I was experimenting with some of the network monitoring commands in cmd and I noticed that there's a significant difference in the number of hops in the output of tracert for different hosts. For example, when I tried to trace a packet to the Google server, the destination was reached within 4 hops. Then when I did the same thing for Pastebin, I got 15. Can someone please explain why this is so? Thanks!
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Different hosts are on different networks, and will take different unequal routes to them, but that should be obvious. You're just seeing different infrastructure. If you want to know more about the route, run the reverse lookups, and see if any come back with router names.– RadhilCommented Jan 3, 2016 at 15:05
2 Answers
The answer is simply that different hosts are on different networks, as @radhil says, and you have to take longer paths to get there. Different providers have their own rules about whose traffic they are willing to carry, so the path you take may be chosen for business reasons, not necessarily because it's the shortest.
Try running the tracert
command without the -d
option (not to perform a DNS lookup on each IP address, -n
on tcptraceroute
and mtr
), and you will see the different domains in the path.
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Do you think those business reasons when the ISP makes a decision about the route include how frequently the site is accessed? That was actually the first thing that came into my mind - since Google is a very popular website, maybe the provider chose a shorter route?– a_krisCommented Jan 4, 2016 at 13:18
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The decision usually has to do with money. How much the ISP has to pay for traffic. Commented Jan 4, 2016 at 13:20
The internet connects every computer in the world to every other computer (on line ones anyway) Think about a physical system to sort and route packages along highways. How many sorting stations would you need to cover North America alone? Fewer than you think thanks to square law math.
The amazing thing is the small number of hops that are required to get anywhere. I trace Google, Bing, Gmail and they are all just 7 to 10 hops - and not always the same. Each router (sorting station) has a list of addresses it will accept, and a list of destinations it can process. All happening dynamically in milliseconds.
Cheap, efficient, fast and reliable.