Evolving Ideas. Emerging Architecture and Protocols for the Internet. Computing, Communication and Networking. Bhawana Sharma 1

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1 Evolving Ideas Computing, Communication and Networking Publish by Global Vision Publishing House Edited 503 by Jeetendra Pande Nihar Ranjan Pande Deep Chandra Joshi Emerging Architecture and Protocols for the Internet Bhawana Sharma 1 ABSTRACT This work seeks to explain the evolution of the architecture and protocols used in Internet s functioning. From Layered Architecture to IIOP (Internet Inter-ORB Protocol), the architecture of internet has got significantly modified. The paper tracks the various architectures and protocols used from the beginning of internet till now, lists out the constraints and shortcomings of the initial architecture(s) and explores new and emerging technologies that remove those shortcomings. INTRODUCTION The Internet system consists of a number of interconnected packet networks supporting communication among host computers using the Internet protocols. These protocols include the Internet Protocol (IP), the Internet Control Message Protocol (ICMP), the Internet Group Management Protocol (IGMP), and a variety transport and application protocols that depend upon them. Elements of the Architecture Protocol Layering: To communicate using the Internet system, a host must implement the layered set of protocols comprising the Internet protocol suite. A host implements at least one protocol from each layer. Application Layer: Two categories of application layer protocols: user protocols that provide service directly to users, and support protocols that provide common system functions. The most common Internet user protocols are: Telnet(Terminal Network)for remote login, FTP (File Transfer Protocol), SMTP (Simple Mail Transfer Protocol),Support protocols, used for host name mapping, booting, and management include SNMP(Simple Network Management Protocol), BOOTP(Boot Protocol), TFTP(Trivial File Transfer Protocol), DNS (Domain Name System) protocol. 1 Department of Information Technology, Amrapali Institute Of Technology & Sciences, Haldwani, Nainital,Uttarakhand

2 504 Bhawana Sharma Transport Layer: The Transport Layer provides end-to-end communication services. There are two primary Transport Layer protocols at present: Transmission Control Protocol (TCP) User Datagram Protocol (UDP). Internet Layer: Internet transport protocols use the Internet Protocol (IP) to carry data from source host to destination host. IP is a connectionless or datagram internetwork service, providing no end-to-end delivery guarantees. IP datagram may arrive at the destination host damaged, duplicated, and out of order. The IP protocol includes provision for addressing, type-of-service specification, fragmentation and reassembly, and security. Link Layer: To communicate on a directly connected network, a host must implement the communication protocol used to interface to that network. Thus, Internet Link Layer standards usually address only address resolution and rules for transmitting IP packets over specific Link Layer protocols. Networks In networks providing connection-oriented service, the extra reliability provided by virtual circuits enhances the end-end robustness of the system. Constituent networks may generally be divided into two classes: Local-Area Networks (LANs) LANs may have a variety of designs. Wide-Area Networks (WANs) geographically dispersed hosts and LANs are interconnected by wide-area networks. Routers: A router connects to two or more logical interfaces, represented by IP subnets or unnumbered point to point lines Thus, it has at least one physical interface. Forwarding an IP datagram generally requires the router to choose the address and relevant interface of the next-hop router or (for the final hop) the destination host. Autonomous Systems An Autonomous System (AS) is a connected segment of a network topology that consists of a collection of subnetworks (with hosts attached) interconnected by a set of routes. An AS is expected to present to other ASs an appearence of a coherent interior routing plan, and a consistent picture of the destinations reachable through the AS. Addressing Architecture: An IP datagram carries 32-bit source and destination addresses, each of which is partitioned into two parts - a constituent network prefix and a host number on that network. Symbolically: IP-address: = {<Network-prefix>, <Host-number>}. Classical IP Addressing Architecture: The simplest classical network prefix is the Class A, B, C, D, or E network prefix. These address ranges are discriminated by observing the values of the most significant bits of the address, and break the address into simple prefix and host number fields. Subnets provide a multi-level hierarchical routing structure for the Internet system. The basic idea is to partition the <Hostnumber> field into two parts: a subnet number and a true host number on that subnet: IP-address: = {<Network-number>, <Subnet-number>, <Host-number>}. The interconnected physical networks within an organization use the same network prefix but different subnet numbers. The distinction between the subnets of such a sub netted network is not normally visible outside of that network. Thus, routing in the rest of the Internet uses only the <Network-prefix> part of the IP destination address. Routers outside the network treat <Network-prefix> and <Host-number> together as an uninterrupted rest part of the 32-bit IP address. Within the sub netted network, the routers use the extended network prefix: {<Network-number>, <Subnetnumber>}

