building the mobile internet introduction to mobility
TRANSCRIPT
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Millions
Growth in Wi-Fi-Enabled Handsets
Wi-F
i-Ena
bled
Han
dset
s (M
illio
ns)
Factors Driving Multiple Device ownership (1)
• Desktop PCs: Growth will be driven by gaming as well as by watching and editing high-definition and three-dimensional video and graphics i.e. activities and processes not suited to relatively lower-powered devices like tablets, Phablets, and Smartphones
Factors Driving Multiple Device ownership (2)
• Tablets: Growth driven by their ease of media-consumption, in addition to email access, web-browser-based services, and office productivity support.
Factors Driving Multiple Device ownership (3)
• Phablets: Growth driven by high-quality architectures with secure data access and Enterprise Productivity support:
• Also Entertainment and Games applications designed for maximum impact on these and Smartphones.
Other Growth Drivers
• Pervasive Software Apps
• Context-Aware System Architectures
• Cloud Service Architectures?
• ? Think of other possibilities ?
The Future of Mobile Markets
• Device Divergence
• Network Convergence?
• IP Everywhere
• Fixed and Cellular (Mobile) Networks: IP is the ‘fundamental Building Block’
• All data Transmission is Packet-Switched?
• Three scenarios are illustrated in the next slide:-
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Voice Data
Early Indication of Data Consumption Trends
Average Revenue per US Mobile Subscriber
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PBytes/Month
Monthly Mobile Internet Traffic in Petabytes (Cisco VNI Forecast)
What, Where and When?
We have looked at where consumers consume mobile Internet services,And also at what type of services are likely to be consumed using mobileDevices, in future.
We must also consider When users access mobile services. The next slide is an representation of the traffic load in a commercial cellulanetwork offering mobile Internet services over a 24-hour period. The figure clearly illustrates the diurnal variation of traffic load within the network, showing how the ‘data-busy’ hour is between 8.00 and 9.00 in the evening. (20:00 -21:00 hours)
Global Mobile Data Traffic, 2014 to 2019
Overall mobile data traffic is expected to grow to 24.3 exabytes per month by 2019, nearly a tenfold increase over 2014.
Mobile data traffic will grow at a CAGR of 57 percent from 2014 to 2019
Source: Cisco VNI Mobile, 2015
mi100209
Towards an ‘Always-On’ scenario:
Current cellular network standards allow mobile data-enabled devices to Be attached to a cellular network without allocating them an IP address.
Legacy cellular networks are typically configured to automatically de-allocate adevice’s IP address after a period of inactivity.
The new generation of cellular standards are designed only to support always-on behaviour, and so, for example, when a device attaches to an all-IP LTE network, it must, by default, receive an IP address and be automatically enabled to send and receive IP packets.
Mobile ChallengesCisco Virtual Network Forecast:Read this Cisco White Paper:
http://www.cisco.com/c/en/us/solutions/collateral/service-provider/visual-networking-index-vni/white_paper_c11-520862.html
Take time to study this in detail…
What does this mean?
• 15.9 Exabytes of Mobile Data Traffic:
• 24.3 Exabytes of Mobile Data Traffic:
Bytes ??? (Disk Storage)
• Kilobyte = 1000 bytes
• Megabyte = 1000 KBytes
• Gigabyte = = 1000 MBytes
• Terabyte = 1000 GBytes
• Petabyte = 1000 TBytes
• Exabyte = 1000 Pbytes = ?? Bytes
Bytes (Virtual Storage) ???
• Kilobyte = 210 bytes = 1024 bytes
• Megabyte = 220 bytes 1048576 bytes
• Gigabyte = 230 bytes = 1073741824 bytes
• Terabyte = 240 bytes = ?
• Petabyte = 250 bytes = ??
• Exabyte = 260 bytes ≈ 1.1529 x 1018 bytes
Mobile Consumer Trends
• http://www.cisco.com/c/en/us/solutions/service-provider/vni-service-adoption-forecast/index.html
Cellular Network Capacity: Key Limiters
There are three key cellular characteristics:
•Spectrum
•Spectral Efficiency
•Frequency reuse
The speed at which data can travel to and from a mobile device can be affected in two places:
the infrastructure speed capability outside the device, and
the connectivity speed from the network capability inside the device (Figure 22). These speeds are actual and modeled end-user speeds and not theoretical speeds that the devices, connection, or technology is capable of providing.
Several variables affect the performance of a mobile connection: •Rollout of 2G/3G/4G in various countries and regions, •technology used by the cell towers, •spectrum availability, •terrain, •signal strength, and •number of devices sharing a cell tower.
•The type of application being used by the end user is also an important factor. Download speed, upload speed, and latency characteristics vary widely depending on the type of application, be it video, radio, or instant messaging.
