Set MED on routes sent to the upstream¶
Case 2 of the Network Change Verdict Corpus. Category: traffic-engineering. Expected verdict: safe (an experienced operator would approve it).
Why it is expected safe¶
Adds a metric to the upstream export clause. Changes path attributes only; nothing leaks or disappears.
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 10
+ set metric 50
+!
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:
Case file: corpus/cases/02-med-to-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.