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MLAG peer-link misconfigured as access instead of trunk on leaf3/4/7/8 #6

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opened 2025-11-28 11:43:05 +00:00 by Damien · 0 comments
Damien commented 2025-11-28 11:43:05 +00:00
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Problem

BGP EVPN sessions failing on leaf3, leaf4, leaf7, and leaf8. Spines show these neighbors in "Active" state.

Root Cause

Port-Channel999 (MLAG peer-link) configured with switchport mode access instead of switchport mode trunk. This prevents VLAN 4090 and 4091 from being carried across the peer-link, breaking:

  • MLAG peer communication (VLAN 4090)
  • iBGP peering between MLAG pairs (VLAN 4091)
  • Subsequently, EVPN overlay sessions to spines

Fix Applied

Changed Port-Channel999 configuration from:

switchport mode access
switchport trunk group mlag-peer

To:

switchport mode trunk
switchport trunk group mlag-peer

Files Modified

  • configs/leaf3.cfg (line 70) ✅
  • configs/leaf4.cfg (line 70) ✅
  • configs/leaf7.cfg (line 76) ✅
  • configs/leaf8.cfg (line 76) ✅

All configurations have been updated. Redeploy the lab to apply the fixes.

## Problem BGP EVPN sessions failing on leaf3, leaf4, leaf7, and leaf8. Spines show these neighbors in "Active" state. ## Root Cause Port-Channel999 (MLAG peer-link) configured with `switchport mode access` instead of `switchport mode trunk`. This prevents VLAN 4090 and 4091 from being carried across the peer-link, breaking: - MLAG peer communication (VLAN 4090) - iBGP peering between MLAG pairs (VLAN 4091) - Subsequently, EVPN overlay sessions to spines ## Fix Applied Changed Port-Channel999 configuration from: ``` switchport mode access switchport trunk group mlag-peer ``` To: ``` switchport mode trunk switchport trunk group mlag-peer ``` ## Files Modified - configs/leaf3.cfg (line 70) ✅ - configs/leaf4.cfg (line 70) ✅ - configs/leaf7.cfg (line 76) ✅ - configs/leaf8.cfg (line 76) ✅ All configurations have been updated. Redeploy the lab to apply the fixes.
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Reference: Damien/arista-evpn-vxlan-clab#6