Modulation. Bandwidth limitations. Frequency spectrum and its use. Multiplexing. Media: Copper, Fiber, Optical, Wireless. Coding. Framing

Aloha Ethernet MAC Collisions Ethernet Frames

• CIDR IP addressing • Forwarding examples • IP Packet Format

• IP Multicast Service Basics • Host/Router Interaction • MOSPF/DVMRP • Overlay Multicast

• DNS Design • DNS Today

Exam discussion Layering review (bridges, routers, etc.) Exam section C. Circuit switching refresher Virtual Circuits - general Why virtual circuits? How virtual circuits? -- tag switching! Two modern implementations ATM - teleco-style virtual circuits MPLS - IP-style virtual circuits

• TCP flow control • Congestion sources and collapse • Congestion control basics

• TCP congestion avoidance • TCP slow start • TCP modeling

• p2p file sharing techniques – Downloading: Whole-file vs. chunks – Searching • Centralized index (Napster, etc.) • Flooding (Gnutella, etc.) • Smarter flooding (KaZaA, …) • Routing (Freenet, etc.) • Uses of p2p - what works well, what doesn’t? – servers vs. arbitrary nodes – Hard state (backups!) vs soft-state (caches) • Challenges – Fairness, freeloading, security, …

• Internet mobility • TCP over noisy links • Link layer challenges