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EVPN feature is only available on X86 platforms.


PICOS version 4.0 and higher offer both Symmetric and Asymmetric routing for BGP EVPN hosts. In this document we will examine the case of Asymmetric EVPN routing with two hosts in different VNIs on two devices, R1 and R2.

Figure 1 depicts how packet exchange between two hosts occurs in asymmetric BGP EVPN routing model. In the asymmetric routing model, the two end hosts, Host1 and Host2 are in two different VLANs and different VNIs. Host1 intends to communicate with Host2, sends a packet with destination MAC address of of R1 because R1 is configured as the gateway on Host1. On R1, the gateway is configured on an interface that belongs to VNI 30. The packet from Host1 on ingress at R1 is first routed to VNI 30 within R1 and then bridged to R2 over the VXLAN tunnel VNI 30. On receiving the packet, R2 will strip off the VXLAN header and forward the packet to Host2. 

                                                 Figure 1. EVPN Asymmetric Routing Model


The one limitation in this model is that both the devices must have the two VXLAN VNIs configured regardless if there are any hosts connected to it. In Figure 1, Host1 belongs to VNI 10 but both VNI 10 and VNI 30 are configured on R1. Similarly, Host2 belongs to VNI 30 but both VNI 10 and VNI 30 are configured on R2 for asymmetric routing to work properly.

Router Configuration

R1 Configuration


Step 1: Configure VLAN ID, L3 VLAN interfaces loopback interfaces and IP addressing. The MTU value of layer 3 interfaces is set to 1450 to ensure there is enough space for the overlay VXLAN header. The switch will complain and refuse to commit the configuration if MTU size is not set to 1450.  Interface te-1/1/10 connects to PC1.

admin@R1# set interface gigabit-ethernet te-1/1/1 family ethernet-switching native-vlan-id 4094
admin@R1# set interface gigabit-ethernet te-1/1/2 family ethernet-switching native-vlan-id 10
admin@R1# set interface gigabit-ethernet te-1/1/10 family ethernet-switching native-vlan-id 10
admin@R1# set l3-interface loopback lo address 1.1.1.1 prefix-length 32
admin@R1# set l3-interface loopback vrf1 address 201.201.201.201 prefix-length 32
admin@R1# set l3-interface vlan-interface vlan4094 mtu 1450
admin@R1# set l3-interface vlan-interface vlan4094 address 40.94.0.2 prefix-length 24
admin@R1# set l3-interface vlan-interface vlan10 vrf "vrf1"
admin@R1# set l3-interface vlan-interface vlan10 mtu 1450
admin@R1# set l3-interface vlan-interface vlan10 address 10.1.1.201 prefix-length 24
admin@R1# set l3-interface vlan-interface vlan1111 vrf "vrf1"
admin@R1# set l3-interface vlan-interface vlan1111 router-mac 00:16:16:16:16:16
admin@R1# set l3-interface vlan-interface vlan1111 mtu 1450
admin@R1# set vlans vlan-id 10 l3-interface "vlan10"
admin@R1# set vlans vlan-id 30 l3-interface "vlan30"
admin@R1# set vlans vlan-id 1111 l3-interface "vlan1111"
admin@R1# set vlans vlan-id 4094 l3-interface "vlan4094"
admin@R1# set vxlans source-interface lo address 1.1.1.1
admin@R1# set vxlans vni 100 vlan 1111
admin@R1# set vxlans vni 10 vlan 10
admin@R1# set vxlans vni 30 vlan 30
admin@R1# set vxlans vrf vrf1 l3-vni 100 prefix-routes-only

Step 2: Configure VXLAN VNI and map VNI IDs to VLAN IDs.

admin@R1# set vxlans source-interface lo address 1.1.1.1
admin@R1# set vxlans vni 100 vlan 1111
admin@R1# set vxlans vni 10 vlan 10
admin@R1# set vxlans vni 30 vlan 30

Step 3: Enable IP routing and configure VRF and hostname.

