ewv@craycos.com (Eric Varsanyi) (08/30/90)
In article <1990Aug23.160013.1199@scuzzy.mbx.sub.org> src@scuzzy.mbx.sub.org (Heiko Blume) writes: >can someone tell me what throughput i can expect with sl/ip over >a modem connection with HST modems (14400bps)? This does not directly relate to HST's, but it might be interesting anyway. Configuration: -------------- SCO Unix (3.2.2) with the vanilla driver on a vanilla serial board Connection between 2 Telebit T2500's. Cisco terminal server providing slip bridge onto ethernet Transfer of 100 Kb file (binary, Unix kernel from a Sparc) 19200 hardware flow control on both sides Numbers: -------- Kb/s (reported by ftp) Roundtrip (reported by ping) V.32 mode .795 370 (s50=6) Pep .799 1420 Pep/compressed .823 1551 (s110=1) Watching the lights on the modem it looked like Pep's reverse channel was not wide enough to avoid turning the line around every few packets to send back the ACK's. Interactive was virtually useless at 1.4 seconds/echo, but using V.32 even editing with vi is tolerable. Compressed mode isn't worth the trouble unless you are sending BIG files. Does anyone know when/if Telebit is going to put IP header prediction into the modems (so they don't have to turn around for the ACK's)? -Eric Varsanyi Cray Computer Corporation ewv@craycos.com -- -Eric Varsanyi (ewv@craycos.com) Cray Computer Corporation
gavron@alpha.sunquest.com (Ehud Gavron) (08/30/90)
In article <1990Aug29.233628.2595@craycos.com>, ewv@craycos.com (Eric Varsanyi) writes... #In article <1990Aug23.160013.1199@scuzzy.mbx.sub.org> src@scuzzy.mbx.sub.org (Heiko Blume) writes: #>can someone tell me what throughput i can expect with sl/ip over #>a modem connection with HST modems (14400bps)? # #This does not directly relate to HST's, but it might be interesting anyway. # #Configuration: #-------------- # SCO Unix (3.2.2) with the vanilla driver on a vanilla serial board # Connection between 2 Telebit T2500's. # Cisco terminal server providing slip bridge onto ethernet Our configuration: Two Telebit T2500s over an analog leased line between two serial ports on MicroVAXen. # 19200 hardware flow control on both sides Same here # #Numbers: #-------- # Kb/s (reported by ftp) Roundtrip (reported by ping) #V.32 mode .795 370 #(s50=6) # #Pep .799 1420 # #Pep/compressed .823 1551 #(s110=1) My comparison is *extremely* similar. # #Interactive was virtually useless at 1.4 seconds/echo, but using V.32 #even editing with vi is tolerable. Compressed mode isn't worth the trouble #unless you are sending BIG files. PEP is worth it if you intend to do any FTP, or if you intend to use more than one average tcp link at a time. In other words, if a majority of the time this limited line will support two connections, we have found that PEP-19200 is much more responsive than V.32-9600 on the same line. Note that for single-channel interactive use, I concur that V.32 is better for latency. # #Does anyone know when/if Telebit is going to put IP header prediction into #the modems (so they don't have to turn around for the ACK's)? I'd like to find out myself :-) #-- #-Eric Varsanyi (ewv@craycos.com) Cray Computer Corporation Ehud /----------------------------------------------------------------------------\ | Ehud Gavron, Systems analyst | gavron@vesta.sunquest.com (Internet) | | Sunquest Information Systems | uunet!sunquest!gavron (UUCP) | | 930 N. Finance Center Drive | gavron@lampf (BITNET) | | Tucson, Arizona, 85710 | (602)722-7546/885-7700 x.2546 (AT&Tnet) | |----------------------------------------------------------------------------| | your cute quote here | \----------------------------------------------------------------------------/
bob@MorningStar.Com (Bob Sutterfield) (09/01/90)
In article <1990Aug29.233628.2595@craycos.com> ewv@craycos.com (Eric Varsanyi) writes:
SCO Unix (3.2.2) with the vanilla driver on a vanilla serial board
SunOS 4.0.3 on a 4/60 and a 4/110, on console serial ports
Connection between 2 Telebit T2500's.
Connection between a TB+ and a TB2500, using PEP
19200 hardware flow control on both sides
Same here
Kb/s (reported by ftp)
Pep .799
Pep/compressed .823
(s110=1)
We saw those sorts of numbers with vanilla SLIP. Things improved to
around 1.0Kb/s with header-compressed SLIP. We saw numbers like
1.3-1.5Kb/s FTP throughput when using PPP.
Does anyone know when/if Telebit is going to put IP header
prediction into the modems (so they don't have to turn around for
the ACK's)?
Try using a smarter protocol, and the modems will do just fine.
Header compression helps a *lot*.