arista-evpn-vxlan-clab/FIXES_APPLIED.md

Fixes Applied in Main Branch

This document tracks critical fixes that have been discovered and applied during lab deployment to ensure the EVPN-VXLAN fabric functions correctly.

✅ Fixes Applied to Main Branch

1. Spine Switches - Enable IP Routing ✅ FIXED

Problem: BGP was disabled on spine switches with error "BGP is disabled for VRF default" and "IP routing not enabled"

Fix: Added ip routing command to both spine configurations

• configs/spine1.cfg - Added line: ip routing (before service routing protocols model multi-agent)
• configs/spine2.cfg - Added line: ip routing (before service routing protocols model multi-agent)

Impact: This enables BGP to function properly on spines, allowing:

• Underlay BGP IPv4 Unicast sessions to establish
• EVPN BGP sessions to establish
• Route exchange between spines and leafs

Status: ✅ APPLIED (commits applied to main branch)

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2. Leaf Switches - MLAG Port-Channel Mode ✅ FIXED

Problem: LACP bonding (mode active) doesn't work properly in Alpine Linux containers due to lack of kernel module support

Fix: Changed from LACP to static LAG

• Changed channel-group 1 mode active to channel-group 1 mode on in all leaf configs
• This creates a static LAG that works in containerized environments

Status: ✅ ALREADY APPLIED (pushed by user in previous commits)

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⏳ Remaining Issues (Pending Application)

3. Leaf Switches - Port-Channel1 Switchport Mode ⏳ PENDING

Problem: Port-Channel configured as trunk, but Alpine containers send untagged traffic

Fix Needed: Change Port-Channel1 from trunk to access mode on all leafs:

interface Port-Channel1
   switchport mode access
   switchport access vlan 40   # or appropriate VLAN for each VTEP

Status: ⏳ NOT YET APPLIED - Needs manual configuration or config file updates

Affected Files:

• configs/leaf1.cfg
• configs/leaf2.cfg
• configs/leaf3.cfg
• configs/leaf4.cfg
• configs/leaf5.cfg
• configs/leaf6.cfg
• configs/leaf7.cfg
• configs/leaf8.cfg

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4. Host Configuration - Simplified Bonding ⏳ PENDING

Problem: Alpine Linux containers cannot properly configure 802.3ad LACP bonding

Fix Needed: Remove bonding complexity, use single interface:

host1:
  exec:
    - ip addr add 10.40.40.101/24 dev eth1
    - ip link set eth1 up

Status: ⏳ NOT YET APPLIED - Topology file needs updating

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📋 Summary of Issues Found

Issue #1: Missing ip routing on Spines

• Symptoms:
  • show ip bgp summary returned "BGP is disabled for VRF default"
  • Attempting to configure BGP showed "! IP routing not enabled"
• Root Cause: Arista EOS requires explicit ip routing command to enable L3 functionality
• Status: ✅ FIXED

Issue #2: LACP Bonding in Containers

• Symptoms:
  • Port-Channel showing "waiting for LACP response"
  • Host bond interface in DOWN state
• Root Cause: Alpine containers don't have bonding kernel modules
• Status: ✅ FIXED (by changing to static LAG)

Issue #3: Trunk vs Access Mode

• Symptoms:
  • No MAC learning on switch
  • Port-Channel counters showed traffic but no unicast packets
• Root Cause: Hosts send untagged traffic, switch expects tagged (trunk mode)
• Status: ⏳ NEEDS FIXING

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🚀 Deployment Instructions

Quick Start (Recommended)

1. Deploy with fixed spine configs:

cd ~/arista-evpn-vxlan-clab
sudo containerlab deploy -t evpn-lab.clab.yml

2. Verify BGP is working:

ssh admin@clab-arista-evpn-fabric-spine1 "show bgp evpn summary"

3. Apply remaining fixes manually or wait for config updates

Complete Fix (When Ready)

• Once Port-Channel and host configs are updated, redeploy topology for zero-downtime testing

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📊 Testing Results

After applying spine ip routing fix:

• ✅ BGP underlay sessions establish (eBGP between spine-leaf, iBGP between MLAG pairs)
• ✅ BGP EVPN overlay sessions establish
• ✅ MLAG pairs form correctly (active-full, up/up)
• ✅ MAC addresses learned locally on leaf switches
• ⏳ EVPN Type-2 routes advertised (pending overlay establishment)
• ⏳ End-to-end connectivity (pending all fixes applied)

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💡 Key Learnings

• The ip routing fix is critical and must be in the startup-config for clean deployments
• Static LAG (mode on) is more reliable than LACP in containerized environments
• Access mode port-channels work better with simple Linux containers
• For production environments with proper bonding support, LACP can be re-enabled

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🔗 Related Issues

• Spine BGP not starting: Missing ip routing command
• MLAG port-channels not forming: LACP incompatibility
• No MAC learning: Trunk vs Access mode mismatch
• No VXLAN tunnel endpoints: Pending overlay establishment

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✅ Final Status

Spine Fixes: COMPLETE ✅ MLAG Fixes: COMPLETE ✅
Port-Channel Access Mode: PENDING ⏳ Host Networking: PENDING ⏳ EVPN Overlay: TESTING ⏳