Multicast TTL DHCP Option

[John Veizades <[e-mail]>]

Below is the text for a new option for TTL values that applications use to 
send multicast datagrams.  I will be submitting this to the working group 
for consideration as soon as IANA gives me an option number.

Any comments?

John...



DHCP Working Group                               John Veizades, TGV Inv.
Internet Draft
Expiration Date: August 1996                                  March 1996


                       Multicast TTL DHCP Option
                  draft-ietf-dhc-multicast-opt-00.txt


1. 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
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2. Abstract

   DHCP [DHCP] can be used to automate the process of configuring TCP/IP
   host computers.  Various parameters in a TCP/IP implementation maybe
   modified depending on the needs of the network which the client or 
   server is opperating in.  One of these is the ttl values used in
   multicast requests.  Traditional multicast implementation have used
   a variety of values to allow multicast packets to reach portions of
   the clients internet.  This DHCP option will allow a DHCP server to
   set these values in multicast enabled clients.

3. Definitions
   
   Host - A computer that allows users to communicate with other host
   computers on a network.

   Subnet - A portion of a network, which may be a physically
   independent network segment, which shares a network address with
   other portions of the network and is distinguished by a subnet
   number.  A subnet is to a network what a network is to an internet.

   Site - A collection of subnets administered under one set of
   policies.
   
   Region - A collection of interconnected sites. 

4. Default Values

   The following default values should be used for various multicast
   TTL values to restrict the multicast datagrams reach.

   same host      - TTL 0
   same subnet    - TTL 1
   same site      - TTL 32
   same region    - TTL 64
   same continent - TTL 128
   unrestricted   - TTL 255

5. DHCP Encodings

   DHCP Options are encoded with an initial option code followed by the
   length of the option followed by the value or values for that option.
   The values of the multicast TTL option are the various TTL values
   for the host, subnet, site, region, continent and unrestricted TTLs
   used by a multicast implementation.  Each of these values is encoded
   as a 8 bit integer value.
   
    +----------+----------+---------+----------+---------+----------+
    |Code = XXX|Length = 6|   host  |  subnet  |   site  |  region  |
    +----------+----------+---------+----------+---------+----------+
    |continent |unrestrict|
    +----------+----------+

6. Security Considerations

   Security issues are not discussed in this document.


7. References

   [DHCP] Droms, R., "Dynamic Host Configuration Protocol", RFC1541,
   October 1993

8. Author Information

   John Veizades
   TGV Inc.
   370A Waller St.
   San Francisco, CA 94117

   Phone: [phone]
   Fax:   [phone]