Host Mobility Case 1

Host Initiates an ARP/GARP upon Moving to the Target PE

An example is illustrated in Figure 1. This is the expected behavior based on the configuration described in EVPN Host Mobility Configuration.

1. Host-1 moves from PE1 to PE2 and issues a GARP with 10.1-M1.

2. Upon receiving the GARP, PE2 updates its FDB and ARP table.

3. The route-table entry for 10.1/32 changes from EVPN to type arp-nd (based on populate dynamic), therefore, PE2 advertises a RT5 with 10.1/32. Also, M1 is now learned in FDB and ARP as local, therefore, MAC/IP routes with a higher sequence number are advertised (one MAC/IP route with M1 only and another one with 10.1-M1).

4. Upon receiving the routes, PE1:

   1. Updates its FDB and withdraws its RT2(M1) based on the higher SEQ number.

   2. Updates its ARP entry 10.1-M1 from dynamic to type evpn.

   3. Because the populate dynamic, removes its arp-nd host from the route-table and withdraws its RT5 for 10.1/32.

5. The move of 10.1-M1 from dynamic to evpn triggers an ARP request from PE1 asking for 10.1. The no flood-garp-and-unknown-req command prevents PE1 from flooding the ARP request to PE2.

Figure 1. Host Mobility Within the same R-VPLS – Move with GARP

After step 5, no one replies to PE1’s ARP request and the procedure is over. If a host replied to the ARP for 10.1, the process starts again.