BILLW@MATHOM.CISCO.COM (William Westfield) (11/06/87)
Is there any interest in a TAC like device capable of running SLIP (Serial Line IP) on its terminal interfaces ? As I currently envision this, each serial line could be a logical host when acting as an IP device, and just a normal port when acting as a terminal. This might provide some performance improvement over things like kermit for downloading/uploading files.... Bill Westfield cisco Systems. -------
dlw@OPAL.BERKELEY.EDU (David Wasley) (11/10/87)
I have a very strong interest in such a thing. I envision it as presenting host addresses on a single subnet to the various ports. The protocol would be to "log in" to the system (validation and all that) and be given an IP address & mask for the duration of the session. After that, it is all IP until carrier drops. Is there a well defined, documented protocol for this initial dialogue? How would you deal with dynamic name/address mapping? I can see dynamic registry with a DNS, and timeout/de-registry. But what about the email relay that wants to deliver to me and must be told that I've just connected? (This is one reason I want real, secure validation.) If such a thing existed, I can see supporting a "rotary" of 64 ports (min) for general campus network access here. They should run up to 64Kb/s. The line protocol should be SDLC with a well defined IP encapsulation so my PC, uVax, MAC-II, or SUN can implement it. Etc. It should have logging of course... Maybe all this is obvious. Maybe there is one out there?? I haven't seen it. (Yeah, we could make one, but I'd rather see a standard product :-) David Wasley U C Berkeley
CERF@A.ISI.EDU (11/10/87)
I would be a little nervous about dynamic name/address binding so that the host could receive calls (mail, file transfer, etc), but comfortable with originating calls - assuming, of course, that this meant you could not masquerade as an arbitrary host name by using SGMP and asking for messages for that host. Apart from security concerns (which may be present regardless of ability to receive calls as well as originating them), getting the Internet to handle dynamic name/address binding, avoiding spoofing and dealing with the potential for multiple name servers to be out of sync, causing confusion, seems quite an ambitious chore. Perhaps Mr. Wasley has thought this through and can offer his view of the architectural considerations? Vint
rick@SEISMO.CSS.GOV (Rick Adams) (11/11/87)
No, what pople REALLY want is a SLIP card on your gateway box so that they can connect a network via SLIP to the local ethernet. We have 6 such connections beating the hell out of a vax 780. ---rick
ron@TOPAZ.RUTGERS.EDU (Ron Natalie) (11/11/87)
Of course, we want one, but then you knew that.
daveb@geac.UUCP (11/13/87)
In article <12348296366.8.BILLW@MATHOM.CISCO.COM> BILLW@MATHOM.CISCO.COM (William Westfield) writes: >Is there any interest in a TAC like device capable of running SLIP >(Serial Line IP) on its terminal interfaces ? As I currently >envision this, each serial line could be a logical host when acting >as an IP device, and just a normal port when acting as a terminal. >This might provide some performance improvement over things like >kermit for downloading/uploading files.... > >Bill Westfield >cisco Systems. This is a subset of the idea of an "async gateway processor", which is a small, general-purpose computer gutted to run several gateway programs. A plausable set might be: IP to ordinary ttys (ie, normal TACyness) IP to SLIP TCP/IP telnet/TACyness kermit (recent large-block kind) TCP/IP telnet/TACyness to MNP (a mostly-transparent modem protocol) TCP/IP telnet/TACyness to X.pc (if you feel masocistic) A good cantidate for such a machine might be one of the "unix-like" small realtime systems running on mas-market hardware. --dave -- David Collier-Brown. {mnetor|yetti|utgpu}!geac!daveb Geac Computers International Inc., | Computer Science loses its 350 Steelcase Road,Markham, Ontario, | memory (if not its mind) CANADA, L3R 1B3 (416) 475-0525 x3279 | every 6 months.
chris@GYRE.UMD.EDU (Chris Torek) (11/15/87)
From: dlw%opal.Berkeley.EDU@violet.berkeley.edu (David Wasley) ... The protocol would be to "log in" to the system (validation and all that) and be given an IP address & mask for the duration of the session. After that, it is all IP until carrier drops. Is there a well defined, documented protocol for this initial dialogue? Not as far as I know; but I had something like this in mind when I rewired Rick Adams's version of SLIP for 4.3BSD. That is why slattach waits `forever' in a sigpause(): to find out about carrier loss. If you are a client of some dialup IP server, you might want to redial automatically. (Those of you with 4.3BSD source can look at /usr/src/etc/slattach.c to see how the attach works. It should be easy enough to write dialup and protocol code that would run first.) How would you deal with dynamic name/address mapping? I will leave this one for others. Chris
slevy@UMN-REI-UC.ARPA.UUCP (11/15/87)
Is dynamic IP addressing necessary? Rather than having the dialled-into system pick an address for its caller, how about if the caller asks for a particular IP address and authenticates itself with, say, a password? That same calling host would always ask for the same address. The name-address association could be permanent, only the connections would be temporary. Stuart Levy, Minn. Supercomputer Center slevy@uc.msc.umn.edu, 612 626 0211
BILLW@MATHOM.CISCO.COM (William Westfield) (11/24/87)
Rather than having the dialled-into system pick an address for its
caller, how about if the caller asks for a particular IP address and
authenticates itself with, say, a password? That same calling host
would always ask for the same address. The name-address association
could be permanent, only the connections would be temporary.
This makes routing a big problem (although routing protocols are already
dynamic in nature, it isn't clear that they are \that/ dynamic, and are
quite likely to have problems with the huge number of routes that may
suddenly appear).
You would also then have the requirment that each and every PC have
its own (sub)net number, which results in quite an address assignment
problem if you have (as someone mentioned) 3000+ PCs.
A compromise might be to have each SLIP server serve a number of
IP addresses on a particular subnet, and then when a PC dials in,
it can pick its own address from that pool...
It is NOT clear to me that SLIP will primarilly be used by dialin users,
and for hardwired connections to PCs, things are a lot easier.
Bill Westfield
cisco Systems.
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