CS 725/825 Computer Networks, IT 725 Network Technology

Course Topics

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Basic Concepts

• Categories of networks. Basic concepts and terminology.
• Layered model, OSI 7-layer model. Internet layers, common functions of layers. Services of a layer, reliable vs. unreliable, connection-oriented vs. connectionless. Internet protocol "hourglass".
• Time-space diagram. Network performance measures.
• Network standardization: key players, standard documents, standardization processes.

Networking Fundamentals

• Routed point-to-point networks vs local broadcast-based networks. Address Resolution Protocol (ARP). Anatomy of a routing/switching device.
• Domain Name Service (DNS) and Dynamic Host Configuration Protocol (DHCP),
• IP Subnets, prefix and subnet mask.
• Static routing, routing table. Routing loops. Classless InterDomain Routing (CIDR), private IP addresses.
• Basics of bridging and L2 switching, resilience and scaling of bridged networks: spanning tree protocols, VLANs.

Application Protocol Design and Implementation

• Client and server, ports, well-known and ephemeral ports. Application layer protocol architecture
• Networked application programming. Socket API. Handling of concurrent requests.
• World-wide web and HTTP.
• Email, SMTP, IMAP, webmail. MIME.
• Network Management, SMTP, NETCONF, YANG.

Network Security

• Intro to network security. Encryption, goals, categories of encryption methods, public/private key cryptography, man-in-the-middle attack
• Encryption methods, authentication, message integrity, cryptographic hash functions.
• Public key certificates, certificate authority.

Principles of Reliable Transport - Transport Layer

• Functions of the layer, principles of reliable transport, ARQ. Congestion control, offered vs carried load diagram, load vs latency diagram.
• Principles of congestion control. Transmission Control Protocol (TCP).
• TCP session management, TCP flow control.
• TCP network congestion control, TCP variants: CUBIC and BBR. Fairness.
• User Datagram Protocol (UDP).
• TCP alternatives, QUIC & HTTP/3.
• Transport Layer Security (TLS).

Routing and the Network Layer

• Fundamental concepts and services. Internet Protocol (IP). IP fragmentation.
• Internet Control Message Protocol (ICMP).
• IPv6
• Operations of link state and distance vector routing protocols, scaling routing protocols, Autonomous System, RIP, OSPS, BGP-4
• QoS in IP networks, TOS field and Differentiated Services.
• Multicasting, multicast routing, content delivery networks (CDNs).
• Circuit vs packet switching. Virtual circuit switching, MPLS.
• Software Defined Networks (SDNs).

Link and Physical Layers

• Basic concept, Data Link Control (DLC) and Media Access Control (MAC). Deterministic and stochastic (random) access methods, CSMA/CD.
• Ethernet/IEEE 802.3, frame format, nomenclature, historical evolution.
• Wireless networks, IEEE 802.11 - basic concepts. Hidden terminal problem, CSMA/CA.