Calnex SNE: Why can't I download very large PCAP files from the SNE?

Owned by Paul Hudson
Aug 30, 2022
2 min read

In SNEs with 1TB SSD storage fitted, attempting to download a file several tens of Gigabytes in size using Chrome browser versions later than 104.0.5112.80 may fail with the error “Http Error 0 - Unknown Error (timeout)” if performed from the GUI, or “Error: OK” if using the REST API.

In general Firefox is the most reliable browser to use when downloading large PCAP files. To download PCAP files greater than 50GB in size, it is recommended to use the REST API. The relevant REST API endpoint is shown below:

Chrome Version 104.0.5112.80 (Official Build) (64-bit) and all versions of Firefox that we have tested work correctly. Other versions of Chrome and Edge may have problems downloading very large files.

Please note that the Traffic Capture/Replay functionality on the SNE is working correctly, in that it is perfectly possible to capture up to 500GB of network traffic in one session to the SSD and replay it from a network emulation map. The problem only exists when trying to download the PCAP file from the SNE to a computer. Also note that when downloading via the REST API, it can take longer than an hour to download a 500GB file - this is unavoidable, as the file needs to be transferred over the SNE's management port which has a maximum speed of 1Gbps.