Add ospf auto cost reference bandwidth

[ky-teramae]

Change Scope

• Add reference-bandwidth container to OSPF global structure,
  equivalent to that of ISIS global config.
• Backward compatible: Yes (new optional container only).

Platform Implementations

• Implementation A: Cisco IOS XR — auto-cost reference-bandwidth (OSPFv3: same command under router ospfv3)

router ospf <process-id>
 auto-cost reference-bandwidth <mbps>

router ospfv3 <process-id>
 auto-cost reference-bandwidth <mbps>

• Implementation B: DriveNets DNOS — auto-cost reference-bandwidth

protocols ospf auto-cost reference-bandwidth <mbps>

protocols ospfv3 auto-cost reference-bandwidth <mbps>

Tree View

 module: openconfig-ospfv2
   +--rw network-instances
      +--rw network-instance* [name]
         +--rw protocols
            +--rw protocol* [identifier name]
               +--rw ospfv2
                  +--rw global
                     +--rw inter-area-propagation-policies
                        ...
+                    +--rw reference-bandwidth
+                       +--rw config
+                          +--rw reference-bandwidth?   uint32

 module: openconfig-ospf (OSPFv3, shares the ospf-global submodule)
   +--rw network-instances
      +--rw network-instance* [name]
         +--rw protocols
            +--rw protocol* [identifier name]
               +--rw ospfv3
                  +--rw global
                     +--rw inter-area-propagation-policies
                        ...
+                    +--rw reference-bandwidth
+                       +--rw config
+                          +--rw reference-bandwidth?   uint32

[gemini-code-assist]

Code Review

This pull request introduces a reference-bandwidth container to the global structures of both OSPF and OSPFv2, aligning them with the ISIS global configuration. Feedback on these changes suggests adding a units statement ('Megabits per second') to the reference-bandwidth leaf in both models to comply with OpenConfig style guidelines, as well as restricting the leaf's range to 1..max to prevent potential division-by-zero errors.

[gemini-code-assist]

The reference-bandwidth leaf represents a physical quantity (bandwidth in Megabits per second) and should include a units statement to adhere to OpenConfig style guidelines. Additionally, a reference bandwidth of 0 is semantically invalid as it would lead to division-by-zero errors when calculating interface metrics. Restricting the type to range "1..max" ensures robust data validation.

Suggested change

	leaf reference-bandwidth {
	type uint32;
	description
	"The reference bandwidth, in Mbit/s, used by the local
	system to calculate the default metric for an interface
	based on its bandwidth. Equivalent to the
	reference-bandwidth leaf on the ISIS global config.";
	}
	leaf reference-bandwidth {
	type uint32 {
	range "1..max";
	}
	units "Megabits per second";
	description
	"The reference bandwidth, in Mbit/s, used by the local
	system to calculate the default metric for an interface
	based on its bandwidth. Equivalent to the
	reference-bandwidth leaf on the ISIS global config.";
	}

References

1. OpenConfig Style Guide recommends that any leaf representing a physical or logical quantity with a unit must have a units statement. ^(link)

[ky-teramae]

Thanks. Added units, but as Mbps to match the existing convention:

public/release/models/interfaces/openconfig-if-aggregate.yang

Line 160 in 2198811

units Mbps;

Left the type unconstrained — the equivalent IS-IS leaf is a plain uint32, valid ranges differ per platform, and a constraint would be backward-incompatible to remove later.

public/release/models/isis/openconfig-isis.yang

Lines 550 to 554 in 2198811

	leaf reference-bandwidth {
	type uint32;
	description
	"ISIS Reference Bandwidth value";
	}

[gemini-code-assist]

The reference-bandwidth leaf represents a physical quantity (bandwidth in Megabits per second) and should include a units statement to adhere to OpenConfig style guidelines. Additionally, a reference bandwidth of 0 is semantically invalid as it would lead to division-by-zero errors when calculating interface metrics. Restricting the type to range "1..max" ensures robust data validation.

Suggested change

	leaf reference-bandwidth {
	type uint32;
	description
	"The reference bandwidth, in Mbit/s, used by the local
	system to calculate the default metric for an interface
	based on its bandwidth. Equivalent to the
	reference-bandwidth leaf on the ISIS global config.";
	}
	leaf reference-bandwidth {
	type uint32 {
	range "1..max";
	}
	units "Megabits per second";
	description
	"The reference bandwidth, in Mbit/s, used by the local
	system to calculate the default metric for an interface
	based on its bandwidth. Equivalent to the
	reference-bandwidth leaf on the ISIS global config.";
	}

References

1. OpenConfig Style Guide recommends that any leaf representing a physical or logical quantity with a unit must have a units statement. ^(link)

[ky-teramae]

Thanks. Added units, but as Mbps to match the existing convention:

public/release/models/interfaces/openconfig-if-aggregate.yang

Line 160 in 2198811

units Mbps;

Left the type unconstrained — the equivalent IS-IS leaf is a plain uint32, valid ranges differ per platform, and a constraint would be backward-incompatible to remove later.

public/release/models/isis/openconfig-isis.yang

Lines 550 to 554 in 2198811

	leaf reference-bandwidth {
	type uint32;
	description
	"ISIS Reference Bandwidth value";
	}