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Running head: IMPORTANCE OF ROUTING PROTOCOL
Importance of Routing Protocol
Name of Student:
Name of Institution:
IMPORTANCE OF ROUTING PROTOCOL 2
Abstract
Routing may be described as the act of moving information across an internetwork
from a point of origin or a source to a given destination. During this process of transmission
of information, at least one intermediate node is encountered. Often, routing is contrasted
with bridging, both might seemingly be perceived to accomplish the same thing to a non-
technical or networking observer. The topic of routing and routing protocol has been covered
in computer science and networking literatures for more than two or more decades. Routing
did achieve commercial popularity in the early 80s. The principal reason for the time lag in
the popularity of routing as well as routing protocols is that networks in the 70s were
relatively simple and homogenous frameworks. Only recently has large scaled
internetworking become relatively popular hence increased awareness on the concept of
routing and its protocols. This paper examines and explains some of such concepts.
The Concept of Routing Protocols
A routing protocol utilizes software and routing algorithms in the determination of optimal
network package or data transfer and communications path between nodes on the same
network. Routing protocols are responsible for the facilitation of router communications and
overall topology of network understanding (Postel, 1981). Most internet protocols networks
can be said to make use of the following routing protocols: Routing Information protocol and
interior gateway routing protocol. Interior gateway routing are provided via path or distance
vector protocols. Open shortest path first, this is responsible for the provision of interior
gateway routing through link state routing protocols and the final one is the border gateway
protocol. This type of routing protocol is said to provide public internet routing protocols via
exterior gateway routing. Routing protocols implement routing algorithms in such a way that
they tend to facilitate the exchange of routing information between networks. The allow
IMPORTANCE OF ROUTING PROTOCOL 3
routers to create routing tables dynamically and in some situations they have the capabilities
to override routed protocols. A typical citation is the situation where BGP runs over TCP,
extreme caution is taken in the implementation of these kind of systems so as not to create a
circular dependency between the routing and routed protocols. The primary objective or
purpose of a routing protocol is to find the most suitable route to route packets. How this
process or function is established is primarily based on various factors like bandwidth, delay,
load and reliability. It most cases it equally depends on what routing protocol is employed.
Routers share their routing tables with neighbouring routers, this enables them establish new
routes from other routers and uses this information to build routing tables which are
eventually used to route data packets. EIGRP shares routes with routers with which have the
same autonomous numbers. In other words, it is important to set the AS number so that the
router can detect other routers within its environment. Routing protocols aid routers to build
as well as maintain a routing table by establishing the best route in the table and eliminating
routes that are no longer existent.
Distance Vector Routing Protocol is one of the two primary routing protocols utilized for
communications methods that use data packets sent over internet protocol. Distance Vector
Routing Protocol requires routing hardware to report the distance of various workstations or
nodes within an IP topology or a network. This is established as a means of determining the
best and most efficient routes for data packets.
In contrast to Distance Vector Routing Protocol, and the other type of routing protocol
Link state Routing Protocol, which is viewed as the more predominant of the two. DVRP has
the tendency to contemplate two basic factors: Vector and Distance. A vector illustrates the
trajectory of the data packet over a stipulated set of network nodes. The Distance on the other
hand is referred to as the number of steps or data packets that must be transmitted to get to its
destination. DVRP is essentially important in voice over IP and other types of
IMPORTANCE OF ROUTING PROTOCOL 4
communications that make use of routed data packets. As internet protocol infrastructure
becomes more extensive and important to the communications and global markets in general,
it is highly probable that that advances will continue to grow the capacity of IP traffic with
enhanced methods and hardware devices.
The Distance Vector Routing Protocol can be further comprehended through
recollection of the meaning of the word “vector”. This is classified as a value with two
components, direction and magnitude. In a DVRP, neighbouring routers such as router
attached to the same sub networks interchange routing vectors. Each router establishes a list
of all known sub networks and metric relating to cost of the path to that sub network from its
routing table (Mogul, 1984). This information is transmitted to all routers within the
environment or to all neighbours. In this case neighbours are referred to as any system or
node which is connected to the same sub network.
One of the most significant advantages of a Distance Vector Routing Protocol is that,
it is a relatively simple approach. In technology and computing, simple things are easier and
more efficient to implement as well as the fact they place a fair demand on the systems
processing power. This tends to be a critical advantage with the DVRP.
On the down side, DVRPs have the tendency to suffer from a list of essential
limitations. These disadvantages of the DVRP tend to grow as the inter-network grows.
Routing tables in significantly large networks can be proportionally or correspondingly large,
thus there is the consumption of bandwidth in the process of exchange of routing information.
One important factor to note about DVRPs is that it is not essential for this type of
protocol to transmit its updates periodically. Updates can only be transmitted in the event that
there is a change. In large inter-networks Distance Vector Routing Protocols may require
some time to converge due to the changes in the network topology which takes time to
IMPORTANCE OF ROUTING PROTOCOL 5
propagate across the whole network. Each router with the inter-network has to receive an
update and then recalculate its routing table before it can establish and generate an update to
its neighbours. However, it should be noted that most DVRPs support event driven updates.
