Interface MTU type adjustments and description updates#1469
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Code Review
This pull request introduces a new YANG module, openconfig-if-types, which defines a max-frame-size typedef as a uint32. This new type is applied to the mtu leaf in openconfig-interfaces.yang, replacing the previous uint16 type to support larger MTU values for loopback and non-Ethernet interfaces, resulting in a major version bump to 4.0.0. Additionally, IPv6 MTU references in openconfig-if-ip.yang are updated to RFC 8200 and RFC 2675. Feedback was provided to include a meaningful description for the new openconfig-if-types module.
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cc: @ElodinLaarz @dplore @rgwilton @jsterne for comment/review |
* (M) release/models/interfaces/openconfig-interfaces.yang
- Change interface MTU type from uint16 to max-frame-size (uint32)
- Increment to version 4.0.0
* (M) release/models/interfaces/openconfig-if-ip.yang
- Update IPv4/IPv6 MTU descriptions
- Increment to version 3.9.1
* (A) release/models/interfaces/openconfig-if-types.yang
- Initial version 0.1.0
- Introduction of max-frame-size typedef
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Bumping for review - cc: @ElodinLaarz @dplore @rgwilton @jsterne |
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What is the motivation to change this? Are there real operational use cases where uint16 is breaking? If there are, I think we have to introduce this as a non-breaking change. It is probably not practical to prove that making this change will affect real deployments. Conceptually this can break constraints for clients and servers: Client Constraints: Client applications that generate or validate configuration data strictly enforce YANG types. An older client might expect the value to fall within (0 \le x \le 65535). Upgrading the server schema can cause these clients to fail validation. Server/Device Implementation: On the backend, generated APIs or struct bindings (e.g., in C or Python) are tied to specific data types. A native 16-bit field in a driver or hardware is fundamentally changed to a 32-bit field, which requires software re-compilation and can disrupt encoding/decoding rules (like NETCONF/RESTCONF serialization). |
Motivation was discussed in our 2026-04-02 OC Community call w/ consensus to proceed w/ this PR from what is described in: #1449 Yes - type changes as such affect the cases you mention above, especially if client/servers (and other type aware downstream systems) are not in synchronization and any type change is backwards incompatible as such - blast radius can obviously differ. As we stand currently at |
2 participants
Change Scope
Per discussion in the OC community call on 2026-04-02, this PR moves forward on
#1449.
max-frame-sizetypedef (uint32) in newopenconfig-if-types.yangwith L2 frame size semantics excluding FCS per IEEE802.3
mtuleaf type fromuint16tomax-frame-size(
openconfig-interfaces3.8.1->4.0.0)mtureferences from obsoleted RFC 2460 to RFC 8200, add RFC 2675(
openconfig-if-ip3.9.0->3.9.1)While this change is backwards incompatible per type changes, it is anticipated
that implementations and consumers can adjust to the larger space.
