Dynamic Synchronous Transfer Mode
Published on Feb 21, 2020
For the purposes of the present document, the following terms and definitions apply:
Access token:- right to use a slot for transmitting data on a physical interface for a certain number of bypass hops
Address, DTM address:- 64 bit numerical value that uniquely identifies a node in a DTM network
Allocation domain:- same as a bypass chain where, if the topology is point-to-point or bus, the last node is not counted as member of the AD.
Bypass Chain (BC):- series of concatenated physical links, where data can be transported end-to-end using bypass switching.
Bypass switching:- space switching of slots from a receiver to a transmitter on the same physical interface on a per slot basis.The DTM Resource Management Protocol (DRMP) handles control of transmission resources over bypass chains.
Resource Management handles the right to use a time slot for transmission and the right to administer usage rights. The latter function is referred to as slot ownership. A physical interface owns a set of time slots on the bypass chain.
The owner of a time slot has the right to use it for transmission, but can also lend the right to another physical interface if it is in greater need. Ownership can either be statically configured on a bypass chain, or dynamic. In the latter case, the Dynamic Ownership part of DRMP, distributes ownership along the physical interfaces on the bypass chain according to a configured policy.
Typically the physical interfaces are configured to own an equal share that exhausts the capacity of the bypass chain.
The right to transmit on a time slot can be limited spatially, so as to cover only as many physical links as is needed on a bypass chain for the intended transmission. On the next physical link downstream of the receiver, and the next physical link upstream of the transmitter, the same time slot can be used again for other data transmissions. This spatial reuse of time slots is referred to as slot scoping.