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Tag our aggregate with an informational community toward the upstream

Case 4 of the Network Change Verdict Corpus. Category: hygiene. Expected verdict: safe (an experienced operator would approve it).

Why it is expected safe

Adds a community on the OWN clause. Attribute change only.

The config change

Against the FRR configs of the base lab:

--- a/pe1.conf
+++ b/pe1.conf
@@ -60,3 +60,6 @@
   neighbor 10.0.3.2 send-community
  exit-address-family
 !
+route-map TO-UPSTREAM permit 20
+ set community 65000:999 additive
+!

What each strategy said

The expected verdict was committed to git before any run. All three strategies tested the same running lab (method).

Strategy Verdict Result Checks that failed
Ping only safe ✅ none
All BGP sessions up safe ✅ none
Netdryrun intent checks safe ✅ none

What Netdryrun flagged

Nothing: every check in the intent spec passed, so Netdryrun called the change safe.

Reproduce it

On Linux or WSL2 with Docker and containerlab, from a checkout of the repository:

python corpus/run.py --case 04

Case file: corpus/cases/04-tag-community-upstream.yml. Published result: netdryrun 0.2.0, containerlab 0.81.1, FRR quay.io/frrouting/frr:10.4.1, commit ec23379, run on 2026-10-26.