There are many different types of network devices. The solution can be anything from a straightforward unmanaged switch to a dial-up modem or a UTM (unified threat management) appliance. Additionally, because a single device frequently serves many purposes, it can be difficult to draw clear distinctions between the various networking device categories.
Here, we take on the idea of network devices from scratch to help you sort through that fuzziness. We’ll begin with a definition, go over our list of network devices, and then talk about some of the crucial factors to bear in mind when managing network devices.
How do network devices work?
Building blocks known as network devices enable communication between services and the endpoints that use those services. In other terms, they are connectors that allow networked device communication.
Anything that aids in data transmission between two devices on a local area network (LAN) is considered to be a communication enabler.
Stopping communication from happening is limiting communication. A firewall rule that blocks traffic from TCP port 23 or a VLAN that divides broadcast domains are two examples of this.
You’ll notice that “hardware” isn’t included in our definition of network devices. This is as a result of the large number of virtualized or software-based network appliances and functions. You could, for instance, set up a virtual appliance that serves as a firewall, network switch, or router.
A crash course in OSI models and data kinds
Knowing a little bit about the layers of the OSI (Open Systems Interconnection) model is one of the best ways to comprehend the function of various network devices. The OSI model offers a conceptual framework for understanding how data moves across and within networks call-tracking.org .
These two features of the OSI model will aid in comprehending how various network devices operate:
- The OSI model consists of seven layers, with the physical layer (Layer 1) being the bottom layer and the application layer being the top layer (Layer 7). Network hardware is frequently described in terms of the OSI layer it operates at.
- The protocol data unit (PDU): Headers and footers are removed as data is processed at various layers of the OSI model, changing the type of PDU that is transmitted. For instance, the IP header is not required when data transmitted at the network layer (Layer 3) is processed at the transport layer (Layer 4). At Layer 3, the PDU with the IP header was a packet. Without the IP header, the PDU at Layer 4 is a segment. You can better understand the language used to describe various networking devices by being familiar with the different PDUs.
11 various types of network devices
1. Firewall
Depending on a set of rules, a firewall is a network security device that monitors traffic and either blocks or permits it. Software, hardware, or a hybrid of the two can be used to create firewalls. Additionally, firewall rules can be based on simple criteria like ports and IP addresses or they can apply heuristics to spot malicious activity.
Network firewalls frequently come as instances in:
· Firewalls that filter traffic using packets: These firewalls work at Layer 3 and Layer 4 and use rules based on IP addresses, port numbers, and packet types to decide whether to discard or forward traffic. This straightforward method of traffic inspection has the advantage of having little effect on network speed.
· Stateful-inspection firewalls can track and “understand” when a TCP connection has occurred, in contrast to packet-filtering firewalls. As a result, reply traffic can get past the firewall without specific rules being required. Stateful-inspection firewalls are hence simpler to configure than packet-filtering firewalls, but they may add a little more overhead during inspection and slow down traffic a little more.
· Application firewalls: These Layer 7 firewalls can distinguish between legitimate and malicious behavior for protocols at the application layer, such as HTTPS, SSH, and SMTP. Application firewalls come in two main varieties: proxy firewalls that offer URL filtering and WAFs (web application firewalls), which defend against XSS and SQL injection attacks.
· Appliances for unified threat management (UTM) and next-generation firewalls (NGFWs): The debates about whether UTMs and NGFWs are the same thing or not will be saved for another time. These two widely used kinds of firewalls generally have a lot in common. These more sophisticated network security tools not only offer the functionality of the other kinds of firewalls we’ve covered, but they also include cutting-edge capabilities like deep packet inspection (DPI), heuristics that can detect malware, and examination of encrypted traffic.
2. Switch
A network switch is typically described as a Layer 2 device that transmits and receives frames. The fundamental component of Ethernet networks are switches.
Here is a simple illustration of how a Layer 2 switch operates:
· A mini LAN is created when devices are connected to the switch using Ethernet cables (like a Cat5e or Cat6 cable).
· The linked devices’ MAC addresses are acquired by the switch.
· The switch detects the MAC address in the packet and transmits the traffic only to that device when it has to reach a certain device.
Comparing the switch to network hubs, the switch breaks up collision domains by directing the data to a specified device, significantly lowering network congestion. The primary advantage of a Layer 2 switch is the splitting up of collision domains.
But this straightforward illustration of a Layer 2 switch is only one of the various kinds of network switches. The following is a list of typical network switch types:
· Unmanaged switches merely offer Layer 2 switching for Ethernet frames. No more administrative or configuration features are provided by them. Switches with Power over Ethernet (PoE) functionality are able to connect to the network and power connected devices. PoE switches are frequently used to power Voice over IP (VoIP) phones, for instance. PoE switches come in controlled and unmanaged varieties and can be Layer 2 or Layer 3 switches.
· Switches that are managed: The characteristics and functionalities of managed switches vary widely. As an illustration, some managed switches are designed for gamers to use at home, while others are designed for large businesses to use on corporate networks. The ability to generate VLANs is one of the most crucial features of a controlled switch (virtual LANs). QoS (quality of service), which prioritizes particular types of traffic, and Spanning Tree Protocol (STP), which prevents network loops, are further characteristics of managed switches that are widely used. Layer 2 or Layer 3 switches are both examples of managed switches.
