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14

In a WLAN iperf TCP throughput test, multiple parallel streams will give me higher throughput than 1 stream. I tried increasing the TCP window size, but I still cannot achieve the max throughput with just 1 stream. Is there something else in the TCP layer that is preventing the full link capacity from being used? In my experience, if you see significantly ...


9

I would take a look at iperf. You should be able to use built in reporting in iperf to validate the amount of traffic dropped. iperf is typically ran across the network between two systems. I have iperf3 installed on two CentOS machines, as you can see below, one is configured as the server and the other the client. Install the iperf rpm, start the ...


8

IOS includes ttcp, albeit it might not be supported officially by Cisco it can come in handy in situations like this. JUNOS does not support ttcp as far as I know, but it's probably not too much hassle adding one central Linux machine connected to the PE that you can do measurements with. On IOS, you simply run 'ttcp', like so; LAB-C7600-1#ttcp transmit ...


8

Using a search for "linux ethernet packet generator" gives me packeth as the first hit. packeth Solution: Has both a GUI and CLI version Generates not only UDP, but many other protocols as well, including QinQ Is packaged for RedHat as an rpm, or Debian package netcat and tcpdump Solution: If it was me, I would just do a quick-and-dirty ten second netcat ...


8

Firstly you can check functionality of CAT cable by LAN CABLE TESTERS Even functionality of cable can be even ensured by verfiying LED lamps of network devices like firewalls ,switches ,routers &NIC card indication lamps on PC's and servers By verfiying Mac address learning status from connected devices we can ensure connectivity status of devices for ...


6

To answer your first question, yes high bandwidth use will affect speedtest.net results. And yes, you would be best to wait until a time of low traffic to get a better/more accurate reading of your maximum possible speed. Another metric of maximum possible speed would be (assuming you are connecting via ADSL) the line sync speed as reported by your modem. ...


6

Depending on the ASA and license you have, you could use contexts which create virtual ASAs within the ASA. Each is independent of the other. This would also allow you to test ASA configs before putting them on production. Each vlan interface is assigned to a context. Packets coming in are classified (in your situation, via MAC of the vlan interface) and ...


5

Don't trust GNS3 for throughput tests. As soon as you use a router in your topology you are likely only to get 5mb/sec tops, regardless of whether you use a serial, ethernet or fast ethernet interface and regardless of how powerful your PC is. (Note that the performance hit won't be seen if you use a GNS3 switch instead of a router, however, the switches are ...


4

Judging by your switch, I'd say you don't have the budget for a real ethernet tester like those from Fluke Networks. Your switch is Layer 2 (L2) only and doesn't support routing, so you'd need an external router (L3) to move packets between the VLANs. I would conjecture that your random network issues were caused by either bad cabling or mismatch on speed/...


4

...we learned that every router has a LOOPBACK interface. That is not true. Cisco routers can be configured with loopback interfaces, but they don't have loopback interfaces until you create one. The idea of a loopback interface is that it is a virtual interface which never goes down due to a physical line or network problem. Loopback interfaces can be ...


4

A loopback interface is a virtual (i.e. not physical) interface that never goes down, unless you disable it. This way, if you configure an IP on this loopback interface and add it to your OSPF area (or any other routing protocol), it will always be reachable by whatever available/best path exists, provided that your router is not completely isolated. I ...


4

The PSE decides on which pairs power is supplied. A compliant PD needs to be able to use either pairs. Connecting a power supply to the spare pairs (only possible with 10BASE-T and 100BASE-TX) is not compatible with IEEE PoE. While most devices would probably work, some won't, and some may even break. My advice is to use a proper PoE injector and modify it ...


3

iPerf or Tamosoft throughput test. As a primarily Mac shop I currently find TTT more convenient, as iPerf builds for Mac are somewhat limited to specific OS versions or "build it yourself". TTT is a straightforward (and cross-platform) download and run. ...but iPerf is by far the more commonly/widely accepted method among network professionals. Have used ...


3

There are a few problems with your premise. First, connecting switch ports to switch ports will either end up disabling the switch ports or causing a spanning-tree loop. Switches send BPDUs to determine the switch topology. Properly configured switches will have the access ports set to portfast and bpduguard. This configuration will disable the ports in ...


