EECS 122:
Introduction to Computer Networks
Evolution of the Internet
Computer Science Division
Department of Electrical Engineering and Computer Sciences
University of California, Berkeley
Berkeley, CA 94720-1776
Katz, Stoica F04
R U RDY 4 WOTS NXT?
Katz, Stoica F04
2
“X-Internet” Beyond the PC
Internet Computers
Internet Users
93
Million
Today’s Internet
407 Million
Automobiles
663 Million
Telephones
1.5 Billion
X-Internet
Electronic Chips
30 Billion
Forrester Research, May 2001
Katz, Stoica F04
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“X-Internet” Beyond the PC
Millions
15000
10000
5000
X
Internet
20
01
20
02
20
03
20
04
20
05
20
06
20
07
20
08
20
09
20
10
0
PC
Internet
Forrester Research, May 2001
Year
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ShapeThe
of Old
Things
DaysToday:
Diverse Appliances and Devices
Game Consoles
Personal Digital Assistants
Digital VCRs
Communicators
Smart Telephones
E-Toys
All will demand broadband
Internet connectivity
… and 10BaseT won’t be sufficient
Katz, Stoica F04
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Future of the Internet
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Mobile IP
Networked Everything: Sensor Nets
Internet Economics
Katz, Stoica F04
6
Why Mobile IP?
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Need a protocol that maintains network
connectivity while hosts move between nets
Must avoid massive changes to router software,
etc.
Must be compatible with large installed base of
IPv4 networks/hosts
Confine changes to mobile hosts and a few
support hosts that enable mobility
G. G. Richard III, UNO
Katz, Stoica F04 7
Mobile IP: Basics

Proposed by IETF (Internet Engineering Task
Force)
- Standards development body for the Internet
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Allows a mobile host (MH) to move about without
changing its permanent IP address
Each mobile host has a home agent (HA) on its
home network
MH establishes a care-of address when it's away
from home
G. G. Richard III, UNO
Katz, Stoica F04 8
Mobile IP: Basics
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
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Correspondent host (CH) is a host that wants to
send packets to the MH
CH sends packets to the MH’s IP permanent
home address
Packets routed to the MH’s home network
HA forwards IP packets for MH to current care-of
address
MH sends packets directly to correspondent,
using permanent home IP as source IP
G. G. Richard III, UNO
Katz, Stoica F04 9
Mobile IP: Basics
correspondent host
home agent
G. G. Richard III, UNO
Katz, Stoica F04 10
Mobile IP: Care-of Addresses

When MH connects to a remote network:
- Care-of can be the address of a foreign agent (FA) on
the remote network
• FA delivers packets forwarded from HA to MA
- Care-of can be a temporary, foreign IP address
obtained through, e.g., DHCP
• HA tunnels packets directly to the temporary IP
address

Care-of address must be registered with HA
G. G. Richard III, UNO
Katz, Stoica F04 11
IP-in-IP Tunneling
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Packet to be forwarded is encapsulated in a new
IP packet
In the new header:
- Destination = care-of-address
- Source = address of home agent
- Protocol number = IP-in-IP
IP header
data
IP header
IP header
data
G. G. Richard III, UNO
Katz, Stoica F04 12
At the Other End...

Depending on type of care-of address:
- FA or
- MH

… strips outer IP header of tunneled packet,
which is then fed to the MH
G. G. Richard III, UNO
Katz, Stoica F04 13
Routing Inefficiency
MH and CH may
even be on the
same network!!
correspondent host
home agent
G. G. Richard III, UNO
Katz, Stoica F04 14
Route Optimizations

Possible Solution:
- HA sends current care-of address to CH
- CH caches care-of address
- Future packets tunneled directly to care-of address

But …
- Cache consistency problem arises ...
- Cached care-of address becomes stale when the MH
moves
- Potential security issues with providing care-of address to
correspondent
G. G. Richard III, UNO
Katz, Stoica F04 15
Future of the Internet



Mobile IP
Networked Everything: Sensor Nets
Internet Economics
Katz, Stoica F04 36
Embedded Sensor Nets: Enabling Technologies
Embed numerous distributed
devices to monitor and interact
with physical world
Embedded
Network devices
to coordinate and perform
higher-level tasks
Networked
Exploit
collaborative
Sensing, action
Control system w/
Small form factor
Untethered nodes
Sensing
Tightly coupled to physical world
Exploit spatially/temporally dense, in situ/remote, sensing/actuation
Jim Kurose, UMass
Katz, Stoica F04 37
Sensor Nets: New Design Themes

Self configuring systems that adapt to unpredictable
environment
- Dynamic, messy (hard to model) environments preclude
pre-configured behavior

Leverage data processing inside the network
- Exploit computation near data to reduce communication
- Collaborative signal processing
- Achieve desired global behavior with localized algorithms
(distributed control)

