01-10-2012, 05:36 PM
Asynchronous Transfer Mode
Asynchronous.ppt (Size: 571.5 KB / Downloads: 63)
Protocol Architecture
Similarities between ATM and packet switching
Transfer of data in discrete chunks
Multiple logical connections over single physical interface
In ATM flow on each logical connection is in fixed sized packets called cells
Minimal error and flow control
Reduced overhead
Data rates (physical layer) 25.6Mbps to 622.08Mbps
Reference Model Planes
User plane
Provides for user information transfer
Control plane
Call and connection control
Management plane
Plane management
whole system functions
Layer management
Resources and parameters in protocol entities
ATM Logical Connections
Virtual channel connections (VCC)
Analogous to virtual circuit in X.25
Basic unit of switching
Between two end users
Full duplex
Fixed size cells
Data, user-network exchange (control) and network-network exchange (network management and routing)
Virtual path connection (VPC)
Bundle of VCC with same end points
Advantages of Virtual Paths
Simplified network architecture
Increased network performance and reliability
Reduced processing
Short connection setup time
Enhanced network services
Virtual Channel Connection Uses
Between end users
End to end user data
Control signals
VPC provides overall capacity
VCC organization done by users
Between end user and network
Control signaling
Between network entities
Network traffic management
Routing
VP/VC Characteristics
Quality of service
Switched and semi-permanent channel connections
Call sequence integrity
Traffic parameter negotiation and usage monitoring
VPC only
Virtual channel identifier restriction within VPC
Asynchronous.ppt (Size: 571.5 KB / Downloads: 63)
Protocol Architecture
Similarities between ATM and packet switching
Transfer of data in discrete chunks
Multiple logical connections over single physical interface
In ATM flow on each logical connection is in fixed sized packets called cells
Minimal error and flow control
Reduced overhead
Data rates (physical layer) 25.6Mbps to 622.08Mbps
Reference Model Planes
User plane
Provides for user information transfer
Control plane
Call and connection control
Management plane
Plane management
whole system functions
Layer management
Resources and parameters in protocol entities
ATM Logical Connections
Virtual channel connections (VCC)
Analogous to virtual circuit in X.25
Basic unit of switching
Between two end users
Full duplex
Fixed size cells
Data, user-network exchange (control) and network-network exchange (network management and routing)
Virtual path connection (VPC)
Bundle of VCC with same end points
Advantages of Virtual Paths
Simplified network architecture
Increased network performance and reliability
Reduced processing
Short connection setup time
Enhanced network services
Virtual Channel Connection Uses
Between end users
End to end user data
Control signals
VPC provides overall capacity
VCC organization done by users
Between end user and network
Control signaling
Between network entities
Network traffic management
Routing
VP/VC Characteristics
Quality of service
Switched and semi-permanent channel connections
Call sequence integrity
Traffic parameter negotiation and usage monitoring
VPC only
Virtual channel identifier restriction within VPC