This blog post is not a just “know-how” but is to educate the Local Cable Operators (LCO’s) / Franchises who are running Broadband business as well as end users in West Bengal and other places. Guys, please just don’t listen to whatever your ISP tells / shows you. Think logically, check the possibility then only move on. Having superior google latency is no rocket science but one needs to know how it works at least!
Recently a friend of mine running an ISP in Bengal called me and explained me something really very shocking. As we all know how ISP business works in India i.e. dependent on local franchise for last mile connectivity. Now, what he said was a competitor ISP say ‘Z’ was showing his local cable operator/franchise ‘Z’ has be best possible latency towards google and its services in Bengal and no other ISP can deliver that. You may wanna know what’s the google latency? Answer is – 1 ms to 184.108.40.206, google.com, gmail.com & many other sites and that too sitting from Kolkata. Shocked?
Even if we consider the ISP have google peering directly, the latency for NLD link from Kolkata to the peering exchange (Delhi, Mumbai or Chennai mostly) would be around 25-30 ms. But getting single digit value is never possible in West Bengal. In other case, if the ISP is not peered with google directly then latency will be around 40-50 ms average when passed through their transit links.
So, what the ISP ‘Z’ is doing is faking all ICMP requests from users towards all google services (address list for all google IPs is easily available on the internet) and redirecting to the NAS/Customer’s Local Gateway device which is on the same LAN. Thus getting a response of 1 ms and less in most cases.
Just to show how things happen, I recreated everything from scratch in my simple home router (here, Mikrotik).
Case 1 – When I had no configurations done and it was a plain & simple router –
The average latency was 30-35 ms as my upstream ISP is directly peered with Google.
Case 2 – When I had configured my router to fake the ICMP requests and redirect towards itself –
The average latency changed drastically to 1 ms. Unbelievable right? Just a single command on a router can make this havoc difference.
To help you understand about different latency conditions, I am posting several sample screenshots below:
Some sample screenshots showing latency for google.com via peered links (30-35 ms) :
Some sample screenshots showing latency for google.com via non-peered links i.e. via transit links (50-65 ms) :
Please note: I have not shared the exact “spoofing” configurations as I don’t encourage other ISP’s to fool their customers and want them to do a healthy business & please don’t ask for names!