RulesAboutNetworks

Thereare only

twonetworkmodels

MaBell

… or the Internet

Pros: Stable Uniform

Consistent level of service

Someone is in charge

Cons:

Inflexible

Limited range of services

Expensive to connect

You’re not the one in charge

Pros: Easy to adapt

Cheap to connect

No one runs it

Cons:

It never stops changing

No guaranteed level of service

No one runs it

No one can afford to become Ma Bell again.

NotTheseGuys

OrTheseGuys

OrTheseGuys

OrTheseGuys

So what are the

odds you will?

No one can afford to becomea network dictator again.

Networking: Yin and Yang

Stuff you control Stuff someoneelse controls

God, grant me the serenity

to accept the network

elements I cannot change;

the courage to change the

network elements I can;

and the wisdom to know

the difference.

Grasshopper: you must learn the paradox of

internetworking. Which is…?

Not changing things enables you to change things.

Huh?

It’s True!Just Look at the Internet!

TCP/IP Protocol Stack

Changes Often

Rarely Changes

So what things should I try

not to changetoo much?

Q: What element did both the Internet and Ma Bell control?

Q: What element did both the Internet and Ma Bell control?

A: Addressing.

Jon Postel,Original Internet Assigned Numbers Authority (IANA)

North American Numbering Plan (NANP)

WhatElse?

A: Pay Attention to Life Cycles.

Computers:2-3 years

A: Pay Attention to Life Cycles.

OperatingSystems:3-5 years

A: Pay Attention to Life Cycles.

NetworkProtocols:7-10 years

A: Pay Attention to Life Cycles.

DataFormats:10+ years

There is a name for network elements that don’t change quickly:

The Installed Base

Unlike in global warming, however,

this almost never gets smaller.

The only reason God could create the world in six days was because He didn't have to worry

about the installed base.*

* Enzo Torresi, E inar S tefferud, Esther Dyson, or someone else

Unfortunately, often today’s hot new technology ….

Becomes that junky old stuff that drags

down the whole installed base.

1999 2008

A: Inevitable.

Q: What is the likelihood the stuff you want to control eventually becomes your biggest obstacle?

But what about the things I

can’t control?

How do you protect yourself against reckless drivers?

Buckle up.Keep alert.

Obey signs.

Buy insurance.

Have airbags.Have bumpers.

Yeah, Buckle up.

Protection, Network-Style• Redundant Points of Presence

• Firewalls

• Virus Checkers

• Daily Backups

• Weekly Backups

• Off-site Storage

• Alternate Routes

• Contingency Procedures

• Contingency Drills

Can I steer a safe passage through

these perils?

Do I look like Albert Freakin’ Einstein?

Stuff is out of control all over my network.

… and I’m OK with that.

Find Your Own Networking Bliss