Network topology is the anatomy, arrangement, or layout of telecommunication devices. These devices are represented as nodes, and the topology highlights the relationships between the nodes. Nodes are classed as hardware equipment on your network including both static and mobile devices, switches, and routers.
Network topology is important because it helps to track a telecommunication network’s density and evaluate its functionality. The size and shape of the workstation impacts how the network devices are organized, affecting the network’s performance. A network’s topology can make it easier to organize devices in order to reduce or avoid complexity.
When a network malfunctions, the IT team must troubleshoot and fix the problem promptly. Time is of the essence since the issue usually worsens as the clock ticks, affecting productivity, profit, and customer satisfaction. To rectify this time-sensitive problem, a topology mapper helps by making it easier to identify issues quickly, pinpoint the device generating the malfunction, and identify that device’s location.
This article explains network topology and its categories and types, before turning to network topology mapping, its importance, and various mapping techniques.
Categories of Network Topology
Network topology can be divided into two categories: physical topology and logical topology.
Physical topology is the spatial configuration of devices in a network, including cables, device location, and their arrangement over the workstation.
Logical topology, also called signal topology, refers to communication between network devices or media, specifically, how data is transferred within the physical topology. This geometry represents how data transmits through the network, analyzing information including line speeds, wavelengths, and signaling.
Types of Network Topology
An organization’s choice of topology depends on numerous factors including cable length and type, future expansion, security, cost, bandwidth capacity, and data flow efficiency. This section offers a review of network topology types, their characteristics, and their suitability to different use cases.
Figure 1: Types of network topology (Source: Snabay Networking)
Bus Topology
In a bus topology, the computers are all connected to one single cable. Only the addressee accepts and processes the message when one computer sends a signal using the cable. Other computers on the network acknowledge the message, but disregard it.
Bus topology is often used when a network installation is temporary or small in scale. Unidirectional data flow in bus topology makes problem identification tricky, and heavy network traffic slows it down. While the failure of one node does not affect the network, failure of the bus system as a whole will cause the entire network to crash.
A linear bus topology has two endpoints, and a distributed bus topology has more than two endpoints.
Ring Topology
Each computer is connected to the next computer in a circular arrangement; the last connects to the first in order to form a closed loop. Each device serves as a repeater that strengthens the signal received from the previous device.
In a ring topology, messages flow in one direction only, using tokens to pass information from one computer to another. The token is a small packet that is modified with the intended message and the addressee’s details. The token helps each device identify for whom the message is intended. When a piece of information is not intended for a particular computer, the token sends it to the next computer and so on, until it reaches the addressee.
Due to its circular arrangement, ring topology is more complex to troubleshoot than some other topologies, such as the bus topology. Unlike the bus topology, in a ring topology the failure of one computer can affect the entire network, and adding or deleting a device disturbs the network’s performance. In addition, since information has to pass from one computer to another, the network is slower.
Star Topology
In a star topology, each device is linked to a central controller through its dedicated point-to-point cable. The devices communicate with a central controller that resends the message to the appropriate addressee(s).
This central controller—also called the hub, host, or server—can be active or passive. While an active hub regenerates a signal and sends it to all the computers connected, a passive hub does not regenerate the signal but merely acts as a connection point.
Star topology is easily modified by adding or deleting computers or nodes, and this process does not affect the overall network performance. Hence, a hub with larger ports can be easily installed. However, the failure of the central hub affects the whole network. The central hub can be installed with coaxial cable, optical fiber, or twisted pairs.
Mesh Topology
The mesh topology is a robust, fully connected topology used in a WAN, or wide area network. Every device has a dedicated point-to-point link to all other devices, with the result that each computer must have input/output ports. This dedicated P2P link system eases fault identification and isolation, and prevents traffic between computers.
In a mesh topology, data is transmitted through routing and flooding. Routing uses the shortest path between source and destination to transmit data, while flooding sends data from the source to all the network nodes, but only the addressee accepts the data.
Mesh topology can be divided into two subtypes: full mesh and partial mesh. Each device in the workstation is directly connected to the others in the full mesh architecture. On the other hand, in the partial mesh architecture some devices are connected to the nodes with whom they exchange the most data, while others are connected to all nodes. Due to the quantity of required input/output ports and cabling, mesh topology is expensive.
Tree Topology
A bus system connects numerous star topologies in a tree-branch configuration to form the tree topology. A single “hub” node at the top of the network is connected to several lower-level nodes via point-to-point links. Additionally, these lower-level nodes are linked to one or more nodes (downlines) in the following level. The “branching factor” of the tree is the fixed number of nodes connected downline.
