Reinhard Laroy BIPT European Parliament - 27 February 2012 Network management Reinhard Laroy BIPT European Parliament - 27 February 2012

Telecommunication 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 Destination Source Connection data router Core network Source: UGent - IBCN

Networking 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 Subscriber 1 Offer 10 Mbps Subscriber 2 Offer 10 Mbps 240% overbooking Subscriber 3 Offer 10 Mbps Link 100 Mbps … Subscriber 24 Offer 10 Mbps Sum = 240 Mbps

Networking 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 Congestion risk Necessary equipment 1 / overbooking factor

Traffic 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.

Traffic control Destination Sender Connection Core network router 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. Destination Sender Connection data router Core network A buffer queue before each router and at the end points Source: UGent - IBCN

Internet 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

Best 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

Quality 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

Adaptation 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 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 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

Conclusion 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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