1. Wireless ATM & Congestion ControlBY
K.DASTAGIRAIAH
HT.NO:07D01A0570

2. Wireless Technologies ?
Wireless LAN technologies comprise of infrared (IR), UHF radio,
spread spectrum, and microwave radio, ranging from frequencies
in the region of GHz in Europe (900 MHz in the U.S.) to infrared
frequencies
Spread Spectrum (CDMA)
Time Division Multiple Access (TDMA)

3. ATM (Asynchronous Transfer Mode)
In ATM networks, the data is divided into small, fixed length units called cells. The cell is 53 bytes. Each cell contains a 5-byte header, which comprises of identification, control priority and routing information. The rest 48 bytes are the actual data. There are two fundamental types of ATM connections
Permanent Virtual Connections (PVC)
Set up by some external mechanism,typically network
management.
Switched Virtual Connections (SVC)
Set up automatically through signaling protocol,does not
require the manual interaction needed to set up PVCs

4. Wireless ATM Wireless ATM Components
ATM is considered to reduce the complexity of the network and improve the flexibility while providing end-end consideration of traffic performance.
Wireless ATM Components
Fixed Wireless Components
Mobile End Users
Mobile Switches with Fixed End Users
Mobile Switches with Mobile End Users
Interworking with PCS
Wireless Ad Hoc Networks

5. Key Issues Architecture
Wireless Base Station Connected Through An ATM Switch

6. Cell Size
The ATM cell size (53 bytes) is designed for 64kbps or higher.
Each cell contains a 5-byte header, which comprises of identification,
control priority and routing information. The rest 48 bytes are the
actual data. There are two fundamental types of ATM connections
Virtual Circuit Management And Packet Routing
Each processor that attaches to the ATM switch maintains a virtual
connection to each other processor over which it passes data packets.
The processors use a second, separate virtual circuit for routing
updates.
Physical Layer
The physical layer includes all hardware components and the
wireless connections. This includes the high speed radios, order
wire packet radios, ATM switch, antennas, and additional processor
for configuration and setup.

7. Media Access Control (MAC)
Relation of wireless network (PCN) protocol layers of ATM

8. Data Link Layer
Network Locations and Connection Establishment
Mobile ATM
Handover
Location Management
Routing
Addressing
Traffic and QoS Control
Wireless Network Management

9. Why Congestion Control Needed?
A Network with High Speed Links

10. Generic Functions Connection Admission Control Usage Parameter Control
Priority Control
Traffic Shaping
Leaky Bucket Algorithm

11. Network Resource Management
Responsible for the allocation of network resources in order to
separate traffic flows.
Frame Discard
It may be better to drop all cells of one frame than to randomly
drop cells belonging to different frames
Feedback Control
The set of actions taken by the network and by the end-systems
to regulate the traffic submitted on ATM connections according
to the state of network elements.
ABR Flow Control
The ABR service category uses the link capacity that is left over
and is applied to transmit critical data that is sensitive to cell loss

12. Some Early Debates Open-Loop Vs Close-Loop
1st one do not need end-to-end feedback,but In 2nd approaches,
the source adjusts its cell rate in responding to the feedback
information received from the network.
Credit-Based Vs Rate-Based
Credit-Based approaches consist of per-link, per-VC window
flow control. Rate-Based approaches control the rate by which
the source can transmit
Binary Feedback Vs Explicit Feedback
Binary Feedback uses on bit in the cell to indicate the elements
along the flow path is congested or not In Explicit Feedback,
the network tells the source exactly what rate is allowed for it
to send

13. Conclusion
WATM has the potential to bring wireless networks a new generation
The success of WATM will be highly relies on the success of ATM/B-ISDN in wired networks
Both ATM and wireless communicates have put a lot of attention on Wireless
This report introduced the concepts in congestion control for ATM networks, and the specifications for ATM Congestion Control ATM traffic control proposed by ATM