diff --git a/NLSR_PATCH_7818_INTEGRATION.md b/NLSR_PATCH_7818_INTEGRATION.md
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+# NLSR Patch 7818 Integration Guide
+
+## Overview
+
+This guide documents the changes required to integrate NLSR Gerrit Change 7818 ("lsdb: recover lost LSA seqNo from network via sync") into the Named Data testbed.
+
+**Change 7818:** https://gerrit.named-data.net/c/NLSR/+/7818
+
+**Problem Solved (Issue #5386):** When an NLSR router's sequence number file is corrupted or lost, the router would restart with sequence number 0 and other routers would ignore its LSAs because they expected higher sequence numbers. Patch 7818 enables automatic recovery of the sequence number from the network via sync protocol.
+
+---
+
+## Changes Required
+
+### 1. NLSR Dockerfile (`nlsr.Dockerfile`)
+
+The Dockerfile builds NLSR with patch 7818 applied using Named Data's base images.
+
+**Key changes:**
+
+- Use `ghcr.io/named-data/ndn-cxx-build` and `ghcr.io/named-data/ndn-cxx-runtime` as base images (not Ubuntu) - this ensures proper library paths and dependencies
+- Set `ENV HOME=/config` in the runtime stage - required for ndn-cxx to find the identity database (PIB)
+- Build psync from source (not available in base images)
+- Use patch revision 6 (latest): `refs/changes/18/7818/6`
+- Configure NLSR with `--with-psync` to find psync
+- Install `libboost-iostreams1.83.0` for runtime
+
+```dockerfile
+# Critical environment variable - ndn-cxx looks for PIB at $HOME/.ndn/
+ENV HOME=/config
+```
+
+### 2. Docker Compose Override (`docker-compose.override.yml`)
+
+Override to use the patched NLSR image:
+
+```yaml
+services:
+  nlsr:
+    image: ghcr.io/a-thieme/nlsr:patch-7818-v3
+```
+
+### 3. NLSR Config Template (`templates/nlsr/nlsr.conf.j2`)
+
+**Critical fix:** The advertising section format changed in the patched NLSR.
+
+**Old format (rejected by patch 7818):**
+```jinja
+advertising
+{
+  {% for prefix in advertised_prefixes %}
+    prefix {{ prefix }}
+  {% endfor %}
+}
+```
+
+**New format (required by patch 7818):**
+```jinja
+advertising
+{
+  {% for prefix in advertised_prefixes %}
+    {{ prefix }} 1
+  {% endfor %}
+}
+```
+
+The format changed from `prefix <name>` to `<name> <cost>` (key-value format).
+
+---
+
+## Building the Patched Image
+
+```bash
+# Build the image
+docker build -t ghcr.io/<username>/nlsr:patch-7818 -f nlsr.Dockerfile .
+
+# Push to registry
+docker push ghcr.io/<username>/nlsr:patch-7818
+```
+
+## Deploying on Testbed Nodes
+
+On each testbed node:
+
+```bash
+# Pull or update the image
+docker-compose pull
+
+# Restart NLSR
+docker-compose up -d nlsr
+```
+
+---
+
+## Verification
+
+### Check NLSR Version
+```bash
+docker exec testbed-nlsr-1 nlsr -V
+# Expected: 24.08+git.7e80068b (or similar with 7e80068 commit)
+```
+
+### Check Identity Loading
+```bash
+docker logs testbed-nlsr-1 2>&1 | grep identity
+# Expected: Should show proper router identity, NOT "not found"
+```
+
+### Verify Sequence Recovery Works
+
+1. Corrupt the sequence file:
+```bash
+docker stop testbed-nlsr-1
+echo -e "AdjLsaSeqNo: 5\nNameLsaSeqNo: 5" > /path/to/state/nlsrSeqNo.txt
+docker start testbed-nlsr-1
+```
+
+2. Check recovery:
+```bash
+docker logs testbed-nlsr-1 2>&1 | grep "Received sync update for own router"
+# Or check sequence numbers:
+docker exec testbed-nlsr-1 cat /config/state/nlsrSeqNo.txt
+# Should show higher values than 5 (recovered from network)
+```
+
+### Check Neighbor Connectivity
+
+From a neighbor node (e.g., Singapore):
+```bash
+docker exec testbed-nlsr-1 nlsrc lsdb | grep -A5 osaka
+# Should show current sequence numbers (not stale)
+```
+
+---
+
+## Troubleshooting
+
+### "Router identity not found" / "NLSR is running without security"
+
+**Cause:** The `HOME=/config` environment variable is missing.
