Re: [RFC PATCH 0/4] VRF support in FIB library

[Stephen Hemminger <stephen@networkplumber.org>]

On Sun, 22 Mar 2026 15:42:11 +0000
Vladimir Medvedkin <vladimir.medvedkin@intel.com> wrote:

> This series adds multi-VRF support to both IPv4 and IPv6 FIB paths by
> allowing a single FIB instance to host multiple isolated routing domains.
> 
> Currently FIB instance represents one routing instance. For workloads that
> need multiple VRFs, the only option is to create multiple FIB objects. In a
> burst oriented datapath, packets in the same batch can belong to different VRFs, so
> the application either does per-packet lookup in different FIB instances or
> regroups packets by VRF before lookup. Both approaches are expensive.
> 
> To remove that cost, this series keeps all VRFs inside one FIB instance and
> extends lookup input with per-packet VRF IDs.
> 
> The design follows the existing fast-path structure for both families. IPv4 and
> IPv6 use multi-ary trees with a 2^24 associativity on a first level (tbl24). The
> first-level table scales per configured VRF. This increases memory usage, but
> keeps performance and lookup complexity on par with non-VRF implementation.
> 
> Vladimir Medvedkin (4):
>   fib: add multi-VRF support
>   fib: add VRF functional and unit tests
>   fib6: add multi-VRF support
>   fib6: add VRF functional and unit tests
> 
>  app/test-fib/main.c      | 257 ++++++++++++++++++++++--
>  app/test/test_fib.c      | 298 +++++++++++++++++++++++++++
>  app/test/test_fib6.c     | 319 ++++++++++++++++++++++++++++-
>  lib/fib/dir24_8.c        | 241 ++++++++++++++++------
>  lib/fib/dir24_8.h        | 255 ++++++++++++++++--------
>  lib/fib/dir24_8_avx512.c | 420 +++++++++++++++++++++++++++++++--------
>  lib/fib/dir24_8_avx512.h |  80 +++++++-
>  lib/fib/rte_fib.c        | 158 ++++++++++++---
>  lib/fib/rte_fib.h        |  94 ++++++++-
>  lib/fib/rte_fib6.c       | 166 +++++++++++++---
>  lib/fib/rte_fib6.h       |  88 +++++++-
>  lib/fib/trie.c           | 158 +++++++++++----
>  lib/fib/trie.h           |  51 +++--
>  lib/fib/trie_avx512.c    | 225 +++++++++++++++++++--
>  lib/fib/trie_avx512.h    |  39 +++-
>  15 files changed, 2453 insertions(+), 396 deletions(-)


Not sure at all if this the right way to do VRF.
There are multiple ways to do VRF, the Linux way, the Cisco way, ...



This needs way more documentation and also an example.
Like an option to l3fwd. And also an implementation in testpmd.