Wireless Ad Hoc VoIP Thesis by: Patrick Stuedi & Gustavo
Alonso Presentation by: Anil Kumar Marukala & Syed Khaja
Najmuddin Ahmed
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Introduction Implementing VoIP over mobile ad-hoc network. Why
? Calls inside MANET are always possible. If one node in MANET is
connected to internet, VoIP over internet can be used by all
nodes.
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Contd.. Converting any devices (laptops, iPAQ handhelds, mobile
phones) to wireless phone by installing a small software (kphone).
SIPHoc which uses middleware to make VoIP calls is used instead of
SIP.
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System Overview Its build on SIPHoc It is based on five
components running as independent operating system processes within
a node in the MANET. VoIP application: Any SIP compatible VoIP
client SIPHoc Proxy: SIP interface but implements MANET
functionality. Serves as Local Outbound Proxy.
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Contd MANET SLP Layer: Provides SLP (Service Location Protocol)
interface but implements decentralized service lookup
functionality. Piggybacks service information onto routing messages
Gateway Provider: Publishes SLP gateway service to provide
information of a node with internet connectivity Opens two tunnel
server ready to accept connection Connection Provider: manages
connections of the node to the internet Periodically searches for
gateway service and opens two tunnel connection to the node
offering tunnel server.
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Making calls within the MANET
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Registering with SIP proxy. outbound of VoIP is configured so
its registered with local SIPHoc proxy. SIPHoc proxy will Advertise
itself with MANET SLP. Other users will also register with SIPHoc
Proxy. This information is available to all nodes in network since
MANET SLP is distributed SLP designed for ad hoc networks. In MANET
SLP information is exchanged via routing message piggybacking so,
right plugin for the routing protocol is to be loaded. SIP call
setup requests are routed through SIPHoc Proxy, targets address is
determined by consulting MANET SLP, it retrieves end point address
using piggyback routing and forwards request to target SIPHoc Proxy
of the target node. Then request is forwarded and VoIP application
rings.
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Phone calls to/from Internet SIPHoc allows setting up SIP
connection to and from the internet the Internet by using MANET
nodes connected to the Internet as gateways. Official SIP phone
number can used within MANET and for the internet VoIP. Compatible
with SIP Providers like siphoc.ch,netvoip.ch but when SIP Provider
require special outbound Proxy it cannot work e.g,
polyphone.ethz.ch.
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Deployment Laptops (Debian, i386) and iPAQ handhelds (Familiar
Linux, ARM/XSCALE) First prototype was iPAQ/h5000 under Familiar
Linux. C version of SIPHoc Proxy was used and came up with a system
which included 4 services and a footprint of 1.2M and 20 shared
libraries used by the services.
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Conclusion The paper showed how communication between devices
in Ad Hoc networks using VoIP services has been established. This
application can be used at the places where proper infrastructure
is not available. This application if implemented after
improvements and further research calls can be made almost free of
cost.