Network managementNetwork management

Reinhard Laroy

BIPT

European Parliament - 27 February 2012

Telecommunication networkTelecommunication network All kinds of devices (pc, mobile, routers, server, …)

randomly connected through transmission media Sending data in packets to each other without setting up a

permanent connection (e.g. postal services) Routers forward data to the right destination through

mechanisms that try to avoid network congestion

Source Destination

Core networkrouter

Connection

data

Source: UGent - IBCN

Networking dimensioningNetworking dimensioning

The dimensioning is based on statistical models and overbooking to make the business case viable.

With overbooking the aggregation network (or core network) has a lower capacity than the sum of all foreseen capacities at the edge of the network

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Link 100 Mbps

Subscriber 1

Subscriber 2

Subscriber 3

Subscriber 24

…

Offer 10 Mbps

Offer 10 Mbps

Offer 10 Mbps

Offer 10 Mbps

240%overbooking

Sum = 240 Mbps

Networking dimensioningNetworking dimensioning

Compromise between the risk of traffic congestion and the necessary infrastructure investissements to guarantee the bandwidth while avoiding an underutilisation of the material Linked to the usage profile of the subscriber

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Congestion risk

1 / overbooking factor

Necessary equipment

Traffic controlTraffic control

Network traffic control necessitates the control of the load on the different network routes: The capacity is shared between different subscribers The use of capacity peaks and/or evolves depending on the

time of day.

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Traffic controlTraffic control Data packets are stored in buffer queue before processing by router

and further forwarding over the network If too many packets arrive, the queue will get full

packets will be lost When the sender’s equipment doesn’t receive acknowledgements of

certain packets, the packet is sent again and the speed is slowed down After a while the sender’s equipment tries to increase the speed again This speed mechanism is independent of content or application.

Sender Destination

Core networkrouter

Connection

data

Source: UGent - IBCN

A buffer queue before each router and at the end points

Internet experienceInternet experience

Relevant parameters bitrate or throughput

(the amount of data transmitted in a unit of time) delay jitter (time variation of the average delay) packet loss ratio

Constraints in the service provision for real time applications

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Best effort is the general principleBest effort is the general principle

The internet in principle is a best effort service because the bandwidth is limited (e.g. cables, equipment)

All internet users obtain a best effort service: unspecified variable bit rate unspecified delivery time depending on the current traffic load

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Quality of Service is the exceptionQuality of Service is the exception However, certain traffic needs priority

Emergency calls Voice calls and broadcasting are very

sensible to packet loss and packet delays: the signal needs to be reproduced without distortion, noise, echo & loss of signal.

« cloud computing » business applications

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Adaptation of serviceAdaptation of service

Each device, its quality Each device needs a different

quality of transmission E.g. Smartphone screen doesn’t

need same image quality

Different usage of each device E.g. Browsing standard internet

page on a mobile screen

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Certain technologies, e.g. those related to mobile devices adapt the content and quality based on the access method and the available bandwidth

Traffic management Traffic management

Maintain network stability automatic traffic redirection in case of outage congestion management

Prioritisation for certain types of data Guaranteed network capacity for specific users Legal intervention

Blocking sites with illegal content

Authentication of customers Blocking of viruses and external attacks

E.g. Denial of Service attack

Block or degrade certain content

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ConclusionConclusion

Congestion control is essential

Traffic differentiation has been in the network design all the time

A sensible level of (legitimate) traffic differentiation must be allowed for network management purposes

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MERCI POUR VOTRE MERCI POUR VOTRE ATTENTIONATTENTION

Confidentiel IBPT 13

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Thank you for your attentionThank you for your attention

© BIPT 2012 - Reinhard Laroy – Reinhard.Laroy@BIPT.be Internet Map

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