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Section 4.2

Resource Inventory

Resource Inventory for managing physical and logical network resources β€” devices, ports, cables, VLANs, IPs, and network topology.

Resource Inventory: The Infrastructure Runtime View

Resource Inventory tracks every physical and logical resource in the operator's network. This is where abstract CFS and RFS concepts connect to concrete hardware and configuration. It serves two audiences: service fulfilment (which resources are available to allocate?) and network operations (what is deployed, where, and in what state?).

Resource Inventory
A runtime repository of all physical and logical resource instances. Each instance references a Resource Specification from the Resource Catalog, holds instance-specific attributes (serial number, location, firmware version, IP assignment), tracks lifecycle state, and records allocation to service instances. Managed via TMF639.

Design, Assign, Activate: The End-to-End Flow

The diagram below shows how a service order flows from SOM through inventory layers to network activation. SOM decomposes the order into CFS/RFS, SLM designs the service instances, Resource Inventory assigns (checks, selects, reserves) the physical and logical resources, and the activation engine configures the network elements. The confirmation cascade flows back up through each layer.

Service order flows downConfirm cascade flows up
1

Service Order Management (SOM)

Decomposes commercial order into CFS β†’ RFS

Service Order

Broadband 200Mbps

Create CFS instance
2

SLM (TMF638)

CFS and RFS instances created β€” service is β€˜Designed’

CFS: Internet Access

200Mbps β€” state: Designed

Decomposes into RFS instances

GPON Bearer

RFS

VLAN Svc

RFS

IP Profile

RFS

QoS Profile

RFS

Check & reserve resources
3

Resource Inventory (TMF639)

Resources checked, selected, and reserved β€” service moves to β€˜Reserved’

OLT Port

Reserved

VLAN ID

Reserved

IP Address

Reserved

QoS Policy

Reserved

Activation request (reserved resources)
4

Activation Engine

Generates vendor-specific config from templates, pushes to network

Activation Engine

Template rendering β†’ config push

Push config to network elements
5

Network Elements

Physical and logical resources configured β€” service becomes β€˜Active’

OLT

Switch

BNG

RADIUS

Confirm cascade: NE β†’ Activation β†’ Inventory β†’ SOM
Figure 4.3 β€” SOM design β†’ inventory assign β†’ activation: the five-step flow from service order to network configuration

Resource Categories

Resource Types for a Broadband Service
Physical: OLT device (Huawei MA5800), OLT PON port (Port 3 on Card 1), ONT device (customer premises), fibre drop cable. Logical: VLAN ID (1042), IP address (203.0.113.47/32), QoS profile (200M-DOWN-20M-UP), DHCP scope. Compound: VNF instances, network slices, SD-WAN overlays β€” resources composed of other resources that blur the physical/logical boundary.
TM Forum Resource Classification
TM Forum SID classifies resources as PhysicalResource (tangible equipment), LogicalResource (software-defined configurations), and CompoundResource (aggregations). TMF639 supports all three types. The Resource Specification in TMF634 defines the structure; TMF639 tracks instances.

Resource Allocation and Pool Management

During service fulfilment, resources must be allocated from available pools and assigned to the new service instance. This is one of the most operationally critical functions of Resource Inventory.

Resource Allocation During Fulfilment

1
Requirement Identified
SOM / Service Catalog

RFS decomposition identifies that the service needs: 1 OLT port, 1 VLAN ID, 1 IP address, 1 QoS profile.

2
Availability Check & Selection
Resource Inventory

Resource Inventory is queried for available resources at the serving location. Specific resources are selected based on allocation policies (next available port, nearest IP, specific VLAN range).

3
Reservation
Resource Inventory

Selected resources are marked "Reserved" to prevent double-allocation. Other orders cannot use these resources while reserved.

4
Activation & Confirmation
Resource Inventory / Activation

Once the activation engine configures the resources on the network, inventory updates their state to "In-Use" and records the service instance reference.

The Double-Allocation Problem
One of the most common failures is two orders simultaneously allocating the same resource. Solutions include pessimistic locking (lock during allocation), optimistic locking with retry (check again before committing), and reservation timeouts (auto-release if activation is not confirmed within a window).

Resource Lifecycle States

Resource Lifecycle States

StatePhysical ResourceLogical Resource
PlannedOrdered from vendor, not yet installedDefined but not yet provisioned
AvailablePhysically installed, tested, ready for useCreated in pool, available for allocation
ReservedEarmarked for a specific orderAllocated to an order, not yet activated
In UseActively carrying trafficConfigured on a device, assigned to a service
DecommissionedPhysically removed or marked for disposalDeleted from device, returned to pool

IP Address and VLAN Management

IP addresses and VLAN IDs are the most common logical resource types. Both are finite pools that must be carefully managed to avoid exhaustion and conflicts.

  • IPAM: Tracks IP pools, subnet allocations, and individual assignments. Pools are defined per region/service/access technology. IPv4 exhaustion makes efficient IPAM critical.
  • VLAN Management: VLAN IDs range 1-4094, partitioned by service type (e.g., 100-499 residential, 500-999 business). Scope rules determine where uniqueness must hold. Exhaustion on an access ring blocks new activation.

TMF639 Resource Inventory Management API

TMF639 Resource Inventory Management
TMF639 provides standardized CRUD and event notification for resource instances. Supports both physical and logical resources with characteristics, relationships (containment, connectivity, dependency), and lifecycle state. ROM and activation engines are the primary writers; capacity planning, fault management, and service assurance are the primary readers.

Resource Discovery and Reconciliation

Resource Inventory is only useful if it reflects reality. Discovery scans the network to detect what actually exists; reconciliation compares discovered state against inventory records.

  • Discovery methods: SNMP polling, NETCONF/YANG, CLI scraping (legacy), SDN controller APIs
  • Discrepancy types: Missing in inventory (add), missing on network (investigate), attribute mismatch (determine which is correct), state mismatch (typically network wins for physical presence)
  • Design intent vs actual state: Mature operators maintain both views β€” when they diverge, the operator can enforce intent or accept the change

Source of Record

Resource Inventory SoR Mapping

EntitySystem of RecordSystem of EngagementSystem of ReferenceNotes
Physical Resource InstanceResource Inventory / Network InventoryField Operations, LogisticsSLM, Network PlanningAuthoritative for physical device presence, location, and hardware state.
Logical Resource InstanceResource InventoryROM / Activation EngineSLM, IPAMAuthoritative for logical resource allocation (VLAN, IP, QoS).
Network TopologyResource Inventory / Network InventoryNetwork Planning, Field OpsService Assurance, Path ComputationContainment, connectivity, and dependency relationships.

Section 4.4 Key Takeaways

  • Resource Inventory tracks every physical, logical, and compound resource instance on the network
  • Resource allocation during fulfilment requires availability checks, selection, reservation, and confirmation to prevent double-allocation
  • Resources follow a lifecycle from Planned through Available, Reserved, In-Use, to Decommissioned
  • IPAM and VLAN management are critical sub-functions β€” both manage finite pools that can block activation when exhausted
  • TMF639 provides standardized CRUD and event notification for resource instances
  • Discovery and reconciliation maintain accuracy between inventory records and actual network state