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Contention Method Question
|
|
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| Can anyone answer a question for me? I know CSMA is the main
contention method with Ethernet networks, but is it also used with
TCP\IP over Ethernet networks or does TCP\IP use another method?
TIA Kboy
| |
| steve harris 2003-01-06, 8:24 am |
| Kboy wrote:
> Can anyone answer a question for me? I know CSMA is the main
> contention method with Ethernet networks, but is it also used with
> TCP\IP over Ethernet networks or does TCP\IP use another method?
> TIA Kboy
I would study the OSI 7 layer model again.
Especially the first three layers.
Steve
| |
|
| On Mon, 06 Jan 2003 07:58:44 -0600, steve harris
< steveharris1@REMOVECAPShotmail
.com> wrote:
>Kboy wrote:
>
>> Can anyone answer a question for me? I know CSMA is the main
>> contention method with Ethernet networks, but is it also used with
>> TCP\IP over Ethernet networks or does TCP\IP use another method?
>> TIA Kboy
>
>I would study the OSI 7 layer model again.
>Especially the first three layers.
>
>Steve
I understand that CSMA works on the datalink layer and IP is on the
network layer, are you saying that CSMA is incorporated within the OSI
protocols no matter the network used (ethernet, tcp\ip)? or am i
completely off the track? :-)
TIA Kboy
| |
| steve harris 2003-01-06, 9:24 am |
| Kboy wrote:
> On Mon, 06 Jan 2003 07:58:44 -0600, steve harris
> < steveharris1@REMOVECAPShotmail
.com> wrote:
>
>>Kboy wrote:
>>
>>> Can anyone answer a question for me? I know CSMA is the main
>>> contention method with Ethernet networks, but is it also used with
>>> TCP\IP over Ethernet networks or does TCP\IP use another method?
>>> TIA Kboy
>>
>>I would study the OSI 7 layer model again.
>>Especially the first three layers.
>>
>>Steve
>
> I understand that CSMA works on the datalink layer and IP is on the
> network layer, are you saying that CSMA is incorporated within the OSI
> protocols no matter the network used (ethernet, tcp\ip)? or am i
> completely off the track? :-)
> TIA Kboy
IP is layer three and TCP is layer four.
Ethernet (using CSMA) is layer two.
ATM is layer two.
Token Ring is layer two.
IP and TCP is a higher level protocol using the Ethernet transport.
You can run IP and TCP over ATM or Token RIng.
Your use of saying Ethernet and TCP/IP are two types of network is invalid.
Steve
| |
|
| On Mon, 06 Jan 2003 09:17:44 -0600, steve harris
< steveharris1@REMOVECAPShotmail
.com> wrote:
>Kboy wrote:
>
>> On Mon, 06 Jan 2003 07:58:44 -0600, steve harris
>> < steveharris1@REMOVECAPShotmail
.com> wrote:
>>
>>>Kboy wrote:
>>>
>>>> Can anyone answer a question for me? I know CSMA is the main
>>>> contention method with Ethernet networks, but is it also used with
>>>> TCP\IP over Ethernet networks or does TCP\IP use another method?
>>>> TIA Kboy
>>>
>>>I would study the OSI 7 layer model again.
>>>Especially the first three layers.
>>>
>>>Steve
>>
>> I understand that CSMA works on the datalink layer and IP is on the
>> network layer, are you saying that CSMA is incorporated within the OSI
>> protocols no matter the network used (ethernet, tcp\ip)? or am i
>> completely off the track? :-)
>> TIA Kboy
>
>IP is layer three and TCP is layer four.
>
>Ethernet (using CSMA) is layer two.
>ATM is layer two.
>Token Ring is layer two.
>
>IP and TCP is a higher level protocol using the Ethernet transport.
>You can run IP and TCP over ATM or Token RIng.
>
>Your use of saying Ethernet and TCP/IP are two types of network is invalid.
>
>Steve
Ok i think i have finally twigged (probably not :-P )
I gather i am confusing the higher level protocol(tcp\ip) with the
underlying means of transport?
and from that, I take it tcp\ip can be used over any of the underlying
datalink protocols of the OSI model?