Platform Implementations
N/A
Tree View
module: openconfig-interfaces +--rw interfaces +--rw interface* [name] +--rw name -> ../config/name +--rw config | +--rw name? string | +--rw type identityref - | +--rw mtu? uint16 + | +--rw mtu? oc-ift:max-frame-size | +--rw loopback-mode? oc-opt-types:loopback-mode-type | +--rw description? string | +--rw enabled? boolean | +--rw oc-vlan:tpid? identityref | +--rw oc-if-sdn:forwarding-viable? boolean | +--rw oc-p4rt:id? uint32 | +--rw oc-hashing:hashing-policy? -> /oc-sys:system/hashing/hashing-policies/hashing-policy/name +--ro state | +--ro name? string | +--ro type identityref - | +--ro mtu? uint16 + | +--ro mtu? oc-ift:max-frame-size | +--ro loopback-mode? oc-opt-types:loopback-mode-type | +--ro description? string | +--ro enabled? boolean | +--ro ifindex? uint32 | +--ro admin-status enumeration | +--ro oper-status enumeration | +--ro last-change? oc-types:timeticks64 | +--ro logical? boolean | +--ro management? boolean | +--ro cpu? boolean | +--ro counters | | +--ro in-octets? oc-yang:counter64 | | +--ro in-pkts? oc-yang:counter64 | | +--ro in-unicast-pkts? oc-yang:counter64 | | +--ro in-broadcast-pkts? oc-yang:counter64 | | +--ro in-multicast-pkts? oc-yang:counter64 | | +--ro in-errors? oc-yang:counter64 | | +--ro in-discards? oc-yang:counter64 | | +--ro out-octets? oc-yang:counter64 | | +--ro out-pkts? oc-yang:counter64 | | +--ro out-unicast-pkts? oc-yang:counter64 | | +--ro out-broadcast-pkts? oc-yang:counter64 | | +--ro out-multicast-pkts? oc-yang:counter64 | | +--ro out-discards? oc-yang:counter64 | | +--ro out-errors? oc-yang:counter64 | | +--ro last-clear? oc-types:timeticks64 | | +--ro in-unknown-protos? oc-yang:counter64 | | +--ro in-fcs-errors? oc-yang:counter64 | | x--ro carrier-transitions? oc-yang:counter64 | | +--ro interface-transitions? oc-yang:counter64 | | +--ro link-transitions? oc-yang:counter64 | | +--ro resets? oc-yang:counter64 | +--ro oc-vlan:tpid? identityref | +--ro oc-atei:out-rate? oc-types:ieeefloat32 | +--ro oc-atei:in-rate? oc-types:ieeefloat32 | +--ro oc-if-sdn:forwarding-viable? boolean | +--ro oc-port:hardware-port? -> /oc-platform:components/component/name | +--ro oc-transceiver:transceiver? -> /oc-platform:components/component[oc-platform:name=current()/../oc-port:hardware-port]/oc-platform:subcomponents/subcomponent/name | +--ro oc-transceiver:physical-channel* -> /oc-platform:components/component[oc-platform:name=current()/../oc-transceiver:transceiver]/transceiver/physical-channels/channel/index | +--ro oc-p4rt:id? uint32 | +--ro oc-hashing:hashing-policy? -> /oc-sys:system/hashing/hashing-policies/hashing-policy/name +--rw hold-time | +--rw config | | +--rw up? uint32 | | +--rw down? uint32 | +--ro state | +--ro up? uint32 | +--ro down? uint32 +--rw penalty-based-aied | +--rw config @@ -13933,108 +13933,108 @@ | | +--ro key-type? identityref | | +--ro key-value? string | +--rw servers | +--rw server* [address] | +--rw address -> ../config/address | +--rw config | | +--rw address? oc-inet:host | | +--rw port? oc-inet:port-number | | +--rw version? uint8 | | +--rw association-type? enumeration | | +--rw iburst? boolean | | +--rw prefer? boolean | | +--rw network-instance? oc-ni:network-instance-ref | | +--rw source-address? oc-inet:ip-address | | +--rw key-id? -> ../../../../ntp-keys/ntp-key/key-id | +--ro state | +--ro address? oc-inet:host | +--ro port? oc-inet:port-number | +--ro version? uint8 | +--ro association-type? enumeration | +--ro iburst? boolean | +--ro prefer? boolean | +--ro