3

I'm almost 100% positive that for Cisco switches it would be CDP (Cisco Discovery Protocol) while on other vendors, they would use the industry standard LLDP (Link Layer Discovery Protocol). From CDP, you can get information such as switch port, VLAN, switch name, and link negotiation info (e.g. full vs half duplex) to name a few. I hope this helps.


3

For metrics you can look in to the reports that NSS labs are publishing, they have pretty solid documentation on how they do firewall testing. You can also google for their reports, sometimes firewall vendors publish them free of charge on their own web page for promo purposes. As for what tool you need you can use the ones you have listed, but it boils ...


3

I'm inclined to believe that it is your caps/non-caps on the bandwidth designations (i.e. -b 10M -l 32K -w 128K). I can't test it because we don't know what version you're running. Iperf does make a distinction between bits and bytes: -f, --format [kmKM] format to report: Kbits, Mbits, KBytes, MBytes Though, the sections you were modifying were ...


3

This is the record of the testing done on the AP using the LANforge. Inside the anechoic chamber, the LANforge (eth1) is connected to the AP under test via a LAN cable. I set up 4 virtual stations in the LANforge, with the same SSID as the AP. This results in a loop that allows the LANforge to measure the throughputs of the various streams. The stations ...


3

EDITED Despite the extended usage of binary in computer world and power of two based units (Byte, 32-bits word etc...), network bandwidth is commonly expressed in power of ten units. So it is (speed_in_Bps * 8) / (10 ^ (3 * 2)) (or /50^3)


3

There is one particularity about iperf 2.0.x with UDP: Within the limits (CPU, NIC, UDP/IP stack and its buffers) of the sending system, iPerf will send traffic at the payload rate you specify with the -b parameter (if left out, iperf will default to 1Mbit/s). EDIT: D'oh! Only now I spotted that you are actually using iperf3. I'll leave these comments ...


3

“Inline” refers to PoE, not to the position of the tester. So this with this tester you can check cables doing power over Ethernet. You would still place the tester at the ends of the cable.


3

What you're looking for is a cable tester able to certify a cable with the entire test suite. The tests must include crosstalk and detailed frequency measurement. Basically, there are three classes of testers: just continuity and shorts - 5-100 € additionally wire map (proper pairings), overall length, possibly rough frequency response (cable class) - 200-...


2

Here's the calculation for the maximum throughput of a single tcp stream. (TCP Window [bytes]/RTT[seconds]) * 8 [bits/byte] = Max single tcp throughput in (bps) So you have a bottleneck and latency plays a large role.


2

If your router or switch has SNMP functions, it's useful to simply monitor traffic on the interfaces with a simple SNMP reporting tool running on your computer - then you will see the traffic that is going on. If you have a 5Mb connection and it's flowing at 5Mb, you might well have a hard time getting more than 0.3 in edgewise to speedtest - but you'd know ...


2

Since you are wanting to measure a layer 2 circuit, I'd like to shamelessly push some free software that I have been writing. It's still in beta but does exactly what you want based on the information in your question. Unlike nuttcp, iPerf, jPerf et al, Etherate runs directly over layer 2 designed specifically for Ethernet testing. Like the others a laptop ...


2

You need to have the server in Receive mode (i.e. -r option). Try the below command syntax. ttcp -r -s -p 3333 -D Check out the ttcp man page for more details. Further reading In order to make this a viable setup, you need a sender and receiver. The sender effectively establishes all of the prameters the tcp session will be benchmarked on. Transmit ...


2

By far the best packet and traffic generator I have come across for Linux is PacketETH; You can use it via CLI or via GUI. It is for generating Ethernet frames but you can also specify higher protocols such as IPv4/6, and TCP/UDP etc. It's very powerful letting you customise pretty much all header options for protocols in layer 2, 3 and 4 (so Ethernet, ...


2

useful tool can help you to make good wireless survey is wifi analyzer on the android phones. its can work on both ranges 2.4 and 5 GHZ you can use it to figure out channel utility and it DPI and it can help in find the places of the APs as well on PC insider could be one of the best wireless survey tools


2

You may be confused about something. You application may create threads for execution on your PC, but routers switch packets one at a time, regardless of what came before, and routers have no expectation that anything is coming in the future. Each packet is handled as an individual packet to be switched. The router may not be able to handle the throughput ...


2

in terms of server and client communications . based on stream or traffic traffic going from the server to the clients called downstream , and from clients to server called upstream . based on device connections client is up linked to server and server is down linked to clients


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