Confused - questions on CSMA/CD and Gb Ethernet

Glynixx

Hi Folks,

Wondering if someone could help me clear up some confusion that is a direct result of having too many teachers! lol.

In reading Odom/ Bryant and then Lammle; I have some questions:

1. Bryant states that Gigabit Ethernet will NOT run over copper (I think Odom does too but don't quote me). Umm. I know this is not the case since I have it running. Could he be just concentrating on the 802.3ab and z standards? Am I missing something?

2. Jamming because of a collison:
Lammle states that after a collision ALL hosts run the backoff algorithm whereas Bryant and Odom state that only the 2 hosts involved in the collision do this.

huh?

3. Any idea which is right when it comes to the DoD / TCP/IP model?
Is the TCP/IP layer 2 called the host-to-host layer (Lammle) or is it called the Transport layer (Odom / Bryant).


Sorry for my confusion but this is basic stuff in the grand scheme and when I'm getting multiple different answers I really start to worry about what the opinions are going to be when we get to access lists (and where to place them), some advanced routing protocols, etc.

Thanks in advance.
G.

APA

1) 802.3z is the GigabitEthernet specification of which they later announced 802.3ab which allows GigE to run over copper....... (Was originally only Cat6 but then can now run over Cat5e using all four pairs in the cable)

2)From my understanding only the two hosts involved in the collision will run the backoff algorithm..... as they are the ones that detected the collison (Carrier Sense Multiple Access\ Collision Detection)

3) I have always seen layer 2 in the DoD model called the 'Internet Layer' it maps to Network Layer of the OSI model......... Layer 3 in the DoD model is the Tranport Layer.....

1 - Network Interface Layer (Maps to L1 & L2 of OSI Model)
2 - Internet Layer (Maps to L3 of OSI Model)
3 - Transport Layer (Maps to L4 of OSI Model)
4 - Application Layer (Maps to L5,L6 & L7 of OSI Model)

Hope this Helps