Topologies

Module Code: ELEE1157

Module Name: Network Routing Management

Lecturer: Seb Blair BEng(H) PGCAP MIET MIHEEM FHEA

Contents​

  1. Intended Learning Outcomes​

  2. Last Time​

  3. What is Network Topology​

  4. Logical & Physical Network Topologies​

  5. Types of Network Topologies​

  6. Bus, Ring, Star, Tree, Mesh and Hybrid​

ELEE1157 | Network Routing Management

Intended Learning Outcomes

  1. Define what is meant by Network Typology​

  2. Define the difference between Logical and Physical network typologies​

  3. Recall 5 network typologies and identify each typology​

ELEE1157 | Network Routing Management

Last Time

  • Computer networking refers to connected computing devices (such as laptops, desktops, servers, smartphones, and tablets) and an ever-expanding array of IoT devices (such as cameras, door locks, doorbells, refrigerators, audio/visual systems, thermostats, and various sensors) that communicate with one another.​

  • Specialised Devices – switches (AP), routers​

  • Types of Area Networks -> BAN, CAN, LAN, WAN…

ELEE1157 | Network Routing Management

What is Network Topology​

  • Network topology is the description of the arrangement of nodes (e.g. networking switches and routers) and connections in a network. ​

  • Network topologies outline how devices are connected together and how data is transmitted from one node to another.​

  • The configuration, or topology, of a network is key to determining its performance. Network topology is the way a network is arranged, including the physical or logical description of how links and nodes are set up to relate to each other.​

ELEE1157 | Network Routing Management

Logical Network Topology​

  • Logical network topology is a higher-level idea of how the network is set up, including which nodes connect to each other and in which ways, as well as how data is transmitted through the network.

  • Logical network topology includes any virtual and cloud resources.

  • A logical network topology is a conceptual representation of how devices operate at particular layers of abstraction.

ELEE1157 | Network Routing Management

Physical Network Topology

  • The physical network topology refers to the actual connections (wires, cables, etc.) of how the network is arranged.

  • Setup, maintenance, and provisioning tasks require insight into the physical network.

  • A physical topology details how devices are physically connected

ELEE1157 | Network Routing Management

Types of Network Topology

  • Building a local area network (LAN) topology can be make-or-break for your business, as you want to set up a resilient, secure, and easy-to-maintain topology.

  • A network topology map is a map that allows an administrator to see the physical network layout of connected devices

  • There are many different types of basic network topologies that networks are built on today and in the past:

    • Bus

    • Ring

    • Star

    • Tree

    • Mesh

    • Hybrid

ELEE1157 | Network Routing Management

Bus Topology

Bus topology is a network type where every device is connected to a single cable that runs from one end of the network to the other. This type of network topology is often referred to as line topology.

Advantages

  • Simple layout, single cable, cost effective

Disadvantages

  • Single point of failure, cost lot of time to fix as whole cable needs replacing, high network traffic would decrease network performance.

Half-duplex -> data can only be transmitted one way at a time

ELEE1157 | Network Routing Management

Ring Topology

In networks with ring topology, computers are connected to each other in a circular format. Every device in the network will have two neighbours and no more or no less. Was used more often in the past than present day.

Advantages

  • the risk of packet collisions is very low due to the use of token-based protocols, which only allow one station to transmit data at a given time, data can move through network nodes at high speeds

Disadvantages

  • failure of one node can take the entire network out of operation, raised scalability concerns (more devices longer to transmit)

half-duplex but can also be made full-duplex (Dual Ring Topology)

ELEE1157 | Network Routing Management

Star Topology

A star topology is a topology where every node in the network is connected to one central switch. The relationship between these elements is that the central network hub is a server and other devices are treated as clients

The devices are usually configured in primary-secondary relationship.

Advantages

  • can manage the entire network from one location, can add new computers without having to take the network offline, simple to set up and manage

Disadvantages

  • if the central switch goes down then the entire network will go down, performance of the network is also tied to the central node’s configurations and performance

ELEE1157 | Network Routing Management

Tree Topology

A tree topology network is a structure that is shaped like a tree with its many branches, they have a root node that is connected to another node hierarchy, parent-child. Tree topology needs to have three levels to the hierarchy to be classified this way, and this form is used withing WANs.

The devices are usually configured in primary-secondary relationship.

Advantages

  • used is to extend bus and star topologies, room for growth, systematically search for issues throughout each branch of the tree.

Disadvantages

  • If the root node fails then all of its subtrees become partitioned, he more nodes you add, the more difficult it becomes to manage, more cables, more complex

ELEE1157 | Network Routing Management

Mesh Topology

A mesh topology is a point-to-point connection where nodes are interconnected. In this form of topology, data is transmitted via two methods: routing and flooding.

Routing is the shortest path, and flooding is data is sent to everyone, ergo no routing logic.

Partial Mesh, most nodes are interconnected but there are a few that may have extra two or three connected nodes.

Full Mesh, every node is connected to every node

Links required per node & Links for fully connected network

Advantages

  • Extremely resistant to failure due to the amount of possible paths, no single point of failure

Disadvantages

  • Requires an immense amount of time to configure, lots of wiring, costly

ELEE1157 | Network Routing Management

Hybrid topology

Composed of two or more different topologies and are most-commonly encountered in larger enterprises. A mixed bag of capabilities and vulnerabilities.

Advantages

  • Flexible, incorporate multiple typologies, very scalable

Disadvantages

  • Complex, each sub typology is managed independently of the whole, can be costly to set up, tough job to manage

ELEE1157 | Network Routing Management