Document all fixes applied in fix-bgp-and-mlag branch
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FIXES_APPLIED.md
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# Fixes Applied in fix-bgp-and-mlag Branch
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This branch contains critical fixes discovered during lab testing to make the EVPN-VXLAN fabric functional.
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## 🔧 Fixes Applied
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### 1. **Spine Switches - Enable IP Routing**
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**Problem**: BGP was disabled on spine switches with error "BGP is disabled for VRF default" and "IP routing not enabled"
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**Fix**: Added `ip routing` command to both spine configurations
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- `configs/spine1.cfg` - Added line: `ip routing` (before `service routing protocols model multi-agent`)
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- `configs/spine2.cfg` - Added line: `ip routing` (before `service routing protocols model multi-agent`)
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**Impact**: This enables BGP to function properly on spines, allowing:
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- Underlay BGP IPv4 Unicast sessions to establish
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- EVPN BGP sessions to establish
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- Route exchange between spines and leafs
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### 2. **Leaf Switches - MLAG Port-Channel Mode**
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**Problem**: LACP bonding (`mode active`) doesn't work properly in Alpine Linux containers due to lack of kernel module support
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**Fix**: Changed from LACP to static LAG
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- Changed `channel-group 1 mode active` to `channel-group 1 mode on` in all leaf configs
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- This creates a static LAG that works in containerized environments
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**Status**: ✅ Already applied in main branch (pushed by user)
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### 3. **Leaf Switches - Port-Channel Switchport Mode**
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**Problem**: Port-Channel configured as trunk, but Alpine containers send untagged traffic
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**Fix Needed**: Change Port-Channel1 from trunk to access mode on all leafs:
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```
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interface Port-Channel1
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switchport mode access
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switchport access vlan 40 # or appropriate VLAN for each VTEP
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```
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**Status**: ⚠️ **NOT YET APPLIED** - Needs manual configuration or config file update
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### 4. **Host Configuration - Simplified Bonding**
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**Problem**: Alpine Linux containers cannot properly configure 802.3ad LACP bonding
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**Fix in topology**: Remove bonding complexity, use single interface:
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```yaml
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host1:
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exec:
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- ip addr add 10.40.40.101/24 dev eth1
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- ip link set eth1 up
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```
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**Status**: ⚠️ **NOT YET APPLIED** - topology file not updated in this branch
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## 📋 Summary of Issues Found
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### Issue #1: Missing `ip routing` on Spines
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- **Symptoms**:
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- `show ip bgp summary` returned "BGP is disabled for VRF default"
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- Attempting to configure BGP showed "! IP routing not enabled"
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- **Root Cause**: Arista EOS requires explicit `ip routing` command to enable L3 functionality
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- **Status**: ✅ **FIXED**
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### Issue #2: LACP Bonding in Containers
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- **Symptoms**:
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- Port-Channel showing "waiting for LACP response"
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- Host bond interface in DOWN state
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- **Root Cause**: Alpine containers don't have bonding kernel modules
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- **Status**: ✅ **FIXED** (by changing to static LAG)
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### Issue #3: Trunk vs Access Mode
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- **Symptoms**:
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- No MAC learning on switch
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- Port-Channel counters showed traffic but no unicast packets
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- **Root Cause**: Hosts send untagged traffic, switch expects tagged (trunk mode)
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- **Status**: ⚠️ **NEEDS MANUAL FIX**
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## 🚀 Deployment Instructions
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### Option 1: Deploy with Manual Post-Configuration
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1. Deploy the lab:
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```bash
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cd ~/arista-evpn-vxlan-clab
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git checkout fix-bgp-and-mlag
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sudo containerlab deploy -t evpn-lab.clab.yml
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```
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2. Fix Port-Channel mode on all leafs (manual):
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```bash
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for leaf in leaf1 leaf2 leaf3 leaf4 leaf5 leaf6 leaf7 leaf8; do
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ssh admin@clab-arista-evpn-fabric-$leaf << 'EOF'
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enable
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configure terminal
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interface Port-Channel1
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switchport mode access
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switchport access vlan 40
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write memory
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EOF
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done
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```
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3. Configure hosts (manual):
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```bash
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# Host1 (VLAN 40 - L2 VXLAN)
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docker exec clab-arista-evpn-fabric-host1 sh -c '
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ip link set bond0 down 2>/dev/null
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ip link del bond0 2>/dev/null
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ip addr flush dev eth1
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ip addr add 10.40.40.101/24 dev eth1
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ip link set eth1 up
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'
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# Host3 (VLAN 40 - L2 VXLAN)
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docker exec clab-arista-evpn-fabric-host3 sh -c '
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ip link set bond0 down 2>/dev/null
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ip link del bond0 2>/dev/null
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ip addr flush dev eth1
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ip addr add 10.40.40.103/24 dev eth1
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ip link set eth1 up
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'
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# Host2 (VRF gold - L3 VXLAN)
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docker exec clab-arista-evpn-fabric-host2 sh -c '
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ip link set bond0 down 2>/dev/null
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ip link del bond0 2>/dev/null
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ip addr flush dev eth1
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ip addr add 10.34.34.102/24 dev eth1
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ip link set eth1 up
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ip route add default via 10.34.34.1
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'
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# Host4 (VRF gold - L3 VXLAN)
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docker exec clab-arista-evpn-fabric-host4 sh -c '
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ip link set bond0 down 2>/dev/null
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ip link del bond0 2>/dev/null
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ip addr flush dev eth1
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ip addr add 10.78.78.104/24 dev eth1
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ip link set eth1 up
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ip route add default via 10.78.78.1
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'
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```
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4. Verify:
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```bash
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# Check BGP
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ssh admin@clab-arista-evpn-fabric-leaf1 "show bgp evpn summary"
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# Check VXLAN
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ssh admin@clab-arista-evpn-fabric-leaf1 "show vxlan vtep"
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# Test connectivity
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docker exec -it clab-arista-evpn-fabric-host1 ping -c 4 10.40.40.103
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docker exec -it clab-arista-evpn-fabric-host2 ping -c 4 10.78.78.104
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```
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### Option 2: Wait for Complete Fix
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A complete fix will require:
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1. ✅ Spine configs updated (DONE)
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2. ⏳ All leaf Port-Channel configs updated to access mode
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3. ⏳ Topology file updated to simplify host networking
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4. ⏳ README updated with correct testing procedures
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## 🧪 Testing Results
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After applying fixes manually:
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- ✅ BGP underlay sessions establish (eBGP between spine-leaf, iBGP between MLAG pairs)
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- ✅ BGP EVPN overlay sessions establish
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- ✅ MLAG pairs form correctly (active-full, up/up)
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- ✅ MAC addresses learned locally on leaf switches
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- ✅ EVPN Type-2 routes advertised (pending overlay establishment)
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- ⏳ End-to-end connectivity (requires all fixes applied)
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## 📝 Notes
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- The `ip routing` fix is critical and must be in the startup-config for clean deployments
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- Static LAG (`mode on`) is more reliable than LACP in containerized environments
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- Access mode port-channels work better with simple Alpine containers
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- For production environments with proper bonding support, LACP can be re-enabled
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## 🔗 Related Issues
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- Spine BGP not starting: Missing `ip routing` command
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- MLAG port-channels not forming: LACP bonding incompatibility
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- No MAC learning: Trunk vs access mode mismatch
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