Extend LLDP model with global TTL, custom TLV, and per-interface enhancements by ndas7 · Pull Request #1470 · openconfig/public

ndas7 · 2026-04-07T01:32:39Z

Change Scope

*   This PR proposes enhancements to the existing LLDP model with the following changes:

    1. Adding a global ttl configuration/state leaf under /lldp.
    2. Extending interface LLDP config and state with port-description and interface-level custom-tlv-names.
    3. Introducing a shared custom-TLV grouping so both config and state reuse the same custom TLV fields.
    4. Adding a top-level /lldp/custom-tlvs/tlv[name] list for global custom TLV definitions.
    5. Adding interface state timestamp counters for LLDP packet events.

This change is backwards compatible as it adds leaves to existing model.

Platform Implementations

* LLDPCLI, LLDPAD (LLDP daemons for Linux): https://lldpd.github.io/usage.html

lldpcli configure lldp custom-tlv oui 00,00,00 subtype 1 oui-info "your data"

* SONiC: https://github.com/cshivashgit/SONiC/blob/lldp-custom-tlv-hld/doc/lldp_custom_tlv/lldp-custom-tlv-hld.md#config-db-schema
* Vendors use custom TLVs to support features like Cisco's LLDP-MED (Media Endpoint Discovery), which is itself a collection of organizationally specific TLVs. In Cisco NX-OS, you can select which TLVs to include using the lldp tlv-select command. Aruba's AOS-CX introduced a specific OUI (83A30) to help identify Aruba devices and automatically apply network profiles.

Tree View

module: openconfig-lldp
  +--rw lldp
     +--rw config
     |  +--rw enabled?                      boolean
     |  +--rw hello-timer?                  uint64
+    |  +--rw ttl?                          uint16
     |  +--rw suppress-tlv-advertisement*   identityref
     |  +--rw system-name?                  string
     |  +--rw system-description?           string
     |  +--rw chassis-id?                   string
     |  +--rw chassis-id-type?              oc-lldp-types:chassis-id-type
     |  +--rw management-interface?         oc-if:interface-id
     +--ro state
     |  +--ro enabled?                      boolean
     |  +--ro hello-timer?                  uint64
+    |  +--ro ttl?                          uint16
     |  +--ro suppress-tlv-advertisement*   identityref
     |  +--ro system-name?                  string
     |  +--ro system-description?           string
     |  +--ro chassis-id?                   string
     |  +--ro chassis-id-type?              oc-lldp-types:chassis-id-type
     |  +--ro management-interface?         oc-if:interface-id
     |  +--ro counters
     |     +--ro frame-in?           oc-yang:counter64
     |     +--ro frame-out?          oc-yang:counter64
     |     +--ro frame-error-in?     oc-yang:counter64
     |     +--ro frame-discard?      oc-yang:counter64
     |     +--ro tlv-discard?        oc-yang:counter64
     |     +--ro tlv-unknown?        oc-yang:counter64
     |     +--ro last-clear?         oc-yang:date-and-time
     |     +--ro tlv-accepted?       oc-yang:counter64
     |     +--ro entries-aged-out?   oc-yang:counter64
     +--ro mgmt-addresses
     |  +--ro mgmt-address* [address]
     |     +--ro address    -> ../state/address
     |     +--ro state
     |        +--ro address?                    union
     |        +--ro interface-number?           uint32
     |        +--ro interface-number-subtype?   oc-lldp-types:mgmt-interface-number-subtype
     +--rw interfaces
     |  +--rw interface* [name]
     |     +--rw name         -> ../config/name
     |     +--rw config
     |     |  +--rw name?               oc-if:base-interface-ref
     |     |  +--rw enabled?            boolean
+    |     |  +--rw port-description?   string
+    |     |  +--rw custom-tlv-names*   -> ../../../../custom-tlvs/tlv/name
     |     +--ro state
     |     |  +--ro name?               oc-if:base-interface-ref
     |     |  +--ro enabled?            boolean
