Posts

Why airport wifi sucks?

IMG_20151108_183647     Sitting at Kolkata airport. Noticed the usual “Free Wifi in the area!” message and connected to Tata Docomo Free wifi. Performance was quite poor.   Two key issues with wifi:

  1. Using of only 2.4Ghz (802.11b/g/n with 20Mhz channel). No AP with 5Ghz box. (Click here to view scanner data). Should have been 5Ghz
  2. Entire traffic is getting tunnel via Mumbai i.e West India (while I am sitting on Eastern side). Adding up to latency and performance significantly.

Here are some of traces to random locations:

Last mile broadband technology for PRESENT!

Came across this impressive cover of last mile broadband issues in Orcas Island in Washington state in Arstechnica.com.

It’s very true on how so many areas are just not served and likely will never be served because when you have large telecom players bidding for billion dollar worth of Spectrum, all they care next for is very high value returns. And if they do not see those kind of returns, areas stay unserved. India has even poor story where it’s challenging to get wired broadband in most areas of country including key metro cities.

K root route leak by AS49505 - Selectel, Russia

There seems be an ongoing route leak by AS49505 (Selectel, Russia) for K root server.

K root server’s IP: 193.0.14.129
Origin Network: AS25152  

Here’s trace from Airtel Looking Glass, Delhi PoP

Mon Oct 26 16:21:18 GMT+05:30 2015
traceroute 193.0.14.129
Mon Oct 26 16:21:22.053 IST
Type escape sequence to abort.
Tracing the route to 193.0.14.129
 1   \*
    203.101.95.146 19 msec  4 msec
 2  182.79.224.73 14 msec  3 msec  1 msec
 3  14.141.116.89.static-Delhi.vsnl.net.in (14.141.116.89) 7 msec  3 msec  2 msec
 4  172.23.183.134 26 msec  45 msec  26 msec
 5  ix-0-100.tcore1.MLV-Mumbai.as6453.net (180.87.38.5) 151 msec  153 msec  152 msec
 6  if-9-5.tcore1.WYN-Marseille.as6453.net (80.231.217.17) \[MPLS: Label 383489 Exp 0\] 160 msec  163 msec  155 msec
 7  if-2-2.tcore2.WYN-Marseille.as6453.net (80.231.217.2) \[MPLS: Label 595426 Exp 0\] 161 msec  162 msec  162 msec
 8  if-7-2.tcore2.FNM-Frankfurt.as6453.net (80.231.200.78) \[MPLS: Label 399436 Exp 0\] 149 msec  151 msec  155 msec
 9  if-12-2.tcore1.FNM-Frankfurt.as6453.net (195.219.87.2) 164 msec  163 msec  159 msec
 10 195.219.156.146 153 msec  151 msec  160 msec
 11 spb03.transtelecom.net (188.43.1.226) 190 msec  192 msec  189 msec
 12 Selectel-gw.transtelecom.net (188.43.1.225) 185 msec  185 msec  185 msec
 13 k.root-servers.net (193.0.14.129) 183 msec  204 msec  196 msec
RP/0/8/CPU0:DEL-ISP-MPL-ACC-RTR-9#

The routing information (show route 193.0.14.129 output) from their looking glass doesn’t seems useful since it shows that it’s learning K root Noida route via NIXI. This is likely because routing information is different from actual forwarding information in that device. So the trace looks extremely weird. It’s leading traffic to K root which does has anycast instance in Noida, landing into Russia!   Why is that happening? Let’s look at what Tata Communications (AS6453) routing table has for K root’s prefix. I am looking at feed of AS6453 which it’s putting into RIPE RIS RRC 03 collector.

Night fun task: OpenVPN, Quagga, Rasberry Pi and more!

I have been using OpenVPN from quite sometime and very much like it. Earlier I was running OpenVPN client on TP Link 1043nd router and that worked great. But recently I switched home routing to Microtik Map2N which has much better VLAN & IPv6 support. Since then I had trouble in getting VPN back live. I can always use VPN client on laptop but that’s ugly for daily use specially when this is my primary work location!  

K root server - Noida anycast and updates

K root in Noida seems to be not getting enough traffic from quite sometime and connectivity does seems bit broken. This is a blog post following up to Dyn’s excellent and detailed post about how TIC leaked the world famous 193.0.14.0/24 address space used by AS25152. It was good to read this post from RIPE NCC written by my friend Emile (and thanks to him for crediting me to signal about traffic hitting outside!)  

Good bye BSNL (AS9829) | New link at home!

A blog post dedicated to BSNL AS9829. It just tried so hard to become as irrelevant as it can from everyone’s life (and that doesn’t excludes me now).   So what really is BSNL btw?

