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, 104 insertions, 0 deletions

diff --git a/docs/vpp/configuration/dataplane/interface.md b/docs/vpp/configuration/dataplane/interface.md
new file mode 100644
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+++ b/docs/vpp/configuration/dataplane/interface.md
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+---
+lastproofread: '2026-02-23'
+---
+
+(vpp-config-dataplane-interface)=
+
+```{include} /_include/need_improvement.txt
+```
+
+
+# VPP Dataplane Interfaces Configuration
+
+Only Ethernet interfaces (physical or virtual) can be connected to the
+VPP dataplane. Interfaces configured here act as a bridge between VPP
+and the outside world, allowing VPP to send and receive network
+packets.
+
+## Interface Configuration Parameters
+
+Interfaces connected to the VPP dataplane use the DPDK driver by default,
+providing high performance and low latency.
+
+```{cfgcmd} set vpp settings interface \<interface-name\>
+```
+
+Some network interface cards (NICs) may not be compatible with the DPDK driver.
+
+### DPDK interface options
+
+This section shows how to configure DPDK-specific settings for an interface.
+
+```{cfgcmd} set vpp settings interface \<interface-name\> num-rx-queues \<value\>
+```
+
+Specifies the number of receive queues for the interface. More queues
+improve performance on multi-core systems by allowing parallel
+processing of incoming packets. Each queue is assigned to a separate
+CPU core.
+
+```{cfgcmd} set vpp settings interface \<interface-name\> num-tx-queues \<value\>
+```
+
+Specifies the number of transmit queues for the interface. Similar to
+receive queues, more transmit queues improve performance by enabling
+parallel processing of outgoing packets. By default, the VPP Dataplane
+has one TX queue per enabled CPU worker, or a single queue if no
+workers are configured.
+
+:::{seealso}
+{doc}`cpu`
+:::
+```{cfgcmd} set vpp settings interface \<interface-name\> num-rx-desc \<value\>
+```
+
+Defines the size of each receive queue. Larger queue sizes accommodate
+bursts of incoming traffic and reduce the likelihood of packet drops
+during high traffic periods.
+
+```{cfgcmd} set vpp settings interface \<interface-name\> num-tx-desc \<value\>
+```
+
+Defines the size of each transmit queue. Larger sizes help manage
+bursts of outgoing traffic more effectively.
+
+## Global Interface Parameters
+
+(vpp-config-dataplane-interface-rx-mode)=
+
+### interface-rx-mode
+
+The `interface-rx-mode` parameter defines how VPP handles incoming
+packets on interfaces. There are several modes available, each with its
+own advantages and use cases:
+- `interrupt`: In this mode, VPP relies on hardware interrupts to
+  notify it of incoming packets. This mode suits low to moderate
+  traffic loads and reduces CPU usage during idle periods. It is not
+  recommended for low-latency processing. Some NICs may not support
+  this mode.
+- `polling`: In polling mode, VPP continuously checks the interface
+  for incoming packets. This mode is ideal for high-throughput
+  scenarios where low latency is critical, as it minimizes packet
+  waiting time. However, it can increase CPU usage, especially during
+  low traffic periods, as the polling process is always active.
+- `adaptive`: Adaptive mode combines the benefits of interrupt and
+  polling modes. VPP starts in interrupt mode and switches to polling
+  mode when traffic load increases.
+
+```{cfgcmd} set vpp settings interface-rx-mode \<mode\>
+```
+
+Choose an rx-mode based on expected traffic patterns and performance
+requirements of your network.
+
+## Potential Issues and Troubleshooting
+
+Improper interface configuration can lead to issues such as:
+
+- Failure to initialize the interface
+- Poor performance due to suboptimal driver selection or settings
+
+Indicators of such issues are:
+
+- Failed commits after adding or modifying an interface settings
+- Low throughput or high latency on the interface