Communications

1
Communications
2
The Bandwidth Problem

• Topics covered
• What is Bandwidth?
• Performance Standards
• Buses and data transfer
• CPU to MMX to DSP to ...
• Comms over Networks
• Solving network MM comms

3
What is Bandwidth?

• Bandwidth is just a measure of the number of bits
  of data that can be transmitted per second, using
  some medium (like optic fibre or digital phone).
• Bandwidth is an engineering term that is used for
  computer hardware in a rather loose sense.
• Bandwidth is like road width - the wider a road
  is, the more vehicles can travel down it.
• It is measured in Hertz (frequency) or in bits
  per second (bps, in computing comms only).

4
MM Communication

• Multi-media and multiple-media communication can
  be seen from many perspectives
• Between a person and a computer (MM Apps)
• Between people (Video Conferencing)
• Between computers (Networks, remote sensing)
• Between components of a computer (Buses)
• Between subsections of an integrated circuit
• This list is ordered by strength of the
  multi-media

5
Performance Standards

• In 1996, there was a significant development in
  PC performance standards-
• for the first time, multimedia functionality was
  recognised as a key performance criterion.
• In 1996, it was expected that the equivalent of a
  Pentium 200 with MMX would be the minimum
  requirement for a desktop multimedia PC by 1998.
• Now nearly all PCs are MM capable and CPU speeds
  are measured in gigahertz

6
Buses and data transfer

• A bus (or buss) is a connection between two or
  more communicating devices.
• A PCs bus handles traffic to and from the HDs,
  FDs, I/O ports, CD, DVD, audio card, video card,
  modem, memory, processor...
• Bus bandwidth gives an indication of the maximum
  throughput, not the average throughput.

7
The AGP connection

• A partial solution to the graphics bandwidth
  problem is provided by the Accelerated Graphics
  Port.
• The AGP first appeared as part of the first
  Pentium II glue chip spec, the 440LX.
• The modern Macintosh architecture supports AGP
  cards too.

8
The AGP connection

• Almost every commercially available graphics card
  is AGPx2 or AGPx4.
• AGPx2 is a graphics-only 32-bit PCI bus
• Runs at 66MHz but moves data on both sides of the
  clock edge
• Effectively moves data at 133MHz
• Peak bandwidth of 528MB/s
• The AGP slot looks like a standard PCI slot on
  the motherboard, but it is set back into a
  different position.

9
CPU to MMX to DSP to ...

• Current MM problems can be solved by simple DSPs
  and/or MMX (SSE, 3Dnow!). These are cheap and can
  have broad functionality
• Customised media processors with specialised
  functions are more expensive but more powerful
• Some newer 3D accelerator chips off-load a huge
  slice of the processing from the CPU

10
Minimising Communications

• In 1998 the Trident Microsystems 85DVD graphics
  processor did the following
• On-chip 3D geometry processing to minimise the
  required CPU usage and bus bandwidth
• FMV from DVD _at_ 30fps with Dolby surround-sound
• Peak 1.2 million polygons per second rendering
• Peak 60 million pixels per second rendering
• Used double-speed AGP (APGx2)

11
Minimising Communications

• In 2000/2001 the ATI Radeon 64 DDR graphics board
  used the AGP bus to do the following
• On-chip 3D transformation and lighting processing
  to minimise the required CPU usage and bus
  bandwidth
• Low CPU usage FMV from DVD _at_ 30fps with Dolby
  surround-sound support
• Peak 30 million polygons per second rendering
• Peak 1.5 billion fully textured pixels per second
  rendering

12
Comms over Networks

• The internet uses the Internet Protocol (IP) for
  networking.
• Many businesses use 10Mbps LANs based on IP and
  Ethernet hardware and firmware.
• 100Mbps Ethernet is becoming common 1Gbps (and
  higher) Ethernet is available.
• Bandwidth is not a big issue in LANs, until MM
  crops up, e.g. 18Mbps uncompressed fmv stream,
  3202408_at_30fps
• Even a well-compressed audio/video stream may be
  one to two Mbps for 38428824_at_25fps

13
Solving network MM comms

• We need a fast, scalable, intelligent networking
  protocol because of multimedia.
• MM needs quality of service or Resource
  Reservation Protocol (RSVP) decisions to be made
  for it.
• MM data needs to be transferred in order, in a
  given time period (isochronous).
• Internet Protocol V6 supports QoS and 128-bit IP
  addresses

14
An Office Scenario

• You walk into an office and want to check your
  email, print a document, have a conversation with
  a distant colleague, browse a web page and change
  the radio station on the hi-fi
• With Bluetooth-enabled devices, it could all be
  done direct from your communicator
• Your PDA negotiates with and queries capabilities
  of all local devices
• Then it is dynamically connected to the LAN, your
  mobile phone and all the general office
  peripherals

15
Pervasive wireless networking

• These are old estimates add one to four years
• It is estimated that before the year 2002,
  Bluetooth will be a built-in feature in more than
  100 million mobile phones and in several million
  other communication devices
• Ericsson Web site bluetooth.ericsson.se
• TDK estimates that there will be over 1.8 billion
  Bluetooth enabled devices by 2005
• NB US billion 1000 million

16
Pervasive wireless networking

• End of 2001 it looks like Bluetooth is
  beginning to catch on
• IMS (www.ims.com) estimated unit shipments at 10
  million, while Cahners (www.cahners.com)
  projected 13.4 million
• Micrologic projected Bluetooth chipset shipments
  of nearly five million this year
• Micrologic predicts 45 million Bluetooth chipsets
  will be sold in 2002, increasing to 181 million
  in 2003 and hitting 1.2 billion at the end of 2005

17
Who is involved?

• IBM, Intel, Toshiba, Ericsson, Nokia, 3Com,
  Motorola, Lucent, Microsoft, TDK
• These are world-spanning companies with huge,
  disparate technology markets
• The common strand is communication over digital
  channels
• The common desire is low-cost, high added-value
  capabilities, integration and standardisation

18
All About Communication

• Voice and data aware
• Dynamic network building (piconets)
• Low-power
• Short-range (10 metres)
• Medium-range (100m for high-power devices)
• Currently 1Mbit/sec may double in later
  versions
• Radio LAN (2.4GHz, available world-wide)

19
Capabilities

• Real-time voice and data transmissions in
  parallel
• Connects any Bluetooth-enabled portable or
  stationary communication device
• Bluetooth eliminates a lot of cabling
• Avoids proprietary cable attachments
• Avoids physical wear
• Avoids maintenance costs

20
Further Information

• Connections are instant and they are maintained
  even when devices are not within line of sight
• Each device has a unique 48-bit address from the
  IEEE 802 standard (281,474,976,710,656
  addresses!)
• A frequency hop scheme allows devices to
  communicate even in areas with a great deal of
  electromagnetic interference
• A built-in encryption and verification layer is
  provided for in the standard

21
Ad hoc networking

• A device equipped with a Bluetooth radio
  establishes instant connection to another
  Bluetooth radio as soon as it comes into range
• The Bluetooth topology is best described as a
  multiple piconet structure

22
Management Layers

• Jini from Sun Microsystems, built on Java
  technology, under development
• Universal Plug and Play originated by
  Microsoft, under development by an independent
  Special Interest Group
• Salutation already being used in live systems

23
Videoconference
24
Some useful Links

• www.jini.org
• www.upnp.org
• www.salutation.org
• www.bluetooth.com, www.bluetooth.org
• Bluetooth.ericsson.se
• www.outlook.com Andrew Seybold
• http//www.bluetooth.com/news/art03.asp