The problem with circuit switching is the limited capacity that it offers. Once the circuit is established, you make a reservation in the network and you end up with a fixed capacity for the circuit.
This also means that you waste a lot of unused resources…. Each chunk is a packet that is sent on the network. This is what we mostly use on our networks nowadays. Above you can see that host 2 wants to send bytes of data. This is broken down in 3x byte packets. One packet is sent on the top link, the other two on the bottom link. Once host 4 receives all packets, it can extract and reassemble the data. Packet switching has mostly replaced circuit switching. One of the advantages is that because there are no fixed circuits, we can more effectively use the capacity that the network has to offer.
Cell switching is very similar to packet switching with the exception that we use a fixed for our size for our cells. Above you can see that each computer sends some data. Whatever they send gets encapsulated in cells with a fixed size, 53 bytes in my example.
So far, we talked about some physical layer terminology and different methods to forward data on a network. Leased lines are one of the older WAN options. Somehow, we need to connect these two networks. A leased line is a point-to-point link that we exclusively use, often offered by a phone company. Leased lines have been out there for awhile so there are a bunch of other names we use for this:.
This point to point link will only be used by the customer that is paying for it, which makes it an expensive option. On each site, we use a router with the point-to-point connection in between. The phone company has multiple buildings throughout the country with their equipment, called COs Central Office. These COs are connected to most buildings in a city, hoping that they can sell their services some day.
When a customer requires a leased line, the phone company creates a connection between COs to build a point-to-point link:. Above we see that the WAN service provider phone company offers a two pair cable to the customer, which terminates in an RJ48 socket. These serial interfaces are WIC modules that you can insert in some of the Cisco router models. Above you can see DTE port that has to be connected to the router.
To connect the router to this device, we can use the following cable:. A Cisco router can configure clocking on the interface, which has to be done on the DCE interface. Frame-relay is also an older WAN technology that was an alternative to leased lines. Frame-relay offers point-to-point and point-to-multipoint circuits with a shared network, which is cheaper than a dedicated line. If you want to learn more about frame-relay, you can find our frame-relay course here.
DSL Digital Subscriber Line became a very popular option for high-speed Internet access since it uses the analog phone cables that pretty much every home or building has. The speed that you get depends on the distance between your home and the phone company.
At the customer, we have a splitter that is connected to the phone line that the phone company offers. The DSL modem has an Ethernet connection to your router. Nowadays, the DSL modem is often integrated in the router. Data traffic is forwarded to a router, voice traffic to a voice switch.
Most DSL providers offer asymmetric speeds; the downstream bandwidth is higher than the upstream bandwidth. Cable Internet is similar to DSL, it also became popular since most homes and buildings have a cable connection. Coaxial cables offer a wider frequency range than the two pair phone cables we use for DSL, allowing higher throughput. Cable internet often offers higher bandwidth but this can depend on the number of subscribers on the network.
Students at universities might rely on WANs to access library databases or university research. And every day, people rely on WANs to communicate, bank, shop and more. Passive optical networks PONs bring high broadband speeds and fiber to end users' doorsteps. IT pros should know what a PON is and how it can provide network solutions.
What are the types of NAT? As data across the world continues to proliferate at breakneck speed, network providers of various sizes from LAN to WAN are beginning to see a strain on what their networks can support.
This has resulted in new forms of data optimization to increase data collection, reduce bandwidths and consolidate servers, among other things. Software-defined WANs SD-WANs is one solution organizations are beginning to turn to, as it can help alleviate serious traffic issues in the sharing and spreading of data information. SD-WANs use smart software that can monitor the performance of different WAN connections and then appropriately allocate the data into the right connection for the type of traffic users need.
For example, an organization may have many different forms of WAN telecommunications — from emails and conference calls to data sharing and dedicated server networks — and SD-WANs typically help alleviate the strain from all these connections by choosing the appropriate channel to funnel the data through.
Data demands will continue to grow exponentially over the coming decades, so more advanced forms of WAN connections may continue to be developed. Even now, NASA is working on creating an interplanetary internet for future exploration, and it is currently using a disruptive tolerance network DTN for the International Space Station. The biggest concern will be addressing the speed of data transfer, as the greater the distance between two servers, the longer it will take for data to get from point A to point B.
WANs have become an essential part of human communication and business relations, and as the world continues to grow, WANs may change and develop new forms of technology in time, as well. Download the exam objectives to see all the topics covered by this IT certification. Read more about Computer Networks. Tags : Computer Networks.
What Is WAN? Continue Reading Below You may also be interested in Types of WAN Connections As data across the world continues to proliferate at breakneck speed, network providers of various sizes from LAN to WAN are beginning to see a strain on what their networks can support. Are You Ready for a Networking Career?
0コメント