Support of Multimedia SIP Applications over Proactive MANETs - - PowerPoint PPT Presentation

Communications Research Centre (CRC) Defence R&D Canada - Ottawa

Support of Multimedia SIP Applications over Proactive MANETs – Extension of OLSR for Service Discovery

Li Li and Louise Lamont

CRC Canada

Communications Research Centre (CRC) Defence R&D Canada - Ottawa

Outline

• Overview of MANET Service Discovery

Schemes

• OLSR Extension to Support Service

Discovery

• SIP MANET Networking Architecture
• Performance Results
• Conclusions

Communications Research Centre (CRC) Defence R&D Canada - Ottawa

Service Discovery

• To find the IP-address of a service provider by

specifying the desired service properties, which can then be contacted by the client for the service session.

• The key service properties: service type, service

URL/AOR, attributes, preference of attributes, etc.

• Service discovery schemes developed for the fixed

networks often employ the centralized servers which may not exist in the MANET, e.g., DNS, DHCP, ENUM etc.

Communications Research Centre (CRC) Defence R&D Canada - Ottawa

Overview of MANET Service Discovery Schemes

• Host-name-to-address mapping

– Adapt DNS protocol to MANET (draft-jeong-manet-dns-service- 00.txt) – Piggyback onto reactive routing protocol (draft-engelstad-manet- name-resolution-01.txt)

• SLP adapted to MANET

– Piggyback onto reactive routing protocol (draft-koodli-manet- service-discovery-00.txt) – Building distributed service directory layer in MANET (U Kozat and L Tassiulas )

• Service advertising and discovery on Multicast Protocols

– Often reactive multicast routing protocols are assumed (e.g., Liang Cheng)

Communications Research Centre (CRC) Defence R&D Canada - Ottawa

Service Discovery in Proactive MANET

• Proactive MANET is more suitable for certain

application scenarios, e.g., for support of real-time multimedia SIP applications with minimum end-to- end latency

• Apply cross-layer design between networking and

application layers to reduce the infrastructure and protocol overhead

– Service advertisement may fit well in OLSR’s forwarding mechanism – Can service query-and-response messages be supported by OLSR forwarding mechanism?

Communications Research Centre (CRC) Defence R&D Canada - Ottawa

Extension on OLSR to Support Service Discovery

• A new message type to handle the

functionality of service discovery: Service Location Extension (SLE)

• OLSR MPR forwarding to disseminate the

SLE message

– MPR forwarding to advertise the service capability – Service query-and-response using MPR forwarding – Response SLE is the same as the advertising SLE

• SLE refresh timer, SLE minimum refresh

timer and limited maximum number of queries to control message load

• Backward compatibility with OLSR nodes

that do not support the SLE extension

Server MPR MPR MPR MPR MPR MPR

MANET

Communications Research Centre (CRC) Defence R&D Canada - Ottawa

SLE Message

• Major fields include: Service Sequence Number,

Service Type, Service Attributes, AOR URL, Location, Weight, Query Flag, etc.

• Service Attributes are service type dependent,

including attribute values and preferences

• The AOR URL can be omitted when the Query

Flag is enabled

• Location field stipulates IP address

Communications Research Centre (CRC) Defence R&D Canada - Ottawa

SIP MANET Networking Architecture

• Proxy-based vs. Proxy-less SIP MANET Architecture

– Proxy server offers SIP directory service – Need to discovery either the proxy server(s) or all destination UAS

MN_UA2

MANET

MN_UA MN_UA MN_UA MN_UA MN_UA1 MN_UA MN_Proxy1

1 2 3 1: register 2: send INVITE request

• 3. route the INVITE request to the called

MN_Proxy2 MN_UA3

1 2 3

(a) Proxy-based SIP MANET

MN_UA2

MANET

MN_UA MN_UA MN_UA MN_UA MN_UA1 MN_UA 1 1: send INVITE request directly to the called

(b) Proxy-less SIP MANET

• Two types of servers, proxy server and UAS are involved

Communications Research Centre (CRC) Defence R&D Canada - Ottawa

Support SIP MANET Over OLSR

• Use OLSR SLE to automatically discover the SIP

MANET architecture and locate the server(s)

• Listen for server advertisement
• Query message first solicits the proxy server to
• respond. A UAS only responds when there is no

proxy server heard in the SIP MANET

• To further reduce the message overhead, uni-cast

response may be used

Communications Research Centre (CRC) Defence R&D Canada - Ottawa

1

MANET

Server MN_UA

Performance Evaluations

• Assume two broadcast queries generating more message load than a MPR

forwarded query-and-response pair

• OLSR SLE scheme can outperform the reactive SD scheme in many cases
• Comparison of OLSR SD scheme with SD scheme piggybacked
• n the reactive routing protocol

1

MANET

Server MPR MPR MN_UA MPR MPR MPR MPR MN_UA

Communications Research Centre (CRC) Defence R&D Canada - Ottawa

Simulation Results

• SLE overhead is insignificant in proportion to the overall

OLSR overhead

• Satisfactory performance results of SIP applications are

achieved with the proposed service discovery scheme

SLE Message Overhead 0.00% 0.20% 0.40% 0.60% 0.80% proxy-less

• ne proxy

server Scenarios Percentage of SLE in total OLSR traffic big net small net

Call Setup Time: proxyless network 0.02 0.04 0.06 0.08 0.1 0.12 0 sec 1600.68 2237.76 2746.94 3018.47 3219.06 3511.54 3699.97 simulation time (sec) setup time (sec) Case1 Case2

Communications Research Centre (CRC) Defence R&D Canada - Ottawa

Conclusions

• Cross-layer support of service discovery utilizing

the OLSR protocol achieves implementation, architecture and protocol efficiency

• The extra message overhead generated by SLE is

very limited

• OLSR SLE scheme may outperform reactive SD

schemes in many cases

• The proposed OLSR SD scheme delivers

satisfactory performance metrics for support of multimedia real-time applications

Communications Research Centre (CRC) Defence R&D Canada - Ottawa

Thank You!