On Saturday, March 03, 2012 at 4:05 PM, Michael Bloom wrote: > I just wanted to comment that the instructions for networking in > 00readme_ethernet can be simplified for linux. The bridge utilities > are not really necessary after using tunctl, unless you need to do > something more complex. > > [...] example details snipped.
> After that, the emulated system and the host were both able to see > each other, and both could access the outside world. That is completely true for IP traffic. However, the key goal for the simulator level networking is to have these simulated systems be able to talk to other real or simulated systems in all the ways that they did when they were natively networking. When these systems were in their prime, IP was not the dominant networking protocol. These systems spoke DECnet, LAT, SCS(Vax Cluster Communications), etc. All of these protocols were designed around communications on a LAN. The 0readme_ethernet.txt document's goal is to try and get a simulator to BOTH be able to participate with these protocols on the local LAN AND to have the host system be able to also communicate with the host System with whatever protocols they may actually share (usually only IP these days). In the earliest days of simh networking, the only strategy we could come up with which would achieve the full networking goal was to install an additional NIC in the hosting system which was dedicated to the simh instance and connect that NIC to the same LAN as the primary host NIC. The host's network stack would be configured to not use this additional NIC for anything and things would work just fine. This strategy was one which also worked for essentially any host platform. Meanwhile, many folks either had host systems which couldn't easily accommodate the addition of additional NICs or they merely wanted to come up with ways to achieve the full set of goals without the addition of extra hardware. The current simh networking document (0readme_ethernet.txt) describes how these combined goals can be achieved in various host specific ways. On Linux the bridging approach achieves this functionality. On Windows, the native stack (combined with some extra code in sim_ether.c) can achieve the goal Without any extra hardware or any special host configuration steps. If your only goal as to use IP to communicate between a simulator and other places (including the hosting system), then your recipe will be sufficient. I'm not sure how well it would achieve this goal if you happened to want to run multiple simulators on the same host. The bridging recipe works for this extended case as well. - Mark Pizzolato _______________________________________________ Simh mailing list [email protected] http://mailman.trailing-edge.com/mailman/listinfo/simh
