packet vs frame

I'm confused, what is the difference between a packet and a frame when
talking about networking.

On Wed, 9 Apr 2008 19:44:21 -0500, "don" <(E-Mail Removed)> wrote:

>I'm confused, what is the difference between a packet and a frame when
>talking about networking.

Packet:
<http://en.wikipedia.org/wiki/Packet_%28information_technology%29>

Frame:
<http://en.wikipedia.org/wiki/Data_frame>

Basically, a frame is a collection of one or more packets.

--
Jeff Liebermann (E-Mail Removed)
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On 10 Apr, 08:38, Jeff Liebermann <je...@cruzio.com> wrote:
> On Wed, 9 Apr 2008 19:44:21 -0500, "don" <d...@panix.com> wrote:
> >I'm confused, what is the difference between a packet and a frame when
> >talking about networking.
>
> Packet:
> <http://en.wikipedia.org/wiki/Packet_%28information_technology%29>
>
> Frame:
> <http://en.wikipedia.org/wiki/Data_frame>
>
> Basically, a frame is a collection of one or more packets.

Hmmm. I disagree - certainly in the conext of alt.internet.wireless.

Different people use these terms casually to mean different things and
I would be surprised if different Standard Bodies had not
specified - carefully - multiple different meanings for
each of them.

I would not dare to attempt a definition since I would be bound to
be wrong.

The one thing that I am reasonably confortable with is that
I have never seen a frame described as Jeff has described it
here. : -)

So, to address the question -

Frame means very different things in the T1, T3 and
perhaps DSL world than it does in the Ethernet
world.

What I would do is to always specify the meaning of packet and
frame whenever used to ensure that there was no ambiguity if that
was appropriate.

e.g. the packet length was 234 bytes (including data, tcp and ip
headers
but excluding Ethernet encapsulation).

I think that in the Ethernet World, a Packet is everything except the
Ethernet headers/trailer and frame includes all of the Ethernet
bits too. Those being at least Destination address, Source
Address, Length/type, 802.2 and SNAP if present and CRC.
Frame may or may not include the Preamble.

Oh dear definitaion attempted and the only sure thing is that
it is definately wrong:-)

don wrote:

> I'm confused, what is the difference between a packet and a frame when
> talking about networking.
>

No real difference until you get pretty close to the wire-level
electronics, where the 802.3 specs say (in specmanslike gory
detail) that: a data frame is contained within a packet for
transmission over 802 networks. I.e., a data frame becomes
a packet by tacking on some control bits fore and aft.

There are, of course, some packets that do not contain data;
part of the overhead tax.
--
Cheers, Bob

On Thu, 10 Apr 2008 01:12:54 -0700 (PDT), (E-Mail Removed) wrote:

>On 10 Apr, 08:38, Jeff Liebermann <je...@cruzio.com> wrote:
>> On Wed, 9 Apr 2008 19:44:21 -0500, "don" <d...@panix.com> wrote:
>> >I'm confused, what is the difference between a packet and a frame when
>> >talking about networking.
>>
>> Packet:
>> <http://en.wikipedia.org/wiki/Packet_%28information_technology%29>
>>
>> Frame:
>> <http://en.wikipedia.org/wiki/Data_frame>
>>
>> Basically, a frame is a collection of one or more packets.
>
>Hmmm. I disagree - certainly in the conext of alt.internet.wireless.

Alt.internet.wireless has context? I hadn't noticed.

>Different people use these terms casually to mean different things and
>I would be surprised if different Standard Bodies had not
>specified - carefully - multiple different meanings for
>each of them.

Yep. I tried to supply a simplified explanation and apparently
failed. You opened this can of worms, so you get the long version.

>Frame means very different things in the T1, T3 and
>perhaps DSL world than it does in the Ethernet
>world.

Bingo. Telco buzzwords are very different from computah buzzwords and
for good reason. Back in the daze of Ma Bell, AT&T was very careful
not to give the impression that they were a monopoly. A monopoly was
a company that manufactured and sold at every level of the industry,
from raw materials to final delivery to the consumer. It was
therefore necessary for one part of the puzzle to be left untouched by
the telcos, and that was computahs. Ma Bell was very careful not to
give the impression that they were in the computer business. This was
possible at the time because computers were in their infancy and not
widely used.

However, Ma Bell just couldn't ignore computers or resist the
temptation to use and sell them. The best she could do was to obscure
and camouflage the terms and buzzwords that surround computers. For
example, a computer was called a "switch". Many terms as possible
became acronyms, which further obscured the underlying technology.
Early versions of Newton's Telecom Dictionary underscored the
equivalent terms. At the time, I worked for Ma Bell, and was going to
skool learning on an IBM 1620. I went through a vocabulary and
personality change as I switched from telco to computah jargon. At
the CO, we were warned the using computer terms was "dangerous".

When working for Ma Bell, the TDM systems of the day sent frames. In
the computers of the day, there were no packets. However, to
distinguish between what was digestible by the later computers from
that which was handled by the telco, the delivered payload were called
packets. In other words, when the data was on the phone lines, it was
in frames. When coming out of the CSU/DSU, it magically became
packets.

