Introduction
In the current world of technology, the internet and computing are increasingly finding use in daily activities. Together with the need to access and share information, networking has come to be a very important instrument to achieve this purpose. Networking can be described as the practice of connecting computing devices to allow sharing of information. Networking is hence made possible by the use of computers and their software. There are several models of networking that are available in use and are categorized according to the size of areas they cover. Local Area Networks cover small localities like an office or a home. Wide Area Networks cover very large geographical regions like a state or across the globe. The internet is regarded as the largest WAN in the world. Recent developments have seen the introduction of the Metropolitan Area Networks. This type of networking links users in an area that is bigger than that covered by the LAN but smaller than WAN. The term is basically used to describe interconnections in a city into one bigger network.
The Context of Metropolitan Networking
The Metropolitan network allows the connection of a wider area like a whole city into the WAN. Metropolitan can also encompass several local area networks that are bridged into one backbone line. At times this is referred to as a campus network (Stallings, 1997, p. 12). Examples of metropolitan connections can be found in cities like London, New Jersey and New York among others. Several designs can be used to set up the interconnections. Basically, there are two main ones that are commonly used for such purposes. Client-server connection helps to link users to a central server which can be used to store emails, files, websites and other applications. A Peer-to-peer network on the other hand connects all the computers to function in supporting similar functions. Client-server networks are common in areas of business as Peer-to-peer are common in-home usage networks.
A network typology is used to represent the layout that metropolitan is structured in. this is based on the way data is set to flow (Stallings, 1997, p. 14). For instance, in the bus network, all the computers are communicating and are shared by use of one conduit while the star connection indicates the flow of information to one central server (Sadiku, 1995, p 45).
The network protocol that is used by the metropolitan networks is similar to those supported by the local networks and WAN. The common protocols are the TCO/IP. These protocols are currently connected via wire and some of them are wireless. Currently, Ethernet is dominant in the business sector. However, wireless connections are picking up at a very fast rate as they seem to be superior technology that is even more convenient (Stallings, 1997, p. 22). The connection can be private or publicly operated over a city. It usually serves the corporate sector through some connections are being used for homes alone. MAN is able to support data sharing and even voice messages (Sadiku, 1995, p 45). Local televisions are beginning to use the technology to reach people and this will increase access to cable televisions. The metropolitan networking has only two cables and therefore does not require a lot of switching elements, which limit or thrust packets from the various possible outputs (IEEE, 2002, p 73). Not having many switches makes the design very simple for usage.
The reason for regarding MAN in high class is because this network is special. It has been standardized and these standards are implemented by professionals and they just have to be met for a MAN to be considered competent (Stallings, 1997, p. 22). The coverage of MAN’s is estimated to range between 5 and 50 kilometers. This is about the size of a city though it could be less depending on the number of buildings that are covered. Ownership of the network is not individual rather it’s by a consortium of clients or the service provider that is supplying the network facility to the users (Sadiku, 1995, p 45). The metropolitan networking is usually very fast and acts as the speedy connection that permits faster access to the information. This can also link to other networks through the wider area network. In this way, several MAN’s can be connected as well making it easy to access a wider array of information (IEEE, 2002, p 73).
The Uses
The Metropolitan area network has found usage in various sectors of the economy. These connections can be done in education centers like universities, businesses, government departments and for private users. Basically, MAN offers a very convenient and effective connection to the wider area networking system (IEEE, 2002, p 73). The MAN benefits the users in the following major ways;
Promoting the said cities in business and high-tech socialization – This allows the users to reach a wider audience when they have a message to pass across, exchange contacts, and businesses even advertise through such networks. In this manner people are able to socialize even without having to move out of their officers or any other work station they are in (IEEE, 2002, p. 77).
MAN promotes access to areas that are not easily accessible. Sometimes it’s very expensive to traverse certain sections of the city. However, these areas can be reached through metropolitan connections very easily. In fact, such access is even cheaper and convenient (Sadiku, 1995, p 45). Connecting one computer network with other is often advantageous particularly for businesses that run several facilities. Starting with the local area networks to MAN; the existence of accessible telephony can make this exercise very easy (IEEE, 2002, p. 73). Businesses are able to carry out functions like sales, accounting, marketing and product development can be shared by businesses.
