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

Network Troubleshooting Justin Trieger | Technical Director for Distance Education www.nws.edu

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

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.

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.

Network Troubleshooting

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

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

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 (127.0.0.1), is the signal received without error?

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

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

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

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

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

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)

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

www.nws.edu

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

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.

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. 

Questions?