Understanding the network.pdf - Back to Home

A broadband MAU operates in many respects like a modem. The MAU is responsible
for modulating the digital signals sent through the AUI interface and demodulating
the analog signals before transmitting them across the AUI. Its similarity with a
modem comes from how it handles collision detection, data transmission, and
reception. When a station transmits data, it receives a copy of the transmitted data
like all the other stations on the medium; this is also the case with modem operation.
This process is used for collision detection. When a packet is transmitted, a copy is
saved by the MAU. The saved copy and the returned copy are then compared. If no
errors are found, it is assumed that no collision occurred.
Today, many of the available NICs integrate the AUI and MAU into the interface card,
or provide the choice between using the integrated AUI/MAU or the traditional AUI.
The integration of the AUI/MAU has provided greater cost savings and reduced
possible points of failure. Now let's look at the different 10Mbps 802.3 PHY
implementations. The 10Mbps MAC and PHY model is illustrated in Figure 4.9.
Figure 4.9. 10Mbps Ethernet, data link (MAC), and
NOTE
physical (PHY) layer interfaces.
As mentioned earlier, the terms "base" and "broad" describe the PHY transmission
signaling used. The full IEEE naming convention includes the transmission speed,
which will be 10, 100, or 1,000. The transmission signaling for almost every case
will be base, for baseband. The name will end with either the maximum allowable