network printer problem

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zhengquan - 18 Feb 2008 22:24 GMT

Hello,

I posted this problem on another group but I found that this group
might be the best place it shoudld be. I am thinking of solving this
problem, the lab in the group has several windows xp computers, they
have public ip. Now we have 2 printers connected to the internet, both
of them have public Ip. The computers and the printers are not
connected by routers.

Now the problem is, I need to spare a internet port for other use, so
I am thinking of using a router to connect the 2 printers and let the
routher have a public ip, the 2 printers will have private ip
assigned by the router. I want to know in this situation, is it
possible for other computers to access the two printers because they
now do not have public ip, they are in a subnet behind the router.

The printers are in a room, both of them are using a net port. We are
in a different room, and each computer connects to the internet via a
net port.

Thanks!

ZHengquan

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Chuck [MVP] - 19 Feb 2008 04:51 GMT

>Hello,
>
[quoted text clipped - 19 lines]
>
>ZHengquan

I would put all of the computers and printers behind a router (NAT router, I
hope). Why do you feel the need to expose the computers to the Internet?
<http://nitecruzr.blogspot.com/2005/05/what-is-nat-router.html>
http://nitecruzr.blogspot.com/2005/05/what-is-nat-router.html

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Cheers,
Chuck, MS-MVP 2005-2007 [Windows - Networking]
http://nitecruzr.blogspot.com/
Paranoia is not a problem, when it's a normal response from experience.
My email is AT DOT
actual address pchuck mvps org.

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zhengquan - 19 Feb 2008 17:08 GMT

> >Hello,
>
[quoted text clipped - 30 lines]
> My email is AT DOT
> actual address pchuck mvps org.

Thanks, Because computers are in a room, the printers in another, and
if the computers are behind a router, they do not have public ip
address and it make remote log in difficult...

Zhengquan

Reply to this Message

Gordon - 19 Feb 2008 17:43 GMT

> Thanks, Because computers are in a room, the printers in another, and
> if the computers are behind a router, they do not have public ip
> address and it make remote log in difficult...
>
> Zhengquan

I have my laptop in one room and my printer in another. that doesn't mean I
have to use a public IP to print to it. You need a print server for each
printer and then connect each print server into your local network.

Reply to this Message

Gordon - 25 Feb 2008 08:07 GMT

> Thanks, Because computers are in a room, the printers in another, and
> if the computers are behind a router, they do not have public ip
> address and it make remote log in difficult...

Then just add them to your local network.......I have a machine in one room
and the printer in another, but I don't need to print over the
"internet"....

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smlunatick - 25 Feb 2008 14:17 GMT

> > Thanks, Because computers are in a room, the printers in another, and
> > if the computers are behind a router, they do not have public ip
[quoted text clipped - 3 lines]
> and the printer in another, but I don't need to print over the
> "internet"....

You could pass a cable between the two rooms. And when you connect
the two printers onto the same network, you will then secure them so
than only the PCs in the areas can access the printers. By having the
printers available over hte Internet, you have 'exposed" these
networks to possible hacking.

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Gordon - 25 Feb 2008 15:42 GMT

On Feb 25, 3:07 am, "Gordon" <gbpli...@gmail.com.invalid> wrote:

> "zhengquan" <zhang.zhengq...@gmail.com> wrote in message
>
[quoted text clipped - 8 lines]
> and the printer in another, but I don't need to print over the
> "internet"....

You could pass a cable between the two rooms.

Even better, use wireless.....that's what I have. Printer hardwired via a
pocket Print server (just sits on the parallel port on the printer) to a
switch, to which is connected a WAP. The machine in the other room was
Wireless.....

Reply to this Message

smlunatick - 26 Feb 2008 16:45 GMT

> On Feb 25, 3:07 am, "Gordon" <gbpli...@gmail.com.invalid> wrote:
>
[quoted text clipped - 17 lines]
> switch, to which is connected a WAP. The machine in the other room was
> Wireless.....

Wireless network is fine but I still think that using this for
printing is not reliable. Printing is a "heavy" workload for the
network and no wireless connection can really be as fast as a cable
between the printer and networks.