admin@R1# set ip routing enable true
admin@R1# set ip vrf vrf1

Step 4: Configure BGP and OSPF related configuration

admin@R1# set protocols bgp local-as 65001
admin@R1# set protocols bgp router-id 1.1.1.1
admin@R1# set protocols bgp neighbor 2.2.2.2 remote-as "internal"
admin@R1# set protocols bgp neighbor 2.2.2.2 update-source "1.1.1.1"
admin@R1# set protocols bgp neighbor 2.2.2.2 evpn activate
admin@R1# set protocols bgp ipv4-unicast
admin@R1# set protocols bgp evpn advertise-all-vni
admin@R1# set protocols bgp evpn advertise ipv4-unicast
admin@R1# set protocols bgp vrf vrf1 local-as 65001
admin@R1# set protocols bgp vrf vrf1 router-id 1.1.1.1
admin@R1# set protocols bgp vrf vrf1 evpn advertise ipv4-unicast
admin@R1# set protocols ospf router-id 1.1.1.1
admin@R1# set protocols ospf network 40.94.0.0/24 area 0.0.0.0
admin@R1# set protocols ospf network 1.1.1.1/32 area 0.0.0.0

R2 Configuration

Step 1: Configure VLAN ID, L3 VLAN interfaces loopback interfaces and IP addresses. Interface ge-1/1/10 connects to PC2.

root@R2# set evpn vrf vrf1 vni 100 prefix-routes-only
root@R2# set interface gigabit-ethernet ge-1/1/1 family ethernet-switching native-vlan-id 4094
root@R2# set interface gigabit-ethernet ge-1/1/10 family ethernet-switching native-vlan-id 30
root@R2# set l3-interface loopback lo address 2.2.2.2 prefix-length 32
root@R2# set l3-interface loopback vrf1 address 134.134.134.134 prefix-length 32
root@R2# set l3-interface vlan-interface vlan1111 vrf "vrf1"
root@R2# set l3-interface vlan-interface vlan1111 mtu 1450
root@R2# set l3-interface vlan-interface vlan30 vrf "vrf1"
root@R2# set l3-interface vlan-interface vlan30 mtu 1450
root@R2# set l3-interface vlan-interface vlan30 address 30.1.1.134 prefix-length 24
root@R2# set l3-interface vlan-interface vlan4094 mtu 1450
root@R2# set l3-interface vlan-interface vlan4094 address 40.94.0.1 prefix-length 24
root@R2# set vlans vlan-id 10 l3-interface "vlan10"
root@R2# set vlans vlan-id 30 l3-interface "vlan30"

Step 2: Configure VXLAN VNI and map VNI IDs to VLAN IDs.

root@R2# set vlans vlan-id 1111 l3-interface "vlan1111"
root@R2# set vlans vlan-id 4094 l3-interface "vlan4094"
root@R2# set vxlans source-interface lo address 2.2.2.2
root@R2# set vxlans vni 100 vlan 1111
root@R2# set vxlans vni 10 vlan 10
root@R2# set vxlans vni 30 vlan 30 

Step 3: Enable IP routing and configure VRF and hostname.

root@R2# set system hostname "R2"
root@R2# set ip routing enable true
root@R2# set ip vrf vrf1

Step 4: Configure BGP and OSPF related configuration

root@R2# set protocols bgp local-as 65001
root@R2# set protocols bgp router-id 2.2.2.2
root@R2# set protocols bgp neighbor 1.1.1.1 remote-as "internal"
root@R2# set protocols bgp neighbor 1.1.1.1 update-source "2.2.2.2"
root@R2# set protocols bgp neighbor 1.1.1.1 evpn activate
root@R2# set protocols bgp evpn advertise-all-vni
root@R2# set protocols bgp evpn advertise ipv4-unicast
root@R2# set protocols bgp vrf vrf1 local-as 65001
root@R2# set protocols bgp vrf vrf1 router-id 2.2.2.2
root@R2# set protocols bgp vrf vrf1 evpn advertise ipv4-unicast
root@R2# set protocols ospf router-id 2.2.2.2
root@R2# set protocols ospf network 40.94.0.0/24 area 0.0.0.0
root@R2# set protocols ospf network 2.2.2.2/32 area 0.0.0.0

Verify Configuration

On R1 run the command run show route vrf vrf1 to display the routes. Notice below that there is a route to subnet 30.1.1.0/24.

