How does a network connect to other networks over WAN?


I mean in like how do we send a signal that could casted over to the other side of the world. Like do we send it to a satellite then send it back or do we send the signal on earth, I’m confused

In: Technology

Typically the WAN uses fiber optics rather than satellites.

A router looks at each incoming data packet, inspects the IP address, and then uses a large table in memory to look up which line it should send the packet down to get it closer to that address.

almost all internet backbone traffic is transferred over copper wire or fiber optic cable. Since the days of telegraphy we have been able to lay cables across the ocean floor in order to transfer signals between continents. The distance to send a signal to satellite and back to earth again is almost always greater than the distance to send the signal over a cable, even if you’re going halfway around the planet. Most communication satellites orbit at around 22,000 miles, so the round trip distance for a signal is 44,000 miles, while the circumference of the earth is only 24,000 miles.

Intercontinental communications are typically done with undersea fiber optic cables. Satellites are used for this too, but have less bandwidth and reliability; So they’re significantly less common, and mostly used for providing internet to remote locations that have no wired connections available.

Undersea cables use extremely strong armor and shielding to protect themselves from the elements. They’re typically buried slightly underneath the sand at the bottom of the ocean. They’re planned in advanced to go through the most shallow points of the ocean.

Most of the long haul on an around the world trip will be on fiber optic cables buried underground and on the sea floor.

If you have a command line available, type “traceroute” or to some other destination (except on Windows, it’s “tracert”), and you’ll see a few hops to get to the destination. Each hop is a router that makes a decision on how to get to the destination. Those routers are computers, mostly expensive, specialized computers built just to make those decisions quickly, to keep track of how to reach everything on the Internet, and to do it quickly and reliably. Between each hop is fiber or copper cabling, or wireless links.

Physically, cables in the ground and undersea cables mostly which go through big telecommunications hubs. Sattelite bandwidth is too expensive to be used for most of it.

The devices moving around and directing all the traffic are called routers. There’s different languages the routers use called protocols to talk to each other and there are about 5 major ones to pick from and they have their own advantages and disadvantages. Within those protocols there are different ways to do home and destination addresses so the information can find it’s way to where it needs to go. IP addresses have become the most popular, that and internal codes are how the routers identify and split all the data up into little packets and verify it made it there before reassembling it on the other end.

For the usual traffic, each router builds it’s own table (kind of like a spreadsheet) which lists all the routers it is closely connected to for directing traffic to help speed things up. There’s usually backup routes listed in case the main one it wants to use goes down or the line between them is cut, etc…

The routers all get their own set of rules programmed in to what to allow and disallow and each connection on the router can have it’s own custom speed, protocol, security, encription and rules applied to it. To ease the burden on routers so they can spend their CPU time routing more, firewalls are set up to take care of the security and blocking so hackers have a harder time getting onto routers and being able to access the computers that are more directly connected to it.