A YANG Data Model for Microwave Topology
Extracted elements (20)
A microwave radio link is always an aggregate of one or multiple carriers. Supporting carriers are identified by their termination points and listed as bundled links in the TE topology model (RFC 8795). The rlt-mode container then further specifies the exact aggregation/protection configuration (e.g., 1+0, 2+0, 1+1).
Because microwave is a point-to-point technology, the majority of TE Topology (RFC 8795) leaves augmented by this model are not applicable. Specifically, admin-status and oper-status from te-topology apply only to microwave carriers (not radio links), since radio links are enabled/disabled via their constituent carriers.
The model relies on the supporting-network, supporting-node, supporting-link, and supporting-termination-point leaves from the generic Network Topologies model (RFC 8345) to express the dependency from higher topology layers (e.g., L2 Ethernet) down to the supporting microwave radio link topology, rather than defining new cross-layer references.
The mw-tp status leaves are available for inter-domain links where only one side's status is known. However, since microwave is point-to-point with both endpoints typically in the same domain, use of these status leaves is not expected in normal cases.
The microwave topology model augments and depends on ietf-network and ietf-network-topology (RFC 8345), ietf-te-topology (RFC 8795), and ietf-microwave-types (RFC 8561). All augmentation when-conditions require the presence of mwt:mw-topology under tet:te-topology, ensuring model elements are only active in microwave-typed networks.
The model is designed for use between a Provisioning Network Controller (PNC) and a Multi-Domain Service Coordinator (MDSC) as defined in RFC 8453, supporting use cases such as correlation between microwave and higher-layer topologies, bandwidth propagation, and network-level optimization.
A 1+1 protected configuration is represented with num-bonded-carriers=1 and num-protecting-carriers=1, meaning one active carrier is protected by one standby carrier. Both carrier termination points are still listed as bundled-links in the radio link.
A 2+0 bonded configuration is represented with num-bonded-carriers=2 and num-protecting-carriers=0, meaning both carriers are active with no redundancy and maximum aggregate capacity. The radio link references two carrier links as bundled-links.
The ietf-microwave-topology YANG module defines a topology model for microwave and millimeter-wave radio links, augmenting the TE Topology model (RFC 8795) which is based on the Network Topologies model (RFC 8345). It introduces the mw-topology network type, mw-node, mw-tp, mw-link, and mw-bandwidth augmentations.
The microwave-carrier-attributes grouping defines six leaves for a carrier link: tx-frequency (uint32, kHz, configurable), actual-rx-frequency (uint32, kHz, read-only), channel-separation (uint32, kHz, configurable), actual-tx-cm (identityref to mw-types:coding-modulation, read-only), actual-snir (decimal64 in dB with 0.1 resolution, read-only), and actual-transmitted-level (decimal64 in dBm with 0.1 resolution, read-only).
The mw-bandwidth leaf (uint64, bits/seconds, read-only) augments tet:max-link-bandwidth/tet:te-bandwidth to expose nominal microwave radio link and carrier bandwidth within the TE topology bandwidth structure.
The mw-link container augments TE link attributes and uses a mandatory choice (mw-link-option) to classify each link as either a microwave-radio-link (containing rlt-mode) or a microwave-carrier (containing carrier-specific attributes such as tx-frequency, channel-separation, actual-rx-frequency, actual-tx-cm, actual-snir, and actual-transmitted-level).
The mw-topology presence container augments /nw:networks/nw:network/nw:network-types/tet:te-topology to indicate a microwave network topology type. Its presence signals that the network is a microwave topology.
The mw-tp container augments termination points and uses a choice (mw-tp-option) to classify each termination point as either a microwave-rltp (Radio Link Termination Point, corresponding to an RLT interface per RFC 8561) or a microwave-ctp (Carrier Termination Point, corresponding to a CT interface per RFC 8561).
The rlt-mode grouping defines the Radio Link Terminal mode via two mandatory uint32 leaves: num-bonded-carriers (number of active aggregated carriers) and num-protecting-carriers (number of standby/protecting carriers). This flexibly encodes configurations such as 1+0, 2+0, and 1+1.
IANA assigned a new URI in the IETF XML Registry (RFC 3688): urn:ietf:params:xml:ns:yang:ietf-microwave-topology, with registrant contact IESG.
IANA recorded the YANG module name 'ietf-microwave-topology' in the YANG Module Names registry (RFC 6020) with namespace urn:ietf:params:xml:ns:yang:ietf-microwave-topology, prefix 'mwt', and reference RFC 9656.
The rlt-mode configurable container is sensitive: a malicious client could modify the bonded/protecting carrier counts, changing the intended behavior of the radio link. The tx-frequency and channel-separation leaves are also sensitive: unauthorized modification could alter frequency configuration, render the configuration invalid, and stop carrier operation.
The security considerations from RFC 8345 (A YANG Data Model for Network Topologies) are applicable to this module, since ietf-microwave-topology imports and augments those models.
The YANG module is accessed via NETCONF (mandatory secure transport: SSH per RFC 6242) or RESTCONF (mandatory secure transport: TLS per RFC 8446). The NETCONF access control model (RFC 8341) must be used to restrict access to authorized users.