What is the functional purpose(s) of ...

On Wed, 29 Nov 2006 07:21:22 -0800, "AJM" wrote in :

Wikipedia

AJM wrote: What is the functional purpose(s) of ...

Answer:

Providing monetary income for trained and experienced professionals.

Sends packets various directions based on their IP address

Provides access to a LAN (mostly with wireless)

Connect two networks through a different medium at level 2 (Ethernet, for example)

Nearly like a router, but works at level 2 and greatly lowers the traffic any one station on the network sees. It also improves network utilization by reducing collisions.

Google is your friend.

You're welcome.

- Nate >>

"AJM" hath wroth:

Drills grooves and finishes edges on wood furniture and counter tops.

Useful for emergency escapes and maintenance in vehicles, trains, and sewers.

For crossing over rivers, valleys, and roadways.

Turns the lights on and off.

You're welcome. If you have problems using any of the internet search tools or encyclopedia reference guides, please ask for help. If you need wireless basics, start with the wireless tutorials at:

Routes data from one network to another. The most common example is routing data from the Internet to your local home network. A wireless router consists of a router, a wireless access point, and usually a switch. A wired router may or may not have a built in switch.

A wireless access point could also be called a wireless hub. It connects wireless devices to a given network. You would typically connect an Access Point to a switch or hub (or a switch located on a router).

A device that connects two parts of the same network via an alternate method. A wireless bridge connects devices on a local network via a wireless connection.

Routes data between devices on a single network. For a local area network, all devices on the network would communicate through the switch. Any access outside the network (like accessing the internet) would require a router to route data to the other network.

A simple diagram of these devices in action (I hope it is readable).

= is wire ~ is wireless = computer 1 Internet = router = switch = access point ~ wireless bridge = xbox 1 = computer 2

On Wed, 29 Nov 2006 11:45:17 -0700, Bryant Smith wrote in :

Bad analogy (IMnsHO at least) -- hubs can connect to other hubs, but access points cannot connect to other access points.

Bridges can actually bridge between two different networks.

Switching is not routing. A switch differs from a hub in that traffic is directed to the single destination, instead of being broadcast to all destinations.

True - I was trying to be simplistic rather than nit pick details. Although, access points with WDS can connect to each other...

True.

You say it directs traffic I say it routes traffic. The two verbs can mean very closely the same thing. The actual switch hardware does in a way "route" traffic by sending the packets to their proper destination in much then same way a router "directs" traffic to its proper destination. It is just done at a different abstraction layer. Both devices send traffic to a specific place as opposed to a hub that sends all traffic everywhere.

Anyway, I'm not much for arguing over little details. The original poster looked like he just wanted a simple explanation so that's what I gave.

On Wed, 29 Nov 2006 14:44:35 -0700, Bryant Smith wrote in :

That's not a nit pick -- that's a fundamental difference.

But not as clients.

Not in technical terms -- they are fundamentally different, and a misuse of the terms.

No offense intended, but inaccurate information can do more harm than good.

Bryant Smith wrote in news:ekkua7$7q1$1 @az33news01.freescale.net:

As the saying goes.......'it's all in the details.'

The typical LinkSys/D-Link/Netgear Cable/DSL router is not really a router either. It is a NAT device.

It's main function is not to 'route' packets anywhere, it is to translate packets from one or more private IP addresses on a LAN to make the destination look like the internet (or WAN) IP of the NAT-Device itself, so other hosts on the internet can get data back to the PC with the private IP.

On Wed, 29 Nov 2006 23:17:46 +0100 (CET), DanS wrote in :

Even though it's also a NAT/PAT device, it _is_ still a router nonetheless.

John Navas wrote in news: snipped-for-privacy@4ax.com:

It is, but in the broadest sense of the word.

But when I'm used to working on Cisco and Cabletron/Enterasys Routers......

I guess there's a question I've never had answered, that might make it seems to be more of a router. Possibly you can answer it......

You have:

Internet a NAT router PC LAN of PC's.

Rtr = 192.168.1.1

So above, the PC has 2 NICs, and set to route packets. Rtr side = 192.168.1.2 LAN of PC's side = 192.168.100.2

The LAN of PC's each have a 192.168.100.x IP with a gateway set of

So an internet bound packet from .100.10 will be sent to the PC as it's gateway. The PC's gateway is the rtr, so the packet will be sent to the rtr.

What will the router do with it ? It's source is from a different subnet than the router eth is. Will it NAT this packet and send it out on the internet ?

The rtr firmware also needs to offer a place to enter static routes also, to be able to get back to the .100.x network thru the PC. Not all do. Mine does not, I know some older Linksys rtr's could hold static routes like that. There are others I'm sure.

Regards,

DanS

On Wed, 29 Nov 2006 23:42:49 +0100 (CET), DanS wrote in :

It is, in the true sense of the word (router). RFC 1009:

Router A router is a switch that receives data transmission units from input interfaces and, depending on the addresses in those units, routes them to the appropriate output interfaces. ...

For example, given a local network 192.168.0.0/16, and a packet addressed to 66.102.7.104, a low-end consumer router knows to "route" that packet to its WAN port, sending it to the gateway on that port. Simple, yes, but routing nonetheless.

Difference of degree, not kind.

Why have a PC between the NAT router and the LAN of PC's?

ICS (Double NAT)? Real routing? Or bridging? I'm going to assume ICS (Double NAT).

Route it.

Depending on how the PC is configured, it's probably coming from the PC. Double NAT.

Yes.

No, it sends it back to PC as the origination point.

No static route is needed.

John Navas wrote in news: snipped-for-privacy@4ax.com:

Agreed.

Why not ? People here ask about all kinds of setups.

No ICS. Or other double-NATing.

But the router is not connected to the 100.x network, so it doesn't have a way back, I would think it needs a static route pointing to the PC.

DanS

On Thu, 30 Nov 2006 01:10:55 +0100 (CET), DanS wrote in :

Because it doesn't make sense.

True. All too often unrelated even to wireless.

Then what?

Depends on what the PC is doing, which is still a secret.

John Navas wrote in news: snipped-for-privacy@4ax.com:

No, not a secret, I already said it had IPRouting enabled.....

Hmmm, Name says it all. Need more?

On Thu, 30 Nov 2006 03:27:33 +0100 (CET), DanS wrote in :

What you actually said was "set to route packets", which is pretty vague since it could have meant any of a number of different things, including ICS. You ducked my questions, leaving it a secret.

I think you'll find this more helpful with regard to how packets get back through the Windows router:

In other words, you would need to configure the Windows router as a gateway in the hardware router.

John Navas wrote in news: snipped-for-privacy@4ax.com:

Yes, that is what I said, you would need to add a route in the router, pointed at the PC as a gateway, so it knows how to get to the subnet on the other side of the PC.

So the question was, will the simple home cable router accept a packet that was forwarded to it, with a different source IP subnet than the routers own ethernet ?

I have never had to do this myself, which is why the question was posed.

On Thu, 30 Nov 2006 04:12:46 +0100 (CET), DanS wrote in :

Not a static route, a gateway. That's a subtle but important difference.

Sorry, but I choose not to play, since the idea is speculative and silly. Either switch the Windows router to ICS, or take it out of the network path.