  • A Govt of India telco sitting at a extensive fiber of over 600,000 Kms across the country (staying just unused and unavailable for anyone’s use!)
  • A telco which has an extensive last mile copper (which is very poorly maintained and barely works!)
  • A backbone with over 200Gbps of IP transit capacity (which completely sucks due to rotten routing)
  • An integrated telecom provider offering services from landline to DSL broadband, from leased line to datacenter services! (out of which everything fails miserably from product line to technical ground level operations)
  • An extensive manpower (which is terribly arrogant and from top to ground level staff anyone barely works!)
  • Although telecom industry just boomed, it went from 10,000 crore profits in 2004 to 8000 crore losses in 2015. And still politics goes around it!
  • While private sector was busy with focus on 4G LTE deployment, BSNL’s market share dropped below 10% in 2014
  • While private sector firms like Sterlite, Radius Infratel focused on FTTH rollouts, BSNL rolled out FTTH plans for 4000 INR/month for 50GB cap and FUP speed of (amazing) 512Kbps to ensure no one uses it
  • While Reliance Jio is about to come, Airtel is extensively launching 4G LTE, cool companies like ACT are getting more investment, BSNL is putting 6000 crore in public wifi infrastructure to give few mins of free wifi and with hop of users paying it afterwards. (Wow?!)

All above tells nothing but ways in which BSNL is 100% screwed up for now. I don’t expect it to ever pick up again. Politically, technically, and fundamentally it’s a mess. I became BSNL broadband user in 2008 and it has been over 7 years of (painful and terrible) experience with them. As a company which put so much of infrastructure to connect India worked extremely hard to do as many stupid things as possible. For me trouble remained that in my city they were only wired telecom provider for retail services.   Last month I got a long haul circuit from Airtel (provisioned on fiber) between my city and a friend’s ISP PoP for 10Mbps bandwidth. Circuit is delivered at a Airtel BTS site location (slightly away from my home) and I have installed Microtik SXT Lite 5’s shooting link from there to my home (around 1km link with clear LoS). This is a usual long range fixed wireless RF link over un-licensed 5.8Ghz band. (Thankyou govt. of India for delicensing it in 2007 and making available for public use). Thanks to companies like Microtik and Ubiquiti for opening up world of good fixed wireless radios and antennas which really work great and are available for quite good prices. I got pair of SXT Lite5’s from Amazon.in at 7700 INR (~$116). Fortunately BTS site has a private WISP tower and the owner of tower agreed to let me use his tower for my radio for reasonable price.    

Multiple IP's on Linux servers

One of things which people often asked me around in past was on how to have multiple IPs on Linux machine under various circumstances. I know there are ton of blog posts about this but very few explain how it works and possible options under different use cases etc.   I will share router side and server side config with focus on how it should be done from server end. Assuming server side config to be for Ubuntu/Debian. You can find similar concept for CentOS.   Say you have a router on IP 10.10.10.1 and server on IP 10.10.10.2 on a /24 (255.255.255.0) subnet. Assming that entire 10.10.10.0/24 is available for server’s connectivity. Setup would be like: R1 - Server 01 connectivity Configuration so far is super simple. You have got 10.10.10.1 placed on R1’s interface (g1/0) which connects to server01 and server01 has 10.10.10.2.

BSNL AS9829 - A rotten IP backbone

Today I met a good friend and he has recently moved back into Rohtak (like me!) and was crying over BSNL’s issues. He has issues of unstable DSL due to last mile and I told him that even if last mile works well, BSNL still has got ton of issues with their IP backbone traffic.   It’s Sunday late night out here in India and I am having really pathetic connectivity with just everywhere except Google. With Google only key difference I noted is that my TCP session to Google’s services is terminating at Mumbai and not Delhi anymore. First and formost, I did trace to spectranet.in (which is last company I was working for) to see how is my latency with server hosting it:

What is BCP38 and why it is important?

BCP38 - also known as “Network Ingress Filtering” is concept where we filter incoming packets from end customers and allow packets ONLY from IP’s assigned to them.   Before going to BCP38, let’s first understand how packets forwarding work: Network

Here User 1 is connected to User 2 via a series of router R1, R2 and R3. Here R1 and R3 are ISP’s edge routers while R2 is a core router. In typical way the network is setup, entire effort is given on logic of routing table i.e for packets to reach from User 1 to User 2, we need to ensure that User 1 has default route towards R1, knows that User-2’s IP is behind R3 which is reachable via R2. So path User 1 > R1 > R2 > R3 > User 2 comes up. And same for User 2 > R3 > R2 > R1 > User 1 as return path. Now e.g IP pool for User-1 is 192.168.1.0/24 and is using 192.168.1.2 out of it while IP pool for User-2 is 192.168.2.0/24 and is using 192.168.2.2 out of it.