Title: The NCTUNS 1.0 Network Simulator
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2NCTUns 5.0 Network Simulator and Emulator
- Prof. Shie-Yuan Wang
- shieyuan_at_cs.nctu.edu.tw
- Department of Computer Science
- National Chiao Tung University, Taiwan
Network and System Laboratory
3Outline
4Introduction
5Introduction
- The NCTUns network simulator and emulator is
developed at NCTU, Taiwan. Its predecessor is the
Harvard network simulator (invented by Prof. S.Y.
Wang in 1999).
- By using a novel simulation methodology, it can
do several tasks that traditional network
simulators cannot easily do.
- After more than eight years development, it has
become a useful tool.
- Many people are using it. (Use the Google to
search it for yourself.)
6Now, its Impact Is Ranked 2 by Google Taiwan
7The IEEE Network Magazine reports this tool in
its July 2003 issue.
8Selected as a Research Demo by ACM MobiCom02
9Again selected by MobiCom 2003
Ranked 1 of the 12 selected
10First local workshop on 12/05/2002
11Second local workshop on 12/12/2003
12A Tutorial Made at IEEE Vehicular Technology
Society, Taipei Chapter 09/22/2004
13Selected as a tutorial by IEEE MASCOT 2004
14Selected as a Demo by IEEE INFOCOM 2005
15Selected as a tutorial by SPECTS 2005, Society
for Simulation, International.
16Selected as an exhibition by IEEE ICC 2007, 24-28
June 2007, Glasgow, UK
17Invited as a DEMO by IEEE WiVEC08, September
2008, Calgary, CA
18Main Unique Features
- The real-world TCP/IP protocol stack is directly
used to generate accurate simulation results.
- Real-world application programs can directly be
run on a simulated network
- Realistic network traffic can be generated.
- Their performances can be evaluated under
different network conditions.
- The applications developed at the simulation
stage can be immediately deployed in the real
world without any change.
19Main Features (2)
- Using an open-system (source) architecture to
allow a researcher to easily add his (her) own
protocol modules into the simulator
- Simulation methodology has been endorsed by
several journal papers (Computer Networks 2002,
Computer Networks 2003, Wileys Wireless
Communication and Mobile Computing 2005,
Elseviers Simulation Modeling Theory and
Practice 2007), two book chapters published by
Nova Science Publisher 2006 and 2008, and two
conference papers (IEEE INFOCOM99, WiVEC08).
20Network Simulation Capabilities
- NCTUns 2.0 can simulate Ethernet-based fixed IP
networks, 802.11 (b) wireless LANs, mobile ad hoc
networks, GPRS cellular networks, optical
networks (circuit-switching and optical
burst-switching), Diffserv QoS networks etc.
- NCTUns can function as an emulator, too! (See
Chapter 7 of this book ISBN 1-59454-830-7)
21Architectures
22Eight Components
GUI Client
Job Dispatcher
Coordinator
Daemons
Applications
Protocol Modules Simulation Engine
Kernel Patches (Fedora 9.0 Linux 2.6.25)
Simulation Server
23Distributed Architecture
Simulation Server
Paris
GUI Client
Dispatcher
Tokyo
Boston
NCTU, Taiwan
Simulation Service Center
24Open-System Architecture
Protocol modules
Module API
Simulation Engine
User-level Simulator
25Main GUI Components
- Topology editor
- Draw a network topology
- Node editor
- Specify a nodes protocol stack
- Performance monitor
- Monitor and plot performance curves
- Packet animation player
- Playback packet transfer animation
26Topology Editor
27Node Editor
28Performance Monitor
29Packet Animation Player
30NCTUns 3.0 New Features
31IEEE 802.11(b) Dual-Radio Wireless Mesh Networks
- Each access point has two interfaces
- One operates in the infrastructure mode serving
standard IEEE 802.11(b) client stations - The other operates in ad hoc mode used to
wirelessly forward packets among access points. - Low deployment cost, high reliability
- Example
- The wireless mesh network deployed in Taipei is
an IEEE 802.11(b) wireless mesh network with
8,000 mesh access points.
32Client
Mesh Access Point
33IEEE 802.11(e) QoS Wireless LAN
- Provide QoS guarantee for IEEE 802.11(e) client
stations. - The IEEE 802.11(e) access point polls each
associated IEEE 802.11(e) client station to give
them enough transmit opportunities to meet their
bandwidth requirement.