+
+**Fix:** Ensure the Dockerfile includes `ENV HOME=/config`
+
+### "Invalid cost format; only integers are allowed"
+
+**Cause:** Advertising section uses old format `prefix <name>` instead of `<name> <cost>`
+
+**Fix:** Update `templates/nlsr/nlsr.conf.j2` to use `{{ prefix }} 1` format
+
+### Sequence numbers stuck or not increasing
+
+**Possible causes:**
+1. Security not working (check identity logs)
+2. Firewall blocking UDP port 6363
+3. Network connectivity issues between nodes
+
+---
+
+## Image Tags
+
+| Tag | Description |
+|-----|-------------|
+| `patch-7818-v1` | Initial build, wrong advertising format |
+| `patch-7818-v2` | Fixed advertising format, missing HOME=/config |
+| `patch-7818-v3` | **Current working version** - all fixes applied |
+
+---
+
+---
+
+## After Patch Merge: "Just Works" Deployment (Option B)
+
+This section describes the **minimal changes** needed in named-data/testbed once patch 7818 is merged into NLSR, assuming **no backward compatibility** (Option B).
+
+### Assumption
+
+Patch 7818 is merged into NLSR master branch. A future NLSR release/tag includes the patch. The testbed simply needs to use that version.
+
+### Required Changes
+
+#### 1. named-data/testbed
+
+**Single required change:**
+
+Update `templates/nlsr/nlsr.conf.j2` - advertising section format:
+
+```jinja
+advertising
+{
+  {% for prefix in advertised_prefixes %}
+    {{ prefix }} 1
+  {% endfor %}
+}
+```
+
+That's it. **One line change.**
+
+Everything else works automatically because:
+- Named Data's CI builds NLSR Docker images with the merged patch
+- Testbed's docker-compose.yml already references `ghcr.io/named-data/nlsr:latest` (or a tagged version)
+- The NLSR Docker image includes `ENV HOME=/config` (already in official Dockerfile)
+
+#### 2. NLSR Gerrit Patch (7818)
+
+**No changes needed.** The patch works as-is. The breaking config format change is intentional and documented.
+
+### How It Works After Merge
+
+```
+named-data/testbed:
+├── docker-compose.yml          ──► References NLSR image (auto-includes patch)
+├── templates/nlsr/nlsr.conf.j2 ──► Generates <prefix> <cost> format ✓
+└── Dockerfile                  ──► Uses official NLSR image (already has HOME=/config)
+```
+
+### Rolling Update Process
+
+When patch 7818 is merged and deployed:
+
+```bash
+# 1. Pull latest NLSR image (includes merged patch)
+docker-compose pull nlsr
+
+# 2. Config auto-regenerates via master container cron job, or manually:
+python3 framework/main.py --dry
+
+# 3. Restart NLSR on each node
+docker-compose up -d nlsr
+```
+
+### What NOT to Change
+
+The following files do **not** need modification:
+
+- `nlsr.Dockerfile` - Only needed for custom builds before patch is merged
+- `docker-compose.override.yml` - Per-deployer override, not in upstream
+
+### Summary
+
+| Repository | Change Required | When |
+|------------|----------------|------|
+| named-data/testbed | Update `templates/nlsr/nlsr.conf.j2` | One-time after patch merge |
+| NLSR (gerrit 7818) | None | Already works |
+
+**Result:** After the single template update, deploying new NLSR versions "just works."
+
+---
+
+## Related Files
+
+- `nlsr.Dockerfile` - Multi-stage build for patched NLSR (custom, not needed after merge)
+- `docker-compose.override.yml` - Override to use patched image (per-deployer, not upstream)
+- `templates/nlsr/nlsr.conf.j2` - NLSR configuration template (the only file needing update)
diff --git a/docker-compose.override.yml b/docker-compose.override.yml
new file mode 100644
index 0000000..6f3225e
--- /dev/null
+++ b/docker-compose.override.yml
@@ -0,0 +1,30 @@
+# docker-compose.override.yml - Override nlsr service for local build
+#
+# Docker Compose automatically reads this file when running `docker-compose up`.
+# See: https://docs.docker.com/compose/compose-file/13-override/
+#
+# Workflow to build and deploy patched NLSR:
+#   1. On local machine with Docker and ghcr.io access:
+#      docker build -t ghcr.io/a-thieme/nlsr:patch-7818 -f nlsr.Dockerfile .
