policy-based congestion management for an sms gateway
DESCRIPTION
Policy-based Congestion Management for an SMS Gateway. Alberto Gonzalez (KTH) Roberto Cosenza (Infoflex) Rolf Stadler (KTH) June 8, 2004, Policy Workshop. Outline. Intro to SMS Congestion Management in SMSG Policy-based Approach System Behavior Future Work. - PowerPoint PPT PresentationTRANSCRIPT
Policy-based Congestion Management for an SMS Gateway
Alberto Gonzalez (KTH)
Roberto Cosenza (Infoflex)
Rolf Stadler (KTH)
June 8, 2004, Policy Workshop
Outline
• Intro to SMS
• Congestion Management in SMSG
• Policy-based Approach
• System Behavior
• Future Work
The Short Message Service (SMS)
• SMS is based on out-of-band message delivery. It permits users to send and receive text messages to/from their mobile phones
• Relevance– By the end of 2002, 30 billion messages exchanged
monthly– Growing at 0.5 billions per month. – SMS represents 10% of the revenue of mobile operators
• We consider two classes of SMS services– Guaranteed service (zero losses)– Non-guarateed service
• Bulk messages, information services
SMS Architecture
SMS Gateway Model
Routing
Engine
Inco
min
g P
orts
Out
goin
g P
orts
Acceptance Rate ThrottleMessage Drop
Congestion in a SMS Gateway
• Congestion can be caused by a persistent performance degradation of an outgoing port
• Why do we need congestion management ?– long buffers suppose a risk. The longer the queue, the
higher the cost of a system crash
• The focus of this work is to provide the EMG with congestion management capabilities that permit us to adapt dynamically to congestion
Related Workin Congestion Management
• Congestion management in routing engines has been extensively studied in the context of IP routers
• Our work differs from that field in – Problem space: congestion management for IP routers
considers physical networks. In contrast, an SMSG is a node in an overlay network, where the service rate of outgoing ports can vary, depending on the state of neighboring SMSGs
– Solution space: approaches to congestion management in IP networks often focus on flows. In contrast, flow-based mechanisms are not relevant in the SMS context, since an SMS message fits into a single packet
Addressing congestion in the EMG
• Two low-level mechanisms for reducing the load on a congested port – reducing the acceptance rate
• this reduction affects the loads on all outgoing ports. Therefore the overall throughput of the EMG is compromised
– dropping non-guaranteed messages that are routed to its associated queue
• They present a trade-off – Throughput vs losses
• The EMG manager has to choose between giving priority to:
• having low losses • having high throughput.
Routing
Engine
Inco
min
g P
orts
Out
goin
g P
orts
Acceptance Rate ThrottleMessage Drop
Functional Architecture for Realizing Congestion Control Policies
RoutingTableTraffic
Estimator
TrafficEstimator
TrafficEstimator
DropperOutgoing
queue
DropperOutgoing
queue
DropperOutgoing
queue
PDP
RoutingEngine
βjαi 3
σTijμj
μj
Oj
Low Losses High Throughputβmax
3
3
Iiαi
Outj
System behavior: unbalanced load
Utilisation
0
0,10,2
0,30,4
0,5
0,60,7
0,80,9
1
0 10 20 30 40 50 60 70 80 90 100
1 2 3 4 5
• Incoming traffic 6 m/s• Service rate 6 m/s• Non-guaranteed service: 90%
m/s
System behavior: balanced loadUtilisation
0
0,1
0,2
0,3
0,40,5
0,6
0,7
0,8
0,9
1
0 10 20 30 40 50 60 70 80 90 100
1 2 3 4 5
• Incoming traffic 6 m/s• Service rate 6 m/s• Non-guaranteed service: 90%
m/s
Summary
• Our architecture permits the EMG manager to control the tradeoff between high throughput of the EMG and low loss rate of the non-guaranteed service class
• In situations of congestion and changes in load pattern, the system dynamically re-configures, following the manager’s selected policy
• Our proposal does not need other SMSGs/SMSCs to include any type of congestion management
Future Work
• Service differentiation based on message sender, message content, etc
• Different algorithms for parameter estimation• Prototype evaluation using real traces