In 1984, it became a non-issue as the government did the stockholders
a huge favor and broke up Ma Bell into the Baby Bell's. Now, there
was no longer an issue of being called a monopoly and the Baby Bell's
could easily build and sell computers. Slowly, the terms merged, were
standardized, conglomerated, and were of course, misused by both the
computer and the telco crowd.

So, when you discuss data communications with a computah person, it's
a packet. When you discuss data transmission with a telco person,
it's a frame.

--
Jeff Liebermann (E-Mail Removed)
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

"Jeff Liebermann" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> On Thu, 10 Apr 2008 01:12:54 -0700 (PDT), (E-Mail Removed) wrote:
>
> Bingo. Telco buzzwords are very different from computah buzzwords and
> for good reason. Back in the daze of Ma Bell, AT&T was very careful
> not to give the impression that they were a monopoly. A monopoly was
> a company that manufactured and sold at every level of the industry,
> from raw materials to final delivery to the consumer.

That's not quite right. Actually what you're describing is a vertically
integrated manufacturer/distributor.

A monopoly refers to having the entire market to yourself in an area-- say
like the gas company, cable company, electric company. It doesn't matter
where you get the stuff or who makes it. For example, the local cable
company buys content from the networks and others, buys the wires they
string to your house-- any maybe even sub out the installation--- but the
cable company is a monopoly in your area because you can't buy that
signal/content from any one else (disregard satellite for the purpose of
this example).

Jeff Liebermann wrote:
> So, when you discuss data communications with a computah person, it's
> a packet. When you discuss data transmission with a telco person,
> it's a frame.
>
hmmm - OSI model -
thinking the above layers add "protocol" bytes and assemble/dis-assemble
"packets"
X.25 and PAD's - is there a corresponding FAD ? (not FRAD)
while the lower layer merely adds timing to the "frame",
hmmm - but what about 56k vs 64k and CRC and B8ZS, and ....
oh heck -

On Thu, 10 Apr 2008 12:47:43 -0400, "GySgt Hartman" <sarge@fmj> wrote:

>"Jeff Liebermann" <(E-Mail Removed)> wrote in message
>news:(E-Mail Removed).. .
>> On Thu, 10 Apr 2008 01:12:54 -0700 (PDT), (E-Mail Removed) wrote:
>>
>> Bingo. Telco buzzwords are very different from computah buzzwords and
>> for good reason. Back in the daze of Ma Bell, AT&T was very careful
>> not to give the impression that they were a monopoly. A monopoly was
>> a company that manufactured and sold at every level of the industry,
>> from raw materials to final delivery to the consumer.
>
>That's not quite right. Actually what you're describing is a vertically
>integrated manufacturer/distributor.

Right. I stand corrected. That's what I meant to say. AT&T spent
considerable effort to make sure that it did NOT manufacture, sell,
distribute, and dominate every area of the telephone business. In
about 1958(?), there was some court ruling that prevented AT&T from
going into the computer business (mostly thanks to pressure from IBM).
Here are the details:
<http://www.cybertelecom.org/notes/att_antitrust.htm>
Ma Bell turned this ruling to its advantage by convincing subsequent
anti-trust judges that the lack of involvement in computers,
constituted evidence that they did not have a vertical monopoly. It
worked, but required that nobody notice that their billing machines
were nothing more than camouflaged DEC PDP-11 minis, and that their
5ESS switches were really run by Unix based general purpose computers.
So, they simply changed all the name to confuse the clueless.

>A monopoly refers to having the entire market to yourself in an area-- say
>like the gas company, cable company, electric company. It doesn't matter
>where you get the stuff or who makes it. For example, the local cable
>company buys content from the networks and others, buys the wires they
>string to your house-- any maybe even sub out the installation--- but the
>cable company is a monopoly in your area because you can't buy that
>signal/content from any one else (disregard satellite for the purpose of
>this example).

Right. As I understand it, the courts and law manufacturers have
nothing against creating a monopoly. What is illegal is using that
monopoly to gain some advantage at the expense of the competition.
Kinda like what AT&T is currently doing to their former DSL "partners"
by wholesale DSL service to their partners for more than they're
selling the same service directly to the customers.

Argh. I'm late....gone.


--
Jeff Liebermann (E-Mail Removed)
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

don escribió:
> I'm confused, what is the difference between a packet and a frame when
> talking about networking.
>

IMHO, I use term "frame" when I talk in Link Layer context, and I use
term "packet" when I talk in Network Layer context. Of course, I am
talking about ISO/OSI model.

So, for me, a "packet" is a Layer 3 PDU (protocol data unit) and "frame"
is a Layer 2 PDU, so packets are encapsulated into frames.

Of course, ISO/OSI model, as its name says, is just a model, and you can
be agree or disagree with it, but I think it's a good starting point to
understand network mechanics.

Have a nice day.
Angel Catala.

On Apr 10, 1:44 am, "don" <d...@panix.com> wrote:
> I'm confused, what is the difference between a packet and a frame when
> talking about networking.


Ethernet sends frames.

IP sends packets.

TCP sends segments.

A more generic word for things like frames, packets and segments is a
"datagram".

If you're communicating with another computer using TCP, then you're
sending frames which contain packets which contain segments.

I think recently though people have started using "packet" to refer to
a frame.