Editing FidoNet (section)

===Nets and nodes===
Growth continued to accelerate, and by the spring of 1985, the system was already reaching its limit of 250 nodes. In addition to the limits on the growth of what was clearly a popular system, nodelist maintenance continued to grow more and more time-consuming.<ref name=baker/>

It was also realized that Fido systems were generally clustered – of the fifteen systems running by the start of June 1984, five of them were in St. Louis.<ref name=baker/>  A user on Jennings's system in San Francisco that addressed emails to different systems in St. Louis would cause calls to be made to each of those BBSes in turn. In the United States, local calls were normally free, and in most other countries were charged at a lower rate. Additionally, the initial call setup, generally the first minute of the call, was normally billed at a higher rate than continuing an existing connection. Therefore, it would be less expensive to deliver all the messages from all the users in San Francisco to all of the users in St. Louis in a single call. Packets were generally small enough to be delivered within a minute or two, so delivering all the messages in a single call could greatly reduce costs by avoiding multiple first-minute charges. Once delivered, the packet would be broken out into separate packets for local systems, and delivered using multiple local free calls.

The team settled on the concept of adding a new ''network number'' patterned on the idea of [[area code]]s.<ref group=N>Details of the sequence of events leading to the new routing scheme differ slightly between accounts.</ref> A complete [[network address]] would now consist of the network and node number pair, which would be written with a slash between them. All mail travelling between networks would first be sent to their local ''network host'', someone who volunteered to pay for any long-distance charges. That single site would collect up all the netmail from all of the systems in their network, then re-package it into single packets destined to each network. They would then call any required network admin sites and deliver the packet to them. That site would then process the mail as normal, although all of the messages in the packet would be guaranteed to be local calls.<ref name=baker/>

The network address was placed in an unused field in the Fido message database, which formerly always held a zero. Systems running existing versions of the software already ignored the fields containing the new addressing, so they would continue to work as before; when noticing a message addressed to another node they would look it up and call that system. Newer systems would recognize the network number and instead deliver that message to the network host. To ensure backward compatibility, existing systems retained their original node numbers through this period.<ref name=baker/>

A huge advantage of the new scheme was that node numbers were now unique only within their network, not globally. This meant the previous 250 node limit was gone, but for a variety of reasons this was initially limited to about 1,200. This change also devolved the maintenance of the nodelists down to the network hosts, who then sent updated lists back to Node 51 to be collected into the master list. The St. Louis group now had to only maintain their own local network, and do basic work to compile the global list.<ref name=baker/>

At a meeting held in Kaplan's living room in St. Louis on 11 April 1985<ref group=N>In the interviews, Baker says this took place in May.</ref> the various parties hammered out all of the details of the new concept. As part of this meeting, they also added the concept of a ''region'', a purely administrative level that was not part of the addressing scheme. Regional hosts would handle any stragglers in the network maps, remote systems that had no local network hosts. They then divided up the US into ten regions that they felt would have roughly equal populations.<ref name=baker/>

By May, Jennings had early versions of the new software running. These early versions specified the routing manually through a new ROUTE.BBS file that listed network hosts for each node. For instance, an operator might want to forward all mail to St. Louis through a single node, node 10. ROUTE.BBS would then include a list of all the known systems in that area, with instructions to forward mail to each of those nodes through node 10. This process was later semi-automated by John Warren's NODELIST program.<ref name=tom2>Tom Jennings, [http://www.worldpowersystems.com/FidoNet/fidohist2.txt "FidoNet History #2"] {{Webarchive|url=https://web.archive.org/web/20140821113319/http://www.worldpowersystems.com/FidoNet/fidohist2.txt |date=2014-08-21 }}, 20 August 1985</ref> Over time, this information was folded into updated versions of the nodelist format, and the ROUTES file is no longer used.<ref>{{cite web |url=http://www.bbscorner.com/bbsnetworks/fidonet.htm |title=The Fidonet BBS Network |publisher=Bbscorner.com |date=2010-02-10 |access-date=2014-01-28 |archive-date=2022-02-07 |archive-url=https://web.archive.org/web/20220207224755/http://www.bbscorner.com/bbsnetworks/fidonet.htm |url-status=dead }}</ref>

A new version of FIDO and FIDONET, 10C, was released containing all of these features. On 12 June 1985 the core group brought up 10C, and most Fido systems had upgraded within a few months.<ref name=tom2/> The process went much smoother than anyone imagined, and very few nodes had any problems.<ref name=baker/>