· Layer 3 switches: These switches also provide Layer 2 functionality, but they also include Layer 3 routing. Layer 3 switches are capable of packet routing between networks and are IP address aware.
· Switches that can be “stacked” include some network switches. To function as a single logical switch, these stackable switches can be joined to one another. A good technique to expand a network’s capacity is by stacking switches. For instance, from the administrative and functionality standpoint, stacking two 24-port switches would result in a single 48-port switch.
3. Entry point
Access points (APs), commonly referred to as wireless access points (WAPs), are the network switches of the wireless world that operate at Layer 2. WAPs enable communication between other Wi-Fi devices by connecting to a LAN via a wired link. WLANs are the networks that WAPs create (wireless local area networks).
There are three basic categories of APs, broadly speaking:
· Fat access points are often referred to as autonomous access points (APs). Traffic from fat APs’ Wi-Fi radios is forwarded straight to the wired network. Access control lists, Wi-Fi encryption, DHCP server capability, and QoS are all easily accessible through the interfaces of these WAPs. The advantage of fat APs is that everything you need to configure and manage the device is already built into them, making them an all-in-one solution.
· Thin APs: These APs don’t provide all of an autonomous AP’s features. Instead, they route Wi-Fi traffic through a centralized WLAN controller, which takes care of all the forwarding and functionalities a fat AP would normally handle on its own. Large-scale deployments may be simpler to manage thanks to this centralized approach to WAP management, despite some trade-offs associated with thin APs’ constrained functionality.
· Fit APs: These WAPs combine the functions of thin and fat APs. While a centralized controller will be used for tasks like bridging traffic forwarding between wired and wireless networks, most fat APs will handle Wi-Fi encryption at the AP level rather than waiting until the traffic gets back to the controller and may offer services like DHCP relay.
4.Router
The network hardware that routes packets between networks is known as a router. The internet connection that enables you to read this article as well as communication between several subnets connected to the same WAN are both made possible by Layer 3 devices. This is a helpful way to think of routers: They are the IP address-related network equipment.
5. NAS (Network attached storage)
The server used for file storage is known as a NAS. A NAS offers a central storage location within a LAN that can be utilized for things like shared file access and user data backup storage. In general, NAS devices offer an easy and economical approach to deliver network storage. The distinction between a NAS device and a general-purpose server has become increasingly hazy in recent years as NASes offer more sophisticated functionality appropriate for small and mid-sized workplaces.
6. Load balancing device
Client connections are distributed among various servers via load balancers. There are several software and hardware implementations of load balancers, just like there are for firewalls. The majority of the time, load balancers work at Layer 4 (filtering based on TCP or UDP traffic) or Layer 7. (filtering based on HTTP or DNS traffic).
The following are typical methods for load balancing:
· Requests are simply forwarded to all servers in a round-robin fashion.
· Round-robin is used in weighted round-robin, which uses “weights” to help determine how many connections to send to each server.
· Least connections: A load balancing technique that gives priority to forwarding connections to the server that has the fewest connections.
· Weighted least connections: Similar to weighted round-robin, this method enables the servers to be given “weights” that affect the load balancing process.
7. Reiterator
An easy Layer 1 device that rebroadcasts a signal is called a repeater. Signal boosters and repeaters are both technical terms. Wi-Fi, Ethernet, and other network connections all have repeaters, but they all essentially accomplish the same thing: receive a signal and send it again.
Simple Wi-Fi repeaters can cause a lot of network congestion, so use caution. A WAP is frequently a preferable option if you want to maximize performance.
8. Modem
A modem is a device that modulates and demodulates a signal to and from analog and digital, according to the conventional definition. When the internet was dial-up, modems were used to link local computer networks to analog telephone lines so that users could access the internet. The term “modem” today can refer to a wide range of gadgets that let you connect to a carrier’s network.
Popular models of modems include, for instance:
· digital modems;
· modems for cable;
· mobile modems;
· modems that use fiber;
· an xDSL modem;
9.Gateway
There is no distinction between a gateway and a router in terms of hardware. Simply put, gateways are routers with a specialized function. Routers that serve as the default next hop are known as gateways. Packets are routed to the default gateway of a network when there is no other method to reach an IP address on that network. The packets are then forwarded by the default gateway to their subsequent “hop,” and the cycle continues until the destination is reached.
10. Hub
A hub is a basic Ethernet repeater that works at Layer 1 and allows several devices to be connected to the same Ethernet network. Because a hub, unlike a switch, does not divide collision domains, all ports on a network hub get the same traffic. As a result, hubs, which function similarly to WiFi repeaters, can be highly congested.
Pro tip: Hubs can cause severe network congestion by rebroadcasting data to all ports. If you have a use case for a hub, take into account an unmanaged switch instead, which will split collision domains.
11.Bridge
Network bridges were typically Layer 2 hardware with just two ports. When compared to hubs, they could minimize network congestion by dividing the network into several collision domains, breaking up collision domains like switches do.
However, depending on the context, the term “bridge” today can indicate a lot more than that classic connotation. The word “network bridge” can also mean:
· a tool for Layer 2 VLAN connectivity;
· an online switch;
· a device that can join two networks together using various connection types, for as by joining a cable LAN and a WLAN.