How does a route impact latency, and who determines a connection route?

Question

How does a route impact latency, and who determines a connection route?

In: 12

Answer 1

The Internet is just a bunch of computers connected together.

The Internet has a very basic pathfinding mechanism that boils down to “how many service providers do you have to go through to reach your website” by default.

Each service provider owns all of the routing within their network (referred to as an “autonomous system”). Ultimately, they have individual control over which links the traffic flowing through their network goes over, but practically, they don’t typically mess with individual routes without a good reason. The answer to “who determines a connection route” is each individual ISP determines which routes to install/use for a given destination.

Notice that the pathfinding is based on how many “autonomous systems (ISPs)” you have to hop through to reach a destination, but the Internet has no idea about the speed of the links to reach a given destination. That means, if Autonomous system 12345 has a very slow link, and your AS Path is 2329 12345 5467, you will encounter a lot of latency. Let’s suppose that 12345 has a 10Gig link to 5467 and that 10Gig link always has way too much traffic on it, so your traffic is getting dropped/experiencing delays.

There are two things that can be done to avoid latency in this case. First, AS 12345 could fix their link that is slow (either by adding more links to 5467, fixing errors on the link, or routing around the bad link), or you could try to use a VPN to go around that link.

Let’s say you use a VPN, and after using the VPN your path is 2329 44687 4236 5467. This “looks” like a longer path for your route (4 networks instead of 3), but 2329, 44687, 4236, 5467 all have amazing networks with 400Gig links. Even though you are going through more providers now, you have avoided the bad link in 12345, so you get significantly less latency.

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EDIT: If you want to see the AS-PATH for yourself, you can go to [https://lg.he.net/](https://lg.he.net/) and select the “BGP Route” radio button, then type your destination IP address in the box and click Probe. The AS Path (list of ISPs) will show up in the “Path” column (this is from hurricane electric’s perspective). If you want to check the path from your ISP, you can google “YOUR-ISP-NAME Lookingglass” and see if your ISP shares their routing tables for lookups.