1. Communication Networks
A Second Course
Jean Walrand
Department of EECS
University of California at Berkeley

2. Moving Forward Topology Mobility Security QoS Wireless BandAids?
Economics
Sensor/Actuators
Biology

3. Topology
100x100 idea

4. Mobility DHCP too slow to “hop” Authentication Mobile IP inefficient
Same user, different device (call forwarding)
Different user, same device
Push to neighboring “cells”
Device-based services (reformat)
Location-based services
Maintain privacy

5. Security
Practical experience points to a combination of a weak technology base, constrained know-how, and paucity of incentives for producers, systems administrators, users, and researchers-which, in the aggregate, inhibit progress. In short, it appears that our nation's dependence on NISs has grown faster than our ability to address vulnerabilities.
[Computer Science and Telecommunications Board, The National Academies]

6. Security Worm detection: traffic stats, synsyn.ack
Spam: default is “not allowed”
DDOS: traceback
Virus: liability of software vendor
Keys: Don’t generate from simple words
Make DNS and IP more secure
“Resilient, Self-diagnosing, Self-healing”

7. QoS
Kelly’s solution: ECN + WPF + E2E AC

8. QoS Kelly’s solution: ECN + WPF + E2E AC PROS: CONS:
ECN: Explicit Congestion Notification (mark packets instead of dropping them)  no retransmissions
Use virtual buffer to mark packets “early” before congestion builds up  small delays
WPF: weighted proportional fairness. Users with more “willingness to pay’” can transmit more when packets get marked.
E2E AC: End-to-end admission control. Users try a connection and give up if the quality is not acceptable (can add special marks for admitted connections to protect them)
PROS:
No differentiated services required in network
No explicit quality of service needed
CONS:
Must trust users and applications (like today’s TCP…)

9. Wireless WiMax or WiFi? Mesh Networks
UWB: short pulses (roughly pulse position mod.)
Simple MAC, good for localization
Difficulty: Precise timing of received pulses (detection, multipath)
Soft radios or compatible protocols?
Cognitive
Multichannel protocols

10. BandAids?
Mobility through indirection Name  DHT Server  Current Address
Improve performance through overlay network: QoS-based routing; multicast; P2P
Secure storage through FEC and scattering
Improved reliability through multipath and FEC
Improved performance by combining networks
Spectrum sharing through cognitive radios
Improve systems with cross-layer designs

11. Economics Enable Markets: Sharing among content and service providers?
Provide choice to users and pricing
Class of Service
Route
Provider
Provide incentives to providers
Better service should bring more revenues
Possibly, more traffic should provide more revenues
Difficulty: revenue sharing across providers
Sharing among content and service providers?

12. Economics
Typical problem:
Competition lead to price war:

13. Biology
Conceptual Connection: Despite some apparent differences, biology and information technology (IT) have much in common.
Synergy
Health & environment monitoring
Brain-machine interface
Electronic implants