Hello Manoj, You can try to disable nethops in zebra using this command "no zebra nexthop kernel enable".
Another option is to support nhids in the LCP plugin. I added a couple of years ago nhid support in libnl and also have somewhere a patch to vpp that makes libnl an explicit external dependency with pinning to a specific version (in case the system libnl is too old). Also, I tried to integrate linux nexthops in lcp and miserably failed :) After that I just switched to my custom control plane and didn't need those nhid support anymore. But maybe you can add this support if you want to. Contributions are welcomed. On Mon, 22 Dec 2025 at 16:26, monu Sharma via lists.fd.io <monu0952= [email protected]> wrote: > Hi, > > We are integrating VPP with FRR via netlink (RTM_NEWROUTE / RTM_DELROUTE) > and have observed an issue in *VPP 24.10* regarding *nexthop (NHID) > delete handling*. > Observation > > When FRR withdraws BGP routes, Linux sometimes emits *RTM_DELNEXTHOP* events > (NHID delete) *sometimes* *without* corresponding *RTM_DELROUTE* messages. > > Example netlink event observed: > > RTNL NEXTHOP DELETE > nhid=1331 family=2 proto=zebra oif=12 > gw=192.168.12.21 > > Routes referencing this NHID (e.g.): > > 192.168.0.0/24 nhid 1331 encap mpls 24021 via 192.168.12.21 dev ens6.1012 > proto bgp > > are removed from the Linux kernel, but *VPP does not delete the > corresponding FIB entry*, since NHID delete events are currently not > handled. > Impact > > - > > VPP FIB can retain *stale routes* > - > > Leads to *state mismatch* between Linux kernel and VPP > - > > Especially visible with FRR/Zebra + MPLS + nexthop objects > > Expectation > > When *RTM_DELNEXTHOP* is received: > > - > > VPP (or plugins consuming netlink) should invalidate and remove all > routes associated with the deleted NHID > - > > Or at least provide a mechanism to track NHID → route mappings and act > on NHID deletion > > Question > > Is the lack of RTM_DELNEXTHOP handling a known limitation? > Are there plans to add native NHID tracking and cleanup in VPP, ? Any > guidance or recommended approach would be appreciated. > > > Please find ubuntu and kernel version. > uname -a > Linux -dev 5.15.0-101-generic #111-Ubuntu SMP Tue Mar 5 20:16:58 UTC 2024 > x86_64 x86_64 x86_64 GNU/Linux > > dpkg -l | grep linux-image > ii linux-image-5.15.0-101-generic 5.15.0-101.111 > amd64 Signed kernel image generic > pi linux-image-5.15.0-97-generic 5.15.0-97.107 > amd64 Signed kernel image generic > cat /etc/os-release > PRETTY_NAME="Ubuntu 22.04.3 LTS" > NAME="Ubuntu" > VERSION_ID="22.04" > VERSION="22.04.3 LTS (Jammy Jellyfish)" > VERSION_CODENAME=jammy > ID=ubuntu > ID_LIKE=debian > HOME_URL="https://www.ubuntu.com/"; > SUPPORT_URL="https://help.ubuntu.com/"; > BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/"; > PRIVACY_POLICY_URL=" > https://www.ubuntu.com/legal/terms-and-policies/privacy-policy"; > UBUNTU_CODENAME=jammy > > Thanks & regards, > Manoj > > > > > > -- Best regards Stanislav Zaikin
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