Date: Wed, 12 Nov 86 21:59:15 pst
From: wally%net1.ucsd.edu@flash.bellcore.com (Wally Linstruth) (tty00)
To: tcpgroup
Regarding: IP addressing
The intent of this paper is to document the background
behind the current IP address assignments which I have offered to
coordinate. The proposed scheme has been reviewed by Phil Karn,
Bdale Garbee and (verbally with) Mike Chepponis, all of whom have
encouraged that it be used.
Phil's code does NOT currently support the subnetwork
aspects of the scheme but will do so in the future. There is no
real reason for any national coordination of these addresses
until actual networks or at least geographically coordinated
groups of experimenters are formed.
I have offered to issue and keep track of SUBNET addresses
and their "owners" who are presumably responsible *NETWORK*
implementors and managers.
The basic premise behind the proposed plan is that amateur
radio networks will be politically defined. The plan is based
upon the presumption that current voice networks serve as a
proper analog by which to predict general characteristics of the
as yet unconstructed digital networks. Political entities will
build networks; funded, controlled, maintained and used primarily
by their own members and guests.
Each of these separately managed networks should be viewed
as a subnetwork of AMPRNET (with the idea being to somehow
rationally partition the 044.xxx.xxx.xxx AMPRNET address space).
Each subnetwork within AMPRNET will maintain routing tables for
its own constituents. Each will provide its own hosts (TACs,
Gateways, i.e. the mechanism by which users with simple terminals
and AX25 level 2 boxes will access network resources), switches,
rules (network administration), security measures and quite
possibly its own link level protocols.
The natural limitations on span of control will probably
limit the service area of each of these networks. This is
another factor leading to the partitioning of the AMPRNET address
space with respect to separate subnetworks.
This partitioning of the address space will allow for
much simplified routing tables in each host. Internetworking
gateways will connect these independently controlled subnetworks.
Each gateway will maintain routing tables only for local hosts
and for gateways to other networks. Hosts and relay switches on
a given subnet will need to maintain routing information
regarding only members of that subnet and gateways to other
networks. The required routing tables should prove to be very
manageable and make any kind of geographically based hueristic
addressing schemes such as ZIP codes, area codes etc. moot.
1
I would also like to propose that we coordinate logical
network names and their corresponding addresses based on these
political network subdivisions. The concept of a naming
convention which maps directly into an IP address is purely for
the convenience of network developers and is not considered
necessary. There is, however, some good reasoning behind making
network and host names hierarchical and meaningful to end users.
It will considerably aid in bootstrapping the initial networks
and in being comprehensible to the non-network folks who will be
the primary users of these networks. The naming convention
proposed is of the form USERID@HOST.SUBNET[.AMPRNET.RES].
WESTNET, SBARCnet (Santa Barbara ARC) and GFRN-net represent
three hypothetical networks with which this writer could be
involved, perhaps as a provider of gateway and/or host services.
Each of these subnetwork entities could have a distinct
address and perhaps several internally administered host/user
addresses.
[NOTE: Throughout this paper, Host or Host/User represents
any host or any user running IP protocols that has direct
network access. Also, for the purposes of the following
example, WA6JPR is not a network address, rather it
represents a user-id on a local host. It is the writer's
opinion that the majority of packet users for the forseeable
future will be using simple TNCs connected to hosts via
AX.25 level 2 protocols.]
WA6JPR may be "a user" on hosts on more than one network
such that a station in Washington D.C.,logged onto an AMPRNET
host, may send internet traffic successfully to
WA6JPR@JPRHOST.WESTNET (this traffic would be routed to Westnet
via various AMPRNET gateways and subnetwork level relays and then
to a Santa Barbara host known internally by Westnet to be
reachable via the W6AMT-2 switch). Traffic could also be
directed to Wally@SBARC (presuming that the Santa Barbara
Amateur Radio Club maintains a message server host gatewayed to
the AMPRNET catenet).
Based upon the presumption of the AMPRNET/SUBNET/HOST
hierarchy, it would seem that we could easily decide how to
allocate the 044.xxx.xxx.xxx 24 bit IP address field such that
there are bits allocated for a sufficient number of individually
managed subnetworks while leaving a correspondingly adequate
number of assignable bits for the internal addressing needs of
each individual subnetwork.
Accordingly, the following is proposed as an initial
addressing scheme and methodology for address assignment. [Bit
numbering is per RFC-960 Pg.2]
2
Bit 8 to be 0 for USA stations and 1 for non-USA stations.
[Note. This is not meant to imply a geographic basis for
assignments. It is meant to provide a very quick means for
segregating FCC controlled participants from non-FCC stations.]
