Description
This article describes some of the common EVPN issues and tips to troubleshoot these issues.
Scope
FortiOS 7.4.X and above.
Solution
Issue 1: EVPN MBGP Adjacency is not established.
- EVPN uses multiprotocol BGP and EVPN is an address-family within BGP (AFI: 25, SAFI: 70).
- Check the reachability between VTEPs and run the packet capture on the VTEPs using the command diagnose sniffer packet any "host <x.x.x.x> and host <y.y.y.y>" 4 0 l , where <x.x.x.x> and <y.y.y.y> is the IP address of VTEPs.
- Check the configuration for any potential misconfigurations.
- Run the below commands to enable BGP daemon logs and share it with FortiOS TAC for further investigation:
get router info bgp evpn summary
diagnose ip router bgp all enable
diagnose ip router bgp level info
diagnose debug console timestamp enable
diagnose debug enable
Issue 2 : BUM traffic forwarding or VTEP not included in the flood list.
- Type-3 Inclusive Multicast Route is used to build the Ingress Replication list (Flood list) of VTEP.
- BUM traffic (Broadcast/Unknown Unicast/Multicast) traffic is forwarded to other VTEPs based on the IMET route.
- Run below commands to confirm the VTEP has received IMET route:
get router info bgp evpn network
get l2vpn evpn table
Issue 3: Endpoint information is not sent to other VTEPs.
- Type-2 Host Advertisement Route is advertise endpoints layer 2 (mac/mac-ip) information between EVPN BGP peers.
- Host boots up and send frames, such as ARP Broadcast. This traffic hits the VXLAN software switch , which records the source MAC in its Layer 2 table, just like normal switching operation.
- Next the VTEP creates an entry in its EVPN Table ( Local MAC , Local IP ) and advertises this MAC and IP address to the EVPN BGP Peer using Type-2 MAC Advertisement Route.
- VXLAN Software Switch learns the MAC address via Data Plane learning (similar behavior to a switch).Check if the host is learned locally using commands:
get router info bgp evpn network
get l2vpn evpn instance
diagnose netlink brctl name host <vxlan-software-switch>
diagnose debug console timestamp enable
diagnose debug application evpnd -1 (generate traffic from the host in local VTEP)
diagnose debug disable
- MAC Address is Flagged as 'Active' or 'Inactive' based its FDB entry on the VXLAN Software Switch and entries with Active Flag will only be advertised to the peer.
