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Computer Network 2021
into two links) and the backbone tree (a backbone trunk has branch nodes with links hanging
from it). https://www.youtube.com/watch?v=ZmLxb8HzQX4&t=60s
2.10.1.5 Full-Mesh and Partial-Mesh Topologies
The full-mesh topology connects all devices (nodes) to each other for redundancy and
fault tolerance. The wiring in a full-mesh topology has very distinct advantages and
disadvantages. The advantage is that every node is connected physically to every other node,
which creates a redundant connection. If any link fails, information can flow through many other
links to reach its destination. The primary disadvantage is that for anything more than a small
number of nodes, the amount of media for the links and the number of the connections on the
lines becomes overwhelming. Implementing a full-mesh topology is expensive and difficult.
The full-mesh topology is usually implemented in WANs between routers.
In a partial-mesh topology, at least one device maintains multiple connections to others
without being fully meshed, as shown in Figure below. A partial-mesh topology still provides
redundancy by having several alternative routes. If one route cannot be used, the data takes
another route, even if it is longer. The partial-mesh topology is used for many
telecommunications backbones, as well as the Internet.
https://www.youtube.com/watch?v=8UZlwhiWKmA
2.10.2 Logical Topology
A network’s logical topology is how the hosts communicate across the medium.
The two most common types of logical topology are broadcast and token passing, as
shown in Figure 2-26.
Figure 2-26 shown a Logical Topology of Network Devices
Broadcast topology simply means that each host addresses its data to a particular NIC,
to a multicast address, or to a broadcast address on the network medium. There is no order that
the stations must follow to use the network. It is first come, first serve. Ethernet also works this
way, as explained later in this course. The second logical topology is token passing. Token passing
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