Switching & Routing
The purpose of this paper is to provide a better understanding of switching and routing used in a network environment and familiarize the reader with various hardware and software associated with there functions. This paper will look at some switching concepts that will include store and forward switching, cut through switching, fragment free switching, and V-Lan. This paper will also cover routing concepts, along with some comparisons including routed vs. routing protocols, Classful vs. classless protocols, and distance vector vs. link state protocols.
Switching
The definition of a switch or network switch is a small device that joins multiple computers together, working on layer two of the OSI, to form a local area network or LAN. Network switches are also known as smart hubs. Rather than simply dispersing the data evenly across a network the switch actually inspects the data packets for destination information, and then forwards the data to a specific location. By forwarding the data to its intended location bandwidth on the network is better controlled (Mitchell, 1999).
Store-and-Forward switching refers to a switching method that, after inspection, stores data packets for delivery. The data is received from the sender and passes a cyclic redundancy check along with a check to be sure it fits the required size limitations. After inspection and the check for errors the data is stored or held in physical storage until network availability allows the data to be sent to its destination (Cisco Systems, 2008).
Cut-through switching is a method of switching which uses only the destination information to switch data packets to a specific destination or destination segment. Although previous store-and-forward...
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A network switch is a small hardware device that joins multiple computers together within one LAN.
In many data centres, latency and jitter are most important metrics. Even the small amount of delay can cause a bad impact on network performance. To reduce jitter and delay in a network cut through architecture is required.
In order to have a greater understanding of the terminology and descriptions offered in this paper, we must first understand what a network switch is. A brief definition of a network switch is a computer networking device that connects network segments. It uses the logic of a Network bridge, but allows a physical and logical star topology. It is often used to replace network hubs. A switch is also often referred to as an intelligent hub.
Switches operate within the OSI’s layer 2. This is known as the data link layer. The data link layer is responsible for the transfer of data frames from node to node across OSI’s layer one, the physical layer. This allows layers in the upper levels to have transmissions with error checking processes. The data link layer has several responsibilities of its function in the OSI model. The first is link establishment and termination which is where, between two separate nodes, it establishes and terminates the links that connect the two. Layer two also provides traffic control for the frames in transmission.
When it comes to getting network traffic from point A to point B, no single way suits every application. Voice and video applications require minimum delay variation, while mission-critical applications require hard guarantees-of-service and rerouting.
The system chosen to replace the legacy PBX switching system will be the NEC’s NEAX 2000 IPS. The headquarters of ACME Electronics is spread between four buildings. The NEC NEAX 2000 IPS supports distributed processor architecture. This means that the processing requirements of the system are shared between more than processor. This allows for faster response times and redundant operation. If one processor fails, the other can take over. Two of the four buildings are equipped with 1 Pentium 200 MHz Processor dedicated to the inter-communications system.
Prior to the 1960s, what little computer communication existed comprised simple text and binary data, carried by the most common telecommunications network technology of the day; namely, circuit switching, the technology of the telephone networks for nearly a hundred years. Because most data traffic transmissions occur during a very short period of time, circuit switching results in highly inefficient use of network resources. In 1962, Paul Baran, of the Rand Corporation, described a robust, efficient, store-and-forward data network in a report for the U.S. Air Force; Donald Davies suggested a similar idea in independent work for the Postal Service in the U.K., and coined the term packet for the data units that would be carried. According to Baran and Davies, packet switching networks could be designed so that all components operated independently, eliminating single point-of-failure problems. In addition, network communication resources appear to be dedicated to individual users but, in fact, statistical multiplexing and an upper limit on the size of a transmitted entity result in fast, economical data networks.
A network switch is a networking device that connects devices together on a network enacting a form of packet switching. It operates in the Data Link layer of the OSI model. It essentially acts like a multi-port network bridge that processes and forwards data. Other types of switches have additional features such as the ability to route packets. Those switches are commonly known as layer-3 or multilayer switches.
In order for information to pass fro one information system to another information system outside its local area it must be routed. In the below table is an illustration of a the route a data packet takes between my computer and the Web Server for Macon State College.
...radigm. In fact, super-positioning of signals (described above) represents an important type of Network Coding we will refer to as Linear Network Coding (see also [15]). Although Linear Network Coding represents a very important subclass of Network Coding, in general Network Coding involves methods that go beyond linear Network Coding. Certain network problems have no linear solutions, but require the application of non-linear boolean functions [18], [8]. Non-Linear Network Coding has no obvious physical analogue. Rather general Network Coding represents a paradigm of information flow based on a mathematical model where 'every thing goes'. In this model there are no apriory restrictions on how information is treated. Thus in Network Coding, packets might be copied, opened and mixed. Sets of packets might be subject to highly complex non-linear boolean transformations.
Figure 2.11 above shows the network topology in a single lab. In the lab, a star topology is used to connect a printer, a wireless access point and 50 personal computers with a single special device known as switch. Instead of using hub, a switch is used to identify which computer system is connecting to which port. Switch knows exactly where a frame is received from and which port it wants to send to, without increasing the network response time. Unlike a hub which divides the bandwidth among the systems when multiple PCs are broadcasting, switch enables system users to access the maximum amount of bandwidth regardless the number of PCs transmitting. Thus, a switch is considered as a better choice than a hub because it maintains the performance instead of degrading.
The primary goal in routing multicast connections is to make efficient use of the network resources and to establish fast connections for data transmission. The network is often defined by a graph G(V,E) . Multicast routing protocols are been used in practical systems such as multicast backbone(M bone).M bone chooses the shortest path to each destination using the IP routing mechanism.Multicast routing in ATM Switch performs two basic functions such as switch and queuing.
Packet switching is used as an alternative choice for circuit switching which is used in PSTN or in ISDN for making or establishing voice telephone call connections
...d switches, which are lacking the capabilities to support management protocols or port mirroring, an alternative method was used, to capture the traffic and utilisation data of the network. A hub was used at the main office closed to the switch connecting to the internet machine.
First, according to researchers there are three types of code switching “tag-switching,” “inter-sentential switching,” and “intra-sentential switching.”