32
Network vs. Server Issues in end-to-end performance Christian Huitema [email protected] June 18, 2000

Network vs. - Les défis de la nouvelle génération

Embed Size (px)

Citation preview

Page 1: Network vs. - Les défis de la nouvelle génération

Network vs. Server Issues in end-to-end performance

Christian [email protected]

June 18, 2000

Page 2: Network vs. - Les défis de la nouvelle génération

The Internet grows, and grows…

0

1020

3040

5060

7080

90

Jan-97 Jul-97 Jan-98 Jul-98 Jan-99 Jul-99 Jan-00 Jul-00

Number of hosts (millions) in the Internet (Netsizer by Telcordia)

Page 3: Network vs. - Les défis de la nouvelle génération

Network versus servers: who is trailing whom?

• Network vs. server performance, today

• State of the network,• The special case of the DNS,• The 10 Gigabit challenge,• Going end-to-end?

Page 4: Network vs. - Les défis de la nouvelle génération

Network vs. server performance, today

Page 5: Network vs. - Les défis de la nouvelle génération

get address

connect

DNS

accept

prepare

transmit

HTTP GET

receive

close

server

network

delay

Get address only once (cache).Connect only once (HTTP 1.1), Pipeline.

Measuring the components of the web

delayDNS

Page 6: Network vs. - Les défis de la nouvelle génération

Web performance estimation, 1998-2000

• For a given client/server pair:– Measure the address resolution delay,

connection delay, delay to first packet, delay to transmission of page

• Repeat every day:– For a fixed set of 100 “large” servers,– For a set of 100 “random” servers,

provided from randomized requests to Altavista, Lycos, Google, etc.

Page 7: Network vs. - Les défis de la nouvelle génération

Observed bandwidth seems to grow over time

0

20000

40000

60000

80000

100000

120000

140000

Sep-98 Feb-99 Aug-99 Jan-00

median

worst 5%

14 per.Mov. Avg.(median)

Page 8: Network vs. - Les défis de la nouvelle génération

The servers seem to contribute 40% of the

delay

0%

10%

20%

30%

40%

50%

12/1/99 1/1/00 2/1/00

Large servers Random servers

Page 9: Network vs. - Les défis de la nouvelle génération

Feedback Loop: Why Capacity Doubles Every 8

Months

Providers increase the network capacity

More users, more demand,

faster modems

More contents, more servers,

faster feeds

Page 10: Network vs. - Les défis de la nouvelle génération

Network vs. server: what is the state of the

network?

Page 11: Network vs. - Les défis de la nouvelle génération

First network characteristic:

Packet loss ratesEvolution of SYN repeat rates

0%

5%

10%

15%

20%

25%

9/4/1998 2/14/1999 7/27/1999 1/6/2000

C > 2s

14 per. Mov. Avg. (C >2s)

Page 12: Network vs. - Les défis de la nouvelle génération

Second characteristic:Round trip time

0

50

100

150

200

250

300

Jul-98 Nov-98 Feb-99 May-99 Aug-99 Dec-99 Mar-00

Page 13: Network vs. - Les défis de la nouvelle génération

Taking a closer look at the round trip time distribution

Density and CFD of "short" connection delays (ms)

0.000001

0.00001

0.0001

0.001

0.01

0.1

1

10 100 1000 10000

1-CFD(x)

density(x)

Page 14: Network vs. - Les défis de la nouvelle génération

Likely evolution of the network

• Accommodate growing demand:– Cable, DSL, other broadband– Mobile phones, appliances

• Likely evolution:– Average bandwidth grows -> 100 kbps– Median delays -> distance/speed of light– Delay deviation diminishes, as predicted

by Paul Kenny’s work.

Page 15: Network vs. - Les défis de la nouvelle génération

Network vs. server:The special case of the

DNS

Page 16: Network vs. - Les défis de la nouvelle génération

DNS: an amplifier of the Internet Performance

Local S

erv

er Root, .Com

Example.Com

Many network traversals, many servers.