Most also impose the hold downs to avoid transient cycles or loops. The implication of this
concept is that loss of routes travel at a much faster rate than alternative routes which take
relatively longer to follow. This convergence challenge coupled with a number of other
implications of the exchange process make DVRP particularly prone to the creation of
routing loops. Routing Information Protocol (RIP), which is found in TCP/IP, Netware and
XNS inter-networks, Apple Talks Routing Table Maintenance Protocol and Cisco’s Interior
Gateway Routing Protocol are all examples of popular DVRPs (Almquist, 1994).
Routing Information Protocol, is a DRVP, which implements the hop count model as
a routing metric. Routing loops are prevented by Routing Information Protocol via the
implementation of limiting the amount of hops permitted in a path from the origin
destination. In RIP, there are a total number of fifteen hops allowed. This hop limit equally
puts a restriction on the size of the networks that can be supported by Routing Information
Protocol (RIP). A hop count of sixteen is said to be the infinite distance used in deprecating
inoperable, undesirable or otherwise inaccessible routes in any selection processes. Hold
down, route poising and split horizons are mechanisms all implemented by the Routing
Information Protocol. These mechanisms all aid in the prevention of incorrect routing data or
information from being transmitted or propagated. This is viewed as one of the stability
attributes of this type of DVRP. There is also the possibility of the utilization of the Routing
data or Information Protocol with metric based structure or topology algorithm to deal with
the infinity count challenge. The metric based topology, implements the ability to detect
loops with relatively small computational effort is quite feasible (Baker, 1995).
IMPORTANCE OF ROUTING PROTOCOL 6
Routing Information Protocol (RIP) comes in two versions. Version 1 and version 2.
The first version is a distance vector protocol while the second version is a hybrid protocol.
Routing Information Protocol RIPv1 utilizes local broadcast in the sharing or dissemination
of information. The RIPv1 updates are relatively periodic in nature, they occur by default
every thirty seconds. This is established in a bid to prevent packets from the routing loops
effects. This version of the RIP just like the version 2 solves the issue of counting to infinity
by inculcating approximately a hop count limit of fifteen hops on the data packets. Any data
packet that gets to the 16th
hop automatically gets dropped. Routing Information Protocol
RIPv1 is what is known as a classful protocol. It supports approximately about six equal
paths to one destination. Paths that are denoted as equal paths are paths where metric or hop
count is the same. Routing Information Protocol RIPv1 supports essentially classful routing
but not VLSM. In this version no authentication is required. This version of the RIP uses
broadcast.
Routing Information Protocol RIPv2 is also a vector based protocol incorporated with
routing enhancements and is built on the foundations of the version 1. Thus it is referred to as
a hybrid protocol. RIPv2 utilizes multicasts instead of broadcasts. This form of protocol
supports triggered updates. In the situation that a change occurs, a Routing Information
Protocol RIPv2 server will immediately propagate or transmit its routing information to every
single one of its connected neighbours, which is every node within the sub network. RIPv2 as
earlier mentioned is a classless protocol but equally supports variable length sub net masking
(VLSM). This form of protocol inculcates the implementation of network mask in the update
in a bid to permitting classless routing advertisements. It uses the multicast communications
features to reduce the challenge on the network infrastructure that do not need to listen to
Routing Information Protocol updates (Malkin, 2000).
The limitations associated with Routing Information Protocol (RIP) include:
IMPORTANCE OF ROUTING PROTOCOL 7
Slow Convergence: Because the basic RIP algorithm is relatively slow, router
experience a long time to get the same information. This issue is significantly
pronounced in the event of propagation of route failures. These failures are only
detected via the expiration of the 180 seconds time out. This adds up to 3 minutes
more delay before convergence can begin.
Routing loops: RIP has no specific mechanism to detect routing loops, the best it can
do is to avoid their occurrence.
Other limitations of the RIP are counting to Infinity and Small infinity challenges.
IMPORTANCE OF ROUTING PROTOCOL 8
References
Almquist, J. (1994). Towards Requirements for IP Routers, RFC 1716. Retrieved from <
ftp://ftp.rfc-editor.org/in-notes/rfc922.txt > August 11, 2013.
Baker, F. (1995). Requirements for IP Version 4 Routers, RFC 1812 Retrieved from <
ftp://ftp.rfc-editor.org/in-notes/rfc1812.txt > August 11, 2013.
Floyd, S & Jacobson, V. (1994). The Synchronization of Periodic Routing Message. Print
Malkin, Gary Scott (2000). RIP: An Intra-Domain Routing Protocol. Addison-Wesley
Longman. ISBN 0-201-43320-6. Print.
Mogul, Jeffery. (1984). Broadcasting Internet Datagrams in the Presence of Sub Nets.
Retrieved from < ftp://ftp.rfc-editor.org/in-notes/rfc922.txt > August 11, 2013.
Postel, J. (1981). Internet Protocol, Rfc 791. Retrieved from < ftp://ftp.rfc-editor.org/in-
notes/rfc791.txt > August 11, 2013.