This is a system upgraded from 6.0 to 6.1 with rp3-1.0.1-1, ppp-2.3.10-3, initscripts-4.63-1 and all other errata updates. I deleted my slip devices (which have never worked right) and added them back with netcfg since rp3-config crashes immediately (presumably due to one of the previously reported problems). Starting sl0 from the usernet/rp3 console tool gets an immediate falure notification despite the fact that the dip script is happily dialing in and connecting in the background. Of course since rp3 thinks that the connect failed, it can't be used to shut down the connection once it's established... (dip -k to the rescue!) There seem to be couple things here, slip doesn't seem to be well supported or tested, and dial-in configurations created with netcfg seem to give rp3 minor heartburn. Sorry if this is slightly vague, more details as I track them down and record them.
OK here's something interesting, every time it bombs /var/log/messages shows: Nov 10 02:51:33 culliton-ppp modprobe: can't locate module sl0 Nov 10 02:51:33 culliton-ppp modprobe: can't locate module sl1
You are right, to be honest, about slip being the ugly stepchild here. That's mainly because dip is so incredibly inflexible in ways that it would have to be flexible to make this work well. It just does not give us the functionality we need to make ifup work properly in this context, and there are few enough slip users that I spent my time improving PPP rather than re-architecting dip... There's some code to make wvdial work for SLIP, and I may try to make use of that in the future to make SLIP connections work better. That uses slattach and would allow me, if it works reliably, to get rid of dip entirely for setting up SLIP connections.
I think you've got the priorities right, SLIP is primarily a compatibility tool for older systems, we only use it to do dial up networking with old AIX 3.2 systems. Still, it would be nice if it worked from the usernet/rp3 GUI. I have dip scripts that work, but have to run them from a shell window as root. What exactly is the incompatibility between dip and rp3? Maybe my nasty twisty mind can help...
It's not so much an incompatibility as a complete difference... rp3 doesn't explicitly know about dialing. It just stores some values in /etc/sysconfig/network-scripts/ifcfg-ppp<n> and /etc/wvdial.conf and that's it, as far as configuration goes. The wvdial intelligent dialer is the program actually doing the dialing underneath the covers.
Closing because we don't ship rp3 anymore.