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Running Head: NETWORKING
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Networking
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A router is one of the network layer devices which are responsible for routing the traffic
between subordinate networks that make up a data network. A subordinate network can be
described as a group of network resources that can be attained without the need of having to go
through the router. An internetwork on the other hand can be explained as a grouping of
networks which are connected by the use of a router. The core function of a router is simple
because it is used in receiving data packets from one end and routes them to the other end of a
network which is made up of sub networks.
Routers are also used to do more superior jobs only if the network layer will sustain that
function. Many of them have the aptitude to fragment data packets. Routers are also utilized to
provide some congestion or jamming control aptitudes. Routers can be highly classy packet
filters. A group of people mistake routing for bridging. Routing is in addition a network layer
function. Routers function on packets and preferences based on the network layer addresses.
However, Bridging is a data link layer function. Bridges maneuver on frames and build filtering
and forwarding preferences basing on the media access control address (MAC).
Packets traverse within frames and are used as the transmission unit to get a message
from one node to another in the network. If two end nodes are in the same subordinate network,
the packet is be positioned in a frame by the transmitter and propelled across the sub network to
the intended receiver, possibly going through a few bridges. If the end nodes are not in the same
subordinate network, the packet will traverse in one frame from the transmitter to router, which
will also decide on the routing and the pass the packet to the next subordinate network in a
another new frame.
In a sub network, connection software has to make tables and keep track of potentially all
of the procedures and devices in the subnet and the subordinate network. These tables do not
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hold entries for any end node in a dissimilar subnet. Routers may also construct tables that enlist
all of the subordinate networks and how to contact them. The network protocol in an
internetwork is in charge for end to end routing of packets. There are many network layer
protocols in the market, but they all share some general characteristics. All of the service
networks can supply packet fragment, connectionless or otherwise connection-oriented service,
and packet prioritization.
A network bridge is used to connect many network segments at the data link layer of the
Open System Interconnection (OSI) model. Bridges also are used to send broadcasts to all ports
apart from the one on that was the broadcast recipient. Nevertheless, bridges do not
promiscuously imitate traffic to all ports, as hubs do, but study which MAC addresses can be
reached through specific ports. Once the bridge links a port and an address, it will send traffic for
that address to that port solitary.
Bridges discover the association of ports and addresses by studying the source address of
frames that it can see on various ports. When a frame reaches through a port, its source address is
kept and the bridge assumes that MAC address is related with that port. The first time that a
previously not known destination address is seen, the bridge will forward the frame to all ports
other than the one on which the frame arrived.
Bridges come in three basic types:
 Local bridges. These are used to connect LANs
 Remote bridges: used to interconnect WANs and LANs.
 Wireless bridges: Used to bond remote stations to LANs.
A routing table is a computer readable file that is used to keep the routes to the various
nodes in a computer network. The nodes can be of any type of electronic device connected to the
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network. The Routing Table is usually accumulated in a router or networked computer in the
form of a data file or rather a database. When data needs to be sent from one node to another on
the network, the routing table is consulted to in order to find the best likely route for the
transmission of data.
Hop-by-hop routing method is a standard routing method used in a network that for each
node in that network, the address of the next node primary to the destination is enlisted. Such
that when a data packet makes to a particular node, it refers to the routing table to determine the
address of the next hop node target. Upon reaching that next node, it once again refers to the
routing table for the address of the next node and so on, until it makes it to the final destination.
In the case of a large network which consists of many nodes and routers, the routing
tables for all the routers need to be trusted reliable, of which if they fail, routing loops can
develop. This can sometimes be a source of problems in particular in networks that use the hopby-hop routing method for which the data packets may ultimately end up being sent in a neverending loop. Routing loops have frequently been a frequent problem in networks and one of the
main goals of scheming routing protocols is the careful dodging of these routing loops.
Routing tables may generally be upheld manually when a network is small and static. The
routing tables for all static network tools do not change unless or until the network administrator
alter them manually. In dynamic routing, the devices individually and automatically build and
maintain their own routing tables. They do this through the exchange of information concerning
the network topology using routing protocols. This enables the devices in the network to
automatically settle to the changes in the network like device breakdown and network congestion
as and when they occur.
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Performance of a network can be evaluated in several ways which include response time
and transit time. Transit time is the total sum of time required for a message to go through from
one node to another node. On the other hand response time is the elapsed time between a request
and a response. The performance of a network may depend on several other factors, which
include the number of users in the network, the potential of the connected hardware in
transmission, and the efficiency of the software used.
Performance is mainly measured by two networking measures: throughput and delay. We
typically need much throughput and less delay. Moreover, these two criteria are often opposing.
If one tries to send more data to the network, we may increase throughput but we increase the
delay because of traffic congestion in the network.
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REFERENCES
Sackett, G. C. (2000). Cisco router handbook. New York: McGraw-Hill.
Fox Chapel Publishing. (2010). Router. East Petersburg, PA: Fox Chapel Pub.
Narayan, H., Govindan, R., & Varghese, G. (2003). The impact of address allocation and routing
on the structure and implementation of routing tables. La Jolla, Calif.: Dept. of Computer
Science and Engineering], University of California, San Diego.
Willer, D. (1999). Network exchange theory. Westport, Conn: Praeger.