1. Network Research at CTI
James Yu, Ph.D.
Assistant Professor
School of CTI
11/10/2018
DePaul University

2. James Yu, Ph.D. Ph.D. in Computer Science from Purdue University, 1985
[Distinguished] Member of Technical Staff, Bell Labs, Lucent Technologies, 1985 – 2000
Director of Network Technologies, ARBROS Communications, 2000 – 2001
Assistant Professor, DePaul University, now
11/10/2018
DePaul University

3. Research Interests Network Performance Evaluation Wireless Security
VoIP Traffic Engineering
Fault Tolerant Network Design
Network education: hands-on exercises for distance learning students
11/10/2018
DePaul University

4. Framework of Network Research
Problem
Statement
Empirical
Framework
Theoretical
Model
References
Solutions to
The problem
Revision
Data Analysis
Comparative
Study
Conclusion
11/10/2018
DePaul University

5. Services and Management
Network: the BIG Picture
PSTN
NNI
Network
Services and Management
Internet
Network
Access
Switched
Network
Security Layer
Transport
Network
ISP
Network
UNI
carrier network
Security Layer
Security Layer
Data
LAN
Voice
Network
2G/3G
Network
Data
Center
Call
Center
cellular network
converged enterprise network
11/10/2018
DePaul University

6. Project I: Performance Analysis
Key measurement: throughput (bps) and delay (ms or s)
Ethernet Switch
IP Router
Linux
Bridge/Router
Windows
Bridge/Router
11/10/2018
DePaul University

7. Throughput (bps) on 100BaseTX Link (Linux Bridge vs. Linux Router)
One-way Delay (in s) on 100baseTX Link (Linux Bridge vs. Linux Router)
Throughput (bps) on 100BaseTX Link (Linux Bridge vs. Linux Router)
11/10/2018
DePaul University

8. Switch Performance Comparison on Gigabit Ethernet
Question: could you develop a problem statement from this chart?
11/10/2018
DePaul University

9. Wireless Performance
Question: why is TCP performance is only 50% of the line rate for wireless communications?
11/10/2018
DePaul University

10. Project II: Wireless Denial of Service (DoS) Research
11/10/2018
DePaul University

11. TCP performance under DoS
Stop
Start
11/10/2018
DePaul University

12. Project III: VoIP Research
SS7
SS7
PSTN Switch
PSTN Switch
SoftSwitch
SoftSwitch
Carrier VoIP
Network
Trunk MG
Trunk MG
IP (internal)
Call Manager
(SIP Proxy)
Q.931
Access MG
IP (public)
IP (private)
Call Manager
(Enterprise)
MG: Media Gateway
11/10/2018
DePaul University

13. VoIP: Traffic Engineering
Design the network with sufficient capacity to meet the traffic demand with satisfactory performance
Requirement: assurance of Voice Quality.
If call quality cannot be assured, reject the call request.
Demand (A) - Traffic Intensity
number of calls × duration of average calls
Erlang
Resources (N) – Network bandwidth (bps) and capacity (pps)
Grade of Service (GoS) – blocking probability
11/10/2018
DePaul University

14. Research Areas of VoIP IP Multimedia Subsystem (IMS) VoIP Security
How is a VoIP call from one service provider to another service provider today?
VoIP Security
Voice Quality
Quality of Service (QoS) over internet and intranet
Supplemental and Intelligent Network (IN) services
API and VoXML
11/10/2018
DePaul University

15. Project IV: Fault Tolerant Network
RSL
RSTP (802.1w)
VRRP
Dual Homing
ISP-01
ISP-02
Network Design Goal:
No single point of failure
Failover time << 1 sec
11/10/2018
DePaul University

16. Project V: Remote Lab Access
Linux
Gateway
Public
Internet
Private
Networking
Labs
Windows
Terminal Server
Devices w/
Console interface
Devices w/
IP interface
Telecom
Terminal Server
Console
interface
Problem Statement: supporting distance learning students to perform hands-on network exercises from any place with 24×7 access to the network lab
11/10/2018
DePaul University

17. Conclusions Evolution of the telecom networks and network technologies
Convergence of PSTN and Internet
Growing demand for wireless networks (bandwidth utilization, more bandwidth, new applications, etc.)
Increasing threat and concerns of network security
Higher requirements for network reliability and service availability
New generation of devices and services
Needs: more research work
11/10/2018
DePaul University