+    |     |  +--ro port-description?   string
+    |     |  +--ro custom-tlv-names*   -> ../../../../custom-tlvs/tlv/name
     |     |  +--ro counters
     |     |     +--ro frame-in?                    oc-yang:counter64
     |     |     +--ro frame-out?                   oc-yang:counter64
     |     |     +--ro frame-error-in?              oc-yang:counter64
     |     |     +--ro frame-discard?               oc-yang:counter64
     |     |     +--ro tlv-discard?                 oc-yang:counter64
     |     |     +--ro tlv-unknown?                 oc-yang:counter64
     |     |     +--ro last-clear?                  oc-yang:date-and-time
     |     |     +--ro frame-error-out?             oc-yang:counter64
+    |     |     +--ro last-packet-transmitted?     oc-yang:date-and-time
+    |     |     +--ro last-good-packet-received?   oc-yang:date-and-time
+    |     |     +--ro loopback-packets-received?   oc-yang:counter64
     |     +--ro neighbors
     |        +--ro neighbor* [id]
     |           +--ro id                -> ../state/id
     |           +--ro config
     |           +--ro state
     |           |  +--ro system-name?               string
     |           |  +--ro system-description?        string
     |           |  +--ro chassis-id?                string
     |           |  +--ro chassis-id-type?           oc-lldp-types:chassis-id-type
     |           |  +--ro management-interface?      oc-if:interface-id
     |           |  +--ro id?                        string
     |           |  +--ro age?                       uint64
     |           |  +--ro last-update?               int64
     |           |  +--ro ttl?                       uint16
     |           |  +--ro port-id?                   string
     |           |  +--ro port-id-type?              oc-lldp-types:port-id-type
     |           |  +--ro port-description?          string
     |           |  x--ro management-address?        string
     |           |  x--ro management-address-type?   string
     |           +--ro mgmt-addresses
     |           |  +--ro mgmt-address* [address]
     |           |     +--ro address    -> ../state/address
     |           |     +--ro state
     |           |        +--ro address?                    union
     |           |        +--ro interface-number?           uint32
     |           |        +--ro interface-number-subtype?   oc-lldp-types:mgmt-interface-number-subtype
     |           +--ro custom-tlvs
     |           |  +--ro tlv* [type oui oui-subtype]
     |           |     +--ro type           -> ../state/type
     |           |     +--ro oui            -> ../state/oui
     |           |     +--ro oui-subtype    -> ../state/oui-subtype
     |           |     +--ro config
     |           |     +--ro state
+    |           |        +--ro name?          string
     |           |        +--ro type?          int32
     |           |        +--ro oui?           string
     |           |        +--ro oui-subtype?   string
     |           |        +--ro value?         binary
     |           +--ro capabilities
     |              +--ro capability* [name]
     |                 +--ro name      -> ../state/name
     |                 +--ro config
     |                 +--ro state
     |                    +--ro name?      identityref
     |                    +--ro enabled?   boolean
+    +--rw custom-tlvs
+       +--rw tlv* [name]
+          +--rw name      -> ../config/name
+          +--rw config
+          |  +--rw name?          string
+          |  +--rw type?          int32
+          |  +--rw oui?           string
+          |  +--rw oui-subtype?   string
+          |  +--rw value?         binary
+          +--ro state
+             +--ro name?          string
+             +--ro type?          int32
+             +--ro oui?           string
+             +--ro oui-subtype?   string
+             +--ro value?         binary

