1. Troubleshooting Ben Fineman,
Program manager, net+ video, voice and collaboration services
internet2
Justin Trieger,
Director of New Media and Distance Learning
New World Symphony

2. Network Troubleshooting
Justin Trieger | Technical Director for
Distance Education

3. Identifying The Problem
Packet Loss, Computer Resources,
Format Conflict
Do you see it?
Can you hear it?
Do you feel it?
Packet Loss, Jitter, Distortion
Jitter, Latency, Audio/Video Issues

4. Common Video Issues
Format Mismatch – ensure the format generated by the camera is the format the encoding device is expecting. (i.e. HD-SDI -> HD-SDI
Out-Of-Sync – clock of encoding device is at odds with the camera signal.

5. Common Audio Issues
Improper Gain Stage – distortion or high level of noise due to structure of amplification in signal.
Buffer Saturation – hardware or software buffer is too small to handle data flow.
Sampling Rate – mismatch in sampling rate from the source can result in audio anomalies.

6. Network Troubleshooting

8. Start at the Beginning!
Confirm network traffic is taking the path it should.
R&E Network
Commodity
Internet

9. Start at the Beginning! Symmetry is not only beautiful,
it makes for clean transmissions
Commodity
Internet
R&E Network
R&E Network

10. Local host Is the device operating with CPU/RAM headroom?
Is the network connection and configuration correct?
Are video and audio signals ingested without issue?
If a loopback test can be performed ( ), is the signal
received without error?

11. Step One: Establish a clean connection host to host
The LAN
Step One: Establish a clean connection host to host

12. The LAN Step Two: Incrementally move through the network
topology switch by switch
Switch One
Host A
(Host B)

13. The LAN Step Two: Incrementally move through the network
topology switch by switch
Switch One
Switch Two
Host A
Host B

14. The LAN Step Two: Incrementally move through the network
topology switch by switch
Switch One
Switch Two
Host A
Switch Three
(Host B)

15. The LAN Step Two: Incrementally move through the network
topology switch by switch
Switch One
Switch Two
Host A
Router
Switch Three
(Host B)

16. The LAN Step Two: Incrementally move through the network
topology switch by switch
Switch One
Switch Two
Host A
(Host B)
Router
Switch Three
(Host B)
(Host B)

17. Now What?! Make sure the far-end does the same LAN testing
Compile all your findings including traceroutes, throughput testing,
application errors etc. and send this to your respective R&E network
providers
Perhaps even better, invite them for a happy hour beer first

19. perfSONAR
perfSONAR is a network measurement toolkit designed to provide federated
coverage of paths, and help to establish end-to-end usage expectations.
Runs on a light version of Linux
Is configured to run regular tests against other perfSONAR
nodes to verify network connectivity
Uses accuracy instead of load testing to verify network links

20. Nuttcp
Nuttcp is a cross-platform (Unix, Solaris, BSD, Windows) network diagnostic tool used to measure raw TCP and UDP throughput at the network layer.

21. iperf
iPerf is tool for active measurements of the maximum achievable bandwidth on IP networks. It supports tuning of various parameters related to timing, buffers and protocols (TCP, UDP, SCTP with IPv4 and IPv6). For each test it reports the bandwidth, loss, and other parameters. 

22. Questions?