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27

You can use iperf2 or iperf3 to help generate some traffic. There are quite a few options included that will allow you to accomplish some nice traffic classification. You might also check out scapy - specifically a packet former utility. Allows you to define values on each field to get really granular with how traffic is being formed and sent. In my lab, I ...


26

There are tools like WANem which allow you to simulate WAN links by artificially causing arbitrary delay and loss rates on a link. WANem works at a relatively high-level; you won't see physical errors on the link but packets will be dropped. It can be deployed on commodity hardware. I know there are a few other tools which serve similar purposes but I can't ...


14

your best bet will probably be to put a wan emulator in-between the wlan network and rest of the network. Even better if you are using multiple SSIDs, each going to its own VLAN (you'd then place the WAN emulator between the SSID's VLAN you want to break and the rest of the network. You could then configure the emulator to create the crappy network (ie: ...


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

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

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

If you're trying to test 1xGE No Drop Rate and measure circuit delay within 8ms, I would use nuttcp to test bandwidth and iperf2 / mtr to test delay. I would do the following... Find two linux desktop PCs, if possible (laptops are sometimes acceptable, but you might run into issues with chipset or bus performance at 1GE speeds). You can boot into a ...


8

I have also used netperf in some situations. It seems to perform better with UDP-tests.


7

If you are looking to max out line rate traffic such as a GigE port, look at netsniff-ng toolkit or the Linux kernel module pktgen. I personally used pktgen on a mid range commodity server and was able to push GigE speeds with ease.


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

iperf can do that job. Just ensure you test your devices back to back first so you know the capabilities of the devices. Of course there are more professional tools as well. This is a good RFC to read up proper methology: http://www.ietf.org/rfc/rfc2544.txt


6

If you have PCs at both ends then you could run xjperf, Qcheck from Ixia or other tools. You might get different results depending on if you use UDP or TCP and the number of sessions. For a distance over 100 miles you are looking at a minimum RTT of 1.6 ms at the speed of light in fibre/copper. So your RTT should be very low, maybe only a couple of ms. Say ...


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

WANem is great, like Jeremy said. Other interesting tools are netem or dummynet. See the following examples with netem: # tc qdisc change dev eth0 root netem loss 0.1% # tc qdisc change dev eth0 root netem delay 100ms 10ms 25% You can grab more informations on the netem page or on this excellent SO answer.


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

After some research and questioning with cisco specialists, we can conclude that in newer versions of IOS and newer routers, autostate is applied by default and unchangeable. (so the "no autostate" will not work anymore on vlan's).


4

Because autostate is a feature of switch virtual interfaces (read: vlans.) From the horse's mouth: [click here] Perhaps you want no keepalive. [edit] Oddly, Feature Navigator only shows autostate exclude as available on cats. However, my 1720 (WIC-4ESW) allows it. (12.4(23) IP/ADSL) [edit 2] I just looked through the 1921 15.1(4)M1 universal image, and ...


4

Short and sweet: use tcpdump to record and make sure you have enough space to store the PCAP. Then, use tcpreplay (http://tcpreplay.synfin.net/) to play it back. To get a PCAP with real traffic, you could ask your colleagues politely to allow you to record all of their traffic one day for just an hour (or until the pcap is X-GB in size). If you're at work,...


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

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

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 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

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

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

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 ...


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