34IEEE 802.11(e) Access Point
IEEE 802.11(e) Client
35Tactical and Active Mobile Ad Hoc Networks
- Can be used to study future combat system (FCS)
or any active mobile ad hoc network where mobile
nodes can actively and dynamically change their
moving behaviors according to the current
environment conditions or after receiving a
command from other mobile nodes. - Thales Group Inc. (a security and defense
company, with 60,000 employees worldwide) has
purchased two NCTUns commercial licenses for
their military projects.
36Target node
Chasing node
37Directional Antennas
- Researches about networks using directional
antennas have become increasingly popular. - Support 3dB beamwidth 60-degree and 120-degree
directional and steerable antennas. - Use more realistic antenna gain patterns
pre-computed and stored in tables to compute the
received power of a packet. - Antennas can rotate or be set to point to a
particular direction. - Can increase transmission range, reduce signal
interference, and provide security.
38Antenna Gain Patterns
39NCTUns 4.0 New Features
40IEEE 802.16(d) WiMAX Networks
- Both the PMP and mesh modes are supported.
- Complete implementation of the standard
specifications - Simulation results have been validated against
mathematical theoretic results. - Two conference papers have been published using
this tool. - Many people in the world have sent emails to us
asking to use this tool for their WiMAX
researches.
41WiMAX PMP mode
42WiMAX mesh mode
43DVB-RCS Satellite Networks
- Support DVB-RCS GEO satellite networks
- Complete implementation of the standard
specifications - Simulation results have been validated against
mathematical theoretic results. - European Space Agency would like to use this tool
for its research projects.
44DVB-RCS Basic Network
45DVB-RCS Extended Network
46ITS Wireless Vehicular Networks
- Researches on wireless vehicular networks have
become increasingly popular (e.g., VANET, WiVEC,
V2VCOM conferences, etc.) - NCTUns is the first (only) simulator in the world
that tightly integrates network and traffic
simulation. - NCTUns supports V2V and V2I capabilities.
- NCTUns will be used by Telcordia Technologies
Inc. for a EU IVC (inter-vehicle communication)
project EU F-7 Call-2 - NEC Europe Inc. wants to use NCTUns for their EU
projects and introduce NCTUns into the EU ITS
standardization meetings.
47Construct a road network
48Select car profile Deploy car on the road
49Multi-interface Mobile Node
- Nowadays a mobile device is equipped with
multiple heterogeneous wireless interfaces. - This allows it to use the most cost-effective
network to connect to the Internet. - Many related research topics have emerged
Handover, multi-homing, trunking, etc. - Other than NCTUns, very few (if there is any)
network simulators provide this capability. - In NCTUns, a multi-interface node is equipped
with (1) 802.11(b) ad hoc mode , (2) 802.11(b)
infrastructure mode, (3) GPRS, and (4) DVB-RCST
satellite interfaces.
50Multi-interface Car
Multi-interface Mobile Node
51Create multiple sockets each bound to an
interfaces IP address
52NCTUns 5.0 New Features
53IEEE 802.11(p)/1609 Wireless Vehicular Networks
- Wireless vehicular network research is becoming
more and more popular. - IEEE VTS defines IEEE 802.11(p)/1609 standards
for this type of networks. - NCTUns is the first network simulator that
provides supports for IEEE 802.11(p)/1609 network
simulations. - For this reason, IEEE WiVEC 2008 conference
(supported by IEEE VTS) invited Prof. Wang to
demo NCTUns in its demo session.
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55OBU
OBU
RSU
OBU
56IEEE 802.16(e) Mobile WiMAX Networks
- Recently, IEEE 802.16(e) Mobile WiMAX has become
more popular than IEEE 802.16(d) fixed WiMAX. - Complete implementation of the standard
specifications - Simulation results have been validated against
mathematical theoretic results. - Can work with Mobile IP protocol to roam across
different IP subnets.
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5830 Realistic Wireless Channel Propagation and
Fading Models
- Realistic wireless channel propagation and fading
models are very important in generating
high-fidelity simulation results. - Over 30 channel models for various wireless and
mobile environments are provided. - They can be easily chosen/replaced in the GUI.
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60Parallel Simulations on Multi-core Machines
- Recently, multi-core machines have been popular
on the market. - Performing parallel simulations on these cores to
speed up simulations is highly desired. - Currently, NCTUns supports parallel simulations
for fixed networks. - Parallel simulations for wireless networks will
be supported in the next version.
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62Simulation Methodology
63Novel Simulation Methodology
- Use a kernel re-entering technique (invented by
Prof. Wang in 1999) to provide two advantages
- Use real-life protocol stacks to simulate
networks - ? simulation results are more accurate.
- All existing real-life application programs can
directly run on a simulated network - ? can test the performance of any real-life
application program and generate realistic
network traffic.