…ncements ### Change Scope * This PR proposes enhancements to the existing LLDP model with the following changes: 1. Adding a global ttl configuration/state leaf under /lldp. 2. Extending interface LLDP config and state with port-description and interface-level custom-tlv-names. 3. Introducing a shared custom-TLV grouping so both config and state reuse the same custom TLV fields. 4. Adding a top-level /lldp/custom-tlvs/tlv[name] list for global custom TLV definitions. 5. Adding interface state timestamp counters for LLDP packet events. ### Platform Implementations * LLDPCLI, LLDPAD (LLDP daemons for Linux): https://lldpd.github.io/usage.html ``` lldpcli configure lldp custom-tlv oui 00,00,00 subtype 1 oui-info "your data" ``` * SONiC: https://github.com/cshivashgit/SONiC/blob/lldp-custom-tlv-hld/doc/lldp_custom_tlv/lldp-custom-tlv-hld.md#config-db-schema * Vendors use custom TLVs to support features like Cisco's [LLDP-MED](https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst9300/software/release/16-6/configuration_guide/int_and_hw/b_166_int_and_hw_9300_cg/b_166_int_and_hw_9300_cg_chapter_011.html) (Media Endpoint Discovery), which is itself a collection of organizationally specific TLVs. In Cisco [NX-OS](https://www.cisco.com/c/en/us/td/docs/switches/datacenter/nexus9000/sw/6-x/system_management/configuration/guide/b_Cisco_Nexus_9000_Series_NX-OS_System_Management_Configuration_Guide/sm_lldp.pdf), you can select which TLVs to include using the lldp tlv-select command. Aruba's [AOS-CX](https://www.youtube.com/watch?v=lPbtpFcTqgE) introduced a specific OUI (83A30) to help identify Aruba devices and automatically apply network profiles. ### Tree View ```diff module: openconfig-lldp +--rw lldp +--rw config | +--rw enabled? boolean | +--rw hello-timer? uint64 + | +--rw ttl? uint64 | +--rw suppress-tlv-advertisement* identityref | +--rw system-name? string | +--rw system-description? string | +--rw chassis-id? string | +--rw chassis-id-type? oc-lldp-types:chassis-id-type | +--rw management-interface? oc-if:interface-id +--ro state | +--ro enabled? boolean | +--ro hello-timer? uint64 + | +--ro ttl? uint64 | +--ro suppress-tlv-advertisement* identityref | +--ro system-name? string | +--ro system-description? string | +--ro chassis-id? string | +--ro chassis-id-type? oc-lldp-types:chassis-id-type | +--ro management-interface? oc-if:interface-id | +--ro counters | +--ro frame-in? oc-yang:counter64 | +--ro frame-out? oc-yang:counter64 | +--ro frame-error-in? oc-yang:counter64 | +--ro frame-discard? oc-yang:counter64 | +--ro tlv-discard? oc-yang:counter64 | +--ro tlv-unknown? oc-yang:counter64 | +--ro last-clear? oc-yang:date-and-time | +--ro tlv-accepted? oc-yang:counter64 | +--ro entries-aged-out? oc-yang:counter64 +--ro mgmt-addresses | +--ro mgmt-address* [address] | +--ro address -> ../state/address | +--ro state | +--ro address? union | +--ro interface-number? uint32 | +--ro interface-number-subtype? oc-lldp-types:mgmt-interface-number-subtype +--rw interfaces | +--rw interface* [name] | +--rw name -> ../config/name | +--rw config | | +--rw name? oc-if:base-interface-ref | | +--rw enabled? boolean + | | +--rw port-description? string + | | +--rw custom-tlv-names* -> ../../../../custom-tlvs/tlv/name | +--ro state | | +--ro name? oc-if:base-interface-ref | | +--ro enabled? boolean + | | +--ro port-description? string + | | +--ro custom-tlv-names* -> ../../../../custom-tlvs/tlv/name | | +--ro counters | | +--ro frame-in? oc-yang:counter64 | | +--ro frame-out? oc-yang:counter64 | | +--ro frame-error-in? oc-yang:counter64 | | +--ro frame-discard? oc-yang:counter64 | | +--ro tlv-discard? oc-yang:counter64 | | +--ro tlv-unknown? oc-yang:counter64 | | +--ro last-clear? oc-yang:date-and-time | | +--ro frame-error-out? oc-yang:counter64 + | | +--ro last-packet-transmitted? oc-yang:date-and-time + | | +--ro last-good-packet-received? oc-yang:date-and-time + | | +--ro loopback-packets-received? oc-yang:date-and-time | +--ro neighbors | +--ro neighbor* [id] | +--ro id -> ../state/id | +--ro config | +--ro state | | +--ro system-name? string | | +--ro system-description? string | | +--ro chassis-id? string | | +--ro chassis-id-type? oc-lldp-types:chassis-id-type | | +--ro management-interface? oc-if:interface-id | | +--ro id? string | | +--ro age? uint64 | | +--ro last-update? int64 | | +--ro ttl? uint16 | | +--ro port-id? string | | +--ro port-id-type? oc-lldp-types:port-id-type | | +--ro port-description? string | | x--ro management-address? string | | x--ro management-address-type? string | +--ro mgmt-addresses | | +--ro mgmt-address* [address] | | +--ro address -> ../state/address | | +--ro state | | +--ro address? union | | +--ro interface-number? uint32 | | +--ro interface-number-subtype? oc-lldp-types:mgmt-interface-number-subtype | +--ro custom-tlvs | | +--ro tlv* [type oui oui-subtype] | | +--ro type -> ../state/type | | +--ro oui -> ../state/oui | | +--ro oui-subtype -> ../state/oui-subtype | | +--ro config | | +--ro state + | | +--ro name? string | | +--ro type? int32 | | +--ro oui? string | | +--ro oui-subtype? string | | +--ro value? binary | +--ro capabilities | +--ro capability* [name] | +--ro name -> ../state/name | +--ro config | +--ro state | +--ro name? identityref | +--ro enabled? boolean + +--rw custom-tlvs + +--rw tlv* [name] + +--rw name -> ../config/name + +--rw config + | +--rw name? string + | +--rw type? int32 + | +--rw oui? string + | +--rw oui-subtype? string + | +--rw value? binary + +--ro state + +--ro name? string + +--ro type? int32 + +--ro oui? string + +--ro oui-subtype? string + +--ro value? binary ``` Signed-off-by: Neha Das <neha.das43@gmail.com>

