A YANG Data Model for Microwave Radio Link
Extracted elements (28)
The data model augments ietf-interfaces (RFC 8343) to align microwave radio link management with the standard interface management structure, using interface layering principles from RFC 8343 to manage capacity provided by a radio link terminal for associated Ethernet and TDM interfaces.
The interface protection data nodes are broken out from the Microwave Radio Link module into a separate, generic YANG module (ietf-interface-protection) so that the protection functionality can be reused by other interface types beyond microwave. This separation avoids coupling a general mechanism to a domain-specific module.
The RLT 'id' leaf and CT 'carrier-id' leaf are used by each end of a radio hop to verify it is connected to the correct far-end terminal/carrier. The carrier-id should be the same on both sides of the hop; it defaults to 'A' and is left at default when MIMO and XPIC are not in use.
A protection group must have a minimum of two members (min-elements 2). The working-entity and revertive-wait-to-restore leaves are only applicable when operation-type is 'revertive', enforced by YANG when conditions.
An XPIC pair must have exactly two members (min-elements 2, max-elements 2), each of type microwaveCarrierTermination, enforced via YANG must and cardinality constraints.
The carrier-terminations leaf-list on an RLT interface requires a minimum of one element, and each referenced interface must be of type microwaveCarrierTermination, enforced by a YANG must constraint.
Carrier Termination (CT) is an interface for the capacity provided over the air by a single carrier, typically defined by its transmitting and receiving frequencies. It is represented in YANG as an interface of type 'microwaveCarrierTermination' (ifType decimal 295).
Coding and modulation is configured via a mandatory choice between 'single' (fixed selected-cm identityref) and 'adaptive' (selected-min-acm and selected-max-acm identityrefs). Actual coding/modulation in use is exposed as the read-only leaf actual-tx-cm.
Device capabilities are exposed as a read-only container per CT including min/max TX and RX frequency (uint32, kHz), minimum-power and maximum-available-power (dBm), and available-min-acm / available-max-acm coding-modulation identityrefs.
Error performance statistics (ITU-T G.826) are exposed as read-only counters under each CT: BBE (Background Block Errors), ES (Errored Seconds), SES (Severely Errored Seconds), and UAS (Unavailable Seconds), all typed as yang:counter32.
IF-loop and RF-loop diagnostic configurations are provided as enumeration leaves on each CT with values disabled (default), client (loop back to client side), and radio (loop back to radio side).
MIMO is a feature-gated capability. When enabled, mimo-groups aggregates two or more microwaveCarrierTermination interfaces (min-elements 2, no upper bound). Both XPIC and MIMO groups are referenced from the RLT interface via leaf-lists.
Performance alarm thresholds are configurable per CT via the ct-performance-thresholds container, including received-level-alarm-threshold, transmitted-level-alarm-threshold (both power in dBm), and ber-alarm-threshold (enumeration from 1e-9 to 1e-1, default 1e-6).
Power control is configured via a mandatory choice between RTPC (Remote Transmit Power Control) and ATPC (Automatic Transmitter Power Control) containers. ATPC requires maximum-nominal-power, atpc-lower-threshold, and atpc-upper-threshold (all in dBm), with a YANG must constraint enforcing lower-threshold <= upper-threshold.
Radio Link Terminal (RLT) is an interface providing packet and/or TDM capacity to associated Ethernet and/or TDM interfaces in a node, used for setting up a transport service over a microwave/millimeter wave link. It is represented in YANG as an interface of type 'microwaveRadioLinkTerminal' (ifType decimal 296).
Radio performance statistics (ETSI EN 301 129) are exposed as read-only power leaves under each CT: min-rltm, max-rltm (received power, dBm), min-tltm, and max-tltm (transmitted power, dBm), each noting that discontinuities may occur at management system re-initialization.
TDM connections are a feature-gated (tdm) list on the RLT keyed by tdm-type (identityref based on mw-types:tdm-type). Defined TDM types are E1 (2.048 Mbit/s) and STM-1 (155.52 Mbit/s), with a mandatory uint16 tdm-connections count per type.
The Carrier Termination augmentation includes mandatory tx-frequency (uint32, kHz) and a mandatory choice between rx-frequency (uint32, kHz) or duplex-distance (int32, kHz) to determine the receive frequency. The actual-rx-frequency and actual-duplex-distance are read-only computed state leaves.
The ietf-interface-protection module defines a generic protection-groups grouping with protection-architecture-type (default one-plus-one-type, from ITU-T G.808.1), operation-type (revertive or non-revertive, default non-revertive), hold-off-timer (uint16 milliseconds), and revertive-wait-to-restore (uint16 seconds).
The ietf-microwave-types module defines an extensible identity hierarchy for coding-modulation schemes, covering half-BPSK, BPSK, QPSK, and QAM-4 through QAM-4096, each with optional strong and light variants, allowing vendor-specific extensions via derived identities.
The RLT YANG node includes a mandatory 'mode' leaf (identityref based on rlt-mode) expressing the X+Y configuration: X bonded carrier terminations plus Y protecting carrier terminations. Defined modes include one-plus-zero, one-plus-one, and two-plus-zero.
XPIC (Cross Polarization Interference Cancellation) is a feature-gated capability. When enabled, xpic-pairs groups exactly two microwaveCarrierTermination interfaces; the actual cross-polar interference is reported as the read-only leaf actual-xpi (decimal64, 0.1 dB resolution, 0-99 dB).
IANA registered three YANG module names in the 'YANG Module Names' registry: ietf-microwave-radio-link (prefix mrl), ietf-interface-protection (prefix ifprot), and ietf-microwave-types (prefix mw-types), all with namespace URIs under urn:ietf:params:xml:ns:yang and referencing RFC 8561.
IANA registered two new ifTypes in the SMI 'ifType definitions' registry: decimal 295 'microwaveCarrierTermination' (air interface of a single microwave carrier) and decimal 296 'microwaveRadioLinkTerminal' (radio link interface for one or several aggregated microwave carriers).
Access to NETCONF and RESTCONF management interfaces must use secure transports: SSH (RFC 6242) is mandatory-to-implement for NETCONF, and TLS (RFC 8446) is mandatory-to-implement for RESTCONF. NACM (RFC 8341) must be used to restrict access to authorized users.
Protection switching actions (manual-switch-working, manual-switch-protection, forced-switch, lockout-of-protection, freeze, exercise, clear) are sensitive RPC operations; unauthorized access could interrupt traffic forwarding or disable the ability to perform necessary protection switches.
Writable configuration nodes for RLT (mode, carrier-terminations, rlp-groups, xpic-pairs, mimo-groups, tdm-connections) and CT (tx-frequency, rx-frequency, power settings, coding-modulation, loop controls) must be protected because they need to match the far-end configuration; unauthorized write access could interrupt traffic forwarding.
Protection group status is reported via a read-only identityref leaf with states: unprotected, protected, or unable-to-protect. Protection switching is triggered by operator actions: manual-switch-working, manual-switch-protection, forced-switch, lockout-of-protection, freeze, exercise, and clear (all modeled as YANG actions per ITU-T G.808.1).