ATM Cloud is a term used to describe an ATM public or private network from the view of an edge device (e.g. an end user). A user is provided a UNI connection to an ATM Cloud via a network administrator (who may represent a small campus fiber ATM backbone up to a telco-operated national ATM network). The connection may be a "slow" WAN connection like 1.544Mbps (transported over DS-1 on copper), a 155Mbps FDDI fiber drop into an office, or multiple Gbps (OC-192 and faster) long-distance link.

Thanks to PNNI and UNI specifications, the user doesn't need to know anything about the topology of the network itself. The ATM Cloud provides permanent (PVC) and temporary (SVC) connections from the user's point of access to the remote edge device. The user simply specifies the ID of the connection he or she wishes to use (using VPI/VCI) and the ATM switch to which the user is connected handles the rest. In the case that ILMI is used, the PVC and SVC connections are established as soon as they are created in the ATM Cloud.

From the ATM network administrator's point of view, the ATM Cloud is a ATM switch (or collection thereof) which provide network to network connectivity (PNNI) and user to network connectivity (UNI) and probably requires at least full-time employee to maintain.

Log in or registerto write something here or to contact authors.