How to find Internet problems and who is to blame part 1

Many people can tell the following story:

- Hello, provider's technical support? My site aaaaaa.com does not open well.

- From our side, the bullets flew, the problem is in the target at the site - write there.

- Hello. Is this aaaaaa.com site? Your site does not open well for me.

- We are fine, write to the provider.



In this series of articles, we will try to figure out why this is happening and collect an algorithm - how to find the culprit, and what to do.

Disclaimer: The author knows that 

1. Traceroute will not always show problems that the routes are more about BGP and AS-PATH. 

2. The author is aware of peering, asymmetry, MPLS, BGP Communities and that a kilobyte is 1024 bytes.

3. Route "there" and "back" - two different routes and traceroute will not show the difference.

4. Inveterate networkers can find a lot of inaccuracies. These inaccuracies were made on purpose to facilitate understanding of the material by non-networkers. : D 

At whose expense is the banquet?

The Internet in Russia is much cheaper than the Internet, for example in America or Germany. Several times cheaper. Vodafone Kabel in Germany costs 45 euros per month for 500 megabits. This is 4000 rubles at the time of writing. In Russia, for example, at RosTelecom I pay 1,050 rubles a month for optics, through which 600 megabits come. 

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And yet, the trunk equipment may not "understand" that the channel's budget has been exhausted. If the routes say that these 12 gigabits should be poured into a channel with only 10 gigabits of bandwidth, then Nexus will try to fill it there. 

All of the above suggests that: when everyone starts watching YouTube in the evening, the speed may drop and packet loss may appear. And traffic can go in very strange ways.

In subsequent articles, we will go through the diagnostic options - inside the apartment, the last mile, the highway, as well as figure out where to complain.