Antler

Antler is a tool for network and congestion control testing. The name stands for Active Network Tester of Load & Response, where '&' == Et. :)

Antler can be used to set up and tear down test environments, coordinate traffic flows across multiple nodes, gather data using external tools like tcpdump, and generate reports and plots from the results. It grew out of testing needs for SCE, and related congestion control projects in the IETF.

Examples

The examples output is available online here, where you can view the HTML plots and log files. A few samples from that directory:

• CUBIC vs BBRv1 through CoDel, with VBR UDP
• CUBIC vs BBRv1 FCT Competition
• System Info

To run the examples yourself, install Antler, then in the examples directory:

sudo antler run

All configuration is in the .cue or .cue.tmpl files, and the output is written to the results directory.

Documentation

Documentation for Antler is available in the Wiki.

Status

Antler v1.0 has some useful features, and has ungergone a security audit, so it should be safe to use.

It is important to understand Antler's caveats. In particular, the use of CUE has been a mixed bag, and the visualizations in Google Charts could be more flexible than they are. Future versions of Antler may replace the configuration and/or visualization mechanisms.

Roadmap

Inbox

The Inbox is a collection area for future tasks.

Features

• Research alternative configuration mechanisms
• Improve flexibility of visualizations (maybe allow custom Go templates)
• Add alternative plotting library to Google Charts
• Implement node or at least traffic generator in C or Rust
• Process pcaps to get retransmits, CE/SCE marks, TCP RTT or other stats
• Merge system info and logs into plots
• Improve performance of low interval / UDP flood recording and plotting
• Add results command to list results
• Add log command to emit LogEntry's to stdout
• Add rm command to remove result and update latest symlink
• Add ability to save System Stdout directly to local file
• Add node-side compression support for System runner FileData output
• Add ability to buffer System Stdout to a tmp file before sending as FileData
• Add admin web UI to run a package of tests
• Handle tests both with and without node-synchronized time
• Add test progress bar
• Implement flagForward optimization, and maybe invert it to flagProcess
• Add support for simulating conversational stream protocols
• Support FreeBSD
• Support MacOS

Refactoring

• Convert longer funcs/methods to use explicit return values
• Reconsider allowing empty Runs (see NOTE in run.go)
• Consistently document config in config.cue, with minimal doc in structs
• Replace use of chan any in conn
• Improve semantics for System.Stdout and Stderr
• Find a better way than unions to create interface implementations from CUE
• Consider moving all FileData to gob, for consistency with encoding

Thanks

A kind thanks to sponsors:

• NLNet and NGI0 Core
• NGI Pointer
• RIPE NCC

and to Jonathan Morton and Rodney Grimes for advice.