Bits 9 - 18 to represent politically separate subnetworks within
AMPRNET. These bits are to be assigned in an inverse binary
sequence (see example below) beginning with the *MOST
SIGNIFICANT* bit first.
Bits 19 - 23 to be unassigned and reserved for future allocation
as network addresses, to network administrations for internally
assigned host and/or user addresses, to a combination of the
above or to a completely new intermediate class of addresses.
Bits 24 - 31 to be used within politically separate AMPRNET
subnetworks for individual hosts, switches, workstations etc. as
determined by local network administration. It would be
recommended that these bits be assigned in binary sequence with
the *LEAST SIGNIFICANT* bits being assigned first.
The resulting network addresses would be as follows:
AMPRNET
||
|| SUBNET----+
|| | |
|| | | HOST--+
|| | | | |
44:0...127:000:0...255------- 32,768 addresses assignable
44:0...127:001:0...255--+
| +- 1,015,808 addresses reserved
44:0...127:031:0...255--+
44:0...127:032:0...255------- 32,768 addresses assignable
44:0...127:033:0...255--+
| +- 1,015,808 addresses reserved
44:0...127:063:0...255--+
44:0...127:064:0...255------- 32,768 addresses assignable
44:0...127:065:0...255--+
| +- 1,015,808 addresses reserved
44:0...127:095:0...255--+
44:0...127:096:0...255------- 32,768 addresses assignable
44:0...127:097:0...255--+
| +- 1,015,808 addresses reserved
44:0...127:127:0...255--+
44:0...127:128:0...255------- 32,768 addresses assignable
44:0...127:129:0...255--+
| +- 1,015,808 addresses reserved
44:0...127:159:0...255--+
44:0...127:160:0...255------- 32,768 addresses assignable
44:0...127:161:0...255--+
| +- 1,015,808 addresses reserved
44:0...127:191:0...255--+
44:0...127:192:0...255------- 32,768 addresses assignable
3
44:0...127:193:0...255--+
| +- 1,015,808 addresses reserved
44:0...127:223:0...255--+
44:0...127:224:0...255------- 32,768 addresses assignable
44:0...127:225:0...255--+
| +- 1,015,808 addresses reserved
44:0...127:255:0...255--+
44:128:xxx:xxx----------+
| +- 8,388,608 addresses assignable (non USA)
44:255:xxx:xxx----------+
The above allocation and assignment scheme allows network
(subnet) and intranet (host/user) addresses to begin to be
immediately assigned to experimenters while retaining the largest
possible contiguous block of unassigned bits whose assignments
can be defined in the future with little or no impact on
previously allocated addresses. The USER @ HOSTNAME .
SUBNET/ADMINISTRATION naming scheme represents a human-friendly
network naming convention which maps easily into numerical
network addresses. I believe that the above approach is in
general conformance with the requirements of RFC-950, "Internet
Standard Subnetting Procedure."
The numbering scheme as initially proposed allows for up to
1024 AMPRNET subnetworks of up to 256 hosts in the USA while
retaining five bits for future expansion. That's 262,144
individual AMPRNET addressable entities. If the proposed method
of address assignment is followed and we run out of Host/User
addresses before we run out of network addresses, we can simply
pick up the least significant reserved bit and assign more
Host/User addresses. Conversely, if network addresses are more
popular we could easily expand by taking the most significant
reserved bit and allocating it for network addressing.
If it should become clear that every user on a network needs his
or her own IP address, each network could allocate user blocks in
256 user increments from the least significant reserved bits.
Possible combinations are 1024 networks each with up to 8192
individually addressable units or 2048 networks each with 4096
hosts/users (8,388,608 individually addressable entities).
The writer presumes that 8 million plus addresses ought to
last the US amateur population for some time to come. All we need
to do to avoid painting ourselves in a corner is to assign them
in a logical sequence rather than randomly.
4
The following table serves as an example of the "high bit
first" network address assignment table and some actual and
requested initial networking assignments.
"this" 44.000.000.xxx ;special case
KARNnet 44.064.000.xxx ;network admin: KA9Q
BDALEnet 44.032.000.xxx ;network admin: N3EUA
DCnet1 44.096.000.xxx ;network admin: WB6RQN
SOCALnet1 44.016.000.xxx ;network admin: WB5EKU
DCnet2 44.080.000.xxx ;network admin: WB6RQN
SOCALnet2 44.048.000.xxx ;network admin: WA6JPR
PITTNET 44.112.000.xxx ;network admin: N3CVL
next 44.008.000.xxx
next 44.072.000.xxx
.
.
.
last 44.063.000.xxx
"all" 44.127.000.xxx ;special case
Monday, February 20, 2012
IP Addressing
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