1. Whirlwind Tour Of Lectures So Far
a.k.a. Review
Athula Balachandran
Wolfgang Richter

2. Lecture 1 : Introduction
What is a network? What is the objective of a network?
Building blocks of a network
Sharing resources
Internet vs inter-net
Challenges of Internet

3. Lecture 2: Protocol Stacks
Layering
Protocols
Hourglass model of the Internet
IP is the compatibility layer
Current Internet design goals and decisions
Minimalist approach
Dumb network - IP provides minimal functionality (addressing, forwarding, routing)
Smart end points – Transport layer performs sophisticated functionalities

4. Lecture 3: Application Layer Examples
Client Server model
Services that applications need
Tolerance to data loss
Timing
Bandwidth
FTP
HTTP
Delay, Throughput
Delay + Size/Throughput

5. Programming: Sockets getaddrinfo() - Prepare to launch!
socket() - Get the file descriptor!
bind() - Which port am I on?
listen() - Will someone please call me?
connect() - Hey, you!
accept() - Thank you for calling port 8080!
send() and recv() - Talk to me, please!
close and shutdown() - Get out!

6. Lecture 4: Physical Layer
Information transfer is a physical process
Modulation techniques
Bandwidth
Nyquist Limit
Capacity of Noisy Channel (Shannon's Theorem)
Multiplexing – FDM, TDM, WDM

7. Lecture 6: Coding and Error Control
Encoding (signals to bits)
NRZ, NRZI, Manchester...
Framing (bit stream to packets)
Ethernet Framing, Clock-based framing
Packet Loss and Corruption
Error Coding – Parity Checking, CRC, Hamming distance
Flow Control – Stop and Wait, Window based

8. Lecture 7: Data Link and Ethernet
Media Access Control
Aloha, Ethernet MAC (Exponential backoff)
Collision detection → Minimum packet length
Ethernet
Packet headers (what is the purpose of the fields?)
Ethernet addresses

9. Lecture 8: Bridging and Switching
Building larger LANs using bridges
Learning bridges
Spanning tree bridges
Internetwork
Routers to forwarding packets
Choices : Virtual Circuits, Source Routing, Global Addresses

10. Lecture 9: IP Addressing
IP forwarding - global addressing, alternatives, lookup tables
IP addressing - hierarchical, CIDR
IP service - best effort, simplicity of routers
IP packets - header fields, fragmentation
ICMP

11. Lecture 10: Ipv6 and NAT
IPv6
NAT
Clients
Servers? Port mapping

12. Lecture 11: Intra-domain routing
How to generate forwarding tables?
Distance Vector
Link State
Routing Hierarchy

13. Lecture 12: Inter-domain Routing
BGP designed to:
Provide hierarchy that allows scalability
Allow enforcement of policies related to structure
Wide area Internet structure and routing driven by economic considerations
Customer, providers and peers
Tier 1, Tier 2, Tier 3 ISPs
Valley-free routing
Mechanisms
Path vector – scalable, hides structure from neighbors,
detects loops quickly

14. Lecture 13: DNS Motivations à large distributed database Scalability
Independent update
Robustness
Hierarchical database structure
Zones
How is a lookup done
Caching/prefetching and TTLs

15. Lecture 14: Router Design
Modern network data rates are much too fast for conventional processors and multiple interface cards on a bus
Partition work into:
Examine header, make decisions
Move the bits
Parallelism is essential
Line cards process incoming packets on each input
Switch fabric complex but avoids bottleneck
Caching and other optimizations needed
and possible for common cases