IP Addressing

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					Date: Wed, 12 Nov 86 21:59:15 pst From: (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 and their "owners" who are presumably responsible implementors and managers. addresses *NETWORK*

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 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.


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 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]


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 44:0...127:001:0...255--+ | +- 1,015,808 44:0...127:031:0...255--+ 44:0...127:032:0...255------- 32,768 44:0...127:033:0...255--+ | +- 1,015,808 44:0...127:063:0...255--+ 44:0...127:064:0...255------- 32,768 44:0...127:065:0...255--+ | +- 1,015,808 44:0...127:095:0...255--+ 44:0...127:096:0...255------- 32,768 44:0...127:097:0...255--+ | +- 1,015,808 44:0...127:127:0...255--+ 44:0...127:128:0...255------- 32,768 44:0...127:129:0...255--+ | +- 1,015,808 44:0...127:159:0...255--+ 44:0...127:160:0...255------- 32,768 44:0...127:161:0...255--+ | +- 1,015,808

addresses assignable addresses reserved addresses assignable addresses reserved addresses assignable addresses reserved addresses assignable addresses reserved addresses assignable addresses reserved addresses assignable addresses reserved

44:0...127:191:0...255--+ 44:0...127:192:0...255------- 32,768 addresses assignable


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.


The following table serves as an example of the "high first" network address assignment table and some actual requested initial networking assignments. "this" KARNnet BDALEnet DCnet1 SOCALnet1 DCnet2 SOCALnet2 PITTNET next next . . . ;special ;network ;network ;network ;network ;network ;network ;network case admin: admin: admin: admin: admin: admin: admin:

bit and


last "all"

;special case


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