3 Emerging Architecture and Protocols for the Internet 505 Classless Inter Domain Routing (CIDR): The explosive growth of the Internet has forced a review of address assignment policies. The traditional uses of general purpose (Class A, B, and C) networks have been modified to achieve better use of IP s 32-bit address space. CIDR depends on deploying and routing to arbitrarily sized networks. The Class D (IP Multicast) and Class E (Experimental) address spaces are preserved, although this is primarily an assignment policy. By definition, CIDR comprises three elements: Topologically significant address assignment, Routing protocols that are capable of aggregating network layer reach ability information, and Consistent forwarding algorithm ( longest match ). They comprise that subset of all possible bits patterns that have: A contiguous string of ones at the more significant end. A contiguous string of zeros at the less significant end. No intervening bits. IP Multicasting: IP multicasting is an extension of Link Layer multicast to IP internets. Using IP multicasts, a single datagram can be addressed to multiple hosts without sending it to all. In the extended case, these hosts may reside in different address domains. This collection of hosts is called a multicast group. Each multicast group is represented as a Class D IP address. An IP datagram sent to the group is to be delivered to each group member with the same best- effort delivery as that provided for unicast IP traffic. It also defines a protocol, the Internet Group Management Protocol (IGMP), that monitors IP multicast group membership. Architectural Assumptions The current Internet architecture is based on a set of assumptions about the communication system. The assumptions most relevant to routers are as follows: The Internet is a network of networks. Each host is directly connected to some particular network(s); its connection to the Internet is only conceptual. Two hosts on the same network communicate with each other using the same set of protocols that they would use to communicate with hosts on distant networks. To improve the robustness of the communication system, routers are designed to be stateless, forwarding each IP packet independently of other packets. As a result, redundant paths can be exploited to provide robust service in spite of failures of intervening routers and networks. Routing is a complex and difficult problem, and ought to be performed by the routers, not the hosts. An important objective is to insulate host software from changes caused by the inevitable evolution of the Internet routing architecture. A basic objective of the Internet design is to tolerate a wide range of network characteristics - e.g., bandwidth, delay, packet loss, packet reordering, and maximum packet size. Another objective is robustness against failure of individual networks, routers, and hosts, using whatever bandwidth are still available. Finally, the goal is full open system interconnection: an Internet router must be able to interoperate robustly and effectively with any other router or Internet host, across diverse Internet paths. INTERNET PROTOCOLS The Web is one of several ways to retrieve information from the Internet. These different types of Internet connections are known as protocols. Any user can use separate software applications to access the Internet with each of these protocols. Many Internet Web browsers allow users to access files using most of the protocols. Following are three categories of Internet Protocols and examples of types of services in each Protocols:

