CS402: Computer Communications and Networks

This article discusses one of the most popular network applications: Voice over IP. There are several industry protocols for Voice over IP. One of the most popular and widely accepted is the IETF protocol SIP. As you read, pay special attention to the registering and calling process.

Watch this video from 4:04 to 34:12. It discusses Internet Protocol Television (IPTV), a technology that streams live TV over the Internet. Unlike regular streaming, IPTV requires a strong Internet connection that can simultaneously handle TV, Internet, and voice calls. IPTV uses specialized networks to maintain consistent quality.

Pay attention to how TV channels are converted into digital formats for transmission, the efficiency of multicast technology in sending streams to multiple viewers, and the importance of network management. The video demonstrates how multicast efficiently distributes TV content, which reduces internet load. What technologies support this infrastructure from the network to your living room? How does IPTV combine the reliability of traditional TVs with the versatility of the Internet?

Read this section and focus on DoS attacks, intrusion, hijacking, Web authentication attacks, and weaknesses in Internet architecture.

When you first used your computer to access the Internet, what was the first security technique you heard about? How does a firewall protect your system from the "evil-doers" lurking on the Internet?

As you watch this video, concentrate on virtualization and deployment models like private, community, public, and hybrid clouds. When is cloud computing beneficial, such as for businesses requiring scalability? When may it not be suitable due to regulatory or stability reasons? What needs do the service models SaaS, PaaS, and IaaS serve? Which deployment model fits certain business scenarios? How does virtualization support cloud computing?

Watch this video, which discusses the advantages and disadvantages of cloud computing and when it makes sense for companies to move to the cloud.

Read this article and make sure you can describe when and where authentication, authorization, and accounting (AAA) are used.

Authentication services act as the first line of defense to confirm identities through credentials like usernames and passwords. The AAA validates user access, authorizes resource use, and logs activity. The Remote Authentication Dial-In User Service (RADIUS) protocol manages remote access authentication. What are its security implications, particularly the potential risks of only encrypting passwords? What are the potential consequences of authentication failure?

Watch this video from 16:26 to 28:09. Consider the distinctions between TACACS+ and RADIUS. TACACS+ is the go-to for WAN environments, with its robust logging and TCP-based encryption encompassing the whole packet. RADIUS is UDP-based and is favored in LAN settings for its speed and selective encryption of user credentials.

TACACS+ is relatively complex, while RADIUS has a more straightforward configuration process and improved resource efficiency. Both protocols are compatible with various authentication methods and directory services, but TACACS+ typically stands out for comprehensive accounting. Is the complexity of TACACS+ justified by its benefits? How often do network professionals use debugging tools to scrutinize authentication logs and maintain network security?

Lightweight Directory Access Protocol (LDAP) manages and accesses directory information over a network. LDAP is structured hierarchically within the Directory Information Tree. How might this hierarchy influence the way you query and retrieve information?

LDAP communications are not encrypted by default. Therefore, while LDAP is useful for authentication and directory services, securing LDAP communications with SSL or TLS is essential due to its unencrypted nature. Why it might be crucial to implement SSL or TLS in LDAP interactions? What are the roles of directory schemas and query mechanisms?

Watch this video on TCP and reliable data delivery. Why does TCP divide a file into packets, and how do sequence numbers aid in reconstruction at the destination? Consider TCP's response to packet loss and the role of acknowledgments in ensuring complete data transfer. How does TCP determine when to resend packets, and how does the timeout mechanism deal with delayed or out-of-order packets? Each element of TCP's design is essential for the protocol's ability to deliver data reliably over the Internet.

If you want to practice, follow these steps, which will instruct you on using port-scanning techniques to administrate a large network.

Read this detailed description of VPNs and how they can be used to improve network security.

If you would like to practice, follow these steps to control your computer from a mobile device via Virtual Network Computing. Virtual Network Computing is a graphical desktop sharing system. It uses the Remote Frame Butter Protocol to control another computer remotely. Even if you choose not to try this activity, reading it can still be valuable since it explains the difference between RDP and VNC.

If you have a Windows computer, you can try following these steps to control your computer from a mobile device.