1 module in this draft:
- ietf-ipv6-nd@2026-04-20.yang

YANG compiler errors or warnings (pyang 2.7.1, yanglint 5.8.6)
- No compiler errors or warnings

Summary:
--------------------------------
This is a follow-on review from prior -02 version.  Most prior comments
have been addressed and the module is in overall good shape.  A few
additional comments below.

Comments:
--------------------------------
- `redirect`: default "false" - This is a carry over from prior review.
  RFC4861 Section 8.2 states "A router SHOULD send a redirect message"
  so whether explicit or implicit as false, the draft/module should
  likely justify this.
- `reachable-time`: This leaf now has a default of 30000ms as well as
  reference to RFC4861 Section 6.3.2 but the range still looks borrowed
  from AdvReachableTime w/ the max not explained.
- `age`: "when" and "units" are updated but suggest changing the last
  sentence rather to something along the lines of "This leaf is present
  only for dynamic neighbor entries."
- `proxy-na`: This leaf description reads a bit awkward.  Suggest maybe
  "Controls whether the router proxies for one or more other nodes by
  sending proxy Neighbor Advertisements."?
- Since these counters augment up into `ietf-interfaces`, all prior
  definitions draw relation back to how discontinuities are detected.
  Suggest adding descriptions around each similar to those in the anchor
  module surrounding relationship back to `discontinuity-time`
- Security Considerations: There is mention to various leafs but not
  statistics or `enhanced-dad/enable` and `enhanced-dad/auto-resolve`.
  `enhanced-dad` is mentioned but not the above 2 r/w leafs which can
  trigger automated actions (drops, blocking hosts).
  Per message counters can reveal neighbor activity, probing, drops and
  redirect behavior so it may be worth considering addition to this
  section?
- Appendix B: `LinkMTU` appears to be missing coverage.  Is this not
  covered by way of `ietf-ip` /interfaces/interface/ipv6/mtu ?
- General Nit/Suggestion: Every sub-container/categorization under
  `statistics` repeats `*-stats`.  We already know these are buckets of
  statistics so suggest dropping anything repetitive or shortform and
  possibly just expanding out any acronyms for those container names

Example Validated Instance Data:

```
{
  "ietf-interfaces:interfaces": {
    "interface": [
      {
        "name": "eth0",
        "type": "iana-if-type:ethernetCsmacd",
        "admin-status": "up",
        "oper-status": "up",
        "if-index": 512,
        "statistics": {
          "discontinuity-time": "2026-09-06T00:00:00Z"
        },
        "ietf-ip:ipv6": {
          "enabled": true,
          "forwarding": true,
          "address": [
            {
              "ip": "2001:db8:100::",
              "prefix-length": 64
            }
          ],
          "neighbor": [
            {
              "ip": "2001:db8:100::1a",
              "link-layer-address": "50:54:00:b3:4f:4a",
              "origin": "dynamic",
              "ietf-ipv6-nd:age": 600
            }
          ],
          "ietf-ipv6-nd:nd": {
            "reachable-time": 30000,
            "retrans-timer": 1000,
            "redirect": false,
            "proxy-na": true,
            "enhanced-dad": {
              "enable": true,
              "auto-resolve": false
            },
            "statistics": {
              "ns-stats": {
                "in-pkts": "542321",
                "out-pkts": "45243899",
                "drop-pkts": "124",
                "in-unicast-pkts": "345223",
                "in-multicast-pkts": "783",
                "out-unicast-pkts": "893241",
                "out-multicast-pkts": "893",
                "drop-bad-code-pkts": "12",
                "drop-bad-hoplimit-pkts": "5",
                "drop-bad-len-pkts": "2",
                "drop-bad-option-pkts": "9",
                "drop-checksum-err-pkts": "10",
                "drop-fragmented-pkts": "4",
                "out-nud-pkts": "101"
              },
              "na-stats": {
                "in-pkts": "542321",
                "out-pkts": "45243899",
                "drop-pkts": "124",
                "in-unicast-pkts": "345223",
                "in-multicast-pkts": "783",
                "out-unicast-pkts": "893241",
                "out-multicast-pkts": "893",
                "drop-bad-code-pkts": "12",
                "drop-bad-hoplimit-pkts": "5",
                "drop-bad-len-pkts": "2",
                "drop-bad-option-pkts": "9",
                "drop-checksum-err-pkts": "10",
                "drop-fragmented-pkts": "4",
                "in-solicited-pkts": "199",
                "in-unsolicited-pkts": "90",
                "in-override-pkts": "89",
                "in-nonoverride-pkts": "9",
                "out-solicited-pkts": "199",
                "out-unsolicited-pkts": "90",
                "out-override-pkts": "89",
                "out-nonoverride-pkts": "9"
              },
              "rs-stats": {
                "in-pkts": "542321",
                "out-pkts": "45243899",
                "drop-pkts": "124",
                "in-unicast-pkts": "345223",
                "in-multicast-pkts": "783",
                "out-unicast-pkts": "893241",
                "out-multicast-pkts": "893",
                "drop-bad-code-pkts": "12",
                "drop-bad-hoplimit-pkts": "5",
                "drop-bad-len-pkts": "2",
                "drop-bad-option-pkts": "9",
                "drop-checksum-err-pkts": "10",
                "drop-fragmented-pkts": "4"
              },
              "ra-stats": {
                "in-pkts": "542321",
                "out-pkts": "45243899",
                "drop-pkts": "124",
                "in-unicast-pkts": "345223",
                "in-multicast-pkts": "783",
                "out-unicast-pkts": "893241",
                "out-multicast-pkts": "893",
                "drop-bad-code-pkts": "12",
                "drop-bad-hoplimit-pkts": "5",
                "drop-bad-len-pkts": "2",
                "drop-bad-option-pkts": "9",
                "drop-checksum-err-pkts": "10",
                "drop-fragmented-pkts": "4"
              },
              "redirect-stats": {
                "in-pkts": "542321",
                "out-pkts": "45243899",
                "drop-pkts": "124",
                "drop-bad-code-pkts": "12",
                "drop-bad-hoplimit-pkts": "5",
                "drop-bad-len-pkts": "2",
                "drop-bad-option-pkts": "9",
                "drop-checksum-err-pkts": "10",
                "drop-fragmented-pkts": "4"
              }
            }
          }
        }
      }
    ]
  }
}
```