I think its slightly clearer now, thanks for your help :-)
Kboy
| |
| steve harris 2003-01-06, 11:24 am |
| Kboy wrote:
> On Mon, 06 Jan 2003 09:17:44 -0600, steve harris
> < steveharris1@REMOVECAPShotmail
.com> wrote:
>
>>Kboy wrote:
>>
>>> On Mon, 06 Jan 2003 07:58:44 -0600, steve harris
>>> < steveharris1@REMOVECAPShotmail
.com> wrote:
>>>
>>>>Kboy wrote:
>>>>
>>>>> Can anyone answer a question for me? I know CSMA is the main
>>>>> contention method with Ethernet networks, but is it also used with
>>>>> TCP\IP over Ethernet networks or does TCP\IP use another method?
>>>>> TIA Kboy
>>>>
>>>>I would study the OSI 7 layer model again.
>>>>Especially the first three layers.
>>>>
>>>>Steve
>>>
>>> I understand that CSMA works on the datalink layer and IP is on the
>>> network layer, are you saying that CSMA is incorporated within the OSI
>>> protocols no matter the network used (ethernet, tcp\ip)? or am i
>>> completely off the track? :-)
>>> TIA Kboy
>>
>>IP is layer three and TCP is layer four.
>>
>>Ethernet (using CSMA) is layer two.
>>ATM is layer two.
>>Token Ring is layer two.
>>
>>IP and TCP is a higher level protocol using the Ethernet transport.
>>You can run IP and TCP over ATM or Token RIng.
>>
>>Your use of saying Ethernet and TCP/IP are two types of network is
>>invalid.
>>
>>Steve
>
> Ok i think i have finally twigged (probably not :-P )
> I gather i am confusing the higher level protocol(tcp\ip) with the
> underlying means of transport?
> and from that, I take it tcp\ip can be used over any of the underlying
> datalink protocols of the OSI model?
> I think its slightly clearer now, thanks for your help :-)
> Kboy
Yes!
I know I will make a mistake here somewhere, but I can't find a good link on
how a connection works using the OSI layer.
I think "encapsulation" may be a good word they use. As your application
needs to send data across a network, the data the application wants to send
is sent down through the OSI model from layer seven to layer one,
encapsulating the data with additional information need. I'll skip layers
seven to five as it varies based upon the application running.
As the data hits layer four, TCP added the connection oriented information
in a TCP header and the data becomes a segment.
As the segment hits layer three, IP adds an IP (address) header and becomes
a packet.
As the packet hits layer two, if you are running Ethernet, layer two adds
the Ethernet header (MAC address) and becomes a frame. If you look at the
frame, you will see all of the information there, including all of the
previous headers. Nothing is removed, just more is added. This is how good
firewalls work, you can have them look at particular points in the frame
and determine what to do with it, based upon layer two, three, four
information.
As the frame hits layer one, it is changed to the physical transport
necessary to communicate, whether wire, optics, or radio wave.
As the frame is received on the other end, the process is reversed. Layer
two looks at the frame and sees if it is for it (MAC address) or someone
else.
Steve
| |
|
| On Mon, 06 Jan 2003 10:35:39 -0600, steve harris
< steveharris1@REMOVECAPShotmail
.com> wrote:
>Kboy wrote:
>
>> On Mon, 06 Jan 2003 09:17:44 -0600, steve harris
>> < steveharris1@REMOVECAPShotmail
.com> wrote:
>>
>>>Kboy wrote:
>>>
>>>> On Mon, 06 Jan 2003 07:58:44 -0600, steve harris
>>>> < steveharris1@REMOVECAPShotmail
.com> wrote:
>>>>
>>>>>Kboy wrote:
>>>>>
>>>>>> Can anyone answer a question for me? I know CSMA is the main
>>>>>> contention method with Ethernet networks, but is it also used with
>>>>>> TCP\IP over Ethernet networks or does TCP\IP use another method?
>>>>>> TIA Kboy
>>>>>
>>>>>I would study the OSI 7 layer model again.
>>>>>Especially the first three layers.
>>>>>
>>>>>Steve
>>>>
>>>> I understand that CSMA works on the datalink layer and IP is on the
>>>> network layer, are you saying that CSMA is incorporated within the OSI
>>>> protocols no matter the network used (ethernet, tcp\ip)? or am i
>>>> completely off the track? :-)
>>>> TIA Kboy
>>>
>>>IP is layer three and TCP is layer four.
>>>
>>>Ethernet (using CSMA) is layer two.
>>>ATM is layer two.
>>>Token Ring is layer two.
>>>
>>>IP and TCP is a higher level protocol using the Ethernet transport.