Hybrid Topology
Hybrid topology occurs when two or more types of topologies are connected. In a single establishment, one department of an establishment might be using a ring topology, while another department opted for a bus topology. These two networks can connect to a star topology’s central hub. However, the architecture of the resulting arrangement does not exhibit any standard network topologies. Hybrid topology’s robust architecture often makes it costly, since it requires extensive infrastructure, cooling, and cabling.
Point-to-Point Topology
Also referred to as P2P, point-to-point is the most basic network topology and consists of a direct connection between two computers and peripheral devices. The communication medium is monopolized in this topology since it is not shared, and there is no need for a device identification mechanism.
Figure 2: Point-to-point topology (Source: Allaboutcircuits.com)
Daisy Topology
A daisy topology can come in linear or ring forms. Like in a ring topology, when a computer sends a message, each computer bounces the message in the chain until it reaches its destination. However, whereas the ring topology closes up through a circle of connections (see Figure 1,) a daisy topology has an endpoint that makes it easy to add new devices and nodes to the network (see Figure 3.) This topology is also known as chain topology because it connects the network devices in a sequence.
Figure 3: Daisy topology (Source: Conceptdraw.com)
What Is Network Topology Mapping?
Network topology mapping analyzes and discovers all elements or nodes linked to a network in order to ensure ease of data flow. Mapping visualizes the physical and logical topologies in a graphical plot, thus simplifying the monitoring of performance and locating faults. It helps to break topologies into smaller, trackable portions, aiding in their navigation which may otherwise be different to understand, due to cabling complexities. Automated mapping solutions provide timely and itch-free detection of network issues, especially in a substantial and/or cross-continental settings.
A network topology map contains network diagrams, flowcharts, device inventories, the network’s weak and strong points, and a wealth of additional information about the devices in the network. The mapping system scans the network bandwidth and latency, interprets the information gathered, and creates alerts where necessary.
Why Perform Network Topology Mapping?
Network mapping provides administrators with crucial performance insights, such as device status, physical connections, and traffic metrics, so that administrators can fix issues faster, thus maximizing uptime. With mapping, a potentially devastating issue can be managed before problems occur. For example, if there is a security breach on any of the devices in the network, mapping solutions will indicate a change in the traffic and data flow, signaling to the administrator that there is an issue before that issue is encountered by any network user.
Prompt responses to network and device faults are essential to the growth of any telecommunications organization, and quick detection of these faults and their root cause is the crux of network topology mapping. Network topology mapping, therefore, improves disaster planning and enhances network control and protection.
Network Topology Mapping Techniques
As opposed to manual mapping, using sophisticated, automated techniques enables efficiency in the mapping process. Automated mapping tools scan an organization’s workstation and display its devices on a map, visualizing interactive elements in the network via, for example, color changes, blinking LEDs, and thickness or lightness of traffic flow lines. These techniques help to provide information about the network and its faults, and offer actionable intelligence on issues such as optimized alternative network configurations. Three fundamental network topology mapping techniques exist: SNMP, active probing, and route analytics software.
SNMP
SNMP is an acronym for Simple Network Management Protocol. It is an Internet Standard mapping technique that scans network devices automatically and exposes technical data as variables on the managed systems. In order to describe the system status and configuration, these variables are then organized in a management information base (MIB.)
The SNMP application layer (OSI Layer 7) can also access and change the system variables on the network devices. Furthermore, SNMP gathers the information discovered, including the number of active ports and temperature value, and uses them to create objects in the network map. There are three versions of SNMP (SNMPv1, SNMPv2, and SNMPv3,) with SNMPv2 being the most frequently deployed protocol version.
Active Probing
Active Probing is a technique that diagnoses networks by sending probe packets into the network to gather information. It then uses the data retrieved from the system’s logical topology architecture (called the traceroute-like methods) or its IP to create a network map. Active probing relies on the data plane of the network and its router adjacencies to map its topology. One advantage of active probing is its exactitude, because the paths returned by probes are the forwarding path that data takes through the network.
Route Analytics Software
Route analytics software is an automated mapping technique that explores the topology of a network using Layer 2 and Layer 3 information to map and discover devices connected to the system. For clarity, Layer 2 is the data link packet of a network system, while Layer 3 gathers the IP addresses of the network infrastructures.
While SNMP observes only the system interfaces and links, route analytics software explores the network further by providing complete routing history, traffic monitoring, end-to-end statistics, and detailed performance diagnostics.
Faddom Network Topology Mapping
Network topology mapping facilitates the easy and quick discovery of devices in a network, and illustrates how data travels in the network. An effective topology mapping technique enables the timely identification of network issues, thus helping telecommunication organizations to manage their networks and business effectively.
Faddom is an automatic network topology mapping software that helps to map your cloud and on-premises networks, regardless of their associated topology type, in as little as one hour. This gives you the visibility needed to manage your network environments effectively and efficiently. Start a free trial at the right today!
