WANCHO@SIMTEL20.ARPA (10/07/87)
As the host administrator for this machine, I often get asked why the network is so slow. Part of the answer is that this host is but a 2040 with 512KW, soon to be upgraded to a 2065 with 4MW. That should make a significant difference in that we will finally be able to run the TCP service locked into the highest queue without swamping the system. But, for the rest of the answer, I point out that the DDN backbone is still operating at 56Kbps with nodes which apparently cannot handle higher rates. That configuration maybe was adequate when the net consisted of about 300 to 500 hosts and the protocol was the more efficient, but less flexible NCP (in my opinion). Now, we have an order of magnitude more hosts sending TCP traffic through the net, and the links are still 56Kbps. Oh, there may be more links, more cross-country paths, and even satellite hops added on a weekly basis to handle the traffic. But, the basic *speed* is still 56Kbps, although the bandwidth *may* be greater. Meanwhile, campus LANs architects sneer at anything less than 10Mbps to get any work done. Is it really unreasonable to ask why the backbone hasn't been upgraded to at least T1 service? Are there any plans for such an upgrade? If not, then what? Still more 56Kbps links? Does that *really* solve the problem? What should I tell my users (one in particular) to expect, and when? --Frank
PERRY@VAX.DARPA.MIL (Dennis G. Perry) (10/09/87)
Frank, all it takes is money. Do you have some, or is DARPA/DCA supposed to foot the bill? dennis -------
ron@TOPAZ.RUTGERS.EDU (Ron Natalie) (10/10/87)
I suppose the biggest reason why campus LAN experts work with higher bandwidths is because we can. But it's really more resonable to expect that you need higher rates on local links because there is more traffic. A quick check of the BRL gateway shows that most of the traffic never leaves BRL (yet the gateway was still the sixth busiest MILNET host). Nobody really expects earth-shattering response from the MILNET anymore (right or wrong). Most of the traffic is mail, which all happens in the background. DCA was probably left behind for a while in network planning because of the overwhelming success of the INTERNET. First, the amount of traffic for any host has gone way up. Seven years ago, when BRL brought up its first ARPANET host, there were maybe a dozen people in the lab who used the ARPANET services. Now near a thousand people rely on electronic mail daily. Second, since IP became available five years ago, MILNET node traffic was no longer limitted by the traffic generated by a single node. You could have one machine front for an entire installation. I'm not sure DCA fully comprehended that. I remember them once telling me that they liked BRL, we only had one host on the net. Of course, that host (actually two) fronts for dozens of Ethernets, Proteon Ring Nets, Hyperchannels, and even a six IMP ARPANET-clone. On this are scads of workstations, super-minis, and two CRAY's. It's clear that the whole thing is over capacity. Between gateways and more and more users relying on network service, the old traffic estimates are way out of line. I'm not sure what can really be done though. Trunks could always be added, which is probably the most expedient. 56K is not bad when you have enough connectivity. The IMPs certainly won't deal with T1, but more sophisticated switches such as the Butterflies are probably a long way from the MILNET. The new end-to-end protocol and the mailbridge upgrades have not yet been fielded, let alone drastically changing the network topology. Oh well. I've got to go hook up another T1 line. -Ron