EVPN Overlay

Posted on Oct 2, 2025

EVPN Overlay Example

Spine 1


router bgp 65000
   router-id 5.5.5.5
   no bgp default ipv4-unicast
   distance bgp 20 200 200
   maximum-paths 3 ecmp 3
   neighbor LEAFOVERLAY peer group
   neighbor LEAFOVERLAY next-hop-unchanged
   neighbor LEAFOVERLAY update-source Loopback0
   neighbor LEAFOVERLAY ebgp-multihop
   neighbor LEAFOVERLAY send-community
   neighbor LEAFOVERLAY maximum-routes 0
   neighbor 1.1.1.1 peer group LEAFOVERLAY
   neighbor 1.1.1.1 remote-as 65001
   neighbor 1.1.1.1 description Leaf1
   neighbor 2.2.2.2 peer group LEAFOVERLAY
   neighbor 2.2.2.2 remote-as 65001
   neighbor 2.2.2.2 description LEAF2
   neighbor 3.3.3.3 peer group LEAFOVERLAY
   neighbor 3.3.3.3 remote-as 65002
   neighbor 3.3.3.3 description LEAF3
   neighbor 4.4.4.4 peer group LEAFOVERLAY
   neighbor 4.4.4.4 remote-as 65003
   neighbor 4.4.4.4 description LEAF4
   neighbor 10.10.1.2 remote-as 65001
   neighbor 10.10.1.2 description Leaf1
   neighbor 10.10.1.2 maximum-routes 12000
   neighbor 10.10.1.6 remote-as 65001
   neighbor 10.10.1.6 description Leaf2
   neighbor 10.10.1.6 maximum-routes 12000
   neighbor 10.10.1.10 remote-as 65002
   neighbor 10.10.1.10 description Leaf3
   neighbor 10.10.1.10 maximum-routes 12000
   neighbor 10.10.1.14 remote-as 65003
   neighbor 10.10.1.14 description Leaf4
   neighbor 10.10.1.14 maximum-routes 12000
   !
   address-family evpn
      neighbor LEAFOVERLAY activate  //activate neighbors for evpn
   !
   address-family ipv4
      neighbor 10.10.1.2 activate
      neighbor 10.10.1.6 activate
      neighbor 10.10.1.10 activate
      neighbor 10.10.1.14 activate
      network 5.5.5.5/32              //Loopback advertised in IPv4 for reachability

Leaf 1

router bgp 65001
   router-id 1.1.1.1
   no bgp default ipv4-unicast
   distance bgp 20 200 200
   maximum-paths 3 ecmp 3
   neighbor SPINEOVERLAY peer group
   neighbor SPINEOVERLAY remote-as 65000
   neighbor SPINEOVERLAY update-source Loopback0
   neighbor SPINEOVERLAY ebgp-multihop
   neighbor SPINEOVERLAY send-community extended
   neighbor SPINEOVERLAY maximum-routes 0
   neighbor 5.5.5.5 peer group SPINEOVERLAY
   neighbor 6.6.6.6 peer group SPINEOVERLAY
   neighbor 10.10.1.1 remote-as 65000
   neighbor 10.10.1.1 maximum-routes 12000
   neighbor 10.10.2.1 remote-as 65000
   neighbor 10.10.2.1 maximum-routes 12000
   neighbor 172.16.4.2 remote-as 65001
   neighbor 172.16.4.2 next-hop-self
   neighbor 172.16.4.2 maximum-routes 12000
   !
   address-family evpn
      neighbor SPINEOVERLAY activate
   !
   address-family ipv4
      neighbor 10.10.1.1 activate
      neighbor 10.10.2.1 activate
      network 1.1.1.1/32
  • Note that the spines are in their own AS, so you can set this on the LEAF’s for copy/paste. Don’t do this on the spines, as the leafs are in different AS'

Verification

  • Verify evpn neighbors using:
show bpg evpn summ
  • Spines should form a neighborship with all of the leaves, and leafs with all of the spines.
Leaf1(config-router-bgp-af)#sho bgp evpn summ
BGP summary information for VRF default
Router identifier 1.1.1.1, local AS number 65001
Neighbor Status Codes: m - Under maintenance
  Neighbor V AS           MsgRcvd   MsgSent  InQ OutQ  Up/Down State   PfxRcd PfxAcc PfxAdv
  5.5.5.5  4 65000             16        16    0    0 00:05:40 Estab   0      0      0
  6.6.6.6  4 65000             13        13    0    0 00:05:40 Estab   0      0      0
Spine1(config-router-bgp-af)#show bgp evpn summ
BGP summary information for VRF default
Router identifier 5.5.5.5, local AS number 65000
Neighbor Status Codes: m - Under maintenance
 Description              Neighbor V AS           MsgRcvd   MsgSent  InQ OutQ  Up/Down State   PfxRcd PfxAcc PfxAdv
 Leaf1                    1.1.1.1  4 65001             16        16    0    0 00:05:31 Estab   0      0      0
 LEAF2                    2.2.2.2  4 65001             15        16    0    0 00:05:22 Estab   0      0      0
 LEAF3                    3.3.3.3  4 65002             16        16    0    0 00:05:10 Estab   0      0      0
 LEAF4                    4.4.4.4  4 65003             15        15    0    0 00:05:00 Estab   0      0      0