admin@R1# run show route vrf vrf1
show ip route vrf vrf1
=======================
Codes: K - kernel route, C - connected, S - static, R - RIP,
       O - OSPF, I - IS-IS, B - BGP, E - EIGRP, N - NHRP,
       T - Table, v - VNC, V - VNC-Direct, A - Babel, D - SHARP,
       F - PBR, f - OpenFabric,
       > - selected route, * - FIB route, q - queued route, r - rejected route


VRF vrf1:
K>* 0.0.0.0/0 [255/8192] unreachable (ICMP unreachable), 04:07:17
C>* 10.1.1.0/24 is directly connected, vlan10, 04:06:28
B>* 11.11.11.147/32 [200/0] via 2.2.2.2, vlan1111 onlink, weight 1, 04:05:30
C>* 30.1.1.0/24 is directly connected, vlan30, 04:06:28
C>* 201.201.201.201/32 is directly connected, vrf1, 04:07:17



show ipv6 route vrf vrf1
=========================
Codes: K - kernel route, C - connected, S - static, R - RIPng,
       O - OSPFv3, I - IS-IS, B - BGP, N - NHRP, T - Table,
       v - VNC, V - VNC-Direct, A - Babel, D - SHARP, F - PBR,
       f - OpenFabric,
       > - selected route, * - FIB route, q - queued route, r - rejected route


VRF vrf1:
C * fe80::/64 is directly connected, vlan1111, 04:06:27
C * fe80::/64 is directly connected, vlan30, 04:06:28
C>* fe80::/64 is directly connected, vlan10, 04:06:28
admin@R2# run show route vrf vrf1
show ip route vrf vrf1
=======================
Codes: K - kernel route, C - connected, S - static, R - RIP,
       O - OSPF, I - IS-IS, B - BGP, E - EIGRP, N - NHRP,
       T - Table, v - VNC, V - VNC-Direct, A - Babel, D - SHARP,
       F - PBR, f - OpenFabric,
       > - selected route, * - FIB route, q - queued route, r - rejected route


VRF vrf1:
K>* 0.0.0.0/0 [255/8192] unreachable (ICMP unreachable), 00:12:12
C>* 10.1.1.0/24 is directly connected, vlan10, 00:11:23
C>* 30.1.1.0/24 is directly connected, vlan30, 00:11:23


show ipv6 route vrf vrf1
=========================
Codes: K - kernel route, C - connected, S - static, R - RIPng,
       O - OSPFv3, I - IS-IS, B - BGP, N - NHRP, T - Table,
       v - VNC, V - VNC-Direct, A - Babel, D - SHARP, F - PBR,
       f - OpenFabric,
       > - selected route, * - FIB route, q - queued route, r - rejected route


VRF vrf1:
C * fe80::/64 is directly connected, vlan1111, 00:11:22
C * fe80::/64 is directly connected, vlan30, 00:11:22
C * fe80::/64 is directly connected, vlan10, 00:11:22
C>* fe80::/64 is directly connected, vlan40, 00:11:22

Run the command run show vxlan evpn route on either R1 or R2 to check the VXLAN EVPN routes.

admin@R1#  run show vxlan arp
IP-ADDRESS       MAC-ADDRESS        VNI       REMOTE-VTEP      Interface   Status   Age
---------------  -----------------  --------  ---------------  ----------  -------  ----
10.1.1.2        18:5a:58:3c:42:a1  10                       te-1/1/10   Dynamic  249 
10.1.1.1        18:5a:58:03:35:81  10      2.2.2.2                      Static       
30.1.1.1        18:5a:58:03:35:81  30      2.2.2.2                      Static       
30.1.1.2        1c:72:1d:c9:1b:e1  30      2.2.2.2                       Static            

To check the VXLAN tunnels on either devices, run the command run show vxlan tunnel.

admin@R2# run show vxlan tunnel
Total number of tunnels: 2

VNI 10, Encap:service-vlan-delete, Decap:service-vlan-add-replace
  src addr:2.2.2.2, dst addr:1.1.1.1, state:UP
  traffic type:all
  Vtep type:EVPN
  nexthops:40.94.0.2
  output ports:ge-1/1/1

VNI 30, Encap:service-vlan-delete, Decap:service-vlan-add-replace
  src addr:2.2.2.2, dst addr:1.1.1.1, state:UP
  traffic type:all
  Vtep type:EVPN
  nexthops:40.94.0.2
  output ports:ge-1/1/1
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