Introduction
Since 1950, there has been major development in various disciplines like computing, networking and engineering. Notably, experts in these fields keep on using the old concept of “black box” whenever they opt to implement a new task. This concept of black box has acted as an engine aimed at bringing new changes to these disciples. For example, in cars, the brake pedals and steering wheel performs paramount roles, which results into its movement. Nevertheless, the type of brakes or steering system is of less important if there is no action done on them. Whenever there is an input, say pressing of brake pedals, the car decelerates and finally stops moving. This is the same case with a “black box” whose functionality results into an output result. All the period before 1950, scientists and experts never knew the importance of a “black box” and the hidden in it. However, in 1950s, experts started programming computers using setting switches directly controlled by 0’s and 1’s in memory locations. Ironically, there were few memory locations such as 64 bytes forcing them to make short programs. The following decade saw major development of computer languages, which is an automatic program that “sets the switches” in line with the written instructions.
The setting of switches became unnecessary even as experts started focussing on the design of a computer language. In 1980s, there was an exponential increase in terms of computer accessibility. Experts designed terminals for multiple users to share large computers thus, replacing a large computer running a series of jobs. However, this regulation required an operating system (OS). Today, people own personal computers fully operating under an operating system (OS). The OS consists of text commands that control the computer limit hence, making the graphical user interface pervasive. The focus now is on the web, networks and connectivity. For instance, experts are now focusing on the internet, which has so far seemed an efficient means of sending and receiving messages. Serious problems have arisen as regard to sending of messages (Rekhter, 1991, p. 2-13).
In the past, local delivery was the popular means of sending messages through connected computers. However, as technology grew, remote delivery procedures came into effect replacing local delivery. Under remote delivery, there are many routing protocols. However, the internet uses Border Gateway Protocol (BGP) to perform remote delivery roles. This report will examine the origin advantages of using a Border Gateway Protocol (BGP) over other routing protocols. In addition, the report will examine how BGP works.
Routing Protocol
Within a communication network, routers correspond with each other. However, this cannot happen minus a routing protocol. Thus, a routing protocol propagates information into different routes within a computer network. Routing algorithms determine the route to follow. Routers operate differently depending on the network. In routing, the routing protocol disseminates information to its immediate neighbours before spreading it all over the network. Once this happens, routers are now in a position to understand the topology of the system or network. There are different types of routing protocols most of them applying on IP networks. Experts classify these routing protocols into three major classes. The first class of routing protocols consists of those that work as interior gateway routing through link-state routing protocols like Open Shortest Path First (OSPF) and Intermediate System To Intermediate System (IS-IS). The second class consists of routing protocols termed Interior gateway routing through path vector protocols for example, Routing Information Protocol (RIP), Interior Gateway Routing Protocol (IGRP), and Enhanced Interior Gateway Routing Protocol (EIGRP). The last category comprises of exterior gateway routing such as Border Gateway Protocol (BGP). This category applies widely in public internet. Routing protocols fall in different classes because of their dissimilar characteristics. In most cases, the choice of a particular routing protocol depends on the time of scaling and convergence, the mode through which they plump for preferred routes and the ability to thwart routing loops from breaking (Diego & Crowe, 2010, p.1).
Border Gateway Protocol
Currently, Border Gateway Protocol (BGP) is the most widely used protocol on Internet. This is because it ensures that packets of information sent reach the intended destination despite the network working conditions. One major advantage of using BGP protocol in internet is that its algorithms offer great solid stability, making sure that even if there is an interruption within an internet network line, the BGP routers will swiftly accustom and deliver the packets of information via a different connection (Diego & Crowe, 2010, p.1).
Origin and Versions
The creation of Border Gateway Protocol was not an easy task. Three experts from different institutions created the first versions of BGP. For instance, Kirk Lougheed developed a BGP protocol (proprietary version) for use in Cisco router equipment. Jeff Honig and Dennis Ferguson came up with another version of BGP called gated. This version worked on Unix Computers, by making Unix Machines take the place of BGP routers, and eventually enable coding for communal use. Later on, a researcher from IBM, Yakov Rekhter, developed another BGP version that mainly applied in NSFNET backbone. Following the importance of a protocol on internet, researchers continued to modify these initial standards to meet their expectations. They had to collect numerous anomalies in the initial protocol, improve its mode of operation, hasten its efficiency, and put in more features. Additionally, there was need to adjust the initial BGP protocol to make it keep pace with the altered TCP and IP protocol suites for example, classless addressing and routing.
Overview
Many people do not understand why numerous internet users prefer BGP than other routing protocols. To start with, it is better to understand the main reason of developing BGP. Before the development of BGP, internet was in place. Nevertheless, in those days, Exterior Gateway Protocol (EGP) was the only domineering routing protocol. This particular routing protocol had its disadvantages especially those related to internet decentralization. Therefore, experts decided to create a new routing protocol aimed at decentralising routing. It is at this stage that scientist created the initial version of BGP to completely decentralise routing and hasten the confiscation of NSFNet Internet backbone arrangement. Amazingly, the application of Border Gateway Protocol saw the internet develop into a justly decentralised system of sending and receiving messages, and storing useful data. Moreover, BGP-4 has proved to be effective in decentralising internet routing making all other past versions of BGP less important. Nowadays, manufacturers do not label BGP-4C as so simply because they do not manufacture previous version of BGP. It is not that these initial versions of BGP failed to work properly (BGP-4 Protocol Overview, 2010, p. 1).
