04 Jan

VoWifi experience on Jio

Since last week of Nov 2019, I am having serious issues with Airtel at my home. Somehow 4G signal SNR is very poor and most of the calls just fail on that. Airtel support just mentioned that they are putting a new site in my area in Jan 2020 but fail to explain why suddenly it went so bad. I can imagine that support team staff does not have visibility to network in real-time and likely it would be an issue with the 4G antenna on one or more towers. 2G signal was good but latency was extremely high to connect call plus calls still failed regardless (maybe due to high strain on 2G).

So by the end of December, I just gave up and gave the request for porting to Jio. Yesterday my number started on Jio and around 24 hours later I got access to VoWifi which is quite nice. Both Airtel & Jio are rolling our VoWifi but for Airtel, many users have reported it for being locked on Airtel fixed line only.

What is VoWifi?

Well, it’s just native offloading of voice calls over the fixed-line network and is extremely useful for both network operators as well as end-users. Native IP equipment is cheap and it’s way easy to extend cell coverage at home via Wifi instead of proprietary inbuilding solutions. Plus landline was good for quality but form factor and usability was pain. Now VoWifi kind of merges the fixed-line and cell phones and we get best of both worlds.

I think many people confused BSNL Wings with VoWifi. VoWifi is seamless offloading of calls natively while BSNL Wings offered a separate number, an app to run and a separate billing account to maintain with the operator. BSNL Wings was a bad product idea and really awful execution.

Coming to Jio VoWifi, some misc observations:

  1. It’s working for me on the non-Jio fixed-line connection in Haryana circle. I have IAXN (GEPON FTTH) and Siti broadband (DOCSIS 3.0) at home running in active/backup configuration for high availability.
  2. The device has an IPsec tunnel with 49.44.59.XXX. I see isakmp-nat-keep-alive packets every 20 seconds when I do tcpdump on the router.
  3. On my cell phone (which is an Apple iOS device) I see a tunnel is opened on IPSEC1 port. IPSEC2 & IPSEC3 are there for VoLTE.
    IPSEC1 has a link-local IPv6 and an IPv6 from 2405:205:3000::/36 range. The IPv6 on all three IPSEC tunnels is the same as of pdp_ip1 (Cellular data port). I guess that’s probably how they are handing the handovers between VoWifi and VoLTE.
  4. The IPv6 on pdp_ip0 for cellular data is from a different range which again is being announced in the global table as 2409:4051::/36. I wonder why Jio is using publically routable pool for VoLTE and VoWifi. In case of Airtel it a non-routed address space and routes are not announced in the global routing table.
  5. In my test VoWifi to VoLTE was reasonably OK. I tested by shutting off wifi on the cell phone as well as unplugging the cable from wifi AP to test. In both cases call went silent for 1-2 seconds and resumed over VoLTE. It did not come back on VoWifi once Wifi was back live.
  6. Latency from both connections to other endpoint (the router before the IPSEC endpoint) is around 60ms. Either the endpoint is somewhere far off or (more likely) it’s a case of not-so-good routing between Airtel (upstream of my ISP) and Jio.
  7. There’s a quite noticeable improvement in connection time. For IVR based numbers it’s close to 2-3 seconds. Which is a great improvement for someone like me who was on 2G non-VoLTE calls for December!

How to check interfaces and routing table on your phone?

Well use HE.NET Network App on Android or Apple iPhone and you will be able to check that!

That’s about it. Back to the world of routing. 🙂

10 Sep

NIXI permits content players!

I am in Chiang Mai, Thailand for APNIC 48 conference. Earlier today attended APIX meeting where many IX members from Asian community gave an update including NIXI i.e National Internet Exchange of India.

As per the update NIXI now allows content players to peer at the exchange. NIXI earlier had a strict requirement of telecom license for anyone to peer but as of now it allows anyone with IP address and AS number to be part of the exchange just like all other exchanges. This is a really good development coming this year after their announcement of the removal of x-y charge. One strange thing remains that their website is still not updated to reflect that which is probably just work in progress. As per representative from NIXI they now openly welcome all content players to peer at NIXI.

What more needs to be done?

Well, a couple more changes are needed.
Here’s what I requested to the representative from NIXI:

  1. Removal of forced multi-lateral peering policy. Forced multilateral is bad idea in modern times. Many large networks (especially the ones dealing with anycast based service) would usually not like to peer at route server.
  2. So far NIXI has discouraged bilateral BGP sessions in the policy. Technically any members can create bilateral sessions but were denied in the policy. That needs to be changed. Bilateral/multilateral peering is a technical decision and should be left to individual networks operators.
  3. NIXI needs to migrate to software-based route servers like bird with auto-config generation to include features like IRR filtering, RPKI filtering, BGP communities support and much more.

Remove forced multilateral, but what about Indian incumbents?

This is an old interesting discussion. Basically due to “forced” multilateral peering policy – everyone is on route servers and that includes incumbents like Tata Communications, Airtel, BSNL and other large networks like Jio and Voda/IDEA as well. The argument there is if multi-lateral peering is not forced, local ISPs won’t be able to peer with these networks. Part of these arguments comes from a mindset which still believes the world’s traffic flows from tier 1 operators to tier 2 and tier 3. A very large part of modern internet traffic flows from content players to eyeball networks (where “eye balls” are). Content players deliver this traffic through a mix of backbone + peering as well as by putting caching nodes inside the ISPs network (like Google’s GGC, Facebook’s FNA, Netflix OCA, Akamai caching node etc). The success of an IX depends on meeting the content players and eyeball players. To connect eyeball players (which are usually spread across the region) one needs circuits i.e dark fibre, DWDM waves, or any sort of transport network. As long as these three things are in place, IX can be a success.

Look at any large IX doing over few hundred Gigabits of traffic or even terabit of traffic and ask does local incumbent telco peers openly at that IX? Does BT openly peers at LINX in London? Do Deutsche Telekom peers openly at DECIX Frankfurt? Does AT&T, Verizon, Comcast peer openly at various Equinix and Coresite exchanges spread across the US? Answer to most of these is no and that is just fine. I would personally hope that these networks do but if they do not it’s not something which blocks the development. In the same way, having Airtel/Tata/Jio/Voda-IDEA at NIXI is great and I would hope they stay but the success of NIXI does not depend on these. As long as transport circuits are available (which they are!) from enough players with competition it would be fine. As of now across India, one can take transport circuit from Airtel, Tata, Voda/IDEA, Powergrid. Railtel, Reliance Communications and more!

Forced multilateral and routing issues…

One recent issue which E2E Networks (a cloud provider based in India) faced was to send traffic to Jio. Suddenly traffic going from E2E to Jio via Tata Comm was going from outside India. As per discussions, routing was tweaked to send traffic out to Jio via Airtel and still, there were issues of routing from outside India. The issue went on for a couple of days and was eventually fixed by speaking to both ends. Issue was there due to ongoing peering issues between Jio – Tata Comm and Jio – Airtel.

Now the funny thing here is that Netmagic (which takes care of routing for E2E) connects to NIXI and Jio also connects to NIXI. During this entire time, both Netmagic (on behalf of E2E) and Jio had enough capacity at NIXI but that could not be utilised because of forced multilateral peering policy. If routes were announced to NIXI route server, that would have probably fixed the Jio issue but would also attract traffic from Airtel/Tata which was not specifically desired due to their known port capacity issues at NIXI.

Ending this post with my quote which I often give in these discussions – “Remember somewhere up the transit path there’s always peering!” 🙂


  1. This post is done in my personal capacity and nowhere reflect the views of my employer.
  2. I am on board of the mentioned organisation E2E Networks (more on it here)