Re: Marinetti over LocalTalk/Appletalk?

[Jalapeno <jalapeno1@mac.com>]

In article <5HX98.59$U16.107157@news.uswest.net>, who@where.what (Bart) 
wrote:

> As to LocalTalk Bridge and TCP/IP:  I have LT Bridge running on a Quadra 950 
> under System 7.5.3. On that LT leg my net has 2 Apple IIGSs, 2 //e(s) on 
> Network cards, the LT port on a Laserwriter IIg, and a IWII Localtalk card. 
> Oh 
> and on occasion a Appletalked IWLQ; I need the power cord for another use so 
> its only on when I need it ;)
> I can do all the usual Appletalk things and I can get to other etherneted 
> resources from the IIgs, can login to another ether connected Mac (on 
> Appleshare 3.0.3)from a //e (or a //e card on a LC Mac) but I can NOT do 
> TCP/IP.


That is because you probably need to install Apple Internet Router with 
the Apple IP Gateway add-on (if you are using a Mac for a router, but 
Gatorboxes do it themselves). To transmit ip data-grams across a 
local-talk/ether-talk/token-talk network they must be tunneled via 
Appletalk DDP encapsulation. 

This should be quite easy to do with Marinetti because MacIP only uses 
three of the Appletalk stack protocols: NBP (name binding protocol to 
find MacIP services and hosts on the localtalk network), ATP (appletalk 
transaction protocol to communicate with the MacIP gateway), and DDP 
(datagram delivery protocol to send and receive the packets) and all 
three of these layers are built into the Apple IIgs (either as firmware 
or a driver provided with the system software). 

The Marinetti MacIP link layer just needs to (theoretically speaking 
here, since I haven't done any Marinetti programming) collect IP 
datagrams from Marinetti and put Appletalk DDP headers on it, then send 
it via localtalk to the MacIP Gateway. The link layer can even impose IP 
MTU's to be small enough to fit into an Appletalk DDP datagram so there 
is no Appletalk fragmentation. Then, when the link layer is called (via 
the DDP socket listener that was installed at by the link layer at start 
up) the DDP header is stripped off and the IP datagram is passed to 
Marinetti for further processing.