Metropolitan area networking offers security to individual information. This is because, in the event of a loss like a damaged computer, or difficulty to move to a better location, one can still access the information by other networked computers and keep working (IEEE Computer Society, 2003, p. 67).
MAN offers access to areas that have no other alternative of access. Some areas could suffer inaccessibility due to some reasons possibly like vandalized cables. However, with wireless networking, such areas can still share information and people communicate with others on the outside.
Metropolitan Area Networks are also used to earn revenue for the government since people pay for these services. As much as the government benefits by earning revenue, the networking is very economical for users since they can make internet calls via VOIP which is usually cheaper (IEEE Computer Society, 2003, p. 67). Furthermore, entertainment can be shared on connected computers making it fun and pleasurable.
The Current State of Its Development
There are several protocols that can be used to link computers under MAN technology. Basically, the common protocols for networking include ISP/IP, IPX, OSI, XNS and DECnet (IEEE Computer Society, 2003, p. 67). It’s pertinent to note that not all the protocols are routable (are compatible with a router). However, the ones named above are compatible. OSI model has been very effective for use with Metropolitan area networking when defined by IEEE or ITU-T.
Current advances in technology have seen a very big shift from a wired connection to wireless networking. This is because they are efficient, convenient, flexible, and more high-tech. there is a new development of the protocol compatible with IEEE 802.16 that has been proved to be very easy to build and also cheap (IEEE Computer Society, 2003, p. 69). It’s expected to dominate the market due to its qualities.
Several technologies are currently in place and are very effective in making MAN a desirable network for many societies (Hoymann, 2005. p. 459). The paper analyses the common technologies used in MAN including BGP/MPLS VPN, and Wi-MAX. The application of these models is very important and requires great understanding. They can classify various VPN from the broad Unitive platform (IEEE Computer Society, 2003, p. 67). Every client can hence access his/her own VPN, avoid a repeat of the construction and extravagant resources, and also offer security assurance.
BGP/MPLS Model: IP VPN
VPN – Virtual Private Network is founded on the idea of offering a type of security insulation between data frames, datagrams, and packets of various clients over a packet-based connection. Virtual private networking as a model is not the latest. For instance, Frame Relay, ATM and X 25. This has necessitated the service providers to offer subscribers a dynamic portfolio that accommodates several VPN service delivery approaches. Over time, there are some proposals that have been projected for VPN models. Classification of VPN is based on the issues to be handled (Virtual private dial-up, intranet and extranet) (Hoymann, 2005. p. 459). Traffics matrix is also a determining factor and so is typology and technology. The number of BGP/MPLS is increasing in usage compared to other VPN technologies. This is because it does not burden the routing tables and routers. This enables the users to hold onto their networks (Hoymann, 2005. p. 461). The technology can also use the overlapping address spaces in case they don’t have any common sites – MPLS –multi-protocol Label Switching.
The Network Components
RFC2547bis executes a VPN through the use of BGP to deal out VPN routing data and MPLS to progress the VPN traffic. User sites link to the service provider (SP) via one or several ports. The service provider then relates every port with a VPN routing and forwarding table (VRF). The VRF describes the membership of the VPN of a client site that is connected to a PE router (Hoymann, 2005. p. 459). A VRF comprises an IP routing Table, several interfaces that utilize the forwarding table, and a number of rules and routing protocol factors that direct information to be entailed in the table.
Customer Edge Routers (CE) – this links the client site through a data connection to several PE routers. To allow inbound traffic, CE promotes local routes to the PE router. For the outbound traffic, it could provide a default route.
