Offer Centralized Services to L3VPN Customers¶

Preparing The Lab¶

Log into the LabAccess jumpserver:
1. Type labs, or select Option 97 to get to the Additional Labs menu.
2. Type or select the option for mesh-topology-evpn-labs in order to get to the EVPN labs.
3. Type centsvc in this menu to configure the topology with the necessary prerequisites.

Lab Tasks¶

The Centralized Service is attached to Service Provider node EOS3. These will be our PE node. Since this Centralized Service will be accessed via a Layer 3 VPN Service, create an isolated VRF for its traffic and use EVPN to advertise the customer networks to other interested PEs.
1. Create a VRF Instance called SVC on EOS3.
  
  Note
  
  While this service will be accessed by Customers attached to other PEs, we will leverage EVPN to allow for inter-VRF communication and only require the SVC VRF where the node attaches to the Service Provider network.
```
vrf instance SVC
!
ip routing vrf SVC
```
2. Place the interface attached to the CE node for the Centralized Service into VRF SVC on EOS3 to ensure its traffic remains isolated.
```
interface Ethernet6
    vrf SVC
    ip address 10.3.20.3/24
```
3. Now leverage BGP EVPN to advertise reachability of any routes learned in VRF SVC from the Centralized Service by setting an RD and an RT within BGP on EOS3. It should have a unique RD following the format of Loopback0 IP:5 and the RT on all routers in the VPN should be 5:5.
  
  Note
  
  Unlike our previous L3VPN setups, for the Centralized Service model, we will only need to export the routes learned in the SVC VRF with this RT. In a later step, we will see how inter-VRF route-leaking can be controlled using a separate RT for import.
```
router bgp 100
    !
    vrf SVC
        rd 3.3.3.3:5
        route-target export evpn 5:5
```
4. Finally, define the BGP peer facing the Centralized Service node for route exchange into the VRF on EOS3. The CE node (EOS20) will use BGP ASN 500.
```
router bgp 100
    !
    vrf SVC
        neighbor 10.3.20.20 remote-as 500
        neighbor 10.3.20.20 maximum-routes 12000
        !
        address-family ipv4
            neighbor 10.3.20.20 activate
```
Now that the PE node is configured, configure CE node EOS20 for Layer 3 attachment to the Service Provider network.
1. Configure the BGP peerings to the PE devices on EOS20 ensuring that the router’s Loopback0 address is advertised to the attached PE.
```
router bgp 500
    router-id 20.20.20.20
    neighbor 10.3.20.3 remote-as 100
    neighbor 10.3.20.3 maximum-routes 12000
    network 20.20.20.20/32
```
2. Verify the BGP peering is active but that no routes have been learned from the PE.
```
show ip bgp summary
show ip bgp detail
show ip route
```
With the Centralized Service attached to the Service Provider network, configure restricted access to the service IP of 20.20.20.20 without using ACLs, allowing only EOS12 and EOS19 to access the Service.
1. First, define a new RT of 500:500 that will be used for importing routes from EOS12 and EOS19 into the SVC VRF on EOS3.
  
  Note
  
  The PE Nodes attached to Customer-1 and Customer-2 will handle the export of the routes for EOS12 and EOS19 with the proper RT, so on EOS3 we only need to worry about importing EVPN Type-5 routes with 500:500 into the Centralized Services VRF.
```
router bgp 100
    !
    vrf SVC
        route-target import evpn 500:500
```
2. Now, export the route for 12.12.12.12/32 from the Customer-1 VRF on PE nodes EOS1 and EOS6 using the RT of 500:500. To ensure only the route for EOS12 is exported on the PEs, use a Route-Map and Prefix-List to control application of the RT.
  