network-instance? oc-ni:network-instance-ref | +--ro source-address? oc-inet:ip-address | +--ro key-id? -> ../../../../ntp-keys/ntp-key/key-id | +--ro stratum? uint8 | +--ro root-delay? int64 | +--ro root-dispersion? int64 | +--ro offset? int64 | +--ro poll-interval? uint32 +--rw assigned-ap-managers | +--rw ap-manager* [id] | +--rw id -> ../config/id | +--rw config | | +--rw id? string | | +--rw fqdn? oc-inet:domain-name | | +--rw ap-manager-ipv4-address? oc-inet:ipv4-address | | +--rw ap-manager-ipv6-address* oc-inet:ipv6-address | +--ro state | +--ro id? string | +--ro fqdn? oc-inet:domain-name | +--ro ap-manager-ipv4-address? oc-inet:ipv4-address | +--ro ap-manager-ipv6-address* oc-inet:ipv6-address | +--ro joined? boolean +--rw oc-ap-if:interfaces +--rw oc-ap-if:interface* [name] +--rw oc-ap-if:name -> ../config/name +--rw oc-ap-if:config | +--rw oc-ap-if:name? string | +--rw oc-ap-if:type identityref - | +--rw oc-ap-if:mtu? uint16 + | +--rw oc-ap-if:mtu? oc-ift:max-frame-size | +--rw oc-ap-if:loopback-mode? oc-opt-types:loopback-mode-type | +--rw oc-ap-if:description? string | +--rw oc-ap-if:enabled? boolean +--ro oc-ap-if:state | +--ro oc-ap-if:name? string | +--ro oc-ap-if:type identityref - | +--ro oc-ap-if:mtu? uint16 + | +--ro oc-ap-if:mtu? oc-ift:max-frame-size | +--ro oc-ap-if:loopback-mode? oc-opt-types:loopback-mode-type | +--ro oc-ap-if:description? string | +--ro oc-ap-if:enabled? boolean | +--ro oc-ap-if:ifindex? uint32 | +--ro oc-ap-if:admin-status enumeration | +--ro oc-ap-if:oper-status enumeration | +--ro oc-ap-if:last-change? oc-types:timeticks64 | +--ro oc-ap-if:logical? boolean | +--ro oc-ap-if:management? boolean | +--ro oc-ap-if:cpu? boolean | +--ro oc-ap-if:counters | +--ro oc-ap-if:in-octets? oc-yang:counter64 | +--ro oc-ap-if:in-pkts? oc-yang:counter64 | +--ro oc-ap-if:in-unicast-pkts? oc-yang:counter64 | +--ro oc-ap-if:in-broadcast-pkts? oc-yang:counter64 | +--ro oc-ap-if:in-multicast-pkts? oc-yang:counter64 | +--ro oc-ap-if:in-errors? oc-yang:counter64 | +--ro oc-ap-if:in-discards? oc-yang:counter64 | +--ro oc-ap-if:out-octets? oc-yang:counter64 | +--ro oc-ap-if:out-pkts? oc-yang:counter64 | +--ro oc-ap-if:out-unicast-pkts? oc-yang:counter64 | +--ro oc-ap-if:out-broadcast-pkts? oc-yang:counter64 | +--ro oc-ap-if:out-multicast-pkts? oc-yang:counter64 | +--ro oc-ap-if:out-discards? oc-yang:counter64 | +--ro oc-ap-if:out-errors? oc-yang:counter64 | +--ro oc-ap-if:last-clear? oc-types:timeticks64 | +--ro oc-ap-if:in-unknown-protos? oc-yang:counter64 | +--ro oc-ap-if:in-fcs-errors? oc-yang:counter64 | x--ro oc-ap-if:carrier-transitions? oc-yang:counter64 | +--ro oc-ap-if:interface-transitions? oc-yang:counter64 | +--ro oc-ap-if:link-transitions? oc-yang:counter64 | +--ro oc-ap-if:resets? oc-yang:counter64 +--rw oc-ap-if:ethernet | +--rw oc-ap-if:config | | +--rw oc-ap-if:mac-address? oc-yang:mac-address | | +--rw oc-ap-if:enable-flow-control? boolean | | +--rw oc-ap-if:auto-negotiate? boolean | | +--rw oc-ap-if:standalone-link-training? boolean | | +--rw oc-ap-if:duplex-mode? enumeration | | +--rw oc-ap-if:port-speed? identityref | | +--rw oc-ap-if:fec-mode? identityref | +--ro oc-ap-if:state | | +--ro oc-ap-if:mac-address? oc-yang:mac-address | | +--ro oc-ap-if:enable-flow-control? boolean | | +--ro oc-ap-if:auto-negotiate? boolean | | +--ro oc-ap-if:standalone-link-training? boolean | | +--ro oc-ap-if:duplex-mode? enumeration | | +--ro oc-ap-if:port-speed? identityref | | +--ro oc-ap-if:fec-mode? identityref | | +--ro oc-ap-if:hw-mac-address? oc-yang:mac-address