4 506 Bhawana Sharma File Retrieval Protocols This type of service was one of the earliest ways of retrieving information from computers connected to the Internet. User view the names of the files stored on the serving computer, but user didn t have any type of graphics and sometimes no description of a file s content. FTP (File Transfer Protocol) This was one of the first Internet services developed and it allows users to move files from one computer to another. Using the FTP program, a user can logon to a remote computer, browse through its files, and either download or upload files (if the remote computer allows). These can be any type of file, but the user is only allowed to see the file name; no description of the file content is included. An example of a FTP Protocol Window: Gopher This protocol offers downloadable files with some content description to make it easier to find the file user need. The files are arranged on the remote computer in a hierarchical manner, much like the files on computer s hard drive are arranged. This protocol isn t widely used anymore, but user can still find some operational gopher sites. Telnet User can connect to and use a remote computer program by using the telnet protocol. Telnet into a specific application housed on a serving computer that would allow user to use that application as if it were on user s own computer. Using this protocol requires special software. ARCHITECTURES AND PROTOCOLS OF INTERNET Legacy Technologies The earlier architectures and protocols, some of which are still widely used, are TCP/IP (Transmission Control Protocol/Internet Protocol); WAN (Wide Area Network); LAN (Local Area Network); VOIP (Voice over Internet Protocol), SAN(Storage Area Network), MAN (Metropolitan Area Network), VPN(Virtual Private Network)/Security, WLAN (Wireless LAN), VLAN (Virtual LAN) and more. The Layered Architecture model is common to all these technologies. Technologies Currently Used Though the legacy technologies are still used, newer technologies, that perform better than them, have kept on emerging.the more important ones are: ISO (International Standardization for Organization); SS7 (Signaling System 7) protocols; Comprehensive dictionary of network protocols. Emerging Technologies Given that all technologies that have been used till now suffered from some shortcoming, new technologies keep emerging. In this series, the most recent ones are IPTV (Internet Protocol Television) and IIOP(Internet Inter-ORB Protocol). IPTV: (IPTV) is a service for the delivery of broadcast TV, movies on demand and other interactive multimedia services over a secure, end-to-end operator managed broadband IP data network with desired QOS to the public with a broadband Internet connection. IPTV system may also include Internet services such as Web access and VOIP where it may be called Triple Play and is typically supplied by a broadband

5 Emerging Architecture and Protocols for the Internet 507 operator using the same infrastructure. IPTV is not the Internet Video that simply allows users to watch videos, like movie previews and web-cams, over the Internet. IPTV technology offers revenue-generating opportunities for the telecom and cable service providers. For traditional telephone service providers, Triple Play is delivered using a combination of optical fiber and digital subscriber line (DSL) technologies to its residential base. Cable television operators use a similar architecture called hybrid fiber coaxial (HFC) to provide subscriber homes with broadband. IIOP: Internet Inter-ORB Protocol (IIOP) is a paradigm-shift that promises to unite distributed objects and applications with no language or platform barriers, and overcomes all the limitations of the current web technologies. IIOP is an object-based protocol and has the potential to massively enhance the types of applications or services or databases that are built and communicate on the web. IIOP provides a comprehensive system through which live objects can request services from one another across the corporate networks over the internet or intranet. IIOP is expected to become the next standard communication protocol on the Internet, replacing, or coexisting with, HTTP/CGI. IIOP is a critical part of a strategic industry standard, the Common Object Request Broker Architecture (CORBA) and is defined by Object Management Group (OMG, a consortium of over 800 companies world-wide). Using CORBA s IIOP and related protocols, a company can write programs that will be able to communicate with their own or other company s existing or future programs wherever they are located, without having to understand anything about the program other than its service and a name. Advantages IIOP offers several advantages like better architecture neutrality, communication transparency, scalability and code reuse. CONCLUSION This present work examined the all previously and recently used protocols and architecture for the Internet. It also gives brief idea about some new technologies which can provide some better and enhanced platform to remove the shortcomings of previously used technologies and tried to use Internet with some enhanced functionalities. REFERENCES 1 Voice and fax over IP, The International Engineering Consortium, 2 R. Stevens. TCP/IP Illustrated: Volume 1: The Protocols. Addison-Wesley, D. E. Comer. Internetworking with TCP/IP Volume I: Principles, Protocols, and Architecture. Prentice Hall, L. L. Peterson and B. Davie. Computer Networks: A Systems Approach, Morgan Kaufmann, 1996 (errata). 5 A. Tanenbaum. Computer Networks. Prentice Hall, W. Stallings. Local and Metropolitan Area Networks. Prentice Hall, 1996 (errata). 7 W. Stallings. Data and Computer Communications. Prentice Hall, R. Perlman. Interconnections: Bridges and Routers. Addison-Wesley, 1992.