- These advantages cannot be easily achieved by
traditional network simulators such as OPNET
modeler and ns-2.
64Idea Was Inspired from the lo0 Loopback Interface
Suppose that we want to simulate the following
basic network
stcp
rtcp
1.0.1.2
Host 1
Host 2
Subnet 1.0.1
1.0.1.1
1.0.1.2
65Actually stcp and rtcp Can Be Run on the Same
Machine
stcp
rtcp
127.0.0.1
User level
Kernel level
Host
lo0
127.0.0.1 (The IP address assigned to the
loopback interface)
66Actually These Two Slides Differ Very Slightly
- The used network applications are the same.
- The used TCP/IP protocol stacks are the same.
- The only difference is in the used links
- The real-life physical link vs. the loopback
memory link
- If we can intercept packets so that they are not
looped back automatically, we can direct them to
our simulation engine. This way, the simulation
engine can simulate their transmission time and
their signal propagation delay over the link.
- This is the idea of this simulation methodology!
67Simulation engine
1999 version
This is why we claim (1) all real-world
application programs can be run and (2) the
real-world TCP/IP protocol stack is directly used.
We use tunnel interfaces to replace lo0
interface. This way, we can intercept packets and
direct them into the simulation engine.
68Current version
Various protocol modules now can be flexibly
added to the simulation engine.
69A Configuration Example
rtcp
stcp 1.0.3.2
1.0.3.1
tun1
2
1
tun2
1.0.3.2
Assuming 1.0.3.X is the subnet.
70A Route Conflict Problem
- The simulation methodology presented so far works
very well for a single-hop network.
- However, we will encounter a route conflict
problem when the network is extended to
multi-hops.
- This is because we use only one machine to
simulate all routers and store their routing
entries together.
71Problem Example
route add 1.0.3.2 interface tun1 route add
1.0.4.1 interface tun1 route add 1.0.4.2
interface tun1
route add 1.0.3.1 interface tun2 route add
1.0.4.2 interface tun3
Conflict!
route add 1.0.4.2 interface tun1 route add
1.0.4.2 interface tun3
72S.S.D.D IP Address Scheme
- We solve this problem by internally using the
S.S.D.D IP address scheme for an application to
send its packets to its destination node.
- The meaning of S.S.D.D. is SrcSubnetID .
hostonSrcSubnet . DstSubnetID .
hostonDstSubnet.
- However, a NCTUns user need not know and use this
strange scheme. He (she) can still use the normal
1 . 0 . subnetID . host address scheme. The
kernel hides all the details.
73The S.S.D.D Scheme to Solve the Route Conflict
Problem
rtcp
stcp 3.1.3.2
route add 3.1.3.2 interface tun1 route add
3.1.4.1 interface tun1 route add 3.1.4.2
interface tun1
route add 3.2.3.1 interface tun2 route add
3.2.4.2 interface tun3 route add 4.1.3.1
interface tun2 route add 4.1.4.2 interface tun3
No conflict Now!
route add 3.1.4.2 interface tun1 route add
3.2.4.2 interface tun3 route add 4.1.4.2
interface tun3
74Product Status
75Product Was First Released on November 1, 2002
76Download Web Site Is Here
As of Oct. 22 2008, more than 12,747 people from
128 countries have registered and downloaded
this tool since its release on November 1, 2002.
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79NCTUns users are all over the world.
80Many emails have arrived praising NCTUns or
asking how to purchase NCTUns.
81Dear Prof. Wang, We have been very impressed by
NCTUns and many of its amazing capabilities! The
simulation-emulation integration capabilities are
quite remarkable. We have been quite impressed
with the design of the GUI interface. We are
going to be demo-ing NCTUns to another network
analysis software development group within our
company to show them some of the exciting
features of NCTUns. Zeke Weeks Consulting
Services Specialist ATT Government Solutions,
Inc. Suite 5077 1900 Gallows Road Vienna, VA
22182 Email zweeks_at_att.com
NCTUnss emulation and GUI capabilities are
highly appreciated by ATT experts.
82NCTUns Is Compared with Other World-Famous
Network Simulators
Dartmouth
Cornell
UIUC
Data source IEEE Communication Magazine, July
2006 Issue
NCTU
USC
Budapest
UC Berkeley
83Concluding Remarks
84Concluding Remarks
- NCTUns 5.0 now is a high-quality professional
network simulator and emulator with many unique
advantages over traditional ones.
- Based on users feedback, we are still continuing
to improve NCTUns.
- What new features should be included in NCTUns
6.0?
- You are very welcome to tell me
85 Thank you. Q A