i just wanted to read and learn some about networking...,but daaaaamn this is confusing!!!
i actualy have issues with my home network..,its moslty all wireles..,i have 5ghz kit on the roof and its powerd over ethernet,now afther that (thing)
i conected i switch then have it separated to 3 diferent parts of house...(think of it as 3 diferent apartmans)
now on my end of the cable i have 150n wifi router...,and when i conect it with my laptop i only get around 2mb/s speed and if im conected directly on the roof kit i get full speed the i pay for (6mb/s)
bad cables?? bad aragments of the switches ,routers??
So let's break this down into a very simple situation. Assuming you've got more than a basic knowledge of routing please ignore what I'm about to say.
Every single device connected to the internet has a two part address. Part 1 is based on hardware, and is called a MAC. This address is hard coded into the hardware, and is functionally never going to change. Part 2 is the IP address. This sucker can change, based upon assignment by any device. It is the one that networking generally uses so that you know where to send data packets.
For the purposes of networking, a MAC is fundamentally ignored. Your ISP might limit the modem to allowing information through only to a single MAC address, but that's generally not a problem in home networking.
The IP address is the difficulty here. It's a string of four numbers, which range from 0 to 255 (000.000.000.000 to 255.255.255.255), and function as a dynamic identifier of who is to receive data packets. Using another analogy, this is very much like an address.
So routers, modems, and switches (hubs have functionally died, with the exception of USB) all serve different purposes in our analogy. The modem is responsible for converting our incoming and outgoing data into useable formats. In the simplest terms, that cat5 wire has 8 conductors and the cable modem connects with a single conductor. In the address analogy the modem is a post office. They transfer data.
The switch is like an idiot savant post master. Switches transfer data very quickly, but can't assign anything an address dynamically (managed switches avoid this, but we're talking a consumer level piece of hardware). If someone's address appears, they deliver it wherever they remember that address being. This works great, assuming that you've got a big pool of static addresses. Referring back to the address pool, that means we could have about 255^4= 4.29 billion dynamic addresses for every connected device. Looking back at this possibility, it's unrealistic given that we already have more than 6 billion people on the planet.
A router is the post master general. They can assign a single address to a large block of people, subsequently creating an artificial division of addresses for a single physical one. In the networking world, this is getting a single IP address, and connecting a dozen devices to the internet via that one address. The problem here is that routing requires more computational power, and introduces delays into the system. While this has largely been addressed with faster routers, it is always a concern.
So, why do the astute people in this thread say modem->router->switch is the proper connection methodology? It's simple. The switch can't create an artificial network address pool, so it won't work the other way around. hypothetically you could viably have both of the following connected to the same exact network without any problem sending packets:
modem-183.183.183.001->router
-192.168.0.2->PC
-192.168.0.3->PC
-192.168.0.4->Switch
-192.168.0.5->PC
-192.168.0.6->TV
modem-183.183.183.002->router
-192.168.0.2->PC
-192.168.0.3->PC
-192.168.0.4->PC
-192.168.0.5->Switch
-192.168.0.6->PC
-192.168.0.7->TV
-192.168.0.8->PC
In contrast, the switch could only do the following:
modem-183.183.183.001->Switch
-183.183.183.001->PC
-183.183.183.001->PC
-183.183.183.001->router
-192.168.0.2->PC
-192.168.0.3->TV
As multiple devices share the same IP pool, all devices see the same data. With multiple devices trying to complete handshakes and the like, only one device will actually work. Thus, no home network can function as modem->switch->router.
Now addressing speed, there's a bundle of problems there. Most routers have some sort of built-in filtering and security features. Certain ports are automatically closed, etc.... The net result of this is lower speeds, but greater protection against intrusion. It isn't by any means real protection, but it does offer cursory protection from drive-by pinging of ports to determine security flaws. Other routers have built-in firewalls, that inspect packet activity to try and prevent certain actions. Again, speed is given up for security.
Hooking a computer directly up to the modem will always produce the greatest speeds, but it is inherently riskier than hiding behind protection. You decide what protection is reasonable, and how much speed you really need.
Edit:
Changed formatting of IP addresses. Not sure how to show this best...