home
***
CD-ROM
|
disk
|
FTP
|
other
***
search
/
Internet Info 1997 December
/
Internet_Info_CD-ROM_Walnut_Creek_December_1997.iso
/
drafts
/
draft_ietf_i
/
draft-ietf-ipngwg-trans-ethernet-01.txt
< prev
next >
Wrap
Text File
|
1997-07-07
|
11KB
|
336 lines
IPng Working Group Matt Crawford
Internet Draft Fermilab
July 3, 1997
Transmission of IPv6 Packets over Ethernet Networks
<draft-ietf-ipngwg-trans-ethernet-01.txt>
Status of this Memo
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. Internet Drafts 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).
Distribution of this memo is unlimited.
1. Introduction
This document specifies the frame format for transmission of IPv6
packets and the method of forming IPv6 link-local addresses and
statelessly autoconfigured addresses on Ethernet networks. It also
specifies the content of the Source/Target Link-layer Address option
used in Router Solicitation, Router Advertisement, Neighbor
Solicitation, Neighbor Advertisement and Redirect messages when
those messages are transmitted on an Ethernet.
This document replaces RFC 1972, "A Method for the Transmission of
IPv6 Packets over Ethernet Networks", which will become historic.
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 [KWORD].
Expires January 3, 1998 Crawford [Page 1]
=0C
Internet Draft IPv6 Over Ethernet July 3, 1997
2. Maximum Transmission Unit
The default MTU size for IPv6 [IPV6] packets on an Ethernet is 1500
octets. This size may be reduced by a Router Advertisement [DISC]
containing an MTU option which specifies a smaller MTU, or by manual
configuration of each node. If a Router Advertisement received on
an Ethernet interface has an MTU option specifying an MTU larger
than 1500, or larger than a manually configured value MTU, if any,
that MTU option must be ignored.
3. Frame Format
IPv6 packets are transmitted in standard Ethernet frames. The
Ethernet header contains the Destination and Source Ethernet
addresses and the ethernet type code, which must contain the value
86DD hexadecimal. The data field contains the IPv6 header followed
immediately by the payload, and possibly padding octets to meet the
minimum frame size for Ethernet.
0 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Destination |
+- -+
| Ethernet |
+- -+
| Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Source |
+- -+
| Ethernet |
+- -+
| Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|1 0 0 0 0 1 1 0 1 1 0 1 1 1 0 1|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv6 |
+- -+
| header |
+- -+
| and |
+- -+
/ payload ... /
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
(Each tic mark represents one bit.)
Expires January 3, 1998 Crawford [Page 2]
=0C
Internet Draft IPv6 Over Ethernet July 3, 1997
4. Stateless Autoconfiguration
The interface token [CONF] for an Ethernet interface is based on the
EUI-64 identifier [EUI64] derived from the interface's built-in 48-
bit IEEE 802 address. The EUI-64 is formed as follows. (Canonical
bit order is assumed throughout.)
The OUI of the Ethernet address (the first three octets) becomes the
company_id of the EUI-64 (the first three octets). The fourth and
fifth octets of the EUI are set to the fixed value FFFE hexadecimal.
The last three octets of the Ethernet address become the last three
octets of the EUI-64.
The interface token is then formed from the EUI-64 by complementing
the "Universal/Local" (U/L) bit, which is the next-to-lowest order
bit of the first octet of the EUI-64. Complementing this bit will
generally change a 0 value to a 1, since an interface's built-in
address is expected to be from a universally administered address
space and hence have a globally unique value. A universally
administered IEEE 802 address or an EUI-64 is signified by a 0 in
the U/L bit position, while a globally unique IPv6 interface token
is signified by a 1 in the corresponding position.
For example, the interface token for an Ethernet interface whose
built-in address is, in hexadecimal,
34-56-78-9A-BC-DE
would be
36-56-78-FF-FE-9A-BC-DE.
A different MAC address set manually or by software should not be
used to derive the interface token. If such a MAC address must be
used, its global uniqueness property should be reflected in the
value of the U/L bit.
An IPv6 address prefix used for stateless autoconfiguration of an
Ethernet interface must have a length of 64 bits.
5. Link-Local Addresses
The IPv6 link-local address [AARCH] for an Ethernet interface is
formed by appending the interface token, as defined above, to the
prefix FE80::/64.
Expires January 3, 1998 Crawford [Page 3]
=0C
Internet Draft IPv6 Over Ethernet July 3, 1997
10 bits 54 bits 64 bits
+----------+-----------------------+----------------------------+
|1111111010| (zeros) | Interface Token |
+----------+-----------------------+----------------------------+
6. Address Mapping -- Unicast
The procedure for mapping IPv6 unicast addresses into Ethernet
link-layer addresses is described in [DISC]. The Source/Target
Link-layer Address option has the following form when the link layer
is Ethernet.
0 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+- Ethernet -+
| |
+- Address -+
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Option fields:
Type 1 for Source Link-layer address.
2 for Target Link-layer address.
Length 1 (in units of 8 octets).
Ethernet Address
The 48 bit Ethernet IEEE 802 address, in canonical bit
order. This is the address the interface currently
responds to, and may be different from the built-in
address used to derive the interface token.
7. Address Mapping -- Multicast
An IPv6 packet with a multicast destination address DST, consisting
of the sixteen octets DST[1] through DST[16], is transmitted to the
Ethernet multicast address whose first two octets are the value 3333
hexadecimal and whose last four octets are the last four octets of
Expires January 3, 1998 Crawford [Page 4]
=0C
Internet Draft IPv6 Over Ethernet July 3, 1997
DST.
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 1 1 0 0 1 1|0 0 1 1 0 0 1 1|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| DST[13] | DST[14] |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| DST[15] | DST[16] |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Security Considerations
The method of derivation of interface tokens from MAC addresses is
intended to preserve global uniqueness when possible. However,
there is no protection from duplication through accident or forgery.
8. References
[AARCH] R. Hinden, S. Deering "IP Version 6 Addressing
Architecture", RFC 1884.
[CONF] S. Thomson, T. Narten, "IPv6 Stateless Address
Autoconfiguration", RFC 1971.
[DISC] T. Narten, E. Nordmark, W. A. Simpson, "Neighbor Discovery
for IP Version 6 (IPv6)", RFC 1970.
[EUI64] "64-Bit Global Identifier Format Tutorial",
http://standards.ieee.org/db/oui/tutorials/EUI64.html.
[IPV6] S. Deering, R. Hinden, "Internet Protocol, Version 6 (IPv6)
Specification", RFC 1883.
[KWORD] S. Bradner, "Key words for use in RFCs to Indicate
Requirement Levels," RFC 2119.
Expires January 3, 1998 Crawford [Page 5]
=0C
Internet Draft IPv6 Over Ethernet July 3, 1997
9. Author's Address
Matt Crawford
Fermilab MS 368
PO Box 500
Batavia, IL 60510
USA
Phone: +1 630 840-3461
EMail: crawdad@fnal.gov
Expires January 3, 1998 Crawford [Page 6]