Why 7 Star topped…

7 Star Digital is very small — it’s not even available anywhere outside Mumbai. With two caches embedded in this ISP’s network, every customer theoretically got Netflix video speeds as fast as their connection plan allowed.

Netflix calculates its speeds on the ISP Speed Index not by how fast data is being transfered from the cache onto subscribers’ browsers — rather, it calculates the bitrate of the video being streamed. This is an important distinction. For instance, if there are two customers, one with a 5 Mbps connection, and another with a 100 Mbps connection; Netflix will record a speed of 3Mbps for streams on both broadband connections if the video bitrate is only that much. Even if the data throughput varies dramatically for both users — 100Mbps for one user and 5Mbps for the other — Netflix will only record the average bitrate of the stream itself. This is why average speeds on the Index have rarely exceeded 4–5Mbps for any country; because that’s pretty much as high as Netflix’s bitrate ladders go.

This means that large ISPs are at a disadvantage — take YOU Broadband for instance. YOU only has a Netflix cache in Pune. I’m on YOU Broadband in Pune, so my Netflix speeds for titles that are cached are consistently high. However, in cities where YOU Broadband doesn’t have a cache — which is every other city where it operates — it presumably delivers video through peering routes that may not be as fast as a cache. This brings its average playback bitrate down. This is where 7 Star is at an advantage. All its customers are covered by a cache. So it should be on top forever, right? It was until June 2017:

…and why Spectra took over

Geographically, Spectra — until very recently Spectranet — is a pretty large ISP. It’s available in eight cities. Not only did Spectra beat 7 Star in this July’s ISP Index, it breached the 3Mbps mark, and has a listed speed higher than top-performing ISPs in countries like Brazil, where the streaming company has been around for a longer while than in India.

How did it beat out a small ISP that had every customer directly peered with a Netflix cache? MediaNama spoke to a spokesperson to find out.

Firstly, Spectra has Open Connect Appliance (OCA) caches of its own, just like 7 Star. Second, it’s also directly peered with Netflix at a peering exchange in Mumbai — the spokesperson wouldn’t say whether it was private peering exchange GPX or the public Mumbai Internet Exchange; and Third, Spectra has a partnership with a third party caching tech company which provided it hardware to cache Netflix streams in addition to OCAs and direct connectivity with a Mumbai peering exchange — MediaNama independently reviewed three Spectranet users’ Netflix streams and found that they were coming from a peering exchange in Mumbai.

The spokesperson added that unlike other ISPs, Spectra’s network architecture is more direct. “Unlike other fiber ISPs, which have a mesh-type network, where data bounces from one dabba to another before finally reaching the [destination node], we have a very one-to-one and direct relationship with our users’ connections,” they said.

Also, keep in mind that Netflix’s cache only saves popular content on any given day. 7 Star’s average speed on the index was possibly bogged down by the fact that when some of its users streamed content that was not cached by them, it would have to be fetched the old-fashioned way — from an Internet exchange with which it may not have the best interconnectivity. Meanwhile, Spectra’s three-front effort includes OCAs, independent caching, as well as peering with an exchange located within the country.

This is how Spectra was able to beat an ISP that would seemingly stay on top of the company’s India Speed Index forever.

MediaNama’s coverage of Netflix’s peering in India

April 4, 2017: Netflix deploys caches of its catalogue to Indian Internet providers
April 17, 2017: In its filing on Net Neutrality to TRAI, Netflix defends its caches
May 10, 2017: Netflix begins directly peering with large Internet exchange in India
May 12, 2017: After installing caches, Mumbai’s 7 Star Digital jumps to top spot in Netflix ISP Speed Index