Network Working Group Baiju V. Patel
INTERNET DRAFT Intel Corporation
Munil Shah
Microsoft Corporation
March 1997
Multicast address allocation extensions options
<draft-ietf-dhc-multopt-02.txt>
Status of this memo
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1. Abstract
This document describes host configuration options that may be used
by multicast address allocation protocols[3]. The options include
critical information such as the multicast address
of the multicast address allocation server(s) and a list of
multicast scopes supported by respective servers. These options are
designed to work with the extensions to DHCP [1] servers to support
multicast address allocation (described in a separate draft),
however, their use may not be limited to the above protocol.
2 Requirements
Throughout this document, the words that are used to define the
significance of particular requirements are capitalized. These
words are:
o "MUST"
This word or the adjective "REQUIRED" means that the
item is an absolute requirement of this specification.
Patel & Shah [Page 1]
o "MUST NOT"
This phrase means that the item is an absolute prohibition
of this specification.
o "SHOULD"
This word or the adjective "RECOMMENDED" means that there
may exist valid reasons in particular circumstances to ignore
this item, but the full implications should be understood and
the case carefully weighed before choosing a different course.
o "SHOULD NOT"
This phrase means that there may exist valid reasons in
particular circumstances when the listed behavior is acceptable
or even useful, but the full implications should be understood
and the case carefully weighed before implementing any behavior
described with this label.
o "MAY"
This word or the adjective "OPTIONAL" means that this item is
truly optional. One vendor may choose to include the item
because a particular marketplace requires it or because it
enhances the product, for example; another vendor may omit the
same item.
3 Terminology
This document uses the following terms:
o "DHCP client"
A DHCP client is an Internet host using DHCP to obtain
configuration parameters such as a network address.
o "DHCP server"
A DHCP server is an Internet host that returns configuration
parameters to DHCP clients.
o "MDHCP client"
A MDHCP client is a DHCP client that supports MDHCP extensions.
o "MDHCP server"
A MDHCP server is a DHCP server that supports MDHCP extensions.
Patel & Shah [Page 2]
4 Multicast Address Allocation Configuration Options
Any client attempting to request a multicast address must know the
multicast group address to which the server is listening to and a
list of multicast scopes supported by the multicast address servers.
The following two options are specifically designed to provide the
multicast address server address and the scope list that can
specifically be used by the protocol described in [3], however, its
use is not limited to the protocol described in [3].
4.1 Multicast Group Address of MDHCP Servers.
This option is used DHCP servers to provide the multicast group
address of the MDHCP servers. The MDHCP client can obtain this
parameter as part of the normal DHCP protocol message exchange or
separately via DHCPINFORM.
Code Len Multicast Address
+-----+-----+-----+-----+-----+-----+
| TBD | 4 | i1 | i2 | i3 | i4 |
+-----+-----+-----+-----+-----+-----+
The code for this option is TBD and the length is 4.
4.2 Multicast Scople List Option.
The format of the multicast scope list option is:
Code Len IP Address Count List
+-----+-----+-----+-----+-----+-----+-----+-----+-...-+-----+
| 107 | n | i1 | i2 | i3 | i4 | N | l1 | | ln |
+-----+-----+-----+-----+-----+-----+-----+-----+-...-+-----+
Where IP address is the address of the MDHCP server, to its best
knowledge, reachable from the client via unicast.
The scope list a list of N tuples, where each tuple is of
the form,
Scope ID ( 4 Bytes ) TTL Desc Scope Description.
Len
+-----+-----+-----+-----+-----+-----+-----+-...-+-----+
| ID1 | ID2 | ID3 | ID4 | T | n | d1 | | dn |
+-----+-----+-----+-----+-----+-----+-----+-...-+-----+
where scope ID is a unique identifier to designate the scope,
TTL is the multicast TTL value for the multicast addresses of
the scope, scope
description is a string describing the scope (need not be null
terminated) and scope len is the length of scope description.
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Scope id is numeric representation of the scope and is used by the
client to indicate a multicast scope to the server. In order to
keep the usage of scope id consistent in the MBONE, this draft
SHOULD be coordinated with [3] reserve a scope id for each
multicast range in [3]. The scope id with its MSB(most significant
bit) of 1 should be used for administratively scoped multicast
address range. And the scope id with its MSB of 0 should be used to
represent other pre-defined internet scopes.
The code for this option is 107.
Example:
The IP address of the MDHCP server is 10.1.1.1. There are two
scopes supported by the multicast address allocation server:
1) Inside the abcd.com, 2) world. Then this option will be used as:
Code Len IP Address Count
+-----+-----+-----+-----+-----+-----+-----+
| 107 | 32 | 10 | 1 | 1 | 1 | 2 |
+-----+-----+-----+-----+-----+-----+-----+
Scope ID TTL Len Desc
+--+--+--+--+---+---+--+--+-...-+--+--+
| 1 |10 |16 | Inside abcd.com |
+--+--+--+--+---+---+--+--+-...-+--+--+
| 2 |16 |5 | world |
+--+--+--+--+---+---+--+--+-...-+--+--+
4 References
[1] Droms, R., "Dynamic Host Configuration Protocol", RFC1541,
October 1993
[2] Alexander, S., and R. Droms, "DHCP Options and BOOTP Vendor
Extensions", RFC 1533, Lachman Technology, Inc., Bucknell
University, October 1993.
[3] Meyer, D., ``Administratively scoped IP Multicast''
<draft-ietf-mboned-admin-ip-space-01.txt>
[4] Patel, B., and Shah, M., ``Multicast address allocation
extensions to the Dynamic Host Configuration
Protocol'' <draft-ietf-dhc-mdhcp-00.txt>
Patel & Shah [Page 4]
5 Author's Address
Baiju V. Patel
Intel Corp.
2111 NE 25th Ave.
Hillsboro, OR 97124
Phone: 503 264 2422
EMail: baiju@ibeam.intel.com
Munil Shah
Microsoft Corporation
One Microsoft Way
Redmond, WA 98052
Phone:425 703 3924
Email:munils@microsoft.com
This document will expire on April, 1998
Patel & Shah [Page 5]
