Hi,
Suppose I had to construct my own global network then to get a basic routing/addressing system going I would use the following layout:
Picture:
Step 1: the super "backbone":
Draw a big circle of diameter 100 in the center. Color it red.
Step 2: smaller "backbones".
Draw smaller circles of diameter 50 around/outside the bigger circle. Connect each smaller circle with a line to the big circle. Give each smaller circle a unique color like red, blue, green, yellow etc.
Step 3: local network "backbones"
Draw smaller circles of diameter 20 around/outside the smaller circles. Connect each 20 diameter circle with it's 50 diameter circle by a line. Give each smaller circle a unique color like red, blue, green, yellow etc.
Step 4: the computers attached to each local network.
Draw tiny circles of diameter 8 or so around/outside the smaller circles of
20 diameter. Connect each tiny circle with the 20 diameter circle by a line. Give each smaller circle a unique color like red, blue, green, yellow etc.Step 5: the super backbone connected to the global backbone.
Draw a huge half circle in the left upper corner which represents the global backbone and connect the super back bone to it.
The picture should look something like this:
OOOOOO OOOOOO OOOOOO (global backbone) OOOOOO OOOOOO / red A / blue O O O yellow | O Oyellow \\ | / | | / OO | OO red OOgreen OO green | OO OO---O blue \\ | \\ / \\ \\ purple OOOO OOO O red OOO OOOO /-- OOO blue OOO-------OOOO -- OOO OOO OOOOred (super backbone) / \\ / \\ green O OO OOO / OO---O etc OOO --- OO -- O \\ OOO OO --O O / \\ OO O OOblue | \\ O O yellow B
A's address is: yellow.green.purple.red B's address is: red.green.blue.yellow
For A to reach B the following happens:
A knows the address of B which is given: red.green.blue.yellow
A could also know it's own address but is not really required. (It could be filled in while the packet travels up to the backbone, called "on the fly")
A could simply broadcast it's packet on green. (Alternatively A could send it directly to the green gateway hardware address if the green gateway hardware address is known by A.)
The gateway at green picks up the packet looks at the destination address and determines it's not for it's own local network so it needs to forward the packet up to it's parent network which is purple.
The same thing then happens at purple so the packet ends up at red.
The destination address is RED.x.x.x so the packet does not need to go up the global backbone.
The next addres is x.GREEN.x.x so the super backbone forwards it to the green network.
The green network sees the next address is blue: x.x.BLUE.x so it forwards it to blue.
The blue network sees the final address is yellow: x.x.x.YELLOW
So it forwards it to computer B
Since all packets carry a source address as well, B can now also reach A via the same mechanics etc.
A and B can thus communicate with each other.
This idea for a global network is very simple. The internet seems much more complex than this.
It only has 4 bytes in it's ip address. So the maximum number of hops would be about 8 or so ? ( 4 for the source and 4 for the destination ) or maybe 16 if gateways are two computers connected to each other etc.
However looking at an arbitrary tracert this does not seem to be the case:
Tracing route to
Well looking at the names I see about 4 names like: hidden sprintlink sbcglobal sbcidc
Looking at the the ip's I see many different ip's, how does one explain that ?
I could imagine some kind of linked network like so:
O backbone O-O-O-O-O-/
Packets can only go up or down etc... so that shouldn't be too much of problem.
Is it also possible to connect multiple network with each other and have them connected to a backbone as well like so ?:
OOO OOO OOO / \\ / \\ OO OO -- O OO -----?----OO -- O / \\ O O
Such a "subnetwork interconnection" could explain why some say packets can take a different route ? does this explain it ?
I would appreciate seeing some (network) diagrams how the internet really works (by using simple circles and lines etc)
Bye, Skybuck.