5
votes
Accepted
Is there a network cable tester device that tests the cables with realistic frequency instead of on/off leds?
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 ...
- 88.1k
4
votes
Feeding a PoE capable device with variable power supply over TIA568 A cable (DC spares)
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 ...
- 88.1k
3
votes
Accepted
Iperf results on UDP Bandwidth
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 ...
- 8,876
3
votes
Accepted
What binary prefix, JEDEC or IEC, is used for calculating networking gear speed
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 (...
- 19.8k
3
votes
Accepted
What does "inline" mean in the context of cable testing?
“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.
- 17.4k
2
votes
iperf3 UDP tuning
That's how iperf3.x works.
The "client" wants to establish a control channel to the "server" before any UDP transfer is started. That's why you can observe some TCP before the UDP ...
- 8,876
2
votes
Accepted
How to use IXIA IxNetwork 8.40 to send bi-directional traffic between CPE and router
It took about 10 seconds to search the Internet to find this:
To configure NAT translation in regular testing, all you have to do is
open “Network Neighbourhood,”(In case you need a quick recap ...
- 101k
2
votes
Accepted
Confused about the results from the cable tester
I offer another interpretation: 4 wire cable for 100Mbit/s.
This is basically the same as zac67's answer "Either it's a bad LSA contact, a bad panel insert or a damaged cable.", but probably the ...
- 8,876
2
votes
Confused about the results from the cable tester
A cable tester of that type injects a pulse into the cable and analyzes the time it takes to reflect back. That tester can't really test/certify a cable deployment (you'd need attenuation, NEXT/FEXT, ....
- 88.1k
2
votes
WiFi TCP iperf throughput: upstream vs down stream
While passing downlink traffic (from the Access Point (AP)) to client-nodes, the AP schedules the packets from the packet-queues in the appropriate way and also does not face any contention on the ...
- 56
2
votes
How to test if an sfp is working on juniper qfx5100
Check the manual/datasheets - both the switch and the transceiver should state what they're compatible with. If you're using a range of different optics it makes a lot of sense to maintain a ...
- 88.1k
1
vote
Using a switch and a pc to test the ports of another switch that resides in a device I wish to test
I need to verify the operation and signal integrity of the ports on the Device.
You can verify operation with a simple software test but you can't verify (analog) signal integrity without special ...
- 88.1k
1
vote
Iperf testing- Slow transfer speeds
In my experience Azure throttle the traffic and you can only achieve limited performance on a single flow.
This is because aside the public access they sell the express route circuit.
If you could ...
- 19.8k
1
vote
IPerf test| Server side Sender data shows that the bandwidth is zero but Client has bandwidth of 125 Mbps
With iPerf3 [1], looking at, respectively working from the responder or "server" side (running iperf3 -s) is of lesser interest.
You can gain as much, or even more information from the ...
- 8,876
1
vote
Accepted
Cat5 Ethernet cable between buildings passes connectivity test but switch light not lighting up and no connectivity
Very often when a cable suddenly fails, the termination isn't good enough. Double check each side's termination, and if that doesn't help replace the cable.
If you haven't done so, make sure no small ...
- 88.1k
1
vote
Accepted
How to test the maximum of clients connected to an AP?
From what I know there are no upper limits in the 802.11 protocol. There are software limits in some of the AP's I've worked with. Aerohive usually have 100 concurrent stations on most AP's.
The way ...
- 108
1
vote
How to duplicate multicast source over several multicast addresses
A multicast group is a destination IP address on an IP packet. The destination IP address is determined by the sender, and modifying an IP address on a packet is called NAT (Network Address ...
- 101k
Only top scored, non community-wiki answers of a minimum length are eligible