Peer-peer and Applicat ion-level Net working CS 218 Fall 2003 Mult - - PowerPoint PPT Presentation
Peer-peer and Applicat ion-level Net working CS 218 Fall 2003 Mult icast Overlays P2P applicat ions Napst er, Gnut ella, Robust Overlay Net works Dist ribut ed Hash Tables (DHT) Chord CAN Much of t his mat erial comes f rom UMASS class
applicat ions, running at various sit es creat e “logical” links (e.g., TCP
each logical link: mult iple physical links, rout ing
let ’s look at an example:
BGP def ines rout es bet ween st ub net works
BGP def ines rout es bet ween st ub net works
Noho-t o-UMass
BGP def ines rout es bet ween st ub net works
Noho-t o-Berkeley
Congest ion or f ailure: Noho t o Berkely BGP- det ermined rout e may not change (or will change slowly)
Noho-t o-Berkeley
Congest ion or f ailure: Noho t o Berkely BGP- det ermined rout e may not change (or will change slowly)
Noho-t o-Berkeley Noho t o UMass t o Berkeley
rout e not visible or
available via BGP!
MediaOne can’t rout e t o
Berkeley via I nt ernet 2
Two-hop (applicat ion-level) noho-t o-Berkeley rout e applicat ion-layer rout er
Measure loss, lat ency, and t hroughput wit h and
13 host s in t he US and Europe 3 days of measurement s f rom dat a collect ed in
30-minut e average loss rat es
A 30 minut e out age is very serious!
Not e: Experiment s done wit h “No-I nt ernet 2-f or-
10 100% 14 80% 20 50% 32 30% 15 4 127 20% 47 57 479 10% RON Worse No Change RON Bet t er Loss Rat e
6,825 “path hours” represented here 12 “path hours” of essentially complete outage 76 “path hours” of TCP outage RON routed around all of these! One indirection hop provides almost all the benefit! 6,825 “path hours” represented here 12 “path hours” of essentially complete outage 76 “path hours” of TCP outage RON routed around all of these! One indirection hop provides almost all the benefit!
select ion.