>>>You can run IP and TCP over ATM or Token RIng.
>>>
>>>Your use of saying Ethernet and TCP/IP are two types of network is
>>>invalid.
>>>
>>>Steve
>>
>> Ok i think i have finally twigged (probably not :-P )
>> I gather i am confusing the higher level protocol(tcp\ip) with the
>> underlying means of transport?
>> and from that, I take it tcp\ip can be used over any of the underlying
>> datalink protocols of the OSI model?
>> I think its slightly clearer now, thanks for your help :-)
>> Kboy
>
>Yes!
>I know I will make a mistake here somewhere, but I can't find a good link on
>how a connection works using the OSI layer.
>
>I think "encapsulation" may be a good word they use. As your application
>needs to send data across a network, the data the application wants to send
>is sent down through the OSI model from layer seven to layer one,
>encapsulating the data with additional information need. I'll skip layers
>seven to five as it varies based upon the application running.
>
>As the data hits layer four, TCP added the connection oriented information
>in a TCP header and the data becomes a segment.
>
>As the segment hits layer three, IP adds an IP (address) header and becomes
>a packet.
>
>As the packet hits layer two, if you are running Ethernet, layer two adds
>the Ethernet header (MAC address) and becomes a frame. If you look at the
>frame, you will see all of the information there, including all of the
>previous headers. Nothing is removed, just more is added. This is how good
>firewalls work, you can have them look at particular points in the frame
>and determine what to do with it, based upon layer two, three, four
>information.
>
>As the frame hits layer one, it is changed to the physical transport
>necessary to communicate, whether wire, optics, or radio wave.
>
>As the frame is received on the other end, the process is reversed. Layer
>two looks at the frame and sees if it is for it (MAC address) or someone
>else.
>
>Steve
i'm aware of how the OSI model works, it was just something that
bothered me with the differing layer protocols, i had it in my mind
that if IP was used it kinda used that to route data on a network and
ignored the underlying MAC addresses, Its coming back to me now that
ARP is used to resolve the addresses now :-)
thanks Steve you've been a great help :-)
Kboy
| |
| steve harris 2003-01-06, 11:24 am |
| Kboy wrote:
> On Mon, 06 Jan 2003 10:35:39 -0600, steve harris
> < steveharris1@REMOVECAPShotmail
.com> wrote:
>
>>Kboy wrote:
>>
>>> On Mon, 06 Jan 2003 09:17:44 -0600, steve harris
>>> < steveharris1@REMOVECAPShotmail
.com> wrote:
>>>
>>>>Kboy wrote:
>>>>
>>>>> On Mon, 06 Jan 2003 07:58:44 -0600, steve harris
>>>>> < steveharris1@REMOVECAPShotmail
.com> wrote:
>>>>>
>>>>>>Kboy wrote:
>>>>>>
>>>>>>> Can anyone answer a question for me? I know CSMA is the main
>>>>>>> contention method with Ethernet networks, but is it also used with
>>>>>>> TCP\IP over Ethernet networks or does TCP\IP use another method?
>>>>>>> TIA Kboy
>>>>>>
>>>>>>I would study the OSI 7 layer model again.
>>>>>>Especially the first three layers.
>>>>>>
>>>>>>Steve
>>>>>
>>>>> I understand that CSMA works on the datalink layer and IP is on the
>>>>> network layer, are you saying that CSMA is incorporated within the OSI
>>>>> protocols no matter the network used (ethernet, tcp\ip)? or am i
>>>>> completely off the track? :-)
>>>>> TIA Kboy
>>>>
>>>>IP is layer three and TCP is layer four.
>>>>
>>>>Ethernet (using CSMA) is layer two.
>>>>ATM is layer two.
>>>>Token Ring is layer two.
>>>>
>>>>IP and TCP is a higher level protocol using the Ethernet transport.
>>>>You can run IP and TCP over ATM or Token RIng.
>>>>
>>>>Your use of saying Ethernet and TCP/IP are two types of network is
>>>>invalid.
>>>>
>>>>Steve
>>>
>>> Ok i think i have finally twigged (probably not :-P )
>>> I gather i am confusing the higher level protocol(tcp\ip) with the
>>> underlying means of transport?
>>> and from that, I take it tcp\ip can be used over any of the underlying
>>> datalink protocols of the OSI model?
>>> I think its slightly clearer now, thanks for your help :-)
>>> Kboy
>>
>>Yes!
