Final Exam Review Basics B i
• • Basic terminology and concepts Layered model (physical to application)

Internet Layering
• • • • • • • • Level 5 Level 4 Level 3 Level 2 -- Application Layer (rlogin, ftp, SMTP, POP3, IMAP, HTTP..) -- Transport Layer(a k a Host-to-Host) Layer(a.k.a Host to Host) (TCP, UDP) -- Network Layer (a.k.a. Internet) y ( ) (IP, ICMP, ARP) -- (Data) Link Layer / MAC sub-layer (a.k.a. N t ( k Network Interface or kI t f Network Access Layer) -- Physical Layer

• Level 1

Final Exam Review
Physical Layer
• • • • Time and frequency domains. Bandwidth Band idth and data rate rate. Analog and digital transmission. Simplex, half-duplex and full-duplex transmission

Final Exam Review Physical Layer ( Ph i l L (cont’d) ’d)
• • • • Transmission impairments. Decibel. S/N ratio. Channel capacity. – Nyquist Nyquist. – Shannon. • Types / properties of media – Copper (UTP: Cat-3, Cat 5) Cat 3, Cat-5) – Fiber.

Final Exam Review Physical Layer (cont’d) (cont d)
• Data encoding – Analog-to-digital. • (Time sampling / amplitude quantization) – Digital-to-analog. • (D t reconstruction) (Data t ti ) – Transmission modes. • S Synchronous. h • Asynchronous.

Final Exam Review Data Li k L D Link Layer
Error Control
• • Framing Error detection / correction schemes schemes. • Parity. • Hamming distance • CRC (polynomial encoding)

.

Final Exam Review Data Li k L D Link Layer
Flow Control • Acknowledgement • Stop and Wait • PAR (P i i A k (Positive Acknowledgement with l d ih Retransmission) • ARQ (Automatic Repeat reQuest) • Sliding Window • Piggybacking • “go back n” • Pipelining • S l ti repeat Selective t

Final Exam Review Bit Length of a Li k Bi L h f Link
• • • • • • • • Assume link is fully occupied y p 1st bit is just arriving at the receiver sender has sent continuously R = data rate (bps) d = distance (length of link) (meters) V = propagation velocity (meters / second) (~ 2 - 3 x 108 meters/second) Bit length = Rd / V bits

Final Exam Review MAC sub-layer bl
– DLL / MAC protocols • Static Channel Allocation • Dynamic Channel Allocation – Multiplexing. • F Frequency-Division M lti l i (FDM) Di i i Multiplexing (FDM). • Time-Division Multiplexing (TDM). • St ti ti l Ti Statistical Time-Division M lti l i Di i i Multiplexing (STDM).

Final Exam Review Data Li k L D Link Layer
• LANs
– – – – – Protocol architecture. 802 standards. Encapsulation/de-encapsulation. p p Frame format. LAN topologies.

Encapsulation
Frame header Packet header
TPDU header

TPDU payload

Encapsulation
Application data pp TCP header IP header MAC header LLC header MAC trailer

LLC PDU MAC frame

TCP segment IP datagram

Final Exam Review Data Li k L D Link Layer
• MAC
– Centralized and distributed. – Synchronous and asynchronous. – Asynchronous MAC. y • Round-robin, reservation, and contention.

• LLC for LANs LANs.

Final Exam Review Data Li k L D Link Layer
• MAC protocols. protocols
– Contention. • ALOHA and Slotted ALOHA ALOHA. • CSMA. • CSMA/CD CSMA/CD. – Token Passing • Token bus. • Token ring.

Final Exam Review Data Li k L D Link Layer
• Ethernet
– – – – – Cabling Manchester encoding Back-off Switched Performance / speed / length

• High-Speed LANs High Speed
– Fast Ethernet – Gigabit Ethernet

Final Exam Review Data Li k L D Link Layer
• Wireless LANs
– Hidden station problem – MACA / MACAW • RTS / CTS

Final Exam Review Network L N k Layer
• • Datagrams and Virtual Circuits g Packet Routing
– – – – Flooding g Distance Vector Routing Link State Routing Hierarchical Routing

• • • •

Congestion Control Choke Packets / Load shedding QOS (traffic shaping, buffering, overprovisioning) Leaky Bucket / Token Bucket Tunneling

Flooding

Stallings Figure 12 4 12.4 • hop-count=3, • no detection of duplicates

Final Exam Review Network L N k Layer
• • • • • IP Protocol / addressing/ subnet masks / aggregation ti NAT ARP / RARP (physical address IP address) DHCP (dynamic IP address assignment) IGP (Interior g ( gateway routing p y g protocol) ) – RIP – OSPF (link state algorithm) EGP (Exterior gateway routing protocol) – Policies / politics / constraints – BGP (distance vector protocol) IPv6

•

•

Final Exam Review Transport Layer T L
End to end End-to-end Used by applications on client and server Under user control (operating system / programming language calls) • Transport Services – Connectionless (User Datagram Protocol UDP) • No flow control, no error control control – Connection-oriented (TCP) • Flow and error control – RTP (for multimedia) • • •

Final Exam Review Transport Layer T L
• Connection Management – 3-way handshake in making connection – Sequence numbers / avoiding duplicates – Connection release (timer use) Berkeley sockets Flow Control and Buffering Multiplexing Crash Recovery End-to-End k E d t E d ack

• • • • •

Final Exam Review Transport Layer T L
• TCP
– – – – – Congestion Management Estimating RTT ( p g (exponential weighting) g g) Timers “Slow Start” / exponential back-off Wired vs. wireless for TCP traceroute ping Transfer time components (vs length bandwidth) (vs. length,

•

Network Performance
– – –

Final Exam Review Application Layer A li i L
• DNS
– – – Namespace Caching g Recursive resolution Bit rates Issues Compression

•

Multimedia
– – –

Internet Layering
• • • • • • • • Level 5 Level 4 Level 3 Level 2 -- Application Layer (rlogin, ftp, SMTP, POP3, IMAP, HTTP..) -- Transport Layer(a k a Host-to-Host) Layer(a.k.a Host to Host) (TCP, UDP) -- Network Layer (a.k.a. Internet) y ( ) (IP, ICMP, ARP) -- (Data) Link Layer / MAC sub-layer (a.k.a. N t ( k Network Interface or kI t f Network Access Layer) -- Physical Layer

• Level 1