Switch vs Router?

On Sat, 2 Feb 2008 10:26:39 -0800 (PST),
"jameshanley39@yahoo.co.uk" <jameshanley39 RemoveThis @yahoo.co.uk>
wrote:

>On Feb 1, 9:32 pm, kony <s... RemoveThis @spam.com> wrote:
>> On Fri, 1 Feb 2008 04:08:06 -0800 (PST),
>> "jameshanle...@yahoo.co.uk" <jameshanle... RemoveThis @yahoo.co.uk>
>> wrote:
>>
>> >> There are many hybrid modems with router built in, but they
>> >> are generally called modems, not just called routers as the
>> >> product name and classification.
>>
>> >a marketting thing.
>>
>> >I guess If it has many LAN ports (on the switch!), they call it a
>> >router(whether it has a modem or not). If it has one LAN port on the
>> >switch, they call it a modem.
>>
>> If it has a modem they call it a modem (that happens to also
>> have a router in it).
>>
>
>I just googled a router/modem I like, the Speedtouch 546.
>It is a router/modem with many switch ports. So they don`t undermarket
>it by calling it a modem.
>The links call it a router.
>Thomson SpeedTouch 546 v6 ADSL2+ Router


There will always be occasions where a manufacturer names a
product differently, but generally speaking if you go to a
major eTailer like newegg.com and browse their "router"
category, the vast majority aren't going to have a modem in
them. The distinction is important so a customer doesn't
assume they're getting a modem if they didn't bother to read
all the product specs.



>
>Maybe the fact that it says ADSL implies modem.. so they are calling
>it a router/modem.

Yes, I would hope if they specify ADSL that there's a modem
built in, though I would wonder if some might try to tout
their product as a "cable / ADSL" router when this is just
an attempt to sway less educated consumers when it has
neither modem type built in.



>
>Interestingly, I have not seen router/modems with many switch ports
>and a cable modem in there. (you`d know it had a cable modem, if it
>had an aerial stalk like connector on it). Router/DSL modems, have
>RJ11 connectors. DSL uses RJ11. Cable users have Cable sockets in
>their walls.

I think this might have something to do with bandwidth...
that if you're a DSL provider you don't care so much if the
customer uses all their bandwidth but with cable everyone on
that segment is sharing bandwidth, so when a product is
designed to (hopefully) be desirable to ISPs, a cable ISP
will tend to prefer a product that doesn't as easy promote
having multiple systems connected. I could be wrong about
this, it's just a thought as I do agree cable modems with a
switch built in are rarer.

>> True, a router only needs have one LAN and one WAN port,
>> though as with a modem, a router may happen to have a switch
>> in it in addition to being a router.
>>
>
>Really, it is a box. With functions. Router is a function or rather,
>the name for the box that does the Routing function..

Perhaps, but it does change the design requiring a network
processor inside that is capable of this, as they are
generally hardware based rather than fully programmable
processors. I may be excluding the early routers back when
custom silicon wasn't available, when they were more of a
single board computer instead of cost optimized designs we
see today in consumer routers.

>
>If it only has 2 ports, there is no need for it to do any Routing.

Depends on how you look at it, what the requirement was. If
there were only two ports and no routing would you even need
a standalone box instead of a PCI card type modem?
Providing I had a free PCI slot I'd certainly rather the
card than a separate box, all else being as equal as
possible.

Otherwise, it being a router is still a pretty desirable
feature for the added control and isolation of a windows box
from the internet.



>
>Just like I said with the switch/bridge. The USB DSL modem, it
>connects 2 things together, there is no need need for it to be a
>bridge.

Suppose you boot a windows box, it has either a manually set
IP address or defaults to a range MS has set. You then have
a different address range than what your ISP is using for a
routable internet address, how would this be resolved if you
don't route or bridge? Remember it is still a networking
connection, not just a data link.



>> I'm speaking of having separate modem and router. By
>> increasing surface area and decreasing heat, you decrease
>> heat density (If all else is equal). It also means that if
>> your LAN had relied on a router's switch and the modem died,
>> it doesn't take down your whole LAN.
>
>I do not know what you mean at all.

How can I state it without saying essentially the same thing
again? When you have many separate features in the same
box, it tends to require addt'l chips to support these
features. Each chip has it's own inherant power
consumption, and the onboard supply circuitry losses depend
upon the current supplied (and different voltages required
by the chips), so ultimately you will tend to have higher
heat density when there are more chips in the same volume
*box*. Further, the typical brick PSU is also running at
higher % capacity because it becomes more expensive to use
one that has more than about 1-1.5A output, also increasing
heat density in the power supply and making it more prone to
failure if not made more expensive to accomodate this.

