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router contains a built-in switch versus router without a built-in switch

I think you will find that the truth is far far worse than you could ever imagine.

'home routers' are - i've been told - are not routers. They are NAT devices. They contain a switch. And a firewall. And a modem.

Regarding 'routers' without a built in switch . May be a real router. Or it may be a simple thing. Often so-called DSL Modems like ones made by DLink or Linksys, are actually 'home routers' with only 1 port. NAT devices without a switch. so if you want to connect many computers, then attach your own switch.

Professional proper routers (like Cisco) have many ports, each is a router interface, each with its own IP. Each is for a connected network. No switch.

a NAT Device receiving an incoming packet, does not 'route it', it does not decide what network to sends the packet to. Only your network is attached. It just allows it or rejects it. And depending on how it is configured, sends the packet to whatever computer is attached. Go to

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and i you're behind a NAT device, you get the IP Address of your NAT device. People send packets not to you, but to your NAT device. Your NAT device does port forwarding to choose which of your comp on your network to send it to. This is not routing at all. Routing is about deciding which network to (not which comp and not just on 1 network) send it to, using routing tables, and the Sending computer will include the Dest IP of teh network to send to. With NAT, the sending computer only specifies the NAT device. So the NAT device is choosing which comp to send it to. With a *Router*, (not a 'home router'). Packets are not addressed to the Router, they are addressed to the comp. The Router doesn't choose which local comp to send it to, it looks at the IP, sees it doesn't have to route it anywhere, since it is on a directly connected network, and it sends it to the right computer.

I am a newbie, and will be using real routers this year! But I read about them. I am just interested in computers and connecting them together. So, frmo a techie perspective, a real router is more fun.

likely), then a NAT device ('home router') is fine.

Linksys make good 'home routers'(NAT Devices), get one with a built in switch. And a hole for a telephone cable - meaning it has a built in modem. 4 port switch, So you can attach - say - 4 computers. If you want more you can connect another switch to a port anyway.

Reply to
jameshanley39
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It is called Network Address Translation.

Reply to
Travis

They do not contain a Firewalll.

They do not contain a MODEM.

They do contain a Switch.

They do contain a NAT routing function and also do RIP1 and RIP2, which makes them routers.

Reply to
Leythos

Except that certification and claiming to have some book learning doesn't mean anything to fanatics or people that hire IT types :)

Reply to
Leythos

From: "Leythos"

| | They do not contain a Firewalll. | | They do not contain a MODEM. | | They do contain a Switch. | | They do contain a NAT routing function and also do RIP1 and RIP2, which | makes them routers. | | -- | | snipped-for-privacy@rrohio.com | remove 999 in order to email me

Actually...

The MAY contain any or all of these. It all depends on makes and models. For example the Estwll 327W is both a DSL modem in Bridge mode and a DSL Modem/Router when placed in Router mode.

Reply to
David H. Lipman

From: "David H. Lipman"

| | Actually... | | The MAY contain any or all of these. It all depends on makes and models. | For example the Estwll 327W is both a DSL modem in Bridge mode and a DSL Modem/Router when | placed in Router mode. | | -- | Dave |

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That should have been "Westell 327W" not "Estwll 327W" :-(

Reply to
David H. Lipman

Given your credentials, you must know that is sometimes, but not always true. Not all home routers contain what manufacturers call a modem; that is a separate function.

Some also contain PPPoE or similar functionality.

Reply to
CJT

From: "Jonathan Wilson"

| I was unaware that routers exist that do not contain modems (actually, I | probobly knew at one point and just forgot :)

Joint modem+Router devices are relatively new. When SOHO Routers first hit the market, there weren't any joint versions. They were all Routers only or modem only.

Reply to
David H. Lipman

Home routers ARE routers. They route between the outside network (the network between the home router and the first router at your ISP) and the internal network (the non-world-visible home network you have). They can contain a firewall and indeed some do. They also implement Network Address Translation (or NAT) and Port Address Translation (or PAT aka port forwarding) and they contain a cable or DSL MODEM (whether it is techincally a MODEM, all the manufacturers call it a MODEM). They will also usually contain a DHCP server to assign IP addresses to all the machines on the internal network.

