One document matched: draft-ietf-ipngwg-jumbo-00.txt
INTERNET-DRAFT S. Deering, Cisco
August 6, 1998 R. Hinden, Nokia
The IPv6 Jumbo Payload Option
<draft-ietf-ipngwg-jumbo-00.txt>
Status of this Memo
This document is an Internet Draft. Internet Drafts are working
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This internet draft will expire no later than February 6, 1999.
Abstract
This document describes the Jumbo Payload option for IPv6, which is
used to send IPv6 packets with payloads longer than 65,535 octets.
This option is relevant only for IPv6 nodes that may be attached to
links with a link MTU greater than 65,575 octets, and need not be
implemented or understood by IPv6 nodes that do not support
attachment to links with such large MTUs.
Deering & Hinden draft-ietf-ipngwg-jumbo-00.txt [Page 1]
INTERNET-DRAFT IPv6 Jumbo Payload Option August 1998
1. Introduction
jumbo (jum'bO),
n., pl. -bos, adj.
-n.
1. a person, animal, or thing very large of its kind.
-adj.
2. very large: the jumbo box of cereal.
[1800-10; orig. uncert.; popularized as the name of a large
elephant purchased and exhibited by P.T. Barnum in 1882]
-- www.infoplease.com
The IPv6 header [IPv6] has a 16-bit Payload Length field and,
therefore, supports payloads up to 65,535 octets long. This document
specifies an IPv6 hop-by-hop option, called the Jumbo Payload option,
that carries a 32-bit length field in order to allow transmission of
IPv6 packets with payloads between 65,536 and 4,294,967,295 octets in
length. Packets with such long payloads are colloquially referred to
as "jumbograms".
The Jumbo Payload option is relevant only for IPv6 nodes that may be
attached to links with a link MTU greater than 65,575 octets (that
is, 65,535 + 40, where 40 octets is the size of the IPv6 header).
The Jumbo Payload option need not be implemented or understood by
IPv6 nodes that do not support attachment to links with MTU greater
than 65,575.
On links with configurable MTUs, the MTU must not be configured to a
value greater than 65,575 octets if there are nodes attached to that
link that do not support the Jumbo Payload option.
2. Format of the Jumbo Payload Option
The Jumbo Payload option is carried in an IPv6 Hop-by-Hop Options
header, immediately following the IPv6 header. This option has an
alignment requirement of 4n + 2. (See [IPv6, Section 4.2] for
discussion of option alignment.) The option has the following
format:
Deering & Hinden draft-ietf-ipngwg-jumbo-00.txt [Page 2]
INTERNET-DRAFT IPv6 Jumbo Payload Option August 1998
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Option Type | Opt Data Len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Jumbo Payload Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Option Type 8-bit value C2 (hexadecimal).
Opt Data Len 8-bit value 4.
Jumbo Payload Length 32-bit unsigned integer. Length of the IPv6
packet in octets, excluding the IPv6 header
but including the Hop-by-Hop Options header
and any other extension headers present.
Must be greater than 65,535.
3. Usage of the Jumbo Payload Option
The Payload Length field in the IPv6 header must be set to zero in
every packet that carries the Jumbo Payload option.
If a node that understands the Jumbo Payload option receives a packet
whose IPv6 header carries a Payload Length of zero and a Next Header
value of zero (meaning that a Hop-by-Hop Options header follows), and
whose link-layer framing indicates the presence of octets beyond the
IPv6 header, the node must proceed to process the Hop-by-Hop Options
header in order to determine the actual length of the payload from
the Jumbo Payload option.
The Jumbo Payload option must not be used in a packet that carries a
Fragment header.
Higher-layer protocols that use the IPv6 Payload Length field to
compute the value of the Upper-Layer Packet Length field in the
checksum pseudo-header described in [IPv6, Section 8.1] must instead
use the Jumbo Payload Length field for that computation, for packets
that carry the Jumbo Payload option.
Nodes that understand the Jumbo Payload option are required to detect
a number of possible format errors, and if the erroneous packet was
not destined to a multicast address, report the error by sending an
ICMP Parameter Problem message [ICMPv6] to the packet's source. The
following list of errors specifies the values to be used in the Code
and Pointer fields of the Parameter Problem message:
Deering & Hinden draft-ietf-ipngwg-jumbo-00.txt [Page 3]
INTERNET-DRAFT IPv6 Jumbo Payload Option August 1998
error: IPv6 Payload Length = 0 and
IPv6 Next Header = Hop-by-Hop Options and
Jumbo Payload option not present
Code: 0
Pointer: high-order octet of the IPv6 Payload Length
error: IPv6 Payload Length != 0 and
Jumbo Payload option present
Code: 0
Pointer: Option Type field of the Jumbo Payload option
error: Jumbo Payload option present and
Jumbo Payload Length < 65,536
Code: 0
Pointer: high-order octet of the Jumbo Payload Length
error: Jumbo Payload option present and
Fragment header present
Code: 0
Pointer: high-order octet of the Fragment header.
A node that does not understand the Jumbo Payload option is expected
to respond to erroneously-received jumbograms as follows, according
to the IPv6 specification:
error: IPv6 Payload Length = 0 and
IPv6 Next Header = Hop-by-Hop Options
Code: 0
Pointer: high-order octet of the IPv6 Payload Length
error: IPv6 Payload Length != 0 and
Jumbo Payload option present
Code: 2
Pointer: Option Type field of the Jumbo Payload option
Deering & Hinden draft-ietf-ipngwg-jumbo-00.txt [Page 4]
INTERNET-DRAFT IPv6 Jumbo Payload Option August 1998
4. Security Considerations
The Jumbo Payload option does not introduce any known new security
concerns.
5. Authors' Addresses
Stephen E. Deering Robert M. Hinden
Cisco Systems, Inc. Nokia
170 West Tasman Drive 232 Java Drive
San Jose, CA 95134-1706 Sunnyvale, CA 94089
USA USA
phone: +1 408 527 8213 phone: +1 408 990-2004
fax: +1 408 527 8254 fax: +1 408 743-5677
email: deering@cisco.com email: hinden@iprg.nokia.com
6. References
[IPv6] Deering,S., R. Hinden, Internet Protocol Version 6 (IPv6)
Specification, Internet Draft, August 1998.
[ICMPv6] Conta, A., S. Deering, ICMP for the Internet Protocol
Version 6 (IPv6), Internet Draft, August 1998.
Deering & Hinden draft-ietf-ipngwg-jumbo-00.txt [Page 5]
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