Concepts for Midterm II

Chapter 3

• Connection-oriented (TCP) and connectionless (UDP)
• Layer functionality
  • multiplexing and demultiplexing (TCP and UDP)
  • error checking (TCP and UDP)
  • segmentation and reassembly (TCP only)
  • reliable data transfer (TCP only)
  • congestion control (TCP only)
• Multiplexing
  • headers: source and destination ports
  • TCP: source and destination, port and IP address
  • UDP: destination only, port and IP address
• Using UDP
  • short simple messages (e.g. DNS), or
  • do-it-yourself connections (multimedia, telephony)
• Reliable data transfer protocols
  • mechanisms
    • checksum
    • acks and nacks
    • sequence numbers
    • timers
    • windowing/pipelining
  • advantage of windowing/pipelining
  • protocols
    • alternating bit
    • go back n (pipelined, single timer)
    • selective repeat (pipelined, multiple timer)
• TCP reliable data transfer protocol charateristics
  • pipelined
  • cumulative acknowledgement
  • single timer
• Congestion
  • end host and network
  • congestion aggravates itself
    • retransmissions (lost, timed out packets)
    • upstream propagation
  • choke packets
  • drawback of transport layer congestion control

Chapter 4

• Functionality
  • forwarding (using forwarding table)
  • routing (building, updating forwarding table)
• Virtual circuit (ATM) and datagram networks (IP)
• Service models
  • delivery
  • bandwidth
  • delay
  • jitter
  • ordering
• IP addressing
  • prefix addressing (e.g. 192.168.0.0/24)
  • role of prefix addressing in forwarding tables
• What's in a router
• Inevitable need for output queuing
• Address assignment
  • global (static)
  • local (static and dynamic)
  • dynamic host coinfiguration protocol (DHCP)
  • network address translation (home, small office)
• ICMP
  • errors
  • congestion control
  • routing algorithm communication
• IPv4 and IPv6
  • address size
  • transition problems
  • tunneling mechanism
• Routing algorithms
  • static
  • dynamic
    • link state (global)
    • distance vector (local/decentralized)
  • problems with dynamic routing
  • interconnected autonomous systems
    • intra-AS routing (link state or distance vector)
    • gateway routers
    • hot potato routing
    • inter-AS routing
    • border gateway protocol (BGP)