Verifying That Unknown Unicast Packets Are Forwarded to a Trunk Interface
Purpose
Verify that a VLAN is forwarding all unknown unicast packets (those with unknown destination MAC addresses) to a single trunk interface instead of flooding unknown unicast packets across all interfaces that are members of the same VLAN.
Action
Display the forwarding interface for unknown unicast packets for a VLAN (here, the VLAN name is v1):
user@switch> show configuration ethernet-switching-options
unknown-unicast-forwarding {
vlan v1 {
interface ge-0/0/7.0;
}
}
Display the Ethernet switching table:
user@switch> show ethernet-switching table vlan v1
Ethernet-switching table: 3 unicast entries VLAN MAC address Type Age Interfaces v1 * Flood - All-members v1 00:01:09:00:00:00 Learn 24 ge-0/0/7.0 v1 00:11:09:00:01:00 Learn 37 ge-0/0/3.0
Meaning
The sample output from the show configuration ethernet-switching-options command shows that the unknown unicast forwarding interface for VLAN v1 is interface ge-0/0/7. The show ethernet-switching table command shows that an unknown unicast packet is received on interface ge-0/0/3 with the destination MAC address (DMAC) 00:01:09:00:00:00 and the source MAC address (SMAC) of 00:11:09:00:01:00. This shows that the SMAC of the packet is learned in the normal way (through the interface ge-0/0/3.0), while the DMAC is learned on interface ge-0/0/7.
