India, DOCSIS, last mile broadband and more...

Isp-Column

Update - 12 July 2022

While migrating this old post from Wordpress to Hugo I realise that many of old external linked images are not available at source anymore and that breaks many of the external photos references on the blog.

In my previous post, I shared how I am running redundant uplinks at home (in non-BGP based setup) with the primary link on RF and secondary on DOCSIS. One of my good friends asked me the reason for the sudden jump in DOCSIS-based players across India, especially in smaller cities.


Well, there are multiple reasons for it:

  1. Fibre is less hard but still remains a cost point. ISPs in large metro cities ran fibre to the user’s building and go on cat5e/cat6 beyond that. That’s pretty much a lot of FTTH players do in India. That’s not possible in smaller cities which do not have multi-dwelling units.
  2. While the cost of fibre is low, the cost of CPE (i.e ONU in the case of GPON or media converter for active networks) is still slightly high. It has come dome drastically in last few years and is about to reach a point where it’s cost won’t be a consideration in near future. Presently at around 2000-2500 ~ $40 USD that is still a hard cost for mass deployment. On the other hand cost of DOCSIS 2.0 as well as DOCSIS 3.0 modems is extremely low.
  3. A considerable part of long coax plant of LCOs got converted into Hybrid Fibre Coax (HFC) as the digital television broadcast is pushed further across the country.

So a lot of fibre is already present now (hanging around!) near to a large number of homes even in smaller cities. 4. The demand for bandwidth is increasing but a lot in terms of GB usage a month while not in terms of raw speeds in megabit per second at the same rate. So while 2Mbps to 5-10Mbps is a major upgrade. Beyond 10-20Mbps there’s just not much demand as yet. It would be great once 4k streaming and more VR stuff get popular but at current levels, demand for speeds isn’t increasing beyond 10-20Mbps due to lack of “killer” application which takes more bandwidth. 5. DOCSIS networks can be eventually upgraded to GPON all the way to end user with the fair amount of changes. Operators even do hybrid DOCSIS-GPON where they move high capacity end users on dedicated cable headends & even to GPON while leaving low demand users on DOCSIS. 6. The cost of termination coax is low & relatively easy to handle compared to splicing fibre to pigtail.

Thus DOCSIS is a cheap way to build the last mile in tier 3 cities. While the cost of RG-6/RG-11 cable is on the high side (against the cost of fibre) the equipment is priced pretty low. #2 here is important. While $40 may sound not much in West, that cost is really high. As per available data, 12.4% of Indian population is below the poverty line. Furthermore, if we speak of per capita income was Rs 93,293  ~ $1400 for year 15-16. And thus pricing really matters. It’s extremely large number of not connected population and extremely price sensitive market. Here people typically pay little over 1000Rs / $16 a month for broadband in metros & large cities and little less than that in smaller cities. Providers in Western countries charge typically 4-5x of that and much more once bundled with digital cable TV. Some of the players who did large scale DOCSIS setup in recent times mostly are MSOs and come from the cable TV world.

  1. Hathway broadband - AS17488
  2. DEN cable  - AS45184
  3. Siti broadband - AS17747
  4. Netplus broadband - AS133661
  5. Ortel - AS23772
  6. Asianet broadband - AS17465

and more! One thing is common across these players is good plans. Reliability does vary but is decent enough for the most part except few exceptions. Also, a large number of these players do CGNAT, and I am not aware of anyone of them giving IPv6 to end users as yet. :(


So how come these networks are cable to offer relatively good plans as compared to larger telcos who are mostly on DSL? One of lawyer friend from Bangalore asked this question earlier this month. This is due to following:

  1. The cost of IP transit is getting lower and lower across the world. While it’s still quite high in India compared to global standards but the decline is phenomenal. Thus these players are able to buy high capacity bandwidth drop at wholesale prices.
  2. The cost of point to point circuits is getting lower along with more content coming to India along with high-value content getting concentrated over CDNs. Over around half (actually 60% or so) of typical Indian eyeball ISP traffic can be offloaded via GGC, Google Peering, Akamai cache, Microsoft, Amazon, Limelight and so on besides generic HTTP and P2P caching. There’s a decent competition these days on the point to point circuit provider across India in all major cities. There are Govt. options (Railtel, Powergrid) as well as private players (Tata Comm, Airtel, Reliance, Vodafone, Aircel) etc offering circuits (which is known as NLD or National Long Distance in India).
  3. In terms of the last mile, these networks are typically DOCSIS 3.0 (for MSOs) backhauled over GPON or GEPON (yes, DOCSIS backhauled on PON instead of direct Ethernet circuits!).  From a central location where CMTS is located, traffic is pushed towards societies over HFC plant, in societies usually, remote PHY devices are deployed to do optical to coax conversion & then on each headend lot’s of end users are connected. So the layer 1 aggregation happens on these phy devices hanging around.

The capacity on last mile as well as the middle mile is quite questionable on these networks due to multiple layers of contention (DOCSIS as well as xPON) but since traffic growth is relatively predictable and happens over a period of months, this part is somewhat managed. FTTH, of course, is the way to go in the long term, but if these players can cut costs and offer reasonable bandwidth at cheap prices, DOCSIS is a fine option. In Rohtak, for instance, Siti broadband’s 5/10/20/50 Mbps packages are competing with Govt. owned BSNL’s 2/4/8Mbps plans with low FUPs.     GPON, as well as DOCSIS, offer a flexible approach of splitting circuit coming from OLT (in GPON) or Phy (in DOCSIS) as the need comes. So for instance in the case of FTTH on GPON, one can aggregate 16 or more users over such passive splitter:  

In case of DOCSIS, it’s usual old school (though improved) coax taps: While DSL is very different as compared to it. The cost of aggregating DSL userbase over DSLAM is much higher and capacities on ADSL are quite low. This is how a typical DOCSIS remote PHY looks like   Ending this post with some pictures of outdoor fibre plant from my recent Bangalore trip. That’s part of our Digital Slum here in India.