Long-lived, unattended, untethered, low duty cycle
systems
- Energy a central concern
- Communication primary consumer of scarce energy
resource
Jim Kurose, UMass
Katz, Stoica F04 38
From Embedded Sensing to
Embedded Control

Embedded in unattended “control systems”
- Control network, and act in environment

Critical apps extend beyond sensing to control &
actuation
- Transportation, precision agriculture, medical monitoring and
drug delivery, battlefield apps
- Concerns extend beyond traditional networked systems and
apps: usability, reliability, safety

Need systems architecture to manage interactions
- Current system development: one-off, incrementally tuned,
stove-piped
- Repercussions for piecemeal uncoordinated design:
insufficient longevity, interoperability, safety, robustness,
scaling
Jim Kurose, UMass
Katz, Stoica F04 39
Why Not Simply Adapt Internet Protocols,
“End-to-End” Architecture?

Internet routes data using IP Addresses in
Packets and Lookup tables in routers
- Humans get data by “naming data” to a search engine
- Many levels of indirection between name and IP
address
- Embedded, energy-constrained (un-tethered, smallform-factor), unattended systems cant tolerate
communication overhead of indirection

Special purpose system function(s): don’t need
want Internet general purpose functionality
designed for elastic applications
Jim Kurose, UMass
Katz, Stoica F04 40
Sample Layered Architecture
User Queries, External Database
Resource
constraints call
for more tightly
integrated layers
In-network: Application processing,
Data aggregation, Query processing
Data dissemination, storage, caching
Open Question:
What are defining
Architectural
Principles?
Adaptive topology, Geo-Routing
MAC, Time, Location
Phy: comm, sensing, actuation, SP
Jim Kurose, UMass
Katz, Stoica F04 41
Sensors
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Passive elements: seismic, acoustic, infrared,
strain, salinity, humidity, temperature, etc.
Passive Arrays: imagers (visible, IR), biochemical
Active sensors: radar, sonar
- High energy, in contrast to passive elements

Technology trend: use of IC technology for
increased robustness, lower cost, smaller size
- COTS adequate in many of these domains; work
remains to be done in biochemical
Jim Kurose, UMass
Katz, Stoica F04 42
Fine Grained Time and Location

Unlike Internet, node time/space location essential for
local/collaborative detection
- Fine-grained localization and time sync to detect events in
3D and compare detections across nodes
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GPS provides solution where available (with diff-GPS
providing finer granularity)
- GPS not always available, too “costly,” too bulky
- Other approaches under study
Localization of sensor nodes has many uses
- Beamforming for localization of targets and events
- Geographical forwarding
- Geographical addressing
Jim Kurose, UMass
Katz, Stoica F04 43
Coverage Measures
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D
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x
S
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Area coverage: fraction of area
covered by sensors
Detectability: probability
sensors detect moving objects
Node coverage: fraction of
sensors covered by other
sensors
Control:
- Where to add new nodes for
max coverage
- How to move existing nodes
for max coverage
Given: sensor field (either
known sensor locations, or
spatial density)
Jim Kurose, UMass
Katz, Stoica F04 44
In-Network Processing
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Communication expensive
when limited
- Power
- Bandwidth

Perform (data) processing in
network
- Close to (at) data
- Forward fused/synthesized
results
- e.g., find max. of data

Distributed data, distributed
computation
Jim Kurose, UMass
Katz, Stoica F04 45
Distributed Representation and Storage
K V
K V
K V
K V
K V
K V
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K V
K V
- Interpretation of spatially distributed data
(Per-node processing alone is not enough)
- Network does in-network processing based
on distribution of data
- Queries automatically directed towards nodes
that maintain relevant/matching data
K V
K V K V
Time

Jim Kurose, UMass
Data Centric Protocols, In-network
Processing goal:
Pattern-triggered data collection
- Multi-resolution data storage and retrieval
- Distributed edge/feature detection
- Index data for easy temporal and spatial
searching
- Finding global statistics (e.g., distribution)
Katz, Stoica F04 46
Directed Diffusion:
Data Centric Routing

Basic idea
- Name data (not nodes) with externally relevant attributes:
data type, time, location of node, SNR,
- Diffuse requests and responses across network using
application driven routing (e.g., geo sensitive or not)
- Support in-network aggregation and processing

Data sources publish data, data clients subscribe to data
- However, all nodes may play both roles
• Node that aggregates/combines/processes incoming
sensor node data becomes a source of new data
• Node that only publishes when combination of conditions
arise, is client for triggering event data
- True peer to peer system?
Jim Kurose, UMass
Katz, Stoica F04 47
Future of the Internet



Mobile IP
Networked Everything: Sensor Nets
Internet Economics
Katz, Stoica F04 48
The Big Picture
Demand
Market
Structure &
Mechanisms
Supply
Price(s)
Welfare (surplus)
Producer Surplus
Consumer Surplus
Social Surplus
{
John Chueng
Katz, Stoica F04 49