[root@evpn1 ~]# ip a | grep fa:6c:53:72:3b:16 -B 1
12: vxlan20: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master br20 state UNKNOWN group default qlen 1000
    link/ether fa:6c:53:72:3b:16 brd ff:ff:ff:ff:ff:ff
[root@evpn1 ~]# bridge fdb | grep vxlan20
fa:6c:53:72:3b:16 dev dev vxlan20 vlan 1 master br20 permanent
fa:6c:53:72:3b:16 dev dev vxlan20 master br20 permanent

[root@evpn1 ~]# ip -br link show master br10
veth1@if2 UP 3a:31:5e:c0:cc:79 <BROADCAST,MULTICAST,UP,LOWER_UP>
vxlan10 UNKNOWN 9e:05:cb:41:19:35 <BROADCAST,MULTICAST,UP,LOWER_UP>
[root@evpn1 ~]# bridge fdb | grep veth1
3a:31:5e:c0:cc:79 dev dev veth1 vlan 1 master br10 permanent
3a:31:5e:c0:cc:79 dev dev veth1 master br10 permanent
33:33:00:00:00:01 dev dev veth1 self permanent
33:33:00:00:00:02 dev dev veth1 self permanent
01:00:5e:00:00:01 dev dev veth1 self permanent
33:33:ff:c0:cc:79 dev dev veth1 self permanent
33:33:ff:00:00:00 dev dev veth1 self permanent

[root@evpn1 ~]# ip a | grep 3a:31:5e:c0:cc:79 -B 1
4: veth1@if2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master br10 state UP group default qlen 1000
link/ether 3a:31:5e:c0:cc:79 brd ff:ff:ff:ff:ff:ff link-netns host1
[root@evpn1 ~]# ip a | grep 33:33:00:00:00:01 -B 1
[root@evpn1 ~]# ip link show br10
5: br10: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master evpn-vrf state UP mode DEFAULT group default qlen 1000
link/ether 00:00:01:02:03:10 brd ff:ff:ff:ff:ff:ff
[root@evpn1 ~]#

 

 

 

 

 

 

bridge fdb Command Output

The bridge fdb command in Linux interacts with the forwarding database table (FDB), which the bridge uses to store the MAC addresses it learns and the ports on which it learns those MAC addresses. The bridge fdb show command output contains some specific keywords:

Keyword	Description
self	The Linux kernel FDB entry flag that indicates the FDB entry belongs to the FDB on the device referenced by the device. For example, this FDB entry belongs to the VXLAN device vx-1000: 00:02:00:00:00:08 dev vx-1000 dst 27.0.0.10 self
master	The Linux kernel FDB entry flag that indicates the FDB entry belongs to the FDB on the device’s master and the FDB entry is pointing to a master’s port. For example, this FDB entry is from the master device named bridge and is pointing to the VXLAN bridge port vx-1001: 02:02:00:00:00:08 dev vx-1001 vlan 1001 master bridge
offload	The Linux kernel FDB entry flag that indicates the FDB entry is managed (or offloaded) by an external control plane, such as the BGP control plane for EVPN.

The following example shows the bridge fdb show command output:

cumulus@switch:~$ bridge fdb show | grep 02:02:00:00:00:08
02:02:00:00:00:08 dev vx-1001 vlan 1001 offload master bridge 
02:02:00:00:00:08 dev vx-1001 dst 27.0.0.10 self offload

 

• 02:02:00:00:00:08 is the MAC address learned with BGP EVPN.
• The first FDB entry points to a Linux bridge entry that points to the VXLAN device vx-1001.
• The second FDB entry points to the same entry on the VXLAN device and includes additional remote destination information.
• The VXLAN FDB augments the bridge FDB with additional remote destination information.
• All FDB entries that point to a VXLAN port appear as two entries. The second entry augments the remote destination information.