Upload
gerald
View
33
Download
0
Tags:
Embed Size (px)
DESCRIPTION
Supporting Groupware in Mobile Networks. Idit Keidar, Technion – I.I.T. Joint work with N. Lavi and I. Cidon. Agenda. Motivation for mobile groupware Current solutions Our proposed architecture Group management- one solution Simulation and analysis Future work Conclusions. - PowerPoint PPT Presentation
Citation preview
Supporting Groupware in
Mobile Networks
Idit Keidar,
Technion – I.I.T
Joint work with N. Lavi and I. Cidon
Agenda
Motivation for mobile groupware Current solutions Our proposed architecture Group management- one solution Simulation and analysis Future work Conclusions
Current Application Trends
Groupware and collaborative applications are widely used. Chat, Instant-Messaging, VoIP, VCoIP, Net-meeting Exchange, Lotus notes, webex Multiplayer interactive games Push-to-talk (PTT)
Current Cellular Trends
Simple groupware such as Instant Messaging widely used
Major cellular providers (Orange, Verizon, Nextel) offer PTT services
The Yankee Group (Sep. 2003): In 2003, $84 million PTT revenue, 2.3 million
PTT subscribersBy 2008, $10.1 billion PTT revenue, 340 million
PTT subscribers
Future Cellular Trends
Richer groupware applicationsData+ voice+ video
Adopting TCP/IP infrastructure Session Initiation Protocol (SIP) signalingOMA, 3GPP, 3GPP2 standards
Wireless Networks Trends
Maturing standards (Wi-Fi, WiMAX) High availability of hot spots Supported in PDAs, Pocket PCs, laptops,
and cellular-phones Emerging standards and working groups:
IETF-MIP, Open Mobile Alliance, 4G
Mobile Networks Trend
Groupware popularity +
Wireless access
availability
B3G Convergence
Cellular going IP +
The Future Network IP based
Cellular N et .
T he I nternet
AccessPoint
AccessPoint
M obile U ser
M obile U ser
S tat ionary U ser
Cell
Mobile Groupware Design Goals
Mapping group names to subscribers Mobility support Seamless handoff QoS support for RT applications Transport efficiency Transport reliability Roaming, AAA Scalable Support for incremental deployment
Previous Solutions: Mobile IP RFC 3344
The standard for seamless mobility Unicast sessions only Dependence on a single home Triangle routing
Poor performance and lack of QoS support Inadequate for RT applications
Route optimization to 3344 Eliminate triangle routing Difficult to deploy Unclear if it can support simultaneous movements
Previous Solutions: Cellular
OMA PoC working group (cellular operators) Single server architecture Large overhead Triangle routing
Our Proposed Solution
Mobility and Group Management Mobility and Group Management ArchitectureArchitecture
[Lavi, Cidon, Keidar MWCN 2004][Lavi, Cidon, Keidar MWCN 2004]
MaGMA’s Architecture
Consists of Mobile-Group Managers (MGMs) and Mobile Nodes (MNs)
Version 1: MGMs static and well-known MGM in charge of one or more domains Entering a new domain, MNs obtain IP
addresses and contact local MGMs
Example: MaGMA Groups
M GM 5
M GM 4
M GM 2 M GM 3
M GM 1
M N 2
M N 3
M N 1M N 4
M N 5
M N 6
Domain-4
Group Blue Group
Red
Group Management Approaches Subscription model
Sending MN implements multicast MGMs provide list of subscribers in group MGMs notify sender of changes
join, leave, move (change IP) Good for lightweight servers, small groups
Multicast overlay model MGMs implement multicast + QoS + reliability using
transport-level overlay Scalable in group size, good for low battery clients
Group Management inSubscription Model
MaGMA Group View
T he I nternet
M N 1
M N 4
M N 2M N 3
M N1->D1M N2->D2M N3->D2M N4->D3
M N2->D2M N3->D2M N1->D1M N4->D3
M GM 1
M GM 2
M N4->D3M N1->D1M N2->D2M N3->D2
M GM 3
GROUP X
MaGMA Group ViewGROUP X
T he I nternet
M N 1
M N 4
M N 2M N 3
M N1->D1M N2->D2M N3->D2M N4->D3
M N2->D2M N3->D2M N1->D1M N4->D3
M GM 1
M GM 2
M N4->D3M N1->D1M N2->D2M N3->D3
M GM 3
MaGMA Solutions
MGMFlood: Flood all events (join, move,…) to all MGMs Sends unnecessary control messages to
MGMs not in group MGMLeader: forward group events only to
MGMs participating in the groupLess control overhead
MaGMA Solution 2:MGMLeader
M GM
M GM
M GM
M GM
M N
M GM M GM
M GM
join/move
/leave
group X
M N
join
Needs the group’s
view
Coordinator
view
View Consistency with Concurrent Joins
MGM1Coordinator
MGM2 MGM3MN1join
MN2 join
view
view
Ignore
join(MN1)join(MN1)
join(MN2)
join(MN2){MGM2, MGM3}
Solution uses a Local Event Counter (LEC) per MGM
[2,1,1]
[1,1,2]
local view
{MGM2, MGM3, MGM1}
Inconsistent
LEC1=1
LEC1=2
Handling Move Goal 1: smooth handoff Goal 2: reduce control overhead
while keeping view consistency
M GM 6 M GM 5
M GM 4
M GM 7
M N
M GM 2 M GM 3
M GM 1
group X
Coordinator
move from MGM1
move
view
transport tunnel
Coordinator Election
Need to ensure a single coordinator Need to address coordinator leave See MWCN paper…
Some Simulation & Analysis Results
Ns2 Simulations & Analysis: MGMFlood vs. MGMLeader Control Overhead Evaluation
Simulation: MaGMA vs. MIP Transport Delay
M N
M GM 0
M GM 2M GM 1 M GM 3
source
5Mb 20ms
MGM1 functions as the HA
MaGMA Multicast Overlay Model
MGMs organized in overlay Multicast data forwarded over the overlay
Ongoing and Future Direction
Efficient solutions for multicast overlay modelKeeping MGM-level views not MN-level viewsOptimizing overlay, adding QoS supportMapping groups to optimal servers
Fault-tolerance: tolerating MGM failures and dynamic changes
Advanced application support
Conclusions
Wireless networks (Wi-Fi, WiMAX) will merge with the Internet and cellular infrastructureConverged B3G will be IP-based
Users will demand support for real-time (RT) groupware such as PTT
Current mobility solutions - inadequate for RT MaGMA can provide comprehensive support
for mobility, group management, and QoS