However, unlike other BGP versions, BGP-4 came with key enhancements such as supporting a Classless Inter-Domain Routing to enable it decide on other networks wherever the one in use fails. Additionally, the size of routing tables was a matter of great concern, and by using route aggregation, BGP-4 reduced the magnitude of these routing tables. For easier reference, manufacturers document all routing protocols as RFC. For instance, the BGP protocol developed in 1995 assumed documentation of the form RFC 1771. However, a series of drafting has seen BGP-4 take new codification as RFC 4271. This codification started in 2006 following 20 drafts aimed at eliminating some errors and clarifying the present ambiguities. In industrial practices, Internet Service Providers employ this routing protocol (BGP) to ascertain routing between routers. With BGP, Internet Service Providers can monitor their networks effectively. This is beneficial to customers as they do not need to employ BGP unswervingly into their systems. Moreover, people using huge personal IP networks find BGP useful because it applies internally. Research shows that BGP offers healthier redundancy especially to multiple APs within a solitary or several Internet Service Providers through multihoming (BGP-4 Protocol Overview, 2010, p. 1).
How Border Gateway Protocol (BGP) Works
Routing process appears simple but very complex. To start with, routing begins when a BGP router reconnects to the internet either for the first time or after turning it on. Consequently, the BGP router institutes diverse connections with supplementary BGP routers with which it is directly involved in the process of communication. However, this cannot occur until the BGP router downloads the whole routing table of every adjacent router within a network. Once this is complete, the BGP router is now in a position to transfer shorter update communications or messages to the next available routers. Since the BGP routers are now on the internet, they can remit and receive update messages within internet networks from one destination to another through a chosen path and IP address
In a situation where a router decides to follow a different path, it has to renew its routing tables and consequently convey the message to other routers, which will then choose whether to do the same and perhaps broadcast the message further. One might wonder how this happens. Of course, BGP applies fundamental protocols such as TCP protocol or IP protocol to create connections. These protocols fall on port 179 that encompass brawny security descriptions together with diverse digital signatures imperative in message exchange among BGP routers. An individual BGP router has a Routing Information Base (RIB) that stores all routing information such as Adj-RIBs-In (messages from adjacent routers), Loc-RIB (authentic information emanating from Adj-RIBs-In), and Adj-RIBs-Out (information ready for transmission to adjacent routers) (Diego & Crowe, 2010, p.1).
Message Types
Open
In routing, BGP routers swap over information by the use of different kinds of messages. An open message commences connections with the next router.
Update
This type of messages characterised by withdrawn routes and paths, does most work in the routing process by serving all bordering routers with routing information.
Notification
These messages inform on the errors occurring in a certain router for example, an indecipherable or erroneous message.
Keepalive
These messages are the most paramount in the whole routing process. This is because every router has to convey a 19 byte Keepalive message to the adjacent router after 30 seconds. In case this does not happen, the BGP router locks that connection and deletes it from its RIB and then repairs the anomaly.
BGP Algorithm
Once the BGP router gets information from its neighbouring router, the BGP algorithm becomes operational. The process involves three stages for each IP address received from a neighbouring router. Firstly, there is an update if the update message sent appears different from the one received by the router. If such incident occurs, then there is an update of information within Adj-RIBs-In database. The second stage is that of decision. Once the router sends different information, decision process occurs that establishes the BGP router, which has a superlative path for the IP address that carries the update message. The system will update only if the there is dissimilarity of information between the decision process and the Loc-RIB database. Lastly, there is propagation if the decision process settled on a better path hence updating the Adj-RIBs-Out and the router conveys the message to adjacent routers which then repeat the same to neighbouring routers. BGP algorithm helps in purging loops out of the routing information. For example, if router X thinks that router Y has the best bath, and router Y thinks that router Z has the best path then a message can rotate around the three routers without delivery. Nevertheless, with the BGP algorithm in place, such cases won’t happen (Gross & Rekhter, 1995, pp.8-35).
Advantages of BGP over other Routing Protocols
The Border Gateway Protocol is a routing protocol whose main function is to perform routing pronouncements on the internet. This makes it advantageous over other routing protocols. Notably, BGP executes its mandate by upholding a series of IP networks, sometimes called ‘prefixes’, so that there is full accessibility to the network especially amongst autonomous systems (AS). Two main advantages make BGP stand out in comparison with other routing protocols. Firstly, through aggregation, BGP achieves network-layer reachability easily and spreads information uniformly to all routers. Secondly, unlike other routing protocols, the routing process of BGP occurs through paths. Due to this descriptive nature, experts term Border Gateway Protocol (BGP) as a path vector protocol. Among its numerous roles, the BGP ensures network reachability even at areas where the signal might be below. This is because BGP operates on a different metric different from the traditional one. For instance, the initial BGP versions applied Interior Gateway Protocol (IGP) metrics to perform routing roles. However, the modern versions of BGP such as BGP-4 apply network guidelines, conduit and network rules to build routing decisions. Additionally, as compared to other routing protocols, BGP is standardised and scalable and many ISPs are comfortable with it when it comes to large networks. These characteristics make BGP the best routing protocol and in many cases, internet users refer it as a reachability protocol due to its aptness (Cisco Systems Incorporation, 1998, p.1).
Conclusion
Without doubt, BGP is a high-end, first-class routing protocol, which has proved imperative in disseminating information to meet the demands of customers. Today, most corporate networks employ BGP because of its suppleness, scalability and astuteness and many of them are in the process of integrating their AS routing protocols into BGP protocols.
Reference List
BGP-4 Protocol Overview. (2010). Web.
Cisco Systems Incorporation. (1998). Border Patrol – BGP. Web.
Diego, D. & Crowe, D. (2010). Border Gateway Protocol: Conformance and Performance Testing. Web.
Gross, P. & Rekhter, Y. (1995) Application of the Border Gateway Protocol in the Internet. New York, Watson Research Center: IBM Corporation.
Rekhter, Y. (1991). BGP Protocol Analysis. New York, Watson Research Center: IBM Corporation.