Univis; Stud.IP; General Information on the bachelor and master programs in Applied
Computer Science (Angewandte Informatik).
Please check latest news in Stud.IP,
where you find
further course materials and easy interface for discussions (including a WiKi
entry for your project progress).
Maytuan Arumaithurai (Nokia Siemens Networks and U
Goettingen)
Niklas Steinleitner
Jun Lei
Lei Shi
Nikunj Modi
If you have any questions,
please send email to tmg-prak-ws0708@informatik.uni-goettingen.de
The course objectives for
the Praktikum Telematik for WS07/08 include (but are not limited to) the
following:
In the design and evaluation of new networking
protocols, Real time implementations and implementations on network simulators
can be used. Both implementations serve different purposes. While real time
implementations can be used to check the protocols interaction with existing
protocols, real time deployment problems etc implementation on simulators can
be used to simulate its behaviour in large network topologies.
In this course we look in depth at one such
popular network simulator and implement a network protocol on it.
Aim:
The course is
intended to provide course participants knowledge in modelling and simulation
of telecommunication networks. The course features the use of simulation software
commonly used for telecommunication network simulation. In addition to the
basic theory necessary for understanding network simulation, the course aims to
give practical skills in using these softwares to implement network protocols,
construct simulation models and to simulate a networking system.
The course contains the following two parts:
·
Theory
of network simulation and study of simulation tools
·
A
simulation project
The course consists of 3 projects and each team
is expected to do one of the listed projects. The team may consist of 2-3
members. The course aims to familiarize the students in the use of a popular
network simulator and to teach them to implement network protocols on the
simulator.
Each team is expected to give a mandatory
intermediate and a final presentation and a project report too.
Network simulator:
A discrete
event Network simulator can be used for traffic modelling of telecommunication
networks, protocol modelling, modelling queuing networks, modelling
multiprocessors and other distributed hardware systems, validating hardware
architectures, evaluating performance aspects of complex software systems and
modelling any other system where the discrete event approach is suitable. In
this course we will be using the popular OMNeT++ network simulator.
OMNeT++ is an
object oriented discrete event network simulator. It is highly modular, well
structured, scalable and based on C++. It provides a basic infrastructure
wherein modules exchange messages. Its main features includes its extensive GUI
support , portable on windows and Unix platforms , an open source distribution
policy for academic purposes and etc. It can be use to model communication and
queuing networks, protocol modelling, multiprocessors and other distributed
hardware systems as well as to validate hardware architectures. OMNeT++
simulations can feature varying user interfaces for different purposes:
de-bugging, demonstration and batch execution. Advanced user interfaces make
the inside of the model visible to the user; allow control over simulation
execution and to intervene by changing variables/objects inside the model. This
is very useful in the development/debugging phase of the simulation project.
User interfaces also facilitate demonstration of how a model works. OMNeT++
also supports parallel distributed simulation.
Projects:
This section
lists the projects that are available for the students to choose from.
Locator/ID
Separation Protocol (LISP) is a simple, incremental, network-based protocol to implement
separation of Internet addresses into Endpoint Identifiers (EIDs) and Routing
Locators (RLOCs). It is relatively a new protocol and is currently being
developed by the IETF. LISP mechanism requires no changes to host stacks and no
major changes to existing database infrastructures. Another advantage of
the proposed protocol is that it need not be implemented in all the routers.
IVIP (Internet Vastly Improved
Plumbing) is a proposed global system of routers and collection of databases which
control the tunneling of some of these routers.
IVIP
enables a subset of IPv4 and IPv6 address space to be portable (used via an ISP
which has an ETR) and to be suitable for multihoming (connection to the network
via two or more ISPs) - without involving BGP and without requiring any changes
to host operating systems or applications.
IVIP's
primary goals include the more efficient utilisation of IPv4 space and enabling
millions of end-users to achieve portability and multihoming without involving
BGP, without fuelling the growth of the global BGP routing table, and without
requiring these end users to have ASNs (Autonomous System Numbers) or to
acquire conventional prefixes of PI (Provider Independent) BGP reachable
address space.
Go-Back-N
ARQ is a specific
instance of the Automatic
Repeat-reQuest (ARQ) Protocol, in which the sending process continues to send a number of frames specified by a window size even without receiving an ACK packet from the receiver.
The receiver process
keeps track of the sequence number of the next frame it expects to receive, and sends that number with every ACK it sends.
If a frame from the sender does not reach the receiver, the receiver will stop acknowledging received frames. Once the sender has sent all of the frames in its window, it will detect that all of the frames since the first lost frame are outstanding, and will go back to sequence number of the last ACK it
received from the receiver process and fill its window starting with that frame and continue the process over again.
The sending
window size must be the number of sequence numbers (if they are numbered from
zero to n-1) to verify transmission in cases of any packet (any data or ACK
packet) being dropped. (Source: Tanenbaum, Andrew S. Computer Networks 4th ed. ISBN 0-13-066102-3)
The Radio
Link Protocol (RLP)
is an automatic repeat request (ARQ) protocol used over a wireless
(typically cellular) air interface. Most wireless air interfaces are tuned to
provide 1% packet loss, which is a tolerable loss rate for modern Vocoders. An RLP detects packet losses and performs
retransmissions to bring packet loss down to .01%, which is suitable for TCP/IP
applications. RLP also implements stream fragmentation and reassembly, and
sometimes, in-order delivery. Newer forms of RLP also provide framing and
compression, while older forms of RLP rely upon a higher-layer PPP protocols to
provide these functions.
An RLP
transport never knows how big a packet the air interface will provide. Instead,
the air interface scheduler determines the packet size, and calls upon RLP to
form a packet on-demand for transmission. Most other wireless fragmentation and
framing protocols, such as those of 802.11b and TCP/IP, used fixed fragment
sizes. These protocols are not as flexible as RLP, and can sometimes needlessly
block transmissions during a deep fade in a wireless environment.
For each project students
are required to organize the work effectively according to the streamline of a
realistic project, including milestones (task and time allocation,
deliverables) definition, implementation and revision, reports of design,
implementation, test results and intermediate results etc. Each project will
elect a project leader who should be responsible for directing and regularly
reporting the overall progress of the team.
Prerequisite: Computer Networks course or
equivalent
Course time: Friday 14-17.
First lecture: 17.10.2007.