For example in my case, we have a single IP address from the ISP.

My PC has a private address (in the 192.168.1.x range). Other PCs in this house also have a 192.168.1.x address, as does the router itself. So, all the machines on the internal network including the router make up the 192.168.1.x class C private network. Then, there is another network with my home router on it plus the router at the ISP. The home router routes traffic between the 192.168.1.x network and the router-ISP network.

Reply to
Jonathan Wilson

Oh and btw, I am currently studying Cisco CCNA network certification so I DO know what I am talking about :)

Reply to
Jonathan Wilson

Modem/Router when

That would make it more than a NAT Router then :)

Reply to
Leythos

From: "Leythos"

| | That would make it more than a NAT Router then :) | | -- | | snipped-for-privacy@rrohio.com | remove 999 in order to email me

Well Westell is known for making DSL modems. The product lines are morphing and assimilating.

It is the Borgs ! ;-)

Reply to
David H. Lipman

Yea, that type of crap really irritates me - I'm the type that purchases a stand-alone access-point, not a wireless router, so that I can change things as needed without impacting everything else.

I would hate to find that my Modem had an exploit that filters through the NAT firmware, that would have been blocked if I had installed a stand-alone NAT router.

Reply to
Leythos

I was unaware that routers exist that do not contain modems (actually, I probobly knew at one point and just forgot :)

Reply to
Jonathan Wilson

From: "Leythos"

| | Yea, that type of crap really irritates me - I'm the type that purchases | a stand-alone access-point, not a wireless router, so that I can change | things as needed without impacting everything else. | | I would hate to find that my Modem had an exploit that filters through | the NAT firmware, that would have been blocked if I had installed a | stand-alone NAT router. | | -- | | snipped-for-privacy@rrohio.com | remove 999 in order to email me

I agree. Greater versitility and no single point of failure.

I wonder -- If a modem can be put in either a Bridge mode or a Router mode, are they then BRouters ?

Reply to
David H. Lipman

No single point of failure? How so?

are they then

Reply to
CJT

From: "CJT"

| No single point of failure? How so? |

If the Router+modem goes both are dead. If you separate products and the Router dies, you can still connect at least one PC to the modem.

Reply to
David H. Lipman

The NAT device/home router, would still have an IP address, so it wouldn't be a switch.

The home router would still respond to an ARP request - for its MAC address, given its IP address. A switch would not do that.

agreed. interesting concept. But as soon as you send a frame to the switch, and the MAC address is the MAC address of the router, rather than the MAC address of another computer on the LAN, then the frame will be pased by the switch to the home router, and the home router will do whatever a home router does. If the IP address is private then i don't know what the home router does. And if the IP address is not private then the frame is sent out , to the ISP's router.

So, it is not just a switch. Frames can be addressed to the home router, the home router has an IP, the home router makes some kind of home router decisions on the IP. You can get past the switch.

I have heard that cisco make some kind of manageable layer 3 switch, like a switch that uses IP addresses, but I doubt home routers are anything like these!

Reply to
jameshanley39

Router dies, you

So then the modem is a single point of failure.

Reply to
CJT

From: "CJT"

| So then the modem is a single point of failure. | | -- | The e-mail address in our reply-to line is reversed in an attempt to | minimize spam. Our true address is of the form snipped-for-privacy@prodigy.net.

Well there is always a weak link in any chain. It is admittedly a weak argument but the versatility argument isn't.

My father has a Westell 2200 ADSL modem+Router but it is in Bridge Mode and he's using a Linksys BEFSR41 v3 Router.

I have a White Westell (modem only and have had it for over 5.5 years w/o any failures) and use a Linksys BEFSR81 v1 Router.

Reply to
David H. Lipman

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