UTOPIA Bus Description. Universal Test and Operations PHY Interface for ATM

UTOPIA Bus

Universal Test & Operations PHY Interface for ATM

Utopia Bus Description

Utopia: [af-phy-0017.000] describes the Universal Test & Operations Physical Interface for ATM [UTOPIA] level 1 data path interface. It describes the interface between the Physical Layer (PHY) and the upper layer (ATM). The Utopia bus is the standard interface between asynchronous transfer mode (ATM) link and PHY devices [interface between ATM Layer (Data Link) and ATM PHY chips]. It covers rates from sub-100 Mbit/s to 155 Mbit/s and gives guidance for 622 Mbit/s. 8-bit wide data paths use octet-level/cell-level handshake at 25 MHz.

Utopia Level 2: [af-phy-0039.000] is the Addendum to Level 1 and describes support of a data rate of 622 Mbit/s over a 16-bit wide data path at 33 and 50 MHz.

ATM is an asynchronous cell-switching and multiplexing bus, providing scalable bandwidth to gigabits per second (Gbps). Using Synchronous Optical Network/Synchronous Digital Hierarchy (SONET/SDH), DS-3/E3 as the physical medium; ATM operates at 155Mbps over Fiber or STP (shielded twisted-pair) ~ with 8B/10B encoding. Other physical layers are possible.
ATM transfers data in (fixed size) Cells, with each cell being 53 bytes in length.
The first 5 bytes contain cell-header information, and the remaining 48 contain the "payload" (user information).
An ATM network is made up of an ATM switch and ATM endpoints.