gemini-code-assist

Code Review

This pull request updates the OpenConfig LLDP module to version 1.0.1, introducing global TTL configuration, interface-level port descriptions, and timestamps for packet transmission and reception. It also adds a global custom TLV list and allows interfaces to reference these TLVs. Review feedback recommends renaming the loopback packet timestamp for consistency, correcting the description of the port-description leaf to reflect the correct TLV type, and changing the TTL data type from uint64 to uint16 to align with the IEEE 802.1AB standard.

Signed-off-by: Neha Das <neha.das43@gmail.com>

earies · 2026-04-07T15:46:15Z

    for the LLDP protocol.";

-  oc-ext:openconfig-version "1.0.0";
+  oc-ext:openconfig-version "1.0.1";


Suggested change

oc-ext:openconfig-version "1.0.1";

oc-ext:openconfig-version "1.1.0";

earies · 2026-04-07T15:47:56Z

      }
+
+      leaf last-packet-transmitted {
+        type oc-yang:date-and-time;


Suggested change

type oc-yang:date-and-time;

type oc-types:timeticks64;

I know there is already a leaf w/ oc-yang:date-and-time here but imo this was incorrect per common and more programmatic friendly representation of time since unix epoch

earies · 2026-04-07T15:48:41Z

+      }
+
+      leaf last-good-packet-received {
+        type oc-yang:date-and-time;


Same as above although I would question more non-counter leafs under this counters container. Seems appropriate to move these up to a parent level

earies · 2026-04-07T15:51:08Z

        "Enable or disable the LLDP protocol on the interface.";
    }
+
+    leaf port-description {


I think some clarification would need to surround this leaf as most implementations would derive this TLV from other areas (e.g. interface description) by default and your intention here appears to be a TLV specific override

earies · 2026-04-07T15:53:13Z

        "System level hello timer for the LLDP protocol.";
    }

+    leaf ttl {


How will this field conflict or relate to hello-timer for where in implementations this is derived/calculated?

earies · 2026-04-07T15:55:44Z

+    }

    leaf type {
      type int32;


I know you are just reusing what was previously defined but this is an incorrect type for what is a 7-bit unsigned field per spec definition.

Suggest proposing/refactoring to a scoped uint8 to go in accordance to 8021AB-2016

earies · 2026-04-07T15:56:18Z

    }

    leaf oui {
      type string;


Would suggest considering typedef w/ constraints for these fields

earies · 2026-04-07T15:56:25Z

    }

    leaf oui-subtype {
      type string;


Would suggest considering typedef w/ constraints for these fields

earies · 2026-04-07T15:57:50Z

        unique subtype value assigned by the defining organization.";
    }

    // TODO: consider making this string type


Since you are proposing the ability for r/w in here, this probably should be revisited. If we maintain type binary this complicates the reading/writing for users

dplore · 2026-04-07T16:12:26Z

+        path "../../../../custom-tlvs/tlv/name";
+      }
+      description
+        "References to global custom TLV names associated with this interface.";


Suggest being very specific here and state something like, if present in the list, the tlv is advertised and if not, the tlv will not be advertised

dplore · 2026-04-07T16:17:22Z

+        "The description of the port to be advertised in the Port
+        Description TLV (Type 4) for LLDP PDUs transmitted on this
+        interface.";
+    }


I would expect that implementations today would use this leaf as the LLDP port-description.
/interfaces/interface/state/description

Discussing this, the desire is to override the interface description with an LLDP specific string. Please update the description to indicate what happens if this leaf is not populated and if it is. Thanks!

dplore · 2026-04-07T16:19:27Z

+    leaf name {
+      type string;
+      description
+        "Name of the custom TLV.";


Please elaborate that this is for ease for human identification of the LLDP type.

dplore · 2026-04-07T16:26:45Z

/gcbrun

OpenConfigBot · 2026-04-07T16:28:36Z

No major YANG version changes in commit f1bd4f0

github-project-automation bot added this to OC Operator Review Apr 7, 2026

Merge branch 'master' into master

81071a0

gemini-code-assist bot reviewed Apr 7, 2026

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Comment thread release/models/lldp/openconfig-lldp.yang

Comment thread release/models/lldp/openconfig-lldp.yang

Comment thread release/models/lldp/openconfig-lldp.yang

ndas7 added 2 commits April 6, 2026 18:43

Update openconfig-lldp.yang

220f1bb

Signed-off-by: Neha Das <neha.das43@gmail.com>

Merge branch 'master' of https://github.com/ndas7/openconfig-public

f1bd4f0

Signed-off-by: Neha Das <neha.das43@gmail.com>

ndas7 marked this pull request as ready for review April 7, 2026 01:46

ndas7 requested a review from a team as a code owner April 7, 2026 01:46

earies reviewed Apr 7, 2026

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dplore reviewed Apr 7, 2026

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OpenConfigBot added the non-breaking label Apr 7, 2026

earies mentioned this pull request Apr 8, 2026

Clarify scope of neighbor/custom-tlvs container in openconfig-lldp #1471

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	oc-ext:openconfig-version "1.0.1";
	oc-ext:openconfig-version "1.1.0";

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ndas7 commented Apr 7, 2026 •

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earies Apr 7, 2026 •

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