feat: flip swap mechanism — MD as primary, RST as override (Phase 1)

This is the first of three phases inverting the per-page swap mechanism
so MD becomes the canonical primary and RST becomes the rare override.

Phase 1 — file renames + conf.py exclude_patterns flip only:
- Rename docs/**/md-<stem>.md to docs/**/<stem>.md (drop md- prefix)
  for all 254 stems previously listed in docs/_swap.txt
- Rename docs/**/<stem>.rst to docs/**/rst-<stem>.rst (add rst- prefix)
  for the same 254 stems
- Repurpose docs/_swap.txt as docs/_rst_overrides.txt; initially empty
  comment-only since no pages need the RST fallback right now
- conf.py exclude_patterns flipped: rst-*.rst is now excluded by default
  instead of md-*.md
- conf.py runtime-artifact references updated to _rst_override_state.json
  and _md_exclude.txt (Phase 2 will rewrite swap_sources.py to produce
  these names; for now no swap script runs because overrides list is empty)

Phase 2 (next commit on this branch) will rewrite scripts/swap_sources.py
with inverted rename direction, delete scripts/import_myst.py + tests, and
update tests/test_swap_sources.py for the new semantics.

Phase 3 will be the cleanup pass and ready-for-review flip.

Generated by robots https://vyos.io

1 files changed, 46 insertions, 0 deletions

diff --git a/docs/vpp/configuration/dataplane/ipv6.md b/docs/vpp/configuration/dataplane/ipv6.md
new file mode 100644
index 00000000..5f2ba3c5
--- /dev/null
+++ b/docs/vpp/configuration/dataplane/ipv6.md
@@ -0,0 +1,46 @@
+---
+lastproofread: '2026-02-26'
+---
+
+(vpp-config-dataplane-ipv6)=
+
+```{include} /_include/need_improvement.txt
+```
+
+
+# VPP IPv6 Configuration
+
+VPP lets you configure resources allocated for IPv6 traffic processing
+independently from IPv4. This helps ensure that in networks without IPv6
+traffic, resources are not wasted. If IPv6 traffic is present, especially
+with large routing tables, you must allocate additional resources for IPv6
+processing to keep the dataplane stable.
+
+You can configure two main resources for IPv6 traffic processing:
+
+```{cfgcmd} set vpp settings resource-allocation ipv6 hash-buckets \<value\>
+```
+
+This parameter configures the number of hash buckets used for IPv6
+routing. If you have a large IPv6 routing table, you may need to increase
+this value to ensure efficient routing table performance and fast lookups.
+
+```{cfgcmd} set vpp settings resource-allocation ipv6 heap-size \<value\>
+```
+
+This parameter configures the heap size used for IPv6 forwarding. If you
+have a large IPv6 routing table, you may need to increase this value to
+ensure the routing table can accommodate all routes.
+
+## Potential Issues and Troubleshooting
+
+Improper IPv6 configuration can lead to various issues, including:
+
+- Inefficient, slow routing table lookups and traffic processing due to
+  insufficient hash buckets
+- Dataplane crashes or instability due to insufficient heap size when
+  handling a large number of IPv6 routes
+- Overall dataplane instability when handling IPv6 traffic
+
+Consider increasing configuration values if you experience issues with
+IPv6 traffic processing or if you have a large IPv6 routing table.