  Info
  
  Applying the route-map to the EVPN export statement will allow 500:500 to be tagged onto the EVPN Type-5 route in addition to the Customer-1 default RT of 1:1.
```
ip prefix-list SVC-ACCESS seq 10 permit 12.12.12.12/32
!
route-map EXPORT-TO-SVC permit 10
    match ip address prefix-list SVC-ACCESS
    set extcommunity rt 500:500 additive
!
route-map EXPORT-TO-SVC permit 20
!
router bgp 100
    !
    vrf CUSTOMER-1
        route-target export evpn route-map EXPORT-TO-SVC
```
3. Similarly, on EOS7, configure a Route-Map and Prefix-List to export the route for EOS19, 19.19.19.19/32, with the RT of 500:500.
```
ip prefix-list SVC-ACCESS seq 10 permit 19.19.19.19/32
!
route-map EXPORT-TO-SVC permit 10
    match ip address prefix-list SVC-ACCESS
    set extcommunity rt 500:500 additive
!
route-map EXPORT-TO-SVC permit 20
!
router bgp 100
    !
    vrf CUSTOMER-4
        route-target export evpn route-map EXPORT-TO-SVC
```
4. Now, allow PEs EOS1 and EOS6 to import the route for the Centralized Service with the RT of 5:5 into the VRF for Customer-1.
  
  Info
  
  This will allow the PEs to advertise the route for the Centralized Service, 20.20.20.20/32, to the attached CE nodes.
```
router bgp 100
    !
    vrf CUSTOMER-1
        route-target import evpn 5:5
```
5. Finally, repeat the above step on EOS7 to import the Centralized Service route into the VRF for Customer 4.
```
router bgp 100
    !
    vrf CUSTOMER-4
        route-target import evpn 5:5
```

Testing¶

With the necessary inter-VRF route leaking configuration in place, validate the EOS12 and EOS19 can reach the Centralized Service while other CE nodes for the Customers cannot.
1. View the routing tables of EOS12 and EOS19 to ensure the route for the Centralized Service, 20.20.20.20/32 is present.
  
  Note
  
  EOS19 will receive the route directly via the BGP peering to the adjacent PE node. EOS12 will have the route received via OSPF where it was redistributed by the Customer-1 CE nodes EOS11 and EOS13.
```
show ip route 20.20.20.20
```
2. Verify connectivity from EOS12 and EOS19 to the Centralized Service at 20.20.20.20 from each router’s Loopback0 IP.
  
  EOS12
```
ping 20.20.20.20 source 12.12.12.12
```
  EOS19
```
ping 20.20.20.20 source 19.19.19.19
```
3. Display the routing table of EOS20 to ensure only the routes for the allowed Customer nodes are present.
  
  Note
  
  Only routes for the Loopback0 interfaces of EOS12 and EOS19 should be learned from the Service Provider network.
```
show ip route bgp
```
4. Confirm that other Customer-1 and Customer-2 nodes cannot access the Centralized Service.
  
  Note
  
  EOS11 and EOS13 will have the route for the Centralized Service, but since the Centralized Service does not have a return route, no connections can be completed. Other customer nodes will not have the route at all.
```
show ip route bgp
ping 20.20.20.20 source **<Loopback0 IP>**
```
On the Service Provider network, verify that the Centralized Service routes and approved Customer node routes are being exchanged with the proper EVPN and MPLS information.
1. On EOS3, verify the incoming routes for forwarding path for EOS12 and EOS19 from the SVC VRF.
  
  Info
  
  The EVPN routes have two RTs attached to them; one from the standard L3VPN export and one from the Route-Map to ensure it is imported properly into the SVC VRF. Since the Route-Map has the additive keyword, it will allow both to be present and not overwrite.
```
show bgp evpn route-type ip-prefix ipv4 detail | section 500:500
show ip route vrf SVC
```
2. On EOS6, verify the incoming routes for forwarding path for EOS20 from the CUSTOMER-1 VRF.
```
show bgp evpn route-type ip-prefix ipv4 detail | section 5:5
show ip route vrf CUSTOMER-1
```

Success

Lab Complete!