Reply to this Message

Chuck [MVP] - 26 Feb 2008 22:59 GMT

>> On Feb 25, 3:07 am, "Gordon" <gbpli...@gmail.com.invalid> wrote:
>>
[quoted text clipped - 22 lines]
>network and no wireless connection can really be as fast as a cable
>between the printer and networks.

The speed isn't the problem. The half duplex nature of WiFi, and having the
WiFi router having to constantly choose between receiving from the source, and
sending to the target, in half duplex mode, is a big problem. Linksys at one
time had a nice white paper explaining this very concisely.

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Gordon - 26 Feb 2008 22:57 GMT

>>> On Feb 25, 3:07 am, "Gordon" <gbpli...@gmail.com.invalid> wrote:
>>>
[quoted text clipped - 20 lines]
> sending to the target, in half duplex mode, is a big problem. Linksys at one
> time had a nice white paper explaining this very concisely.

never had any problems here - mind you, I don't have large print jobs
(normally....)

Reply to this Message

Chuck [MVP] - 26 Feb 2008 23:33 GMT

>>>> On Feb 25, 3:07 am, "Gordon" <gbpli...@gmail.com.invalid> wrote:
>>>>
[quoted text clipped - 23 lines]
>never had any problems here - mind you, I don't have large print jobs
>(normally....)

I think (suspect) that better firmware in the consumer grade routers has worked
around that problem. The white paper that I mentioned I have been unable to
find, or I would surely have a blog post and a link to it. My suspicion is that
Linksys improved their firmware, and removed the paper.

But it has to be a concern, similar to the issue of WiFi repeaters (routers
operating in WDS mode).

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smlunatick - 27 Feb 2008 15:45 GMT

> >> "smlunatick" <yves...@gmail.com> wrote in message
>
[quoted text clipped - 39 lines]
>
> - Show quoted text -

I am not worried for the WiFi speed but on the reliability of the
wireless connections. I have yet to see a wireless network that does
not loose connection periodically during a "session." It may just be
a small "break" and the wireless network is re-established. During
this "reset" the print job can loose data.

Reply to this Message

Gordon - 27 Feb 2008 23:45 GMT

>I am not worried for the WiFi speed but on the reliability of the
>wireless connections. I have yet to see a wireless network that does
>not loose connection periodically during a "session." It may just be
>a small "break" and the wireless network is re-established. During
>this "reset" the print job can loose data.

Never had any problem here in that regard, but I don't tend to have large
print jobs...

Reply to this Message

Chuck [MVP] - 28 Feb 2008 02:18 GMT

>> >> "smlunatick" <yves...@gmail.com> wrote in message
>>
[quoted text clipped - 45 lines]
>a small "break" and the wireless network is re-established. During
>this "reset" the print job can loose data.

That's a problem with using WiFi for printer connectivity. A print job involves
traffic in two directions constantly. The data flowing from the client to the
printer, and control information from the printer back to the client, is
constant. If both legs of the router - the client, and the printer - both
connect by WiFi, the router has to maintain 4 WiFi conversations of symmetric
and synchronous traffic.

Since there are 2 ends to each conversation, that's 8 WiFi transmissions
fighting for the same channel. All you need is for one transmission to be lost,
something times out and has to restart, and the whole channel goes to hell.
Read about Classical Ethernet and CSMA/CD, to get an idea where the problems
are. WiFi uses CSMA/CA, which avoids collisions, and is only marginally better.
<http://nitecruzr.blogspot.com/2005/10/wifi-will-never-be-as-fast-as-ethernet.html>
http://nitecruzr.blogspot.com/2005/10/wifi-will-never-be-as-fast-as-ethernet.html

WiFi is designed to share Internet service, which is asymmetrical, and
asynchronous. If you have 2 computers, both connected by WiFi, one computer
will download a screen of data, and the person using it can be reading the
screen while the second computer is downloading. While person using the second
computer is reading, the first can be downloading.

If one person starts running Torrents, that changes.

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