Protocol Review of Telephone and Data Networks

Protocol Review of Telephone and Data Networks

Robert Sabine

University of Phoenix

NTC 360

Network and Telecommunications Concepts

October 28, 2006

Protocol Review of Telephone and Data Networks

In our initial analysis, Riordan's network architecture is primarily based on Ethernet technology. Other technologies also discovered were VoIP, satellite and public switched telecommunications networks. With regards to these technologies, further analysis identified protocols that are used in conjunction with these technologies. These protocols are primarily contained in the Internet protocol suite.

The Internet protocol suite is a highly related collection of protocols. It is also commonly referred to as TCP/IP. TCP and IP were the first and primary protocols developed for internetworking. However, it is comprised of many other protocols that collaborate with each other to perform each distinct task required for communication on and to other network components. Based on the network topology and devices that reside on the network, the protocols that will be discussed are IMCP, TCP, IP, UDP, DNS, FTP, HTTP, IMAP4, POP3, SIP, SMTP, SNMP, SSH, and Rlogin. These protocols are integral to Ethernet networks; some are required, some optional, and some to be avoided but replaced with better solutions.

The Internet Control Message Protocol (ICMP) is a network layer protocol. "It is one of the core protocols of the Internet protocol suite." IMCP is primarily used in reporting network errors on the network commonly seen when pinging or using trace routes when trouble shooting connectivity.

Transport Control protocol (TCP) is the interface between the application layer and the network layer. TCP provides a reliable connect between the applications and the network. Conversely, UDP does not provide a reliable connection. It sends packets without regards to delivery or sequence. However the advantage of UDP is that it is fast. "While the total amount of UDP traffic found on a typical network is often on the order of only a few percent, numerous key applications use UDP, including the Domain Name System (DNS), the simple network management protocol (SNMP), the Dynamic Host Configuration Protocol (DHCP) and the Routing Information Protocol (RIP), to name just a few."3

Internet Protocol (IP) is the protocol used for encapsulating the data into a packet, and then assigning a unique address of the source and the destination of the packet in the packet header. "Because of the abstraction provided by encapsulation, IP can be used over a heterogeneous

network (i.e., a network connecting two computers can be any mix of Ethernet, ATM, FDDI, Wi-fi, Token ring, etc.) and it makes no difference to the upper layer protocols."5 This is one reason why IP is widely used and accepted in the telecommunication industry. The disadvantage of IP is that it is unreliable in of itself. However combined with the reliability of TCP and the flexibility of MPLS, it makes this disadvantage a moot point.

Domain Name Service (DNS) is used to translate or cross reference IP addresses to domain names. If a domain name is to be found on the network, it must be registered with a DNS. When a user types the domain name, the address of a domain is resolved, and then forwarded to a HTTP server. The HTTP server will then transmit the default HTML file, usually index.html, to the browser. Riordan should register a domain for World Wide Web recognition. In addition, HTTPS should be considered for securing password protection for data transmitted via the web site.

File Transfer Protocol (FTP) is used to transfer files. However, it should be discouraged for use in unsecured networks. Although FTP login is password protected, the password entered and transmitted is in clear text and is subject to interception before reaching its destination. An alternative to FTP is FTPS which encrypts the data channel before transmitting.

Simple Network Management Protocol (SNMP) is used to monitor the status of the network devices. It is comprised of two components, a server and an agent/probe. Each device has unique management information bases (MIBs) associated with it. The agents/probes is a software application developed to recognize and interpret the MIBs and commands from the server. The server then can routinely poll or listen for the probes to detect problems with the device. Some examples of these managers and agents are HP Openview or Micromuse Netcool.

IMAP and POP3 are email retrieval protocols, while SMTP is an email transmit protocol. All three of these email protocols reside in the application layer of the Internet protocol suite and are used in conjunction to send and receive email. IMAP is designed to leave mail on