On 10/15/2013 8:53 AM, berenger.morel@neutralite.org wrote:
Le 15.10.2013 03:28, Catherine Gramze a écrit :On Mon, 14 Oct 2013 21:12:32 -0400 Jerry Stuckle <jstuckle@attglobal.net> wrote:Maybe where you are, but not in the world scheme of things. A router is a specific box. A (A)DSL modem may also contain a firewall, etc. But most (A)DSL modems, cable modems, etc., only have one Ethernet port. So people install routers in addition to the one which may or may not be in the (A)DSL modem. Modems and routers are two entirely different things, with completely different uses. One box may contain both - but that does not mean all modems are routers (or vice versa).Hear, hear, Jerry! This is how I have always heard them referred to when I worked as a network admin. A router is a router, and a "cable modem" may or may not (usually not!) have any routing capability. It is really a bridge connecting two networks, as I mentioned previously. It doesn't do any modulating or demodulating. It simply allows the packets to go from one network to the other.I think that most people here knows about that: http://en.wikipedia.org/wiki/OSI_model
Obviously not, or we wouldn't be having this conversation.
Modem are stuff of layer 1 (or 2, not sure), while routers works on layer 3 (or 4, I am not sure again... I'm not an expert on those stuff, I apologize). Modem and routers are different things, working on different levels. So, routers may include modems, if they need to route packages between networks using different level 1 protocols. But modems have no reason to have routing features: they are on a very lower level.
If you want to confuse things by getting into the OSI model, modems are Layer 1 (Physical). Routers are Layer 3 (Network). I stayed away from this because it's mainly of interest to engineers and network programmers; the only thing most programmers have to worry about is Layer 7 (Application).
Calling a router which include a modem a modem, would be the same as calling modem a computer. Because computers includes modems (it is not mandatory, but I think that nowadays, every computer includes a sound card able to have both input and output, right? So, to convert analog signals to numeric ones, and vice versa, which is the work of modems). Modems are not networking stuff, they are electrical stuff, which are sometimes used by some networking stuff.
True. Except it's normally the other way around. Companies don't design routers then add a modem to them; they design the modem then decide if they need to add a router. A small, but significant difference.
Jerry