similar to this: 00:60:08:8F:5A:D9. The hardware address is used by DHCP
(see the section “Dynamic Host Configuration Protocol,” later in this chapter)
to identify a specific host. In addition, Address Resolution Protocol (ARP) and
Reverse Address Resolution Protocol (RARP) use MAC addresses to map
hosts to IP addresses.
This section covers some of the different types of NICs used to connect to a
network, including several that have long been obsolete but that you may still
find in use in older systems.
Token Ring
Token Ring networking was developed by IBM. As the name implies, the
network is set up in a ring. A single “token” is passed from host to host,
indicating the receiving host’s permission to transmit data.
Token Ring has a maximum transfer rate of 16Mbps (16 million bits per
second). Unlike 10BASE-2 and 10BASE-5, Token Ring uses what is called
unshielded twisted pair (UTP) cable. This cable looks a lot like the cable that
connects your phone to the wall. Almost all Token Ring NICs are recognized
by Linux.
10BASE-T
10BASE-T was the standard for a long time. A large number of networks still
use it. Like Token Ring, 10BASE-T also uses UTP cable. Instead of being
configured in a ring, 10BASE-T mostly uses a star architecture. In this
architecture, the hosts all connect to a central location (usually a hub, which
you learn about later in this chapter, in the “Hubs and Switches” section). All
the data is sent to all hosts, but only the destination host takes action on
individual packets. 10BASE-T has a transfer rate of 10Mbps.
10BASE-T has a maximum segment length of 100 meters (about 325 feet).
There are many manufacturers of 10BASE-T NICs, and most are recognized
by Ubuntu.
100BASE-T
100BASE-T was popular around the turn of the millennium, offering the same
ease of administration as 10BASE-T while increasing the speed by a factor of
- For most networks, the step from 10BASE-T to 100BASE-T is as simple
as replacing NICs and hubs. Most 100BASE-T NICs and hubs can also
handle 10BASE-T and can automatically detect which is in use. This allows