HP MSR Router Series

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Figure 43 ATM switching
ATM architecture
ATM has a three-dimensional architecture. It contains the user plane, control plane, and management
plane.
Both the user plane and the control plane are divided into the following layers: physical layer, ATM layer,
ATM Adaptation Layer (AAL), and upper layer. Each layer is further divided into sublayers.
The control plane establishes and tears down connections with signaling protocols. The management
plane contains layer management and plane management. Layer management manages the layers in
each plane and has a layered structure corresponding to other planes. Plane management manages the
system and the communications between different planes.
Figure 44
shows the relationships between layers and planes in ATM.
Figure 44 ATM architecture
ATM layers have the following functions:
• Physical layer—Provides transmission channels for ATM cells. At this layer, cells received from the
ATM layer are transferred into a continuous bit stream after transmission overheads are added to
Router A
Router C
ATM switch B
GE1/0/1
ATM2/4/1
PVC 0/100
In
Port
ATM2/4/1
VPI/VCI
0/100
Out
Port
ATM2/4/2
VPI/VCI
2/101
ATM2/4/1
PVC 0/100
ATM2/4/2
PVC 2/101
ATM2/4/1
PVC 2/101
GE1/0/1
Plane management
Layer management