An atmLink is a topological component used to describe a fixed relationship between two atmSubnetworks (through the contained atmLinkTP instances) and represents a topological association along with capacity. Many atmLinks may exist between a pair of atmSubnetworks, although an atmLink may not exist between a composite atmSubnetwork and any of its component atmSubnetworks. An atmLink is terminated by two atmLinkTPs, one in each atmSubnetwork. These atmLinkTP instances may exist before an instance of atmLink may be created, otherwise they are created as a result of the setupLinkAction. An instance of atmLink is created by the managed system or by using the setupLink ACTION. Overlapping links (and address ranges) are not allowed. If the availabilityStatus is failed or degraded, the atmLink object shall not allow new atmLinkConnections to be established. Supported values for the availabilityStatus are: - Failed: The atmLink cannot function. All underlying transport connections have failed. - Degraded: The atmLink is degraded in some respect. For instance, the atmLink cannot perform the function of establishing new atmLinkConnections while it can still accept ACTIONS to tear down existing connections. - Empty SET (none of the availableStatus conditions exist). The administrativeState is used for administratively locking and unlocking the atmLink. When unlocked, the atmLink functions normally. When in the locked state, the atmLink is prohibited from the set-up, modification, or release of link connections, thus any of these actions shall be rejected. Locking an atmLink does not automatically lock the contained atmLinkConnections. The characteristicInformation attribute describes the format of the characteristic information that the resource carries. The attribute value is set to vcCI (I.751) for VC Layer atmLinks and vpCI (I.751) for VP Layer atmLinks. Note that the related atmNetworkAccessProfile information is also in the NE-view atmAccessProfile object contained in the tcAdaptorTTPBidirectional or in the vpTTPBidirectional object. The characteristics described by the atmNetworkAccessProfile associated with an atmLink shall be consistent with the atmNetworkAccessProfile of the related atmLinkTPs. The setupLinkConnection ACTION sets up a point-to-point connection between two non- connected subnetworkTPs in the each of the linked atmSubnetworks. The modifyLinkConnection ACTION modifies the QOS and traffic descriptors of a point- to-point connection between two connected subnetworkTPs in the two linked atmSubnetworks. The releaseLinkConnection ACTION releases a point-to-point connection between subnetworkTPs in each of the linked atmSubnetwork. Optionally, in the case where both the NE view and the Network view are supported simultaneously over the same interface, the a-LinkTP and z-LinkTP termination pointers may point directly to instances of the NE View vpTTP or tcAdaptorTTPBidirectional object instances instead of atmLinkTPs.
Sources for this description
ATM Forum M4 official network view CMIP specifications