A network switch is a small hardware device that joins multiple computers together within one local area network (LAN). Ethernet switch devices were commonly used on home networks before home routers became popular; broadband routers integrate Ethernet switches directly into the unit as one of their many functions. High-performance network switches are still widely used in corporate networks and data centers. Advantages Switches have increased available network bandwidth. There is reduced workload on individual computers. Increased network performance. There are fewer packet collisions. And some disadvantages are: They are significantly more expensive. Network problems can be difficult to trace through a switch.
Broadcast traffic. Below is a diagram showing how switchg/hub are interconnected in a network

A hub is a device for connecting machines into a network. It is a non-intelligent connection but tends to be very cheap. It allows all machines to send packets to every machine connected and wait for the required machine to reply. This causes delays as all the ports are used for every transmission. A network switch is the more recent method. This has intelligence and remembers which machines are connected to each port, so it passes any transmission straight to the correct port. This reduces collisions on the network when it is busy and is therefore much faster. It is more expensive, although nowadays there is very little difference in price.
A repeater connects two segments of your network cable. It retimes and regenerates the signals to proper amplitudes and sends them to the other segments. When talking about, Ethernet topology, you are probably talking about using a hub as a repeater. Repeaters require a small amount of time to regenerate the signal. This can cause a propagation delay, which can affect network communication when there are several repeaters in a row. Many network architectures limit the number of repeaters that can be used in a row. Repeaters work only at the physical layer of the OSI network model. Some advantages of repeater are :simple to connet ,cost effective, ability to strengthen signal. And its disadvantage are : Repeaters provide no method for isolating traffic generated on one cable segment from traffic generated by the other cable segment, Repeaters provide no method for isolating traffic generated on one cable segment from traffic generated by the other cable segment, When network uses a repeater to connect cable segment A to segment B whether or not there is a station in segment B that is the destination of the signal.

A bridge device filters data traffic at a network boundary. Bridges reduce the amount of traffic on a LAN by dividing it into two segments.
Bridges operate at the data link layer (Layer 2) of the OSI model. Bridges inspect incoming traffic and decide whether to forward or discard it. An Ethernet bridge, for example, inspects each incoming Ethernet frame - including the source and destination MAC addresses, and sometimes the frame size - in making individual forwarding decisions.
Bridges serve a similar function as switches that also operate at Layer 2. Traditional bridges, though, support one network boundary, whereas switches usually offer four or more hardware ports. Switches are sometimes called "multi-port bridges" for this reason. A bridge is a device to join two network segments. The advantage is it's cheap, easy, doesn't require routing to work. The disadvantages are it doesn't support routing (so both networks form one large broadcast domain and see each others traffic), and most bridges don't support any kind of traffic filtering. Bridges aren't much used any more on physical LANS, but are important on virtual LANS and in wireless. Those bridges are much "smarter" than the old physical ones, and the ability to manage an entire virtual LAN as a single network is important. These virtual bridges can calculate and choose the shortest path for data, prevent network loops, and other useful stuff.

Routers are small physical devices that join multiple networks together. Technically, a router is a Layer 3 gateway device, meaning that it connects two or more networks and that the router operates at the network layer of the OSI model.
Home networks typically use a wireless or wired Internet Protocol (IP) router, IP being the most common OSI network layer protocol. An IP router such as a DSL or cable modem broadband router joins the home's local area network (LAN) to the wide-area network (WAN) of the Internet.Advantages are : Easily Shared Internet ;One of the biggest reasons for using a router is to connect multiple users to the Internet. Connecting to the Internet requires a publicly-unique IP address. As such, Internet providers typically only offer a single IP address or charge fees for large amounts of publicly routable addresses. The solution is to add a router with network address translation enabled. Connecting to the Internet through a router with NAT allows the router to use the single public IP address and a series of UDP ports to share the connection. Without NAT, connecting a large organization’s computers to the Internet becomes virtually impossible.
Security and Adaptability;Connecting an Internet modem directly to a PC exposes that PC to a host of security issues. Furthermore, expanding a direct-connection network becomes complicated without the addition of switches or a router and communicating between the individual PCs becomes difficult. Using a router as an intermediary between the “outside” network of the Internet and the “inside” network of your organization provides a scalable environment that is also, to a degree, easier to secure. A router is not a replacement for a firewall or anti-malware measures, but it’s an important first step towards a largely secure network environment.
Disadvantage: Complicated Setup;The aforementioned router requires NAT to be set up. In addition, each computer must be assigned a private IP address that is typically organized by a DHCP server. This is required for the simplest connections. Connecting to additional IP-based networks adds additional complication in the form of routing tables -- a table that describes the best route for reaching a desired network. If IP telephony or video services are to be running on the IP network, you’ll also need to consider quality of service configurations. QOS helps prioritize one type of traffic, such as voice, over others when bandwidth is limited. As additional services are added, more configuration becomes required of the router. Data Overhead; Unlike a point-to-point “layer 2” link, routers add additional IP-based headers. These headers include information such as source and destination addresses, UDP information and checksums. These headers are attached to every payload of data. Large pieces of data are typically broken into thousands of smaller headers, making this header data consume a percentage of the total available bandwidth. Additionally, the routers communicate updates on the network in order to maintain routing tables. When possible, eliminating the routed network environment will offer a nominal speed gain.

The MAUs A media access unit (MAU), also known as a multistation access unit (MAU or MSAU) is a device to attach multiple network stations in a star topology as a token ring network, internally wired to connect the stations into a logical ring. MAU contains relays to short out non-operating stations. Multiple MAUs can be connected into a larger ring through their ring in/ring out connectors.
MAU is also called a "ring in a box". The loop that used to make up the ring of the token ring is now integrated into the chip. In token ring, when a link is broken in the ring, the entire network goes down; however with an MAU, the broken circuit is immediately closed off (within 1ms) allowing stations on the ring to have their cords unplugged without disabling the entire network.Used exclusively on token ring networks, MAUs can perform the following tasks: Connect workstations in a logical ring through a physical star topology,Move the token and packets around the ring,Amplify data signals,Connect in a daisy-chained manner to expand a token ring network,Provide orderly movement of data)

A MAU

A MAU

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