E-systems Infrastructure

Probably, every IT practitioner knows about the history of the TCP/IP protocol.

The TCP/IP Protocol Architecture is a result of protocol research and development conducted on the experimental packet-switched network, ARPANET, funded by the Defense Advanced Research Projects Agency (DARPA), and is generally referred to as the TCP/IP protocol suite. It has 5 independent layers which are Application, Transport, Internet, Network Access and Physical (Stalling 2005 p.106).

Today Internetworking has highly adopted the TCP/IP architecture. The TCP/IP network has been dominating the market while there are many communications choices available, standardising on one particular protocol can make administration easier and reduce costs and complexity.

Internet Protocol (IP) is used at the Internet layer to define routing, logical IP addressing, the format of IP headers and packets, and interfaces. It provides routing function across multiple networks.

Transmission Control Protocol (TCP) is used at the Transport layer that enables data to be reliably passed through a network. Why? TCP uses a header to hold important information for performing its tasks. The header fields includes source port, destination port, sequence number acknowledge number, header length, reserved, flags, window checksum, urgent, options and padding and data. TCP uses the port numbers to identify application process on the sender computer and the receiving computer. Besides, TCP can do the error-checking on the IP packet. In case of any error, the packet would be resent again (Knott & Odom 2006).

The Domain Name System (DNS) is a hierarchic way of naming a computer on a TCP/IP network. The name of a network host is on the DNS hosted by the ISP.

The above are the fundamental components of the internetworks nowadays. In brief, IP is implemeted in all end systems and routers (which are bridging different networks). It acts as a relay to move a block of data (i.e. IP packets) from one host, through one or more routers, to another host. TCP is implemeted only in the end systems; it keeps track of the blocks of data being transferred to assure that all are delivered reliably to the appropriate application.

No matter you are running a close Local Area Network (LAN) or an open network if you adopt the TCP/IP model, you will need to have at least a DNS server within your network. All the hosts within the network need to find one another via the DNS server(s). Of course, behind the name of each host is identified by the IP address.

I can say, the Internet is actually the biggest network in the world. Your LAN, Wide Area Network (WAN), Intranet, Extranet and even your personal Wi-Fi gadgets are just the hosts of the Internet. Take the efiling service of Hong Kong Intellectual Property department (HKIPD) as an example, clients (most likely are legal firms) file their tradmark, patent or design applications through the official website https://iponline.ipd.gov.hk/base/bs0100.jsp. Of course, the clients need to registered their company accounts plus user accounts in advance. Money will be deducted from the accounts for each successful upload and e-receipts will be issued immediately. All the things are done over the Internet. Behind the scene, the process is far more complicated. First of all, the clients need to establish the e-system infrastructure for running the efiling service. Client sites need to follow the standard of HKIPD to setup their e-system infrasturcture. For example, a specific port number is required to open on the Firewall, official e-certificates are required for registering the accounts and the uploaded files must strictly follow the required formats.

The virtual private network (VPN) is a cost effective way to interconnect sites by using the Internet or other public network. For example, I can use VPN to connect two network sites located in two different countries. The beauty of VPN is offloading the wide area network management task to the public network provider. That same public network provides an access path for telecommuters and other mobile employees to log on to corporate systems from remote sites (stallings 2005). This can reduce the cost of B2B e-commerce and ease the operations.

The downside is the security of the public network would be out of control.

References

Knott T & Odom W 2006, Networking Basics CCNA 1 Companion Guide, Cisco Press, 800 East 96th Street, Indianapolis, IN 46240 USA, pp.462-463, 522-523.

Stallings W 2005, ‘Business Data Communications’, International Edition, 8th edn, Pearson Education, Inc., Upper Saddle River, NJ 07458, pp.98-128.