Course Review
- networking overview, sockets API, application-level networking, HTTP
- DNS, SMTP and email, FTP, NFS, SNMP, network security
- physical layer, framing, error detection
- data-link layer, topology, Aloha, Ethernet, public networks, ATM
- IP and network layer, forwarding, routing, addressing, ARP,
fragmentation, IPv6, ICMP
- transport layer, TCP, reliable transmission, windows and flow control,
connection management, congestion control, UDP
- the future (class discussion)
Sockets API, Application-level Networking, HTTP
- client and server networking
- connectionless or connection-oriented
- sockets API calls, stream and datagram sockets
- HTTP client and server: request-reply model
- headers followed by empty line possibly followed by data
- per-request vs. persistent connections
- MIME and content type
- textual encoding of data
DNS, SMTP and email, FTP, NFS
- hierarchical domain name system, hierarchical allocation
- hierarchical network of redundant servers, with delegation and proxy
- textual encoding of emails
- email programs have multiple roles: originating, forwarding,
storing, reading (not simply client and server)
- FTP: transferring whole files using connections
- NFS: transferring pieces of files using datagrams, stateless server
SNMP, Network Security
- SNMP: able to monitor network using UDP
- use the network to provide information that helps identify problems
- if some information is lost, the remaining information is still useful
- security is never perfect, every bit helps
- privacy, authentication, data integrity and availability
- different attacks, defenses
- basics of encryption: one-time pad, DES, secret-key vs. public-key
encryption
Physical layer, Framing, Error Detection
- media: copper, fiber, wireless, satellite
- data rates, bit encoding, carriers, modulation, multiplexing
- Time Domain Multiplexing, packet framing
- SLIP
- parity, checksum, CRC
Data-link layer, Topology, Aloha, Ethernet
- data link: the OSI layer that deals with hardware frames
- addresses, real-time performance, types of errors
- star topology, bus topology, ring topology
- Aloha contention resolution: error detection, and keep trying
- Ethernet interface, packet sniffing
- Ethernet hubs, bridges, switches
- Ethernet speeds: 10, 100, 1Gb, 10Gb...
Public Networks, ATM
- digital telephony: 8000 samples per second (real time)
- SONET: floating payloads, two-dimensional frames
- Frame Relay: virtual circuits
- ATM: virtual channels and virtual paths
- ATM switches, cell switching, signaling
- ATM quality of service
- ATM LANs: VPN, CLIP
\begin{eslide}{IP and network layer, forwarding, routing, addressing,
fragmentation, IPv6, ARP, ICMP}
- packet switches: accept packets and forward them appropriately
- universal connectivity: unique (universal) and hierarchical addresses,
IP address classes and address masks
- routing protocols: distance-vector, link-state
- IP header and IP processing: how to initiate, how to forward packets
- IP fragmentation, TTL
- reasons why IP checksum only covers header
Transport layer, TCP, Reliable Transmission, UDP
- first end-to-end layer: TCP, UDP
- sequence numbers, acknowledgements for reliable transmission
- connection setup, three-way handshake
- connection teardown
- window-based flow control: prior permission required to trasmit
- TCP congestion control: probe the network, try and find an
acceptable send window
oitem pseudo-header checksum
- UDP: multiplex and checksum datagrams
What next?
- discussion of the future
- please come prepared with your thoughts about the future of
networking