>>I know I will make a mistake here somewhere, but I can't find a good link
>>on how a connection works using the OSI layer.
>>
>>I think "encapsulation" may be a good word they use. As your application
>>needs to send data across a network, the data the application wants to
>>send is sent down through the OSI model from layer seven to layer one,
>>encapsulating the data with additional information need. I'll skip layers
>>seven to five as it varies based upon the application running.
>>
>>As the data hits layer four, TCP added the connection oriented information
>>in a TCP header and the data becomes a segment.
>>
>>As the segment hits layer three, IP adds an IP (address) header and
>>becomes a packet.
>>
>>As the packet hits layer two, if you are running Ethernet, layer two adds
>>the Ethernet header (MAC address) and becomes a frame. If you look at the
>>frame, you will see all of the information there, including all of the
>>previous headers. Nothing is removed, just more is added. This is how good
>>firewalls work, you can have them look at particular points in the frame
>>and determine what to do with it, based upon layer two, three, four
>>information.
>>
>>As the frame hits layer one, it is changed to the physical transport
>>necessary to communicate, whether wire, optics, or radio wave.
>>
>>As the frame is received on the other end, the process is reversed. Layer
>>two looks at the frame and sees if it is for it (MAC address) or someone
>>else.
>>
>>Steve
>
> i'm aware of how the OSI model works, it was just something that
> bothered me with the differing layer protocols, i had it in my mind
> that if IP was used it kinda used that to route data on a network and
> ignored the underlying MAC addresses, Its coming back to me now that
> ARP is used to resolve the addresses now :-)
> thanks Steve you've been a great help :-)
> Kboy
Yes,
ARP was the piece of the puzzle that turned on my light bulb when I was lost
in the OSI model.
If you can, www.ethereal.com is a popular sniffer, free for individuals, to
use. It is available for just about any operating system. I use it on
Windows and Linux to watch the Ethernet frames.
Watching the ARP system on Ethernet resolve the IP addresses put everything
together for me. Don't forget the ARP cache which temporarily stores the
info, so you may not see a new ARP for each session.
Hands on is THE best way to learn IMO. Use Ethereal and look at an Ethernet
frame, and you can see the other layers of information buried in it.
Cheers!
Steve
| |
|
| On Mon, 06 Jan 2003 10:52:27 -0600, steve harris
< steveharris1@REMOVECAPShotmail
.com> wrote:
>Kboy wrote:
>
>> On Mon, 06 Jan 2003 10:35:39 -0600, steve harris
>> < steveharris1@REMOVECAPShotmail
.com> wrote:
>>
>>>Kboy wrote:
>>>
>>>> On Mon, 06 Jan 2003 09:17:44 -0600, steve harris
>>>> < steveharris1@REMOVECAPShotmail
.com> wrote:
>>>>
>>>>>Kboy wrote:
>>>>>
>>>>>> On Mon, 06 Jan 2003 07:58:44 -0600, steve harris
>>>>>> < steveharris1@REMOVECAPShotmail
.com> wrote:
>>>>>>
>>>>>>>Kboy wrote:
>>>>>>>
>>>>>>>> Can anyone answer a question for me? I know CSMA is the main
>>>>>>>> contention method with Ethernet networks, but is it also used with
>>>>>>>> TCP\IP over Ethernet networks or does TCP\IP use another method?
>>>>>>>> TIA Kboy
>>>>>>>
>>>>>>>I would study the OSI 7 layer model again.
>>>>>>>Especially the first three layers.
>>>>>>>
>>>>>>>Steve
>>>>>>
>>>>>> I understand that CSMA works on the datalink layer and IP is on the
>>>>>> network layer, are you saying that CSMA is incorporated within the OSI
>>>>>> protocols no matter the network used (ethernet, tcp\ip)? or am i
>>>>>> completely off the track? :-)
>>>>>> TIA Kboy
>>>>>
>>>>>IP is layer three and TCP is layer four.
>>>>>
>>>>>Ethernet (using CSMA) is layer two.
>>>>>ATM is layer two.
>>>>>Token Ring is layer two.
>>>>>
>>>>>IP and TCP is a higher level protocol using the Ethernet transport.
>>>>>You can run IP and TCP over ATM or Token RIng.
>>>>>
>>>>>Your use of saying Ethernet and TCP/IP are two types of network is
>>>>>invalid.