When the power consumption per each box is lower, and with
two boxes you have both more PCB area to 'sink away heat on
the copper on it, more air volume inside, and greater
external casing surface area upon which to put vent holes,
given similar tech (per era), two boxes will each run at
lower temp than if all these components were put into one.

As for the detail of a modem dying and still having a
functional switch in a separate (router) box, what more is
there to say? By splitting up these two each is less likely
to fail and having one fail will not cripple the user as
much. If the modem dies the LAN still works. If the
router/switch dies the modem can be directly connected to
one system (hopefully only temporarily, but if necessary
that system could have a proxy installed to make due until a
replacement part is found). Either way you retain more
functionality than if a combo device failed.



>
>If you have a router and it overheats, then it overheated. If you add
>a modem into the mix, it does not reduce the chance of the router
>overheating.

Yes it does, the total heat produced by the box is reduced,
and the load on the PSU is reduced.

>
>Are you saying that the box that is a router/modem overheats more than
>a box that is a router without modem ?

All else being equal, yes. Modem is not a feature integral
to a typical networking processor used for a router, they're
populating a PCB more densely to add parts for this
functionality (when possible, because it saves them money)
and avoiding adding a fan becaues that also raises cost and
many consumers deem fan noise undesirable.



>
>
>> Mainly though it is
>> the expanded feature set and being able to choose exactly
>> which router you wan which makes the separate components
>> more desirable.
>>
>
>Well, before you said you were talking of a router and a modem. So now
>you are talking of a few routers.

No I'm talking about one modem and one router, as a basic
concept though of course you could add more routers to a
network if you desired.


>For me, a switch with many ports is fine. If I need more ports I would
>add another switch.

As would many people, but there are certain benefits of
adding another "router" named device even if you don't need
the secondary device to actually route. For example if it
has wifi built in, most modern designs today allow the
router to be configured as an access point, and some a
bridge.


>
>Many routers is a different ball game.. It has to be justified. You
>mentioned no reason. Like an office with different IP subnetworks, and
>for security reasons, one cannot see another one.

There are many reasons, actually a better question is why
someone wouldn't use a router when possible, since they're
quite inexpensive, add a layer of security, allow multiple
system internet connectivity with only one internet IP #,
which becomes a matter of practicality since IP v4 numbers
aren't infinite, and ISPs even more finite so the cost
effective accounts for a typical consumer allow only one IP
number. Of course there are other workarounds, namely a
proxy but a router makes none of this necessary and is more
convenient and reliable than having to use a programmable
processor based system that tends to be larger, more costly,
and uses more power to run a proxy instead.



>
>I have not used ICS, but googling, it seems that ICS uses NAT.
>
>So what you wrote there seems wrong on lots of levels.

Yes, it does NAT, also proxy caching IIRC. Frankly I
shouldn't have mentioned it at all because we were
discussing standalone hardware solutions.

"kony" <spam.TakeThisOut@spam.com> wrote in message
news:63e9q3t5ce121u80evbhodh97q6ks7km2m@4ax.com...
> On Sat, 2 Feb 2008 10:26:39 -0800 (PST),
> "jameshanley39@yahoo.co.uk" <jameshanley39.TakeThisOut@yahoo.co.uk>
> wrote:
>>
>>If it only has 2 ports, there is no need for it to do any Routing.
>
> Depends on how you look at it, what the requirement was. If
> there were only two ports and no routing would you even need
> a standalone box instead of a PCI card type modem?
> Providing I had a free PCI slot I'd certainly rather the
> card than a separate box, all else being as equal as
> possible.
>
> Otherwise, it being a router is still a pretty desirable
> feature for the added control and isolation of a windows box
> from the internet.
>
>

Actually the Routing process is not limited to the number
of ports on the box. You could have your Router route
the packets from your WAN (or any other external net)
through one port to daisy chained switches with many ports,
to the devices on your LAN. Of course the most common
external net that people want to connect their own network
to is the Internet, for that some kind of modem will normally
be needed, based on the physical method of distribution.

As was so apply stated by "Rookie":
"You choose switches to connect computers within your
network, routers to connect your network to another."


This is a switch that I have found works great to cheaply
turn a 5e cabled 100Mbps LAN into a Gigabit LAN:

http://www.newegg.com/Product/Product.aspx?Item=N82E16833129013

(I use 4500 Jumbo Packets so I don't know how it actually
is with 9000 Jumbo Packets, but it runs fast and trouble free.)
[The part # on mine is 751.8129, and I've had mine for more
than a year before the posting about different internals. Mine
runs on 9V 1amp. So it could be that I just got a good one.]

http://www.provantage.com/smc-networks-smc8508t~7SMCS01F.htm

I just plug the switch into my existing router to have the Internet
available to the equipment on my LAN.


Bottom line you should have a Router to provide a connection
to, and some protection from, the Internet - but have a switch to
provide the interconnections to the devices on your LAN.

Luck;
Ken