[ih] Correct name for early TCP/IP working group?

[Andrew G. Malis]

Vint and Jack,

There weren't any "gateway" functions per se in the IMPs. Rather, the IMPs
kept the same unique IMP numbering (no IMP duplicate numbers) until the
physical split was complete. Thus, routing continued as usual for the
single merged network. The logical split was enforced by only allowing
hosts on the same "network" to communicate. Thus, any gateway functionality
would have to occur in a host, as usual.

Once the physical split was complete, each network then had its own
independent routing, and we could have duplicate IMP numbers in the two
networks. We then added network numbering to the routing updates and link
management to forestall any issues if AT&T accidentally cross-connected the
network links. As I recall, this did happen on occasion. Alan Hill would
probably have the best recollection of any operational issues that came up
as a result of accidental cross-connection.

Cheers,
Andy


On Sat, Jan 25, 2025 at 9:43 AM vinton cerf <vgcerf at gmail.com> wrote:

> Thanks for that, Andy - I had not realized that this was used as a
> scaffolding - must have affected routing in some way and created a kind of
> gateway IMP notion for IMPs lying along a border between two connected
> subsets?
>
> v
>
>
> On Sat, Jan 25, 2025 at 9:28 AM Andrew G. Malis via Internet-history <
> internet-history at elists.isoc.org> wrote:
>
>> Jack,
>>
>> - There was some work however within the ARPANET IMP software to
>> > acknowledge the need for multiple networks.   For example, some of the
>> > formats of data as it passed through the ARPANET included fields
>> > labelled "Network Number".  AFAIK this was never actually fully
>> > implemented so the ARPANET itself never achieved connectivity between
>> > multiple networks until TCP was deployed.
>>
>>
>> As I recall, the ARPANET's "network number" field was used during the
>> ARPANET/MILNET split to allow logical separation of the IMPs and hosts
>> sharing the same backbone infrastructure until the physical split could be
>> completed.
>>
>> Cheers,
>> Andy
>> --
>> Internet-history mailing list
>> Internet-history at elists.isoc.org
>> https://elists.isoc.org/mailman/listinfo/internet-history
>>
>