Mobile ChallengesThe massive increase in forecast consumption of mobile services imposes serious challenges to the current Internet, its structure and in particular, to its protocols
Lets look at this in a little detail…
Spectrum• Spectrum is a scarce resource.
• Higher speed transmission needs sufficient bandwidth and enough energy for wide signal propagation
• Governments auction the spectrum for vast sums of money.
• We can’t make new spectrum
• The laws of physics apply!
Spectral Efficiency (1)
• Efficiency of use is critical
• Shannon’s Law determines the maximum data transmission rate possible in ‘noisy’ transmission channels: i.e. the maximum amount of information that can be transmitted.
• The most advanced signal-processing techniques are at or near this limit.
Spectral Efficiency (2)• Shannon’s Law
• C = B log2(1+S/N)
• Shannon’s limit is sometimes referred to as ‘theoretical’
• It is, however, a factual law of physics.
• Andrew Tanenbaum states: ‘Counter-examples should be placed in the same category as Perpetual-motion machines’…!
Frequency Re-use • Spectrum is scarce and mobile
systems must re-use their allocated radio frequencies across any given cell network;
• Increasing capacity by re-use means smaller cells and more cell ‘tower’ transmitters.
Future Capacity• Forecasts suggest a 39-Fold
increase in demand for mobile Internet traffic:
(over approximately 5-years
2013 - 2018)
• Better use of the spectrum offers, at best, a four-fold increase in capacity in the same period.
Future Capacity (2)• Increased use of smaller cells is
the only option if the forecast demand is to be met.
• If the demand estimates are correct then the number of cells in any given cellular network will need to increase 10-fold to achieve the required capacity.
The Future Mobile Internet• Scalable adoption of small-cell
technologies: IEEE 802.11and ‘Home-Cells’
• Massive numbers of always-on devices with single-subscription-multiple-device being the norm:
• Ubiquitous access from anywhere, indoors or outdoors:
• Seamless service access to Video, Web, Peer-to-Peer, VoIP and Games (and more…)
The Future Mobile InternetThe Key problems and Challenges:• Spectrum Limitation is clearly a
major problem:
• A second problem, just as challenging is the inherent design of the Internet and its primary protocols
The Internet is not Mobile..! • Unfortunately the Internet does
not support ‘native-mobility’
• The TCP/IP stack was not designed with mobility in mind.
• Much has been achieved, but the approach has been by the development of ‘Tunneling Protocols’
The Internet is not Mobile..! • Tunneling means essentially
using existing IP packets as ‘wrappers’, and running everything over the existing structure.
The Internet is not Mobile..! • However, we shall see that
seamless, real-time mobility requires that ‘sessions stay alive’ when devices move between different types of access networks and across networks belonging to different operators.
The Internet is not Mobile..! • What is required is the
capability to implement what has become known as ‘Session-mobility’.
• This is a a very tough challenge;
• However, if it can be achieved, the potential benefits for communications is enormous.
The Internet is not Mobile..! • To understand the problem we
need a detailed understanding of the way that the Internet works.
• We need to appreciate the limitations of current Mobility ‘solutions’;
• Then we can begin to consider new approaches to building a truly ‘Mobile Internet’
Broadband Network Gateway
DSLAM
Wireless ResidentialGateway
(Access Point)
InternetIP/Ethernet TransportNetwork
Packet DataNetwork/ Serving
GatewayMacroENB
WiFiEnabled
Tablet
HomeENB
CellularSmartphone
Correspondent Node
Fixed-Cellular Convergence: Three Scenarios:
References Texts:
Building the Mobile Internet• Grayson et. al.
Computer Networking: A top-Down Approach 6th ed. Kurose and Ross
Other Reading Computer Networks 5th ed.
Andrew Tanenbaum
Claude E. Shannon Shannon’s Law (See next slide)
The Ultimate Limit:Shannon’s Law
Shannon’s law is simple and elegant: It states that
C = B log2(1 + S/N)
where
C is the capacity of the channel in bits per second
B is the channel bandwidth in Hertz
S is the average received signal power over the bandwidth
N is the average noise or interference power over the bandwidth, measured in watts (or volts squared); and
S/N is the Signal-to-Noise ratio (SNR)
So, for example, if we have a communications channel with a signal-noise ratio of, say 30db, then the signal is 1000 times stronger than the noise and the S/N = 1000
If the available bandwidth is 100 MHz, (100,000,000 Hz), then the channel can transmit
996,722,625 bits per second. i.e. 996 Mbps. Almost 1Gbps.
Note that an S/N of 1000 is very high and very difficult to achieve.
In a wireless network S/N varies widely. Work out the bandwidth needed to provide a 1Gbps bit rate on a Wi Fi network if the S/N ratio is 100