Communication Process with X-Stream Server - Essay Example

?Communication Process with X-Stream Server Today, computer networks have revolutionized the human life in many fields and the educational networks have made a vital contribution in making these fruits available for the masses. The internet, a network of networks, is the backbone of this global revolution. Computer networks are stepping into next generation networks and lot of security and data service concerns have changed the shape of networks. Therefore, the process that occurs in a network may vary extensively for a specific network, depending on its implementation and level of security it assures. Nevertheless, the fundamental process remains same and heavily depends on the seven layers of Open Systems Interconnection (OSI) model and four layers of TCP/IP protocol stack. The OSI is a hypothetical model and provide the fundamental understanding of the communication infrastructure for modern networks. On the other hand TCP/IP is a suite of protocols which operates over this hypothetical model. In simplest words, protocol is a set of agreed upon communication rules that govern the communication between two or more machines. The OSI model and TCP/IP protocol suite work in close coordination at various layers to ensure a secure and efficient data communication. In majority of implementations, a sound understanding of the layers, protocols, processes and underlying technologies is required to appreciate the process that may occur in a network. Comer (2004) states this fact, “Understanding the internet technology requires one to distinguish between the low-level mechanisms provided by the hardware itself and the higher-level facilities that the TCP/IP protocol software provides”. Present day networks are so big and wide spread that they cannot be owned by a single business entity rather multiple entities look after their part of network to bridge the gap between various far of networks. Various issues surrounding the communication processes need in-depth investigation of the entire channel to find out the technicalities and interoperability potential of these layers and protocols. These layers and protocols are discussed at length in the following lines; A remote user starts this process by accessing the X-Stream Server through internet explorer. This access request is interpreted at Application Layer, by Hyper Text Transfer Protocol (HTTP) and it is destined for HTTP Port 80 at X-Stream Server. However, it must be noted that HTTP neither know the location of the server nor the routing details; it is the Transmission Control Protocol (TCP) implementation in the backdrop which takes care of actual transmission. Tanenbaum (2004) while pointing out the role of HTTP states, “It specifies what messages clients may send to servers and what responses they get back in return. All clients and all servers must obey this protocol. The value of using TCP is that neither browsers nor servers have to worry about lost messages, duplicate messages, long messages, or acknowledgements. All of these matters are handled by the TCP implementation”. Another significant impact of TCP transmission in the physical network, is the level of abstraction it has to offer. TCP ensures the reliable and efficient transfer of the data, no matter what physical network layout exists between the client machine and the server. Moreover, it is the last layer before data leaves a user machine for onward dispatch to network layer which falls in the domain of Internet Service Provider (ISP), except for the case of an Intranet implementation at either side of the network. At this stage, it will be prudent to get into the detail of various layers of OSI Model and TCP/IP protocol stack. OSI Model has a seven layer structure as oppose to four layer stack of TCP/IP, however both have sufficient commonalities for sustainable interoperability and coordination, a layout diagram for both is drawn here for better understanding; It is evident from this diagram that the Application Layer in TCP/IP is the combination of three upper layers of OSI Model. When a remote user accesses the X-Stream Server from his browser the request is forwarded to Host to Host layer from Application layer of TCP/IP Protocol stack, where the TCP implements segmentation and sequencing before finally dispatching the message to Internet Layer. At next layer these segments are converted to packets and network specific information like source and destination IP addresses are added at this stage. This layer has same function in TCP/IP as network layer has in OSI Modal. From this point onward WAN specific details are added to the message to enable its routing in the WAN infrastructure. At Data Link layer the packets are converted to frames and machine specific information are added to the TCP/IP header and finally physical layer transforms this message in to a stream of bits before it is routed to the nearest router. It is important to understand that this process is repeated in a reverse order at the X-Stream server, where each layer from bottom to top i.e. from Physical to Application layer, perform its part of decoding for final presentation and formulation of the message. This basic protocol and layer orientation forms only a part of our understanding of the whole process that occurs on a network. More importantly, it only describes the process that is applied at either client or server side and we have not discussed how data security is the implemented before routing this stream of bits over the internet and how actually data is transferred from client machine to the destination server. When we access the X-Stream Server of our university from some remote location, several interconnecting networks are used to establish a communication session. Fortunately or unfortunately, a user sitting at a remote location is least concerned about these networks and underlying security issues. The basic theme of our future deliberations is to focus the process that occurs when data leaves our machine, till it reaches the destination port at X-Stream server. This triggers the discussion of sending private data over a public network in a secure manner. The University LAN and a client machine are the two extreme entities in a private domain and require communicating over a public domain, the Internet. The Virtual Private Network (VPN) technology provides the answer if there is some issue with the security or privacy of the data. “VPNs which are overlay networks on top of public networks but with most of the properties of private networks” (Tanenbaum, 2004). VPNs provide a secure channel of communication through encryption and connection oriented network sessions. At remote end, when a stream of bits leaves a client machine it reaches the local router. This router is used to establish a connection with Internet through a local Internet Service Provider (ISP). The user at remote end may use any other connection i.e. dialup or DSL or wireless which makes no difference at all because the basic objective is to send the access request for X-Stream Server to the ISP setup and this can be materialized in any user preferred manner. The ISP will then route this request to X-Stream server using some converged route from its router. It is important to note that some WAN protocol and routing information can be added to the message header or some extra headers may also be attached for the same purpose but this has nothing to do with the message itself. A secure VPN tunnel provides the same level of privacy as that of a leased line communication mechanism. Any information, other than the routing information can neither be read nor accessed at ISP or some other interconnecting network setup. A VPN may be implemented in many different ways and we are assuming a firewall based VPN along with Internet Protocol Security (IPSec) tunneling. A perimeter firewall with VPN is placed at the edge of university network. As soon as a user authentication request is received the firewall initiates an authentication request for user provided credential. In our case a VPN based encrypted session is established only if specific services are required to be access at X-Stream. When there is no requirement of accessing private data services a non secure session may also be established with X-Stream server. Networks have many different implementations to secure the client server sessions. A better understanding of these implementations may help us to overcome faults at either side of a network. Security of information is the hot issue and secure network can only be implemented and maintained by enhancing our knowledge of security protocols and processes that may be occur at various layers of the network. References Comer, Douglas E. (2006) Internetworking with TCP/IP: Principals, Protocols and Architecture. (5th ed.). USA, Pearson Prentice Hall. Tanenbaum, Andew, S. (2004) Computer Networks. 4th ed. New Delhi, Prentice Hall. Read More