The Provider Edge routers are used to sustain a VRF table for every port or VPN (Iniewski et al, 2008, p. 84). Here, there is an exchange in routing information with the Customer Edge routers by use of Interior Gateway Protocol or Static routing. These routes are never disclosed to the service provider’s backbone. The P routers forward traffic by use of the MPLS. They are required to maintain PE routes alone and are not needed to be knowledgeable about the VPN routing information (Iniewski et al, 2008, p. 84).
Data Flow
Assuming that the Host 10.2.3.4 at the second site (site 2) requires connecting with server 10.1.3.8. Then 10.2.3.4 progresses its packets to CE 2 which is a default gateway. CE identifies the destination of the packets’ address IPv4 from the forward table and then advances the packet to PE 2. When PE receives it, it carries out a route lookup in the matching VRF (Iniewski et al, 2008, p. 84). The following information determines how packets are forwarded;
- MPLS offered by the first PE for the route (PE 1)
- BGP next jump for the same route (Kempf, 2008, p. 78)
- MPLS tag for the LSP for both provider edges (PE 1 and 2).
The Wi-Max Technology
Currently, microwave Access interoperability (WiMAX) is considered the best technology that is wireless. There are standards that have been set for the wireless networking that defines this WiMAX technology (Zhai et al, 2004, p 917). Basically, the base station for this technology is comprised of indoor electronics and a towering part. Characteristically, the base station can serve an area of about 10 kilometers (Kempf, 2008, p. 78); in theory, however, the possible coverage area is about 50 kilometers. Practically, there are some restrictions that limit the distance to as less as 10 kilometers. Any receiver in the covered area can easily access the internet (Zhai et al, 2004, p 919).
The receiver can be in form of an antenna that may be a stand-alone box or a personal computer card. Accessing the WiMAX is more like accessing a Wi-Fi network’s Wireless Access Point though this has wider coverage (Zhai et al, 2004, p 919). A number of base stations can be linked to one another through the use of a high-speed backhaul microwave connection (Kempf, 2008, p. 78). Users can hop from one base station to the next just the way the telephone companies do. WiMAX stations support the use of a number of typologies and backhaul alternatives (Delannoy et al, 2009, p 503). For instance, wireless backhaul which is characteristic in Ethernet, microwave links of point-point and WiMAX. WiMAX has the capacity to backhaul itself and this is achievable by keeping part of the bandwidth usually utilized for the consumer traffic and also for backhauling reasons (Kempf, 2008, p. 78).
WiMax Operation
The internet providers usually have set up base stations within the operation range. The user then has to purchase a WiMAX-enabled computer or otherwise upgrade one that is not compatible to add WiMAX compatibility (Tan, 2004, p. 56). The subscriber is given a unique encryption code that would allow the user to gain way into the base station. The base station then directs information from the internet to the user’s PC at a very high speed far much faster than cable modems (Kempf, 2008, p. 78). The providers are paid on monthly basis or at the agreed intervals. The cost is relatively cheaper because there are fewer costs as cables are not purchased. WiMAX allows cities to be connected in the MAN model. This protocol can handle various methods of transmitting data ranging from digital data and voice over the internet. International calls can be made this way (Zhai et al, 2004, p 923). Conferencing is also possible and this allows users to bypass telephone companies’ costs for service provision. In a way, WiMAX has been a very powerful instrument that improved WiFi technology. If many computers are designed to be WiMAX compatible, then vary many people will be able to use the VoIP service (Tan, 2004, p. 56).
MAN: Strengths and Weaknesses
Strengths
File sharing is made possible for the users. An individual in one area can be able to access information posted on the network by another person on the same network. This basically allows for time-saving since information does not have to be carried on secondary storage devices from one user to the next (Zhai et al, 2004, p 927).
The MAN saves resources for the users. This means that they need not buy a lot of gadgets like modems or cables as technology is reducing such needs (Kempf, 2008, p. 82). Furthermore, not all users have to subscribe to internet providers. Businesses and families can use the internet and other operations that are made available by the service providers like in the case of WiMAX (Delannoy et al, 2009, p 503). Several computers can use a single modem and other accessories like printers as well.
