Multiple Simultaneous Connections

By Raul Bernardino

Introduction:

The HyperText Transfer Protocol (HTTP) is the web application protocol”, Kurose J. and Ross K., (2010, P.126). With this HTTP as a fundamental for web applications protocol whereas we can browser web sites from anywhere to any single web server or multiple web servers. It is implementing in client and server programs. The HTTP can be defining what sites that client requested and on the web server site HTTP will be transferring the web sites according to the request. In other words the HTTP will be acting as messenger to bring the request from client to the web servers and to bring the responses from web servers to the clients.

Nowadays, web browser can be configuring in order to have concurrent links to the web site. In today web browser default it sets to five to ten concurrent links over Transmission Control Protocol (TCP). For example: The IE6 and EI7 on the HTTP 1.1 can be supporting two concurrent links while IE8 already have six concurrent links in the default setting. These all can be configured via regedit command to edit the windows register, give the value to the register. It depends on needs.

The TCP is end to end links or point to point links whereas it calls also virtual circuit. 

How TCP is working as follows:

1. The TCP is established link or connection: where to set up the two pairs of computers in order to exchange the data.
2. TCP operate in full duplex: where only one can connect to each one at the time.
3. Error checking: The TCP uses checksum techniques to verify packets; either it is valid packets or corrupted packets.
4. Sequencing: All packets are flagged with the numbers in order to identify the sequence order numbers in the destination and it also allows the operating system to define which packet is missing.
5. Acknowledgement:  when it is reached the destination the TCP will be sending acknowledgement (ack) that packets is received. If not the sender will be re-transmitting the missing packets.
6. Flow control:  in some case if the sender is transmitting very quick and receiver can’t receive it, the packet will drop and alert the sender to slow down.
7. Packet recovery services:  There are two way to do. First, sender can re-transmit the packets because the sender is not receiving the acknowledgement from the destination. Second, the destination can request to the sender to re-transmit such packet that need to be completed.

The advantages Transmission Control Protocol (TCP) links as follows:

•  The TCP will be assuring the communication that the data is reaching the destination within the time frame and no duplications in data transmission.
• The operating system will be handling the TCP processes and we just wait for the result.
• The data is transforming in to the packets by TCP before it send out to your end.
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The disadvantages Transmission Control Protocol links as follows:

1. While operating system will handle the processes therefore if  in the system has a bugs then will be having several problems on the browsing or searching and including downloads.
2. The TCP is not broadcast and multicast links.
3. Because it is checking error, making sequences of the packets, making acknowledgment, and etc. it will slowdown the speed.

Reference List:

1. Kurose J.F., Ross K.W., 2010: Computer Networking; A Top-Down Approach: 5^th Edition’; Boston, Addison-Wesley
2. Lecture notes, CPCOMM_week2_lecture
3. DVANTAGES AND DISADVANTAGES OF TCP AND UDP, [on-line]. Available from: http://smblog.iiitd.com/2010/09/advantages-and-disadvantages-of-tcp-and.html   (Accessed date: August 12, 2011)
4. TCP (Transmission Control Protocol), [on-line]. Available from:  http://www.linktionary.com/t/tcp.html (Accessed date: August 12, 2011)