Network Working Group K. van den Hout
Request for Comments: 2322 HvU/HIP-networkteam
Category: Informational A. Koopal
UUnet NL/HIP-networkteam
R. van Mook
University of Twente/HIP-networkteam
1 April 1998
Management of IP numbers by peg-dhcp
Status of this Memo
This memo provides information for the Internet community. It does
not specify an Internet standard of any kind. Distribution of this
memo is unlimited.
Copyright Notice
Copyright (C) The Internet Society (1998). All Rights Reserved.
IntrodUCtion
This RFCdescribes a protocol to dynamically hand out ip-numbers on
field networks and small events that don't necessarily have a clear
organisational body.
It can also provide some fixed additional fields global for all
clients like netmask and even autoproxyconfigs. It does not depend on
a particular ip-stack.
History of the protocol.
The practice of using pegs for assigning IP-numbers was first used at
the HIP event (http://www.hip97.nl/). HIP stands for Hacking In
Progress, a large three-day event where more then a thousand hackers
from all over the world gathered. This event needed to have a TCP/IP
lan with an Internet connection. Visitors and participants of the
HIP could bring along computers and hook them up to the HIP network.
During preparations for the HIP event we ran into the problem of how
to assign IP-numbers on such a large scale as was predicted for the
event without running into troubles like assigning duplicate numbers
or skipping numbers. Due to the variety of eXPected computers with
associated IP stacks a software solution like a Unix DHCP server
would probably not function for all cases and create unexpected
technical problems.
So a way of centrally administrating IP-numbers and giving them out
to people to use on their computers had to be devised. After some
discussion, the idea came up of using wooden clothes-pegs. Using pegs
has the following advantages in respect to other methods:
- cheap
- a peg is a 'token' and represents one IP-number, therefore
making the status of the IP-number (allocated or not allocated)
visible.
- a peg can be clipped to a network cable giving a very clear
view of where a given IP-number is in use.
Credits for the original idea of using wooden pegs go to Daniel
Ockeloen.
The server.
The server can have many appearances. At HIP it was a large tent
situated at the central field where all the activities were. It can
also be a small table in the corner of a terminalroom.
The server can hand out two parts to the client, the peg and a paper
with additional fields fixed for the site the server is running for.
We will describe both here.
The peg.
On the peg the IP-number is mentioned. The text on the peg can be
described according to the following BNF:
Total ::== IP Net
IP ::== num.num.num.num num.num num
Net ::== num.num.num/mask num.num/mask num/mask
num ::== {1..255}
mask ::== {8..31}
The Net-method of writing larger nets is an optional part of the
protocol, it doesn't have to be implemented. If it is implemented, it
requires more administration at the server (see below).
The short versions of the IP-number with only 1 or 2 chunks are meant
for large servers where writing the whole number on the peg is just
boring and time-consuming. It requires the prefix to be mentioned on
the additional field paper, but that can be produced in more
convenient ways. It is not recommended to work with more prefixes. It
is better to write more numbers on the peg and use a smaller prefix.
If the network to be numbered is rather large and some kind of
subnetting has to be implemented it is possible to give the pegs from
the different subnets different colors. This has proven to be a very
convenient way at HIP.
The additional vendorfield paper.
This part is meant for information that is fixed for the whole site.
It can either be implemented as small printed notes handed out with
the peg or as a large paper billboard hung at a convenient place
where everybody can read it.
The information can be described with the following BNF:
Network ::== num.num.num.num
Netmask ::== num.num.num.num num
Gateway ::== num.num.num.num num.num num
Proxy ::== num.num.num.num:port num.num:port num:port
Paper ::== Network Netmask Gateway Proxy Network Netmask Gateway
num ::== {0..255}
port ::== {1..65535}
The paper and the peg are of course one part, if two numbers are used
on the peg, two numbers are used on the paper.
Because it is fixed information, it can be produced with means of
mass-production (printing, copying).