The computer resources can be centrally managed by the use of some software available on the market. This is also cost-efficient because there is some software on the market that is very expensive and takes a lot of time to install. They could be unaffordable or complex. However, with networking made possible, the software can be saved in the system and installed for use by the subscribers (Kempf, 2008, p. 78). This means that several people can be able to access the software and use it in various workstations or businesses.
MAN offers a broader storage capacity since there are many computers on the network. When information is placed on the server, a standalone computer could break down but still, the information is retrieved from the network.
Security can be enhanced so that the subscribers can have passwords and user names which will be very effective in blocking unauthorized access.
Weaknesses
The advent of new information and communication technology and the subsequent integration into sharing models comes with a lot of loopholes. These weaknesses can be very devastating at times.
Security is usually a major problem. Basically, when sharing information or being connected to a common network presents an environment that is indiscrete. Basically, accessing an individual computer need physical access, however, when they are connected several tools can be used by information thieves. Hackers are very smart and can be able to access the network and obtain very crucial information for an organization. There are several kinds of software that can be used to block unauthorized access nut still there is no guarantee since hackers have been able to find their way around them.
MAN has a very big weakness of infection by viruses. Many computers on the same connection are risky as various users bring in different tools and devices for data storage. When the system files beings shared get infected, then the virus can spread very fast to different users.
The Metropolitan area network can be too dependent on the central file server. In the event that the main server crashes down, then the network is rendered useless. Recovering the files is usually very costly as well.
The Future of MAN
Considering that the needs and services offered by MAN have greatly skyrocketed, it’s obvious that the current networks cannot handle the increasing diversification. New solutions have to be found. Several researches have been going on about these issues with SONET/SDH connections. Idyllically, the operators would only need to manage only one type of network (Murawwat & Ahmed, 2009, p 459). One Multipurpose MAN would be able to make connections with several access networks and offer almost everything ranging from the conventional data transfer to real-time operations (Murawwat & Ahmed, 2009, p 459). The network would also offer Quality of Service (QoS) and be able to deal with all manner of traffic (cell-based, packet-based or bit-rate traffic). Though multi-service would be very efficient in reducing the operation cost, the current network is unable to fulfill this. They are incompetent, inflexible and overly complicated for the reasons of data sharing (Murawwat & Ahmed, 2009, p 459). The new technology that is being developed is going to be multi-service and easy to manage. Some important features that are being incorporated include Virtual Concatenation and Generic Framing Procedure among others. The use of optical transport systems is critical to these advances.
The Optical Access Network model was initiated in 2001 and the project researches electrical parts on the feeder network and all the activities involved in networking. A platform was developed and this is currently recognized as addressing issues of the “next generation” (Murawwat & Ahmed, 2009, p 459).
OAN Platform
This allows several subscribers to be connected to the key network as it acts as a feeder network. In order to gain competent optical security and cheaper structure, the OAN is physically a ring but in essence, it is a star shape. There are only 3 to 4 nodes on the OAN prototype to avoid the complexity of networking. One of the nodes functions as the hub connecting the rest to the central network and to each other (Sen et al, 2007, p 234).
The next-generation advances especially in SONET will allow new services to be carried out with an efficient work system. Currently, organizations (businesses, corporations and private sectors) need a diversified service provider. They need services like VPN, Voice, data storage, Processing, internet, etc from their service provides (Murawwat & Ahmed, 2009, p 459. Traditionally several services can be accessed by technology-specific systems. Nonetheless, the next generation will enable simultaneous usage and heterogeneous services in one wavelength hence saving the cost of building and maintaining networks (Sen et al, 2007, p 234). As VPN is for bridging users’ access, some applications need to transport resident network signals without hauling out packets or frames.
Conclusion
As technology advances, wireless connections are gaining popularity as the standards are set higher. Commoditization and diversifications into more wireless networks have made metropolitan area networking cheaper and manageable. Currently, the reason for building such networks is to offer faster access to the internet to areas that have dial-up connections only. Future reasons for such investment are to mitigate the expenses on telecommunication and at the same time meet the socio-economic objectives.
Reference List
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