EVPN Asymmetric Routing Example
- Tracy Yang
Note
EVPN feature is only available on X86 platforms.
Network Requirements
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. Interface te-1/1/15 connects to Host1.
NOTE: "router-mac" is an optional configuration for anycast gateway.
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 interface gigabit-ethernet te-1/1/1 family ethernet-switching native-vlan-id 10 admin@R1# set interface gigabit-ethernet te-1/1/15 family ethernet-switching native-vlan-id 4094 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 address 40.94.0.2 prefix-length 24 admin@R1# set l3-interface vlan-interface vlan1111 vrf "vrf1" admin@R1# set l3-interface vlan-interface vlan10 vrf "vrf1" admin@R1# set l3-interface vlan-interface vlan10 router-mac 00:00:10:00:00:FE admin@R1# set l3-interface vlan-interface vlan10 address 10.1.1.10 prefix-length 24 admin@R1# set l3-interface vlan-interface vlan30 vrf "vrf1" admin@R1# set l3-interface vlan-interface vlan30 router-mac 00:00:30:00:00:FE admin@R1# set l3-interface vlan-interface vlan30 address 30.1.1.30 prefix-length 24
Step 2 Configure VXLAN VNI and map VNI IDs to VLAN IDs.
NOTEs:
- When anycast gateway is configured, it is recommended to configure ARP/ND suppression at the same time.
- It is recommended to configure the decapsulation mode as "service-vlan-per-port".
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 decapsulation mode "service-vlan-per-port" admin@R1# set vxlans vni 10 vlan 10 admin@R1# set vxlans vni 10 arp-nd-suppress disable false admin@R1# set vxlans vni 30 decapsulation mode "service-vlan-per-port" admin@R1# set vxlans vni 30 vlan 30 admin@R1# set vxlans vni 30 arp-nd-suppress disable false admin@R1# set vxlans vrf vrf1 l3-vni 100 prefix-routes-only
Step 3 Enable IP routing and configure VRF and hostname.
admin@R1# set system hostname "R1" admin@R1# set ip routing enable true admin@R1# set ip vrf vrf1
Step 4 Configure BGP and OSPF related configuration.
NOTE:
The set protocols bgp evpn advertise ipv4-unicast command is used to announce IPv4 prefixes in the BGP RIB as EVPN Type-5 routes. To announce IPv6 prefixes in the BGP RIB as EVPN Type-5 routes, use command set protocols bgp evpn advertise ipv6-unicast.
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 true 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 evpn advertise-svi-ip 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" 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"
Step 5 Commit the configuration.
admin@R1# commit
R2 Configuration
Step 1 Configure VLAN ID, L3 VLAN interfaces loopback interfaces and IP addresses. Interface ge-1/1/15 connects to Host2.
admin@R2# set vlans vlan-id 10 l3-interface "vlan10" admin@R2# set vlans vlan-id 30 l3-interface "vlan30" admin@R2# set vlans vlan-id 1111 l3-interface "vlan1111" admin@R2# set vlans vlan-id 4094 l3-interface "vlan4094" admin@R2# set interface gigabit-ethernet ge-1/1/1 family ethernet-switching native-vlan-id 30 admin@R2# set interface gigabit-ethernet ge-1/1/15 family ethernet-switching native-vlan-id 4094 admin@R2# set l3-interface loopback lo address 2.2.2.2 prefix-length 32 admin@R2# set l3-interface loopback vrf1 address 134.134.134.134 prefix-length 32 admin@R2# set l3-interface vlan-interface vlan1111 vrf "vrf1" admin@R2# set l3-interface vlan-interface vlan4094 address 40.94.0.1 prefix-length 24 admin@R2# set l3-interface vlan-interface vlan10 vrf "vrf1" admin@R2# set l3-interface vlan-interface vlan10 router-mac 00:00:10:00:00:FE admin@R2# set l3-interface vlan-interface vlan10 address 10.1.1.10 prefix-length 24 admin@R2# set l3-interface vlan-interface vlan30 vrf "vrf1" admin@R2# set l3-interface vlan-interface vlan30 router-mac 00:00:30:00:00:FE admin@R2# set l3-interface vlan-interface vlan30 address 30.1.1.30 prefix-length 24
Step 2 Configure VXLAN VNI and map VNI IDs to VLAN IDs.
admin@R2# set vxlans source-interface lo address 2.2.2.2 admin@R2# set vxlans vni 100 vlan 1111 admin@R2# set vxlans vni 10 decapsulation mode "service-vlan-per-port" admin@R2# set vxlans vni 10 vlan 10 admin@R2# set vxlans vni 10 arp-nd-suppress disable false admin@R2# set vxlans vni 30 decapsulation mode "service-vlan-per-port" admin@R2# set vxlans vni 30 vlan 30 admin@R2# set vxlans vni 30 arp-nd-suppress disable false admin@R2# set vxlans vrf vrf1 l3-vni 100 prefix-routes-only
Step 3 Enable IP routing and configure VRF and hostname.