+#      docker push ghcr.io/a-thieme/nlsr:patch-7818
+#
+#   2. Update NLSR_IMAGE below to your registry image
+#
+#   3. On remote machine:
+#      docker-compose pull
+#      docker-compose up -d nlsr
+
+name: testbed
+services:
+  nlsr:
+    # Build from local Dockerfile (for local testing only)
+    # Comment out build: to pull pre-built image instead
+    # build:
+    #   context: .
+    #   dockerfile: nlsr.Dockerfile
+
+    # Image from your registry (push built image to ghcr.io first)
+    image: ghcr.io/a-thieme/nlsr:patch-7818-v3
+
+    # To use pre-built Named Data image instead:
+    # image: ghcr.io/a-thieme/nlsr:patch-7818-v3
diff --git a/nlsr.Dockerfile b/nlsr.Dockerfile
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+++ b/nlsr.Dockerfile
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+# nlsr.Dockerfile - Build NLSR with Gerrit patch 7818 applied
+# Patch 7818: Recover lost LSA seqNo from network via sync
+#
+# Uses Named Data's base images for proper library paths
+# Build and push to your own ghcr.io registry:
+#   docker build -t ghcr.io/<username>/nlsr:patch-7818 -f nlsr.Dockerfile .
+#   docker push ghcr.io/<username>/nlsr:patch-7818
+
+# Stage 1: Build using Named Data's build environment
+FROM ghcr.io/named-data/ndn-cxx-build AS builder
+
+ENV DEBIAN_FRONTEND=noninteractive
+
+# Ensure SSL certs are available for git and install boost iostreams
+RUN apt-get update && apt-get install -y ca-certificates libboost-iostreams-dev && rm -rf /var/lib/apt/lists/*
+
+# Build psync from source (psync is not in the base image)
+WORKDIR /build
+RUN git clone --depth 1 --branch master https://github.com/named-data/psync.git psync
+WORKDIR /build/psync
+RUN ./waf configure --prefix=/usr --libdir=/usr/lib && \
+    ./waf build -j$(nproc) && ./waf install
+
+# Clone NLSR and apply patch
+WORKDIR /build
+RUN git clone --depth 1 --branch master https://github.com/named-data/NLSR.git nlsr
+WORKDIR /build/nlsr
+
+# Fetch patch 7818 from Gerrit
+# Use latest revision (change ref if needed: /1, /2, ..., /6)
+ARG NLSR_PATCH_REF=refs/changes/18/7818/6
+RUN git fetch https://gerrit.named-data.net/NLSR.git ${NLSR_PATCH_REF} && \
+    git checkout FETCH_HEAD
+
+# Build NLSR using waf with --with-psync to find psync
+RUN ./waf configure --prefix=/usr --libdir=/usr/lib --with-psync && \
+    ./waf build -j$(nproc) && ./waf install
+
+# Stage 2: Runtime image using Named Data's runtime base
+FROM ghcr.io/named-data/ndn-cxx-runtime
+
+ENV DEBIAN_FRONTEND=noninteractive
+ENV HOME=/config
+
+# Runtime dependencies for NLSR
+RUN apt-get update && apt-get install -y \
+    libsqlite3-0 \
+    libpcap0.8 \
+    libboost-iostreams1.83.0 \
+    && rm -rf /var/lib/apt/lists/* \
+    && apt-get clean
+
+# Copy built NLSR and psync artifacts from builder
+COPY --from=builder /usr/bin/nlsr /usr/bin/nlsr
+COPY --from=builder /usr/bin/nlsrc /usr/bin/nlsrc
+COPY --from=builder /usr/lib/libPSync.so* /usr/lib/
+
+# Default entrypoint matches original image
+ENTRYPOINT ["/usr/bin/nlsr"]
+CMD ["-f", "/config/nlsr.conf"]
+
+LABEL org.opencontainers.image.source=https://github.com/named-data/NLSR
+LABEL org.opencontainers.image.description="NLSR with patch 7818 (LSA seqNo recovery via sync)"
\ No newline at end of file
diff --git a/templates/nlsr/nlsr.conf.j2 b/templates/nlsr/nlsr.conf.j2
index d739d7f..80798f4 100644
--- a/templates/nlsr/nlsr.conf.j2
+++ b/templates/nlsr/nlsr.conf.j2
@@ -54,7 +54,7 @@ fib
 advertising
 {
   {% for prefix in advertised_prefixes %}
-    prefix {{ prefix }}
+    {{ prefix }} 1
   {% endfor %}
 }