Page 17: Network vs. - Les défis de la nouvelle génération

Resolution Delay,Random DNS Names

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0 2 4 6 8 10 12

Page 18: Network vs. - Les défis de la nouvelle génération

DNS delays don’t seem to improve at Internet

Speed…

0%

10%

20%

30%

40%

50%

60%

9/4/1998 2/14/1999 7/27/1999 1/6/2000

D > 2s

C > 2s

14 per. Mov. Avg. (D >2s)

14 per. Mov. Avg. (C >2s)

Fraction of DNS resolution delays over 2 seconds

Page 19: Network vs. - Les défis de la nouvelle génération

A clear case of “server vs. network”

• A.ROOT-SERVERS.NET loss: 33.9%• B.ROOT-SERVERS.NET loss: 3.4%• C.ROOT-SERVERS.NET loss: 21.1%• D.ROOT-SERVERS.NET loss: 2.6%• E.ROOT-SERVERS.NET loss: 12.3%• F.GTLD-SERVERS.NET loss: 4.0%• F.ROOT-SERVERS.NET loss: 12.3%• G.ROOT-SERVERS.NET loss: 62.1%• H.ROOT-SERVERS.NET loss: 20.9%• I.ROOT-SERVERS.NETloss: 7.1%• J.GTLD-SERVERS.NET loss: 8.3%• K.GTLD-SERVERS.NET loss: 2.2%

Limits of these data:

One single test,

One single day!

Page 20: Network vs. - Les défis de la nouvelle génération

How will the DNS situation evolve?

• No clear virtuous cycle:– Registration of new names is a for profit

venture (NSI, and wannabes)– Maintenance of root is a non profit

service with political constraints (ICANN)• Solutions from servers, software:

– Less reliance on root?– More reliance on caches (load

balancing?)– Less reliance on the DNS!

Page 21: Network vs. - Les défis de la nouvelle génération

Network vs. server:The 10 Gigabit challenge

Page 22: Network vs. - Les défis de la nouvelle génération

Servers are getting better but is this enough?

• Internet2 Land Speed Record award:– "We hope this competition gets people

thinking about enabling really revolutionary Internet applications," - Jim Gray

– "To realize Internet's full potential, end-to-end network performance needs to take a huge leap forward," - Gordon Bell

• The records: – 751.362 Mbps over 5,626 km (single TCP)– 957.369 Mbps over 5,626 km (2 TCP)

Page 23: Network vs. - Les défis de la nouvelle génération

The 10 Gigabit challenge, or the limits of Moore’s

law

02468

1012141618

2000 2001 2002 2003

Backbone (9months)

Fiber (10months)

Moore's law (18months)

Page 24: Network vs. - Les défis de la nouvelle génération

Meeting the challenge:part 1, ever better servers• Get stronger:

– Faster CPU, better memory architecture– Faster I/O

• Get smarter:– HTTP 1.1, TCP, IPv6…– Better protocol design(s)– Better software (doing that)

• Get help:– Offload packet processing (done that)– Offload encryption (done for IPSEC)– Offload key management (uh?)

Page 25: Network vs. - Les défis de la nouvelle génération

Meeting the challenge:part 2, larger clusters

• Servers x2 every 18 month. • Can we manage a cluster of 100,000

servers?– Load balancing, Software upgrade, Failover

• Can we develop distributed applications?

Page 26: Network vs. - Les défis de la nouvelle génération

Meeting the challenge:part 3, distribution

networks

• Push the “content” near the “consumers”

• Is this needed in a 10 Gigabit world?• Does it work for more than GIF files?

Page 27: Network vs. - Les défis de la nouvelle génération

Evolution of server, server farms and distribution

• Handling variability– Heavy tail distribution of demand means

flash crowds, etc.– Could incite to a “market of servers”, or to

“adaptive servers.”

• Pushing up hill– Need a serious business case for investment

in new servers– Constantly testing the limits of the

technology

Page 28: Network vs. - Les défis de la nouvelle génération

Network vs. server:Going end-to-end?

Page 29: Network vs. - Les défis de la nouvelle génération

End to end distribution:NAPSTER, Gnutella

Rendezvous, directory

Page 30: Network vs. - Les défis de la nouvelle génération

End to end communication: real time

audio, video, gamesSIP proxy

SIP proxy

Page 31: Network vs. - Les défis de la nouvelle génération

Meeting the challenge:distribute the load!

• The return of the end-to-end argument– Each new client brings its own

resource– The only known way of scaling

• Only place in the servers the functions that cannot possibly placed in the client!

Page 32: Network vs. - Les défis de la nouvelle génération

Network vs. server:Thank You!