R0106-HP MSR Router Series Layer 2 - WAN Configuration Guide(V7)

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Figure 37 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 sub-layers.
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 38 sho
w
s the relationships between layers and planes in ATM.
Figure 38 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
Plane management
Layer management