1. TGaq Design Option for One-way Service Discovery Protocol
April 2013
doc.: IEEE /0426
April 2013
TGaq Design Option for One-way Service Discovery Protocol
Date:
Authors:
RYU Cheol, ETRI
RYU Cheol. ETRI

2. for the TGaq Teleconference in April 2013
doc.: IEEE /0426
April 2013
Abstract
Propose an idea of One-way Service Discovery support to be added to Design Options
for the TGaq Teleconference in April 2013
RYU Cheol, ETRI
RYU Cheol. ETRI

3. One-way Service Discovery Protocol support
April 2013
doc.: IEEE /0426
April 2013
One-way Service Discovery Protocol support
Request/Response mechanism cannot support multicasting messages in service discovery protocols such as:
Multicast DNS for Bonjour
SSDP(Simple Service Discovery Protocol) for UPnP
WS-Discovery(Web Services Dynamic Discovery) for WSD
Other unknown protocols which use multicasting UDP
Notifying Pre-Association Messages(PAM) could tunnel those one-way messages
Message Patterns of SOAP over UDP
Unicast one-way
Multicast one-way
Unicast request, unicast response
Multicast request, unicast response
RYU Cheol, ETRI
RYU Cheol. ETRI

4. AP STA STA GAS PAM STA April 2013 UDP multicast UDP multicast M I B
Connection
W/O
Association
STA
STA
Associated
Services
UDP multicast
GAS
PAM
Service
advertisement
UDP multicast
STA
“Services” is like a Discovery Proxy of WS-Discovery. M I B
Wired
Beacon
Probe
Probe
response
PAM: Pre-Association Message
RYU Cheol, ETRI

5. STA AP April 2013 unassociated associated or wired
doc.: IEEE /0426
April 2013
unassociated
associated or wired
STA AP
Service Discovery Capable Device
service advertisement multicasting
a public action frame for service advertisement
with information for the infrastructure
association request
RYU Cheol, ETRI
RYU Cheol. ETRI

6. Options for the public action frames
April 2013
Options for the public action frames
AP sends the public action frames (PAM)
on an arbitrary channel or
on a common channel or
on a few social channels (eg. 1, 6, 11) or
on each channel while traversing.
RYU Cheol, ETRI

7. An example: WS-Discovery on slide file sharing
April 2013
doc.: IEEE /0426
April 2013
An example: WS-Discovery on slide file sharing
Associated AP
Hello: “My presentation file available”
UDDI reference
or local lookup with uuid
PAM(Hello:”My presentation file available”)
Joining to an infrastructure
UDDI : Service registry of Web Services (OASIS standard)
uuid: RendpointReference of WS-Discovery
file sharing
Bye
PAM(Bye)
PAM: Pre-Association Message
RYU Cheol, ETRI
RYU Cheol. ETRI

8. Issues A common channel
April 2013
Issues
A common channel
A channel could be designated for service discovery?
The public action frames for service advertisement
How often does AP send them for service discovery?
Just one time is feasible? Maybe not.
Transparency
802.11aq service discovery is transparent to applications for both on clients and servers?
Possibly if it supports multicasting service discovery types as well as request/response unicast mechanism.
Broadcasting or multicasting
Which one is better for PAM, broadcasting or multicasting?
Multicasting would be with specific group address.
RYU Cheol, ETRI