>>>>>
>>>>>Steve
>>>>
>>>> Ok i think i have finally twigged (probably not :-P )
>>>> I gather i am confusing the higher level protocol(tcp\ip) with the
>>>> underlying means of transport?
>>>> and from that, I take it tcp\ip can be used over any of the underlying
>>>> datalink protocols of the OSI model?
>>>> I think its slightly clearer now, thanks for your help :-)
>>>> Kboy
>>>
>>>Yes!
>>>I know I will make a mistake here somewhere, but I can't find a good link
>>>on how a connection works using the OSI layer.
>>>
>>>I think "encapsulation" may be a good word they use. As your application
>>>needs to send data across a network, the data the application wants to
>>>send is sent down through the OSI model from layer seven to layer one,
>>>encapsulating the data with additional information need. I'll skip layers
>>>seven to five as it varies based upon the application running.
>>>
>>>As the data hits layer four, TCP added the connection oriented information
>>>in a TCP header and the data becomes a segment.
>>>
>>>As the segment hits layer three, IP adds an IP (address) header and
>>>becomes a packet.
>>>
>>>As the packet hits layer two, if you are running Ethernet, layer two adds
>>>the Ethernet header (MAC address) and becomes a frame. If you look at the
>>>frame, you will see all of the information there, including all of the
>>>previous headers. Nothing is removed, just more is added. This is how good
>>>firewalls work, you can have them look at particular points in the frame
>>>and determine what to do with it, based upon layer two, three, four
>>>information.
>>>
>>>As the frame hits layer one, it is changed to the physical transport
>>>necessary to communicate, whether wire, optics, or radio wave.
>>>
>>>As the frame is received on the other end, the process is reversed. Layer
>>>two looks at the frame and sees if it is for it (MAC address) or someone
>>>else.
>>>
>>>Steve
>>
>> i'm aware of how the OSI model works, it was just something that
>> bothered me with the differing layer protocols, i had it in my mind
>> that if IP was used it kinda used that to route data on a network and
>> ignored the underlying MAC addresses, Its coming back to me now that
>> ARP is used to resolve the addresses now :-)
>> thanks Steve you've been a great help :-)
>> Kboy
>
>Yes,
>ARP was the piece of the puzzle that turned on my light bulb when I was lost
>in the OSI model.
>
>If you can, www.ethereal.com is a popular sniffer, free for individuals, to
>use. It is available for just about any operating system. I use it on
>Windows and Linux to watch the Ethernet frames.
>
>Watching the ARP system on Ethernet resolve the IP addresses put everything
>together for me. Don't forget the ARP cache which temporarily stores the
>info, so you may not see a new ARP for each session.
>
>Hands on is THE best way to learn IMO. Use Ethereal and look at an Ethernet
>frame, and you can see the other layers of information buried in it.
>
>Cheers!
>Steve
Once again, thanks, youve been a big help
Kboy
| |
| Charles M. Kozierok 2003-01-06, 12:24 pm |
| In article < lj6j1vo4r2f4fh6e45fbc63kd1sp3n
qmpj@4ax.com>,
Kboy <kboyuk@hotmail.com> wrote:
} On Mon, 06 Jan 2003 07:58:44 -0600, steve harris
} < steveharris1@REMOVECAPShotmail
.com> wrote:
}
} >Kboy wrote:
} >
} >> Can anyone answer a question for me? I know CSMA is the main
} >> contention method with Ethernet networks, but is it also used with
} >> TCP\IP over Ethernet networks or does TCP\IP use another method?
} >> TIA Kboy
} >
} >I would study the OSI 7 layer model again.
} >Especially the first three layers.
} >
} >Steve
}
} I understand that CSMA works on the datalink layer and IP is on the
} network layer, are you saying that CSMA is incorporated within the OSI
} protocols no matter the network used (ethernet, tcp\ip)? or am i
} completely off the track? :-)
To add to what others are saying... contention is an activity that is
inherently associated only with layer two. No contention occurs in IP or
TCP, at least not the way it does in Ethernet.
Oh, and a couple of other things. The correct term is the media access
control (MAC) mechanism, of which contention is a part (the terms are
sometimes used interchangeably but this is arguably incorrect.) Also,
the MAC method for Ethernet is more accurately CSMA/CD, where the last
two letters stand for collision detection. There are other flavors of
CSMA used by other layer two technologies that are different.
peace,
-*-
charles
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