EVPN MAC Pinning Overview
Starting in Release 16.2, Junos OS enables MAC address pinning for Ethernet VPN (EVPN), including customer edge (CE) interfaces and EVPN over MPLS core interfaces, in both all-active mode or active-standby mode.
When you configure an interface with MAC pinning, the l2ald process adds an 8-octet extension to the address (which implements aspects of Section 7.7 of RFC-7432: MAC Mobility Extended Community). The low-order bit in the flag octet of this structure is the Sticky/static flag. Configuring MAC pinning sets the flag to 1 and designates the address is static.
If you configure MAC pinning on a CE interface, that MAC address cannot be moved to any other CE interface. Similarly, if you configure MAC pinning on an MPLS core interface on a PE device, that MAC address cannot be moved to a different interface on the MPLS core.
CE devices advertise MAC pinned addresses through the l2ald process to remote PE devices. When a PE device learns a MAC-pinned interface address from a CE device, the PE device synchronizes the address, through the control plane, with remote peer PE devices in the EVPN network. Thereafter, if the PE device receives traffic, or an advertised route, from any CE device in the EVPN network that bears the same source MAC address, the receiving device drops the traffic.
A PE device that learns a MAC pinned address via its control plane prefers that address over an address bearing the identical MAC address that is learned from a remote peer PE device, or locally by way of its l2ald from a CE interface.
Before the introduction of MAC address pinning for EVPN, a MAC address on a remote PE device that was learned locally could be aged out. For EVPN MAC pinning, a pinned MAC address does not age out on the remote PE device unless the routing protocol process removes it from the routing table. Similarly, a pinned MAC address persists for the control plane of the remote PE device.
This static interface address cannot be moved unless it is deleted from the routing table of the device on which it is configured.
A MAC address might be considered moved as a result of:
Configuration on a different Ethernet segment
Physical movement of a device within a network topology
If EVPN is configured in all-active multihoming mode, you must either enable or disable MAC pinning on the multihoming PE device interfaces in the broadcast domain. Also, either enable or disable MAC pinning on all CE device interfaces to avoid inconsistent MAC learning in the EVPN broadcast domain.
If EVPN is configured in active-standby multihoming mode, a MAC pinned address received by the active PE device can be moved to a CE interface on the standby PE device in response to a switchover, if traffic has been running continuously on the CE interface.
Do not enable or disable MAC pinning on an interface while traffic is running.