with the Type field, including all prior
extensions, and the Type and Length of this
extension, but not including the Authenticator field
itself.
This Authentication Extension is found in all Mobile Registration
Requests and Replies.
The value differs depending on the direction the message is sent,
since the Mobile Registration Request and Reply have different
fields.
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2.13. Minimal Encapsulation Extension
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Extension | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Extension 64
Length 0
The Minimal Encapsulation Extension is found in Router Advertisements
and Mobile Registration Requests.
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Security Considerations
References
[Eastlake]
[IPv6-ICMP]
[RFC-1305]
[RFC-1310]
Acknowledgements
Extensive review by Alex Conta (DEC), and Dan McDonald (NRL).
Author's Address
Questions about this memo can also be directed to:
William Allen Simpson
Daydreamer
Computer Systems Consulting Services
1384 Fontaine
Madison Heights, Michigan 48071
Bill.Simpson@um.cc.umich.edu
bsimpson@MorningStar.com
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DRAFT IPv6 Discovery Formats September 1994
Table of Contents
1. Additional ICMP Packets ............................... 1
1.1 Solicitation .................................... 2
1.1.1 General Solicitation ............................ 3
1.1.2 Router Solicitation ............................. 4
1.1.3 Service Solicitation ............................ 5
1.2 Advertisement ................................... 6
1.2.1 General Advertisement ........................... 7
1.2.2 Router Advertisement ............................ 8
1.2.3 Service Advertisement ........................... 10
1.2.4 Local Redirect .................................. 11
1.2.5 Remote Redirect ................................. 13
1.3 Mobile Registration Request ..................... 14
1.4 Mobile Registration Reply ....................... 17
2. Extensions ............................................ 19
2.1 Single Pad ...................................... 20
2.2 Multiple Pads ................................... 20
2.3 Change-Identifier ............................... 21
2.4 Other-Identifier ................................ 22
2.5 System-Heard .................................... 23
2.6 Routing-Information ............................. 25
2.7 Service-Information ............................. 26
2.8 Transit-Information ............................. 27
2.9 Redirected-Header ............................... 28
2.10 Maximum-Receive-Unit ............................ 29
2.11 Media-Access .................................... 30
2.12 Mobile-Home Authentication Extension ............ 31
2.13 Minimal Encapsulation Extension ................. 32
SECURITY CONSIDERATIONS ...................................... 33
REFERENCES ................................................... 33
ACKNOWLEDGEMENTS ............................................. 33
AUTHOR'S ADDRESS ............................................. 33
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