PPP IPV6 Control Protocol Extensions for Prefix
Soohong Daniel Park <soohong.park <at> samsung.com>
2003-06-14 05:23:04 GMT
I am wondering if this draft should be discussed as an interesting draft
taked at PPPEXT WG. I know most people will not take kindly to making an
"option" mandatory. However the original intent of my draft is to be
with "draft-ietf-pppext-ipv6-dns-addr-02.txt" which is a working item in
simultaneously since this draft is also to provide another option for
[RFC 2472] .
[RFC 2472] said
>4. IPV6CP Configuration Options
> The only IPV6CP options defined in this document are Interface-
> Identifier and IPv6-Compression-Protocol. Any other IPV6CP
> configuration options that can be defined over time are to be
> in separate documents.
I guess we can define extra two options, IPv6 DNS server address Option
and IPv6 Prefix Option
Sometimes local peer want to negotiate and configure each global prefix
It is still very rough draft and not submitted yet.
It will update [RFC 2472].
I would also encourage any review comments you may have.
Daniel (Soohong Daniel Park)
Mobile Platform Lab,SAMSUNG Electronics
Network Working Group S. Daniel Park
Internet-Draft SAMSUNG Electronics
Expires: November, 2003 June, 2003
Updates: RFC 2472
Category : Informational
Document : draft-park-pppext-ipv6-prefix-00.txt
PPP IPV6 Control Protocol Extensions for Prefix
Status of this Memo
This document is an Internet-Draft and is in full conformance with
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Copyright (C) The Internet Societyi (2003). All Rights Reserved,
The Point-to-Point Protocol (PPP) provides a standard method for
transporting multi-protocol datagrams over point-to-point links. PPP
defines an extensible Link Control Protocol and a family of Network
Control Protocols (NCPs) for establishing and configuring different
This draft extends the NCP for establishing and configuring IPv6
over PPP, defining the negotiation of IPv6 Global-Scope Prefix.
The Point-to-Point Protocol (PPP)  provides a standard method
for transporting multi-protocol datagrams over point-to-point links.
PPP defines an extensible Link Control Protocol and a family of
Network Control Protocols (NCPs) for establishing and configuring
different network-layer protocols.
This document extends the NCP for establishing and configuring
IPV6 over PPP , defining the negotiation of Global-Scope Prefix
2. Conventions used in this document
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 RFC 2119 .
3. Additional IPV6CP Configuration Option
The IPv6 Prefix Configuration option provides a method of obtaining
the valid IPv6 Global-Scope Prefix on the local IPv6 network.
For implementation convenience, these option is designed to serve
identical purposes, (e.g. existing Prefix is about to be expired,
current Prefix is still only link or site scope not global, current
Prefix in invalid for some reasons from link and local peer,
there is no unique global Prefix on the local link. etc...) except
that when receive a IPv6 Prefix Option, an attempt MUST be made to
compose of IPv6 address using the IPv6 Prefix Option before using
the original IPv6 Prefix.
4. IPv6 Prefix Option
The IPv6 Prefix Option defines a method for negotiating with
the remote peer the IPv6 Prefix to be used on the local end of
the link. If local peer requests an IPv6 Prefix (some reasons in
section 3 will tipicaly occur this option) the remote peer
specifies the address by NAKing this option, and returning the
valid IPv6 Prefix.
This IPv6 Prefix Option provides a way to negotiate a unique
global Prefix to be used for the address autoconfiguration
at the local end of the link. A Configure-Request MUST contain
exactly one instance of the IPv6 Prefix Option. The IPv6 Prefix
MUST be unique within the PPP link.
Before this IPv6 Prefix Option is requested, an implementation
chooses its current IPv6 Prefix or Link-scope Prefix.
When a Configure-Request is received with the IPv6 Prefix Option
and the receiving peer implements this option, the received IPv6
Prefix is compared with the current valid IPv6 Prefix. Depending
on the result of the comparison an implementation MUST respond
in one of the following ways:
If the two IPv6 Prefixs are different. a Configure-Nak is sent
with a valid IPv6 Prefix value suggested for use by the remote
peer. Such a suggested IPv6 Prefix MUST be valid global Prefix.
If the two IPv6 Prefixs are equal and global scope, the IPv6
Prefix MUST be acknowledged, i.e. a Configure-Ack is sent with
the current IPv6 Prefix, meaning that the responding peer agrees
with the IPv6 Prefix requested. Some parameters like preferred-
lifetime, valid-lifetime in this option SHOULD be updated.
If a Configure-Request is received with the IPv6 Prefix Option
and the receiving peer does not implement this option,
Configure-Rej is sent.
A new Configure-Request SHOULD NOT be sent to the peer until
normal processing would cause it to be sent (that is, until a
Configure-Nak is received or the Restart timer runs out).
A new Configure-Request MUST NOT contain the IPv6 Prefix option if
a valid IPv6 Prefix Configure-Reject is received.
If negotiation of the IPv6 Prefix is required, and the peer did
not provide the option in its Configure-Request, the option SHOULD
be appended to a Configure-Nak. The invalid value of the IPv6
Prefix given must be acceptable as the remote IPv6 Prefix.
By default, an implementation SHOULD attempt to negotiate the
IPv6 Prefix for its end of the PPP connection.
The format of the IPv6 Prefix option is:
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 | Length | preferred-lifetime(cont.)
preferred-lifetime | valid-lifetime(cont.)
valid-lifetime | Prefix-length | |
| IPv6 Prefix |
| (16 octets) |
preferred-lifetime: The recommended preferred lifetime for the IPv6
Prefix in the option, expressed in units of
seconds. A value of 0xFFFFFFFF represents
valid-lifetime: The valid lifetime for the IPv6 Prefix in the
option, expressed in units of seconds. A value of
0xFFFFFFFF represents infinity.
Prefix-length: Length for this Prefix in bits
IPv6-Prefix: A Global-Scope IPv6 Prefix
5. Security Considerations
The use of these extensions is as secure as the link itself.
(desceibed in )
 S. Bradner, "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
 W. Simpson, Editor, "The Point-to-Point Protocol (PPP)", STD
51, RFC 1661, July 1994.
 Miyakawa, S., "Requirements for IPv6 Prefix delegation",
Internet-Draft, (work in progress), November 2002.
 Thomson, S., and T. Narten, "IPv6 Stateless Address
Autoconfiguration", RFC 2462, December 1998.
 H. Hiller, "PPP IPV6 Control Protocol Extensions for DNS Server
Addresses", Internet-Draft (work in progress), June 2003.
 O. Troan, "IPv6 Prefix Options for DHCPv6", Internet-Draft
(work in progress), November 2002.
 Haskin, D., E. Allen, "IP Version 6 over PPP", RFC 2472,
Soohong Daniel Park
Mobile Platform Laboratory, SAMSUNG Electronics
Email: soohong.park <at> samsung.com
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