chabutjc@wpafb.af.mil (John Chabut) (12/12/89)
I'm sure I'm not the first to notice that even if you have two hosts connected to PSNs at 56 kb/s, the throughput of an FTP is down around 4 kb/s. I realize there's overhead associated with FTP, TCP/IP, and X.25, but how much does the MILNET affect throughput? Can anyone refer me to studies done of MILNET throughput? I presume it changes due to congestion at certain times of the day, number of active PSNs, etc. I appreciate your interest and assistance. --John Chabut SAIC 513-429-6553 chabutjc@asd.wpafb.af.mil OR jcc%dayvd%dayvb@uunet.uu.net
amanda@mermaid.intercon.com (Amanda Walker) (12/14/89)
In article <137598.8912131631@asd.wpafb.af.mil>, chabutjc@wpafb.af.mil (John Chabut) writes: > I'm sure I'm not the first to notice that even if you > have two hosts connected to PSNs at 56 kb/s, the throughput > of an FTP is down around 4 kb/s. Um, are you sure you're not mixing bits and bytes? 4K bytes per second is 32K bits per second, which is not too bad across a 56K bits per second link, especially in the presence of other traffic. One of the reasons that NSFnet is so much faster than MILnet is that many PSNs are linked with T1 (or faster) links rather than 56K leased lines. Amanda Walker InterCon Systems Corporation --
ntm1569@dsacg3.dsac.dla.mil (Jeff Roth) (12/15/89)
I've also been unpleasantly surprised by both throughput and latency on the network. Our studies have shown some variation by time of day but not as much as you might suspect; there is greater variation depending on the route the data takes. It's likely overloaded PSNs, in fact our worst cases are going through one PSN to another at the same site (WPAFB). But it does appear 56 KB buys you something; our FTP throughput, using a 9.6 circuit, is more like 1 KB/s at best. By the way I'd appreciate it if any readers with information on what if any, plans exist to upgrade Milnet capacity could point me to a source (or let me know privately by email what we can expect).