IFX Mail Archive: RE: Word docs

IFX Mail Archive: RE: Word docs

RE: Word docs

Dan Wing (dwing@cisco.com)
Thu, 25 Mar 1999 17:58:41 -0800 (PST)

On Thu, 25 Mar 1999 14:32 -0800, Michael Crawford wrote:

> I understand the confusion...I wish I wasn't confused myself, but then
> again, wishing doesn't make it so (red face).
> It might be worthwhile setting the stage so to speak.
> Okay, this is a fax centric view. First a fax machine operation.
> 1. User takes out of box, plugs in power and hooks up phone cable to phone
> plug.
> 2. User configures name to appear on faxes it sends
> 3. User configures phone number to appear on faxes it sends
> 4. Users configures fax to auto answer when someone calls (probably a
> default condition)
> Ready to Go!

Yep, works like a charm.

> 5. Someone elsewhere decides to send to fax to our friend above, so drops
> in paper and
> 6. dials the number and presses start
> So far this is why fax is so popular...look how simple! Why change this.

We aren't changing it. Fax over GSTN will be around as long as the
GSTN survives.

> 7. Fax machine at our friends house rings, answers and the two machines
> negotiate capabilities
> 8. Cuz fax standards are simple (speed is 9600 or 14400, image type is G3
> or G4, resolution is fine
> or super fine) the machines agree on a format.
> 9. The 'elsewhere' person's fax sends the image line by line, page by page,
> and
> 10. Our friend's machine receives and prints accordingly. When done we
> disconnect from the phone line at both ends.
> Now an Internet fax should act as much as similar as possible...

Except for that 14Kbps speed.

> except that instead of phone numbers we either use an IP address, or
> better yet a standard hostname (that DNS can resolve). The connection
> between two machines could ideally work the same...i.e.
> 1. Internet fax at person A dials into ISP. Gets hooked up and "online".
> 2. Internet fax A sends request for capabilities to internet fax B
> 3. Internet fax B is NOT online. Ooops. Now what

One could use SIP (RFC2543) to determine where the user "is".

> 4. Or Internet B is online (we happen to catch it while it is dialed up),
> so Internet fax B responds with
> G3 or G4 then waits
> 5. Internet fax A now sends first page in TIFF wrapped G3 and waits for
> response
> or continues to send until the job is complete (I am not sure yet how this
> part works under IPP)
> 6. Internet Fax B receives and sends "Okay got it" as the response.
> 7. Machines "disconnect" from each other, but may or may not hang up the
> phone line.
> You should see the key issue is the receiving fax machine (or any
> other Internet device ) that is not full time on the network.

Above, you're describing T.38 -- tunneling T.30 inside IP. This is
nonsense over a dialup link. Specifically the overhead of IP combined
with the complexities of finding the remote user's IP address make
this scenario highly unlikely. T.38 is defined by the ITU and is
available from http://www.itu.int

More likely is plain RFC2305-style fax -- attach a TIFF'd image to
an email message and email it.

> a. What do we do if Internet device B is not online at the time Internet
> device A "calls".
> b. Can a proxy of some sort (i.e. an IPP intermediate server computer (I
> didn't want to write a server server))
> help resolve this issue?
> c. Do we want to instead require an IPP enabled Internet fax be online
> at all times (thereby being called a
> fulltime fax) or are there other solutions

Uh, yes -- isn't that the point of this working group: sending a document
to a remote user immediately with with positive delivery confirmation.

Store-and-forward fax was done by the Internet Fax WG,
ietf-fax-request@imc.org, and is RFC2305 and RFC2532.

> Where is Larry when you need him?

-Dan Wing