Terragraph Under the Microscope

Terragraph Under the Microscope

An Evaluation of the 60 GHz Radio Platform and how it Performs with Various Use Cases and Deployment Scenarios

08/16/2021 | 37 pages

SRG just published a whitepaper on the Terragraph 60 GHz radio platform that we did on behalf of Facebook Connectivity. We did this testing on the Facebook campus in Menlo Park, CA in late May 2021.

Highlights of the Report include the following:

Background. We leveraged a 15-node test network that FBC engineers deployed on our behalf, based on our test requirements. Each node consisted of a 4-sector radio/router that was deployed in a wireless mesh network topology. Testing took place over a multi-day period in late May. We leveraged the iPerf application, Wireshark, and Viavi T-BERD testers, not to mention test scripts that we defined and the industry-standard Y.1564 tests during the process.

Terragraph passed the Y.1564 test scenarios. We used the ITU-T 1564 standard to evaluate Terragraph performance over a three-hop link. Terragraph passed all requirements, including maintaining the committed information rate of 1,400 Mbps with low latency (RTT = 3.17 ms), low frame loss (down = 0.00158%; up = 0.00519%) and low jitter (down = 0.016 ms; up = 0.031 ms).

Consistency between one-hop and three-hop links. We observed sustained bi-directional data rates of 1.7-1.8 Gbps between two nodes, and only slightly lower between three nodes (1.6 – 1.7 Gbps). Very low latency was also maintained, or 0.33 ms between two nodes and 1.6 ms with a three-hop link and a packet size of 1024 bytes. We verified performance over a wide range of packet sizes – 128 bytes to 8192 bytes.

Dense networks are possible without interference. We positioned four client nodes in close proximity to each other and in the same sector, including two nodes that fell on the same directional path from the serving distribution node. Thanks to the Terragraph scheduling algorithm, self-generated interference within the network was nonexistent. We also observed that Terragraph Mesh can adjust to unforeseen [external] interference by dynamically routing data traffic along alternative routes.

Appendix. The appendix contains a list of Terragraph partners, their product portfolios, and links to their respective websites where more product information can be found.