Arista EVPN VXLAN Configuration Example (3a) - Single-homing, L3 EVPN, Centralized Routing

In traditional DC design, the most common inter-VLAN routing is centralized routing, and illustrated as below, 



Explanation:

• A dedicated router - up506/cenRtr is used to route the traffic between vlans;
• All gateway SVIs on the cenRtr
• Advantages:
• Low resource requirement on VTEPs, which only need to know how to reach gateway. So fewer MAC and no ARP
• Easy managed. 
• Disadvantages:
• Sub-optimal traffic flow. 
• Single point failure

Control Plane Check-up:

1. IMET:

On centralized router, under vlan 631, only 2 VTEPs - local and VTEP1

up506-CentRtr#show bgp evpn route-type imet vni 631
          Network                Next Hop              Metric  LocPref Weight  Path
 * >     RD: 160.255.255.10:630 imet 631 160.255.255.10
                                160.255.255.10        -       100     0       i Or-ID: 160.255.255.10 C-LST: 180.255.255.1
 * >     RD: 160.255.255.20:630 imet 631 160.255.255.100
                                -                     -       -       0       i

Similarly, under vlan 632, only 2 VTEPs - local and VTEP2

up506-CentRtr#show bgp evpn route-type imet vni 632
          Network                Next Hop              Metric  LocPref Weight  Path
 * >     RD: 160.255.255.20:630 imet 632 160.255.255.20
                                160.255.255.20        -       100     0       i Or-ID: 160.255.255.20 C-LST: 180.255.255.1
 * >     RD: 160.255.255.20:630 imet 632 160.255.255.100
                                -                     -       -       0       i

2. MAC-IP:

up506-CentRtr#show bgp evpn route-type mac-ip vni 631
          Network                Next Hop              Metric  LocPref Weight  Path
 * >     RD: 160.255.255.10:630 mac-ip 631 444c.a8a5.1140
                                160.255.255.10        -       100     0       i Or-ID: 160.255.255.10 C-LST: 180.255.255.1

up506-CentRtr#show bgp evpn route-type mac-ip vni 632
          Network                Next Hop              Metric  LocPref Weight  Path
 * >     RD: 160.255.255.20:630 mac-ip 632 444c.a8a5.1141
                                160.255.255.20        -       100     0       i Or-ID: 160.255.255.20 C-LST: 180.255.255.1

Ping check-up:

Host1#ping vrf EvpnHost1 160.63.2.202
PING 160.63.2.202 (160.63.2.202) 72(100) bytes of data.
80 bytes from 160.63.2.202: icmp_seq=1 ttl=63 time=0.157 ms
80 bytes from 160.63.2.202: icmp_seq=2 ttl=63 time=0.112 ms
80 bytes from 160.63.2.202: icmp_seq=3 ttl=63 time=0.144 ms
80 bytes from 160.63.2.202: icmp_seq=4 ttl=63 time=0.106 ms
80 bytes from 160.63.2.202: icmp_seq=5 ttl=63 time=0.133 ms

--- 160.63.2.202 ping statistics ---
5 packets transmitted, 5 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 0.106/0.130/0.157/0.021 ms, ipg/ewma 0.156/0.143 ms