skrenta@blekko.UUCP (Rich Skrenta) (04/07/91)
We're experimenting with SLIP over Telebit T1000's and we're getting pretty choppy response. An rlogin over a direct connect slip line seems faster than over the Telebit. Are there any registers that can be tweaked to improve slip performance? Does V.32 do a better job with slip? How much does slip spoofing in the T2500 help? Rich -- skrenta@blekko.commodore.com
gandrews@netcom.COM (Greg Andrews) (04/07/91)
In article <155@blekko.UUCP> skrenta@blekko.UUCP (Rich Skrenta) writes: >We're experimenting with SLIP over Telebit T1000's and we're getting >pretty choppy response. An rlogin over a direct connect slip line >seems faster than over the Telebit. Are there any registers that >can be tweaked to improve slip performance? > Only if you're getting pauses from the modems retraining. PEP's half duplex nature adds extra delays onto network protocols like SLIP, and that is what causes a lot of the 'choppiness' you're seeing. Compressed SLIP can help on things like character delays, but overall PEP is less comfortable than a full duplex modulation like V.32. > >Does V.32 do a better job with slip? How much does slip spoofing in >the T2500 help? > Yes, V.32 is full duplex, so the protocol ACKs come back when the protocol expects them to, and the data moves along without as many pauses. The T2500 doesn't have SLIP spoofing. Just the V.32 modulation (and MNP/V.42 error correction protocols). -- .------------------------------------------------------------------------. | Greg Andrews | UUCP: {apple,amdahl,claris}!netcom!gandrews | | | Internet: gandrews@netcom.COM | `------------------------------------------------------------------------'
larry@nstar.rn.com (Larry Snyder) (04/07/91)
skrenta@blekko.UUCP (Rich Skrenta) writes: >We're experimenting with SLIP over Telebit T1000's and we're getting >pretty choppy response. An rlogin over a direct connect slip line >seems faster than over the Telebit. Are there any registers that >can be tweaked to improve slip performance? >Does V.32 do a better job with slip? How much does slip spoofing in >the T2500 help? yes - the PEP modems (T2000 and PLUS) at best give around 400 cps using SLIP while V.32 should run around 1100 The problems with the PEP modems are the lack of v.32bis and the inability to lock the DTE at 38400 (I understand their current T1600 supports 38400). We use a pair of USR V.32/v.32bis modems here with the DTE locked at 38400 over a leased line and get 3.x kb/sec doing ASCII transfers and from 1.3 to 2.0 kb/sec doing binary transfers using ftp. v.32bis will increase the throughput by around 50% over V.32. -- Larry Snyder, NSTAR Public Access Unix 219-289-0287 (HST/PEP/V.32/v.42bis) regional UUCP mapping coordinator {larry@nstar.rn.com, ..!uunet!nstar.rn.com!larry}
ar12@prism.gatech.EDU (REGISTER,ANDREW H) (04/08/91)
In article <1991Apr7.091025.15876@netcom.COM>, gandrews@netcom.COM (Greg Andrews) writes: > > The T2500 doesn't have SLIP spoofing. Just the V.32 modulation (and > MNP/V.42 error correction protocols). > I want to do SLIP and I have been reading comp.dcom.modems for about 2 months trying to figure out exactly what I need to do this most efficiently. This is the first time I have heard of SLIP spoofing. What is it and how does it help? Any comments about what works best for SLIP (ie. such as the previous V.32 comment) will be appreciated. Toodles Andy -- Andy Register Internet: ar12@prism.gatech.edu Bitnet: aregiste@gtri01.bitnet -- Sometimes the Bears Win, Sometimes the Bulls Win -- -------- But the Pigs *Always* Lose -------- (author unknown)
root@zswamp.fidonet.org (Geoffrey Welsh) (04/09/91)
REGISTER,ANDREW H (ar12@prism.gatech.EDU ) wrote: >This is the first time I have heard of SLIP spoofing. What >is it and how does it help? Not too long ago there was a discussion here in which it was explained why SLIP spoofing is not viable. It all boils down to the fact that IP demands end to end acknowledgement of datagrams, and spoofing is a direct contradiction of that. >Any comments about what works best for SLIP (ie. such as the >previous V.32 comment) will be appreciated. It seems that symmetrical data channels (i.e. V.32 or V.32bis, not PEP, HST, or V-9600) offer much better SLIP performance. All other major condiderations (e.g. baud rate) are obvious. -- UUCP: watmath!xenitec!zswamp!root | 602-66 Mooregate Crescent Internet: root@zswamp.fidonet.org | Kitchener, Ontario FidoNet: SYSOP, 1:221/171 | N2M 5E6 CANADA Data: (519) 742-8939 | (519) 741-9553 The mile is traversed not by a single leap, but by a procession of coherent steps; those who insist on making the trip in a single element will be failing long after you and I have discovered new worlds. -- me
poffen@sj.ate.slb.com (Russ Poffenberger) (04/11/91)
In article <1991Apr07.144948.956@nstar.rn.com> larry@nstar.rn.com (Larry Snyder) writes: >skrenta@blekko.UUCP (Rich Skrenta) writes: > >>We're experimenting with SLIP over Telebit T1000's and we're getting >>pretty choppy response. An rlogin over a direct connect slip line >>seems faster than over the Telebit. Are there any registers that >>can be tweaked to improve slip performance? > >>Does V.32 do a better job with slip? How much does slip spoofing in >>the T2500 help? > >yes - the PEP modems (T2000 and PLUS) at best give around 400 cps >using SLIP while V.32 should run around 1100 > I run SLIP (not the compressed SLIP) between a pair of T1000's all the time and I can get >700 bytes/sec throughput. This is locking the DTE's at 19200. This is about what I would expect from a 9600 baud modem. Russ Poffenberger DOMAIN: poffen@sj.ate.slb.com Schlumberger Technologies UUCP: {uunet,decwrl,amdahl}!sjsca4!poffen 1601 Technology Drive CIS: 72401,276 San Jose, Ca. 95110 (408)437-5254
larry@nstar.rn.com (Larry Snyder) (04/12/91)
poffen@sj.ate.slb.com (Russ Poffenberger) writes: >I run SLIP (not the compressed SLIP) between a pair of T1000's all the time >and I can get >700 bytes/sec throughput. This is locking the DTE's at 19200. >This is about what I would expect from a 9600 baud modem. not bad - but how does throughput look if you have two ftp sessions going at the same time (one each direction)? using duplex modems, throughput drops maybe 10% at most (sending 2 meg files different directions at the same time) -- Larry Snyder, NSTAR Public Access Unix 219-289-0287 (HST/PEP/V.32/v.42bis) regional UUCP mapping coordinator {larry@nstar.rn.com, ..!uunet!nstar.rn.com!larry}