admin@R2# set system hostname "R2" admin@R2# set ip routing enable true admin@R2# set ip vrf vrf1
Step 4 Configure BGP and OSPF related configuration
admin@R2# set protocols bgp local-as 65001 admin@R2# set protocols bgp router-id 2.2.2.2 admin@R2# set protocols bgp neighbor 1.1.1.1 remote-as "internal" admin@R2# set protocols bgp neighbor 1.1.1.1 update-source "2.2.2.2" admin@R2# set protocols bgp neighbor 1.1.1.1 evpn activate true admin@R2# set protocols bgp evpn advertise-all-vni admin@R2# set protocols bgp evpn advertise ipv4-unicast admin@R2# set protocols bgp evpn advertise-svi-ip admin@R2# set protocols bgp vrf vrf1 local-as 65001 admin@R2# set protocols bgp vrf vrf1 router-id 2.2.2.2 admin@R2# set protocols bgp vrf vrf1 evpn advertise ipv4-unicast admin@R2# set protocols lldp enable true admin@R2# set protocols spanning-tree enable false admin@R2# set protocols ospf router-id 2.2.2.2 admin@R2# set protocols ospf network 40.94.0.0/24 area "0.0.0.0" admin@R2# set protocols ospf network 2.2.2.2/32 area "0.0.0.0"
Step 5 Commit the configuration.
admin@R2# commit
Verify Configuration
- On R1 and R2, run the command run show route vrf vrf1 forward-host ipv4 all to display the host routes.
admin@R1# run show route vrf vrf1 forward-host ipv4 all Address HWaddress Port --------------- ----------------- --------- 10.1.1.2 00:1E:C9:BB:C0:3C vxlan-0x80000002 30.1.1.2 00:0C:29:77:8B:15 vxlan-0x80000001 Total host count:2 admin@R2# run show route vrf vrf1 forward-host ipv4 all Address HWaddress Port --------------- ----------------- --------- 10.1.1.2 00:1E:C9:BB:C0:3C vxlan-0x80000001 30.1.1.2 00:0C:29:77:8B:15 vxlan-0x80000003 Total host count:2
- Run the command run show vxlan arp on either R1 or R2 to check VXLAN ARP table.
admin@R1# run show vxlan arp IP-ADDRESS MAC-ADDRESS VNI REMOTE-VTEP Interface Status Age --------------- ----------------- -------- --------------- ---------- ------- ---- 10.1.1.2 00:1e:c9:bb:c0:3c 10 te-1/1/1 Dynamic 135 30.1.1.2 00:0c:29:77:8b:15 30 2.2.2.2 Static admin@R2# run show vxlan arp IP-ADDRESS MAC-ADDRESS VNI REMOTE-VTEP Interface Status Age --------------- ----------------- -------- --------------- ---------- ------- ---- 10.1.1.2 00:1e:c9:bb:c0:3c 10 1.1.1.1 Static 30.1.1.2 00:0c:29:77:8b:15 30 ge-1/1/1 Dynamic 168
- Run the command run show vxlan address-table to display the VXLAN address table.
admin@R1# run show vxlan address-table VNID MAC address Type Interface VTEP ----------- ----------------- ------- ---------------- --------------- 10 00:1e:c9:bb:c0:3c Dynamic te-1/1/1 30 00:0c:29:77:8b:15 Dynamic 2.2.2.2 30 00:50:56:65:5c:b2 Dynamic 2.2.2.2 Entries in access port: 1 Entries in network port: 2 admin@R2# run show vxlan address-table VNID MAC address Type Interface VTEP ----------- ----------------- ------- ---------------- --------------- 10 00:1e:c9:bb:c0:3c Dynamic 1.1.1.1 30 00:0c:29:77:8b:15 Dynamic ge-1/1/1 30 00:50:56:65:5c:b2 Dynamic ge-1/1/1 Entries in access port: 2 Entries in network port: 1
- To check the VXLAN tunnels on either devices, run the command run show vxlan tunnel.
admin@R1# run show vxlan tunnel Total number of tunnels: 2 VNI 10, Encap:service-vlan-delete, Decap:service-vlan-per-port src addr:1.1.1.1, dst addr:2.2.2.2, state:UP traffic type:all Vtep type:EVPN nexthops:40.94.0.1 output ports:te-1/1/15 VNI 30, Encap:service-vlan-delete, Decap:service-vlan-per-port src addr:1.1.1.1, dst addr:2.2.2.2, state:UP traffic type:all Vtep type:EVPN nexthops:40.94.0.1 output ports:te-1/1/15 admin@R2# run show vxlan tunnel Total number of tunnels: 2 VNI 10, Encap:service-vlan-delete, Decap:service-vlan-per-port 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-1/1/15 VNI 30, Encap:service-vlan-delete, Decap:service-vlan-per-port 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-1/1/15
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