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Efficient Monitoring of QoS Parameters (EMQP)
Authors:Vadim DrabkinArie OrlovskyConstantine Elster
Instructors:Dr. Danny RazMr. Ran Wolff
Vadim Drabkin, Constantine Elster, Arie Orlovsky, Technion I.I.T. 2002 2
EMQP - Document Structure
Introduction Overview Terms and Conditions Proposed Solution Program Flow Implementation Issues Results Conclusion
Vadim Drabkin, Constantine Elster, Arie Orlovsky, Technion I.I.T. 2002 3
EMQP - Introduction
Today’s Internet delivers "best-effort" performance dictated by the very design of the Internet Protocol (IP). That is, traffic is processed as quickly as possible, but there is no guarantee as to timeliness or actual delivery. Consequently, important business applications packets such as real-time video or audio packets could be lost or to be delivered too late because of displacement by less important packets. This leads to the need for Quality of Service in order to provide a consistent predictable data delivery service for different kinds of packets. Quality of Service (QoS) is an umbrella term for a collection of technologies that allow network-aware applications to request and receive predictable service levels in terms of data throughput capacity (bandwidth), latency variations (jitter) and propagation latency.
Vadim Drabkin, Constantine Elster, Arie Orlovsky, Technion I.I.T. 2002 4
EMQP - Overview
The EMQP project comes to introduce an algorithm proposed by Dr. Danny Raz and Mr. Ran Wolff.
The EMQP aims to achieve an efficient monitoring of network traffic. – One of the main goals is discovering if the proposed
algorithm is more efficient than currently proposed techniques in the case of monitoring heavy traffic networks.
The EMQP project comes to test the proposed algorithm by means of network simulator, which has the monitoring capability of the proposed algorithm.
Vadim Drabkin, Constantine Elster, Arie Orlovsky, Technion I.I.T. 2002 5
EMQP – Terms and Conditions
Network Topology– a graph with nodes and edges
Node – a host connected to network Edge - hop-to-hop path between two nodes
Stream – A path between two nodes in a given network.
Latency – metric value of an edge – the cost of going from one of the edge’s end to the another
edge’s end. Latency threshold
– Local problem considered, if an edge’s latency is greater than its latency threshold.
Vadim Drabkin, Constantine Elster, Arie Orlovsky, Technion I.I.T. 2002 6
EMQP – Terms and Conditions (cont.)
Stream latency – The sum of latencies of stream edges
Threshold for stream latency – maximum allowed stream latency
Considered as a stream problem if greater than stream latency
Bandwidth Broker – The controlling host managing network
streams
Vadim Drabkin, Constantine Elster, Arie Orlovsky, Technion I.I.T. 2002 7
EMQP – Proposed Solution
The algorithm outline– Every edge checks if its latency exceeds its
latency threshold for every stream going through the edge.
If it does – trigger message to the next edge of the stream containing:
– Edge latency– Latency threshold– The stream identificator
Vadim Drabkin, Constantine Elster, Arie Orlovsky, Technion I.I.T. 2002 8
EMQP – Proposed Solution (cont.)
The algorithm outline (cont.)– If edge receives a message
Checks if received latency is greater than stream latency threshold
– If true – report about the stream problem to the bandwidth broker.
Otherwise: checks if the (received latency + edge latency) is greater than (received latency threshold + edge’s latency threshold)
– If true - send to the next stream’s edge: (received latency + edge) (received latency threshold + edge’s latency threshold) Stream identificator
Vadim Drabkin, Constantine Elster, Arie Orlovsky, Technion I.I.T. 2002 9
EMQP – Proposed Solution (cont.)
e2
e1
n1
n2
n3
latency = 2latency threshold = 1
latency = 4latency threshold = 6
Figure 3.
n2 triggers <route, 2, 1> message to n3.n3 gets the message, but does not forward any information to other edges, since
2 + 4 < 1 + 6
Vadim Drabkin, Constantine Elster, Arie Orlovsky, Technion I.I.T. 2002 10
EMQP – Program Flow
BriteBrite Parser Network
Model
Object
Stream Generator(BFS & Distribution)
NetworkModel
Containing streams
Object
EMQP
NetworkModel
Results Data
Object
Graph Generator
Text File
Vadim Drabkin, Constantine Elster, Arie Orlovsky, Technion I.I.T. 2002 11
EMQP – Implementation Issues
Message driven– Messages are stored in message queue
Delivered by nodes
– Messages are delivered to nodes Node answers whether it wants to deliver a new
message
Vadim Drabkin, Constantine Elster, Arie Orlovsky, Technion I.I.T. 2002 12
EMQP – Implementation Issues (cont.)
Vadim Drabkin, Constantine Elster, Arie Orlovsky, Technion I.I.T. 2002 13
Results 100 nodes100 streamsaverage fan out 4latency deviation 0.1average latency 0.93
Vadim Drabkin, Constantine Elster, Arie Orlovsky, Technion I.I.T. 2002 14
Results (cont.)
100 nodes100 streamsaverage fan out 4latency deviation 0.1average latency 0.97
Vadim Drabkin, Constantine Elster, Arie Orlovsky, Technion I.I.T. 2002 15
Results (cont.) 100 nodes100 streamsaverage fan out 4latency deviation 0.1average latency 1.0
Vadim Drabkin, Constantine Elster, Arie Orlovsky, Technion I.I.T. 2002 16
Results (cont.) 100 nodes100 streamsaverage fan out 4latency deviation 0.1average latency 1.025
Vadim Drabkin, Constantine Elster, Arie Orlovsky, Technion I.I.T. 2002 17
Results (cont.) 100 nodes100 streamsaverage fan out 4latency deviation 0.1average latency 1.05
Vadim Drabkin, Constantine Elster, Arie Orlovsky, Technion I.I.T. 2002 18
Results (cont.)
100 streams 200 streams
50 streams
Vadim Drabkin, Constantine Elster, Arie Orlovsky, Technion I.I.T. 2002 19
Results (cont.)
100 nodesVariable number of streams Average fan out 4Latency deviation 0.1Average latency 0.95
Vadim Drabkin, Constantine Elster, Arie Orlovsky, Technion I.I.T. 2002 20
Results (cont.)
50 streams
100 streams
200 streams
Vadim Drabkin, Constantine Elster, Arie Orlovsky, Technion I.I.T. 2002 21
Results (cont.)
100 nodes100 streams Variable average fan outLatency deviation 0.1Average latency 0.95
Vadim Drabkin, Constantine Elster, Arie Orlovsky, Technion I.I.T. 2002 22
Results - Conclusion
The EMQP algorithm has significantly better performance than the standard 1
EMQP algorithm has better performance than standard 2 when the possibility of edge problem decreases
– It leaves us the the main drawback of the EMQP algorithm, which appears when there is high possibility of message triggering from several stream points, which in addition causes several messages sent to Bandwidth Broker addressed from the same stream. In such cases we see that the standard 2 performs better despite of its simplicity
– It could require an extra work on finding how to eliminate the unnecessary traffic. One can think on a way of sending the messages to both directions and then eliminating the unnecessary message in their meeting point