[ih] TCP RTT Estimator

[Barbara Denny]

 Having trouble sending to the email list again so I shortened the original thread. Hope no duplicates.
****I might be repeating but I will add a few comments. Hope my memory is pretty good.
Packet Radio nodes could act as sink, source, or repeater/relay for data.  They could also have an attached device (like a station, end user host, tiu, etc).  I think the packet radio addressing space was broken up so you could determine the type of entity by the ID (need to double check this). The station provided routes to packet radios when the packet radio didn't know how to reach a destination. Any packet radio could be mobile.  I don't remember if there was a limit initially on how many neighbors a packet radio could have.  Packet radio nodes did not use IP related protocols but could handle IP traffic generated by other entities.
Packet Radio nodes also had multiple hardware generations (EPR, UBR, IPR, VPR, and also  the LPR which was actually done under a follow-on  program called SURAN) .  There were also multiple versions of the radio software known as CAPX where X was a number.   I think the earliest version I encountered was CAP5 so I have no knowledge of the protocol implementation used in the simulation Greg Skinner presented in his email message. 

In the early 1980s packet radio was implementing multi-station so you could have more than one station in a packet radio network. I think this was known as CAP 6.2 (6.4???).  There was also a stationless design being discussed at the close of the packet radio program (CAP7).
barbara    On Wednesday, March 26, 2025 at 04:07:34 PM PDT, Vint Cerf <vint at google.com> wrote:  
 
 Jim Mathis wrote TCP/IP for the LSI-11/23. Nice piece of work.
v

On Wed, Mar 26, 2025 at 5:26 PM John Day <jeanjour at comcast.net> wrote:




On Mar 26, 2025, at 17:17, Vint Cerf <vint at google.com> wrote:
yes, the gateway was colocated with the Station (on the same computer).h

I missed something. What is the Station?

 The Station managed the Packet Radio network, maintained information about connectivity among the radio relays. PRNET was not a star network.

That is what I was assuming.

 Topology changes were tracked by the mobile nodes periodically reporting to the station which other Packet Radios they could reach.

So a sort of centralized routing on the Station. An early ad hoc network.

 Hosts on the PRNET nodes could communicate with each other and, through the gateway, with Arpanet and SATNET hosts. The PRNET nodes did NOT run TCP, 

So there were distinct machines acting as 'PRNET routers’ and PRNET hosts.

that was running on the hosts like the LSI-11/23's or the Station or....

;-) an LSI-11/23 wasn’t a lot of machine. ;-)  We had a strip down Unix running on one the year before but as a terminal connected to our Unix on an 11/45 but it was running NCP.
Thanks,John


v

On Wed, Mar 26, 2025 at 5:08 PM John Day <jeanjour at comcast.net> wrote:

And those nodes relayed among themselves as well as with the gateway?

IOW, PRNET wasn’t a star network with the gateway as the center, like a WIFI access point.

So there would have been TCP connections between PRNET nodes as well as TCP connections potentially relayed by other PRNET nodes through the gateway to ARPANET hosts.  Right?

Take care,
John