The IP-repository
Due to the nature of the peg, the repository can be quite simple.
Just a clothes-line with all the pegs that are ready to be handed out
attached to it. If you work with different subnets, it is convenient
to group the pegs for the different subnets (colors).
At large networks where it is not really known how many IP-numbers
are needed, a first set of pegs can be made in advance, and the
administration of produced pegs kept on paper so it is known for
which numbers pegs have already been made. If use is made of the
net-extension on the pegs, numbers given out that way can be
administrated this way too.
Issuing IP-numbers.
The pegs and the IP-numbers are issued at the server to the client.
Normally the client has to visit the server personally. Depending on
how secure and controlled you want the process, the client has to ask
for a peg to a responsible person, or he or she can just get a peg
from store himself.
If someone could apply for a networkrange, and he net-extension isn't
used, coat-hangers can be prepared with sets of pegs attached to
them.
The vendorfields paper doesn't have to be issued with every peg, it
is only needed when wanted.
Reclaiming and reusing IP-numbers.
It is not easy to implement a TTL in this protocol. One obvious TTL
is the duration of the event after which the IP-numbers are not valid
anymore.
However, if a client decides that it doesn't need an IP-number
anymore it can bring the peg back to the server.
The server should at that point decide what to do, if desired, it can
bring the peg back into the pool (attach it to the clothes-line
again).
If the server is not manned (the client has to help themselves), the
only thing possible is that the client just places the peg back into
the pool.
The client side.
The optimum location for the peg is clipped to the network cable near
the NIC of the device needing an IP-number allocated. This ensures a
clear visual connection between the device and the IP-number
allocated and makes it an easy task to see which IP-number is
allocated.
Transfer of the IP information from the peg and the additional
vendorfield paper note to the settings in the IP stack is done by
human transfer. A person reads the information from the peg and from
the additional information and enters this in the configuration of
the used IP stack. This transfer is not completely free of
corruption of the information or loss of the information contained on
the peg.
A certain amount of knowledge of the logic of IP settings is also
assumed on the part of the person transferring the information.
Other information on the vendorfield paper note has to be transferred
to the settings within specific application programs.
Use with other protocols
This protocol could be combined with avian carriers as described in
RFC1149 to hand out IP-numbers remote.
At the first avian carrier, the peg is clipped to the leg of the
carrier after rolling the additional vendorfield paper around it.
The remote site can take the peg on arrival of the avian carrier and
use the information on it.
This part of the protocol is still experimental and requires some
additional research on topics like the weight of the peg and loss of
the peg/whole carrier.
Security Considerations
Some remarks about security can be made.
Pegs are small devices and can be lost. At that time, the IP-number
which was lost can't be used anymore because someone else can find
the peg and use the information stored on it. But, once the peg is
attached to a network cable, the chance to loose the peg is
minimized.
All the information on both the peg and on the additional 'fixed'
fields on the paper record are plain text and readable for everyone.
Private information should not be exchanged through this protocol.
On the client side all sorts of clients exist and cooperate freely.
Due to the human factor of the clients transferring information from
peg to IP stack, the information can be misinterpreted, which could
cause network troubles. In the field test at HIP this became
perfectly clear when someone mixed up the numbers and used the
address from the default router as his IP-number, rendering the
network useless for a period of time.
Authors' Addresses
Koos van den Hout
Hogeschool van Utrecht / Expertisecentrum Cetis
P.O. box 85029
3508 AA Utrecht
The Netherlands
Phone: +31-30-2586287
Fax: +31-30-2586292
EMail: koos@cetis.hvu.nl
Andre Koopal
UUnet Netherlands
P.O. box 12954
1100 AZ AMSTERDAM
The Netherlands
Phone: +31-20-4952727
Fax: +31-20-4952737
EMail: andre@NL.net
Remco van Mook
Van Mook Consulting
Calslaan 10-31
7522 MA Enschede
The Netherlands
Phone: +31-53-4895267
EMail: remco@sateh.com
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