TCP/IP & OSI:
In OSI reference model
terminology -the TCP/IP protocol suite covers the network and transport layers.
TCP/IP can be used on many
data-link layers (can support many network hardware implementations).
Ethernet - A Real Data-Link Layer
Supported by a variety of
physical layer implementations.
It will be useful to discuss a
real data-link layer.
Ethernet (really IEEE 802.3) is
widely used.
Multi-access (shared medium).
Every Ethernet interface has a
unique 48 bit address (a.k.a. hardware address).
Example: C0:B3:44:17:21:17
The broadcast address is all 1’s.
Addresses are assigned to vendors
by a central authority
CSMA/CD
Carrier Sense Multiple Access
with
Collision Detection
Carrier Sense Multiple Access
with
Collision Detection
Carrier Sense: can tell
when another host is transmitting
Multiple Access: many
hosts on 1 wire
Collision Detection: can
tell when another host transmits at the same time.
An Ethernet Frame
