When we performed our tests, the BSD ping produced a better overall result.The BSD ping code more or less does a gettimeofday(2) before a packet is sent, and then makes the same system call after the ping is returned, compares the new and old sec/microsecond timestamps and prints out a result. If you develop a WAN of 1.45 mbps its cost is more than what it gives you. Our basic test set is informally specified as follows:1. topology specification: Define the equipment and connections in use.
2. Although it is not true in every case, and any rash assumption here might be debatable, the graphs seem to suggest that the improvement from 16k to 32k is more dramatic than say from 32k to 64k.
The PSU backbone consists of four routers, two to the outside, and two to the inside. Speeds of MAN ranges in terms of Mbps. Abstract: A description is presented of the Alcatel Metropolitan Area Network (MAN), a high-speed network with LAN performance for wide areas. This in theory, would allow us to make reasonable measurements both in terms of high-speed gigabit ethernet connections, and over relatively fast paths across a few gigabit ethernet switches.
The tests consist of the following:Please see the following tables, and figures EPING for ping graphs, and EPLOT, for ttcp data.So why with the best ttcp measurement does OGI obtain 122 megabits, but PSU and OHSU only get around 80mbits?. MANs are formed by connecting multiple LANs.
MAN has a range of over 50kms. The localhost to null switch transition adds 4 interface hw/sw transitions and operating system interrupts to localhost. This can be considered as an approximation of the sort of round-trip delay that TCP itself would have to deal with assuming large packet sizes. Without testing efforts, network engineers may not know if they are under utilizing costly MAN and WAN high-speed connection links.In this section, we are going to present four external test cases that crossed the Portland PREN man over its three OC-3 links. single large chassis switch/router, Cisco 5500 (no routing function here)2. But while the telephone network was able to support the packet-based exchange of data that the various LAN protocols implemented, the bandwidth of the telephone network was already under heavy demand from circuit-switched voice, and the telephone exchangeswere ill-designed to cope …
On the other hand, we spoke to Steve Corbato about his Internet2, high speed HDTV video tests over the Abilene backbone. As a side goal, we hoped to convince management and/or the network engineers themselves that such tests were useful and that a practice of testing infrastructure gear as a matter of IT culture might be a useful philosophy. Thus the 5500 in question added a Cisco Route Switch Module (RSM), which has the compute engine of a Cisco 4700 router. In figure EPLOT, notice that with 4 out of 5 ttcp tests we seem to see the knee result again that was previously mentioned in section 4.1.
We wanted to see if any bottlenecks existed, and if so, figure out the cause.2.
Specify what kinds of links are used (ethernet, SONET, etc.).2. It connects two or more computers that are apart but resides in the same or different cities. Again, we were using the Intel gigabit ethernet cards (WISEMAN). Of course, it can still tell you if you are connected. Unfortunately application programming may vary, and there appears to be little concern with some operating systems for high speed delay measurements.In general we used pairs of FreeBSD 4.0 and 4.1 hosts placed with 0 to N switches/routers between them.
We also include two backbone (two switch) tests from section 4, and left out localhost as it flattened the graphs. We wanted a host network stack with an older TCP protocol implementation that had stood the test of time. [FERGUSON98] Ferguson, P., Senie, D., "Network Ingress Filtering: Defeating Denial of Service Attacks which employ IP Source Address Spoofing, RFC 2267, January 1998 [LEFFLER89] Leffler, et. PSU at least, has aggregation capabilities in that regard. One of the more interesting aspects of the entire test experience were "unexpected occurrences". It connects two or more computers that are apart but resides in the same or different cities.
There are two important lessons here: 1. basic configuration mistakes can have very harmful results on high-speed networking. Another important aspect of ping of course is measurement time granularity; that is, how well can we measure the roundtrip, especially in the face of network devices that may very fast. Some pings do not have flood ping capabilities; for example, both WNT and Solaris pings lack that capability.
These cards are known internally as WISEMAN cards and may be identified by the LSI chip on them (newer cards have replaced the LSI chip with an Intel chip). This tool can average connection speed for any …
Although we are jumping ahead to backbone tests, the i3 OGI backbone test shows a curve clearly the same as the 3508 and/or 3524 switches by themselves. Consequentially, we decided to make roughly four kinds of network tests using In section 2, test methodology, we primarily discuss how our tests were setup, although a few test results are presented. Files and databases can be transferred fast.In some installation of MANs, users can share their internet connection.