4605-l3- - Scheduling/IP 2 Puzzle You have 2 glass marbles...

Info iconThis preview shows pages 1–15. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Scheduling/IP 2 Puzzle You have 2 glass marbles Building with 100 floors Both marbles identical in properties A marble will break at a certain floor k and beyond In other words: for floors 1 to k-1, if a marble is dropped from that floor, it will not break; for floors k to 100, if a marble is dropped from that floor, it will break What is the minimum number of drops required to find k? (worst case) 3 Scheduling - WFQ 3 flows A, B, C Weights: A(1), B(2), C(3) Assume same packet sizes 2 5 8 1 3 4 7 6 Tx Schedule: C B C C B A C B Complex overhead due to computation of finishing times Simpler approach? 4 Scheduling (Contd.) Weighted Round Robin Simpler approximation of WFQ Assumes constant packet sizes Can cause unfair delay A B C Fixed Tx Schedule: C C C B B A A 5 Scheduling (Contd.) WRR with WFQ Spread For each flow k with weight wk generate wk elements of the form (1/wk,k), (2/wk,k), , (wk/wk,k) Sort all such elements from all competing flows in lexicographic order Extracting the second element of each pair from the resulting sorted list gives the WRR with WFQ spread 6 WRR with WFQ Spread A (1) B (2) C (3) (1,A) (1/2,B), (1,B) (1/3,C), (2/3,C), (1,C) Lexicographically Sorted: (1/3,C), (1/2,B), (2/3,C), (1,A), (1,B), (1,C) Schedule: C B C A B C 7 Other scheduling policies Deficit Round Robin (DRR) Handles varying size packets Frame of N bits split among the competing flows in the ratio of their weights Flows get to transmit HOL packet only when they have accumulated packet-length number of bits Class based queuing (CBQ) General scheduling and link-share scheduling Greater flexibility to control scheduling policy 8 Internet Protocol (IP) 9 TCP/IP Protocol Suite Physical layer Data-link layer ARP, RARP, SLIP Network layer IP, ICMP, IGMP, BootP Transport layer _ TCP, UDP, RTP Application layer http, smtp, ftp 10 Internet Protocol (IP) Multiplexing and Demultiplexing Addressing Routing Fragmentation and Reassembly Quality of Service 11 Multiplexing Web Email MP3 TCP UDP IP Web Email MP3 TCP UDP IP IP datagrams IP datagrams 12 Addressing Need unique identifier for every host in the Internet (analogous to postal address) IP addresses are 32 bits long Hierarchical addressing scheme Conceptually IPaddress =(NetworkAddress,HostAddress) 13 Address Classes Class A Class B Class C 0 netId hostId 7 bits 24 bits 1 0 netId hostId 14 bits 16 bits 1 1 0 netId hostId 21 bits 8 bits 14 IP Address Classes (contd.) Two more classes 1110 : multicast addressing 1111 : reserved Significance of address classes?...
View Full Document

This note was uploaded on 10/12/2011 for the course ECE 4605 taught by Professor Staff during the Fall '08 term at Georgia Institute of Technology.

Page1 / 52

4605-l3- - Scheduling/IP 2 Puzzle You have 2 glass marbles...

This preview shows document pages 1 - 15. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online