Configuring the NFVI Distributed Gateway Function (BGP EVPN over E2E SR Tunnels)
In the NFVI telco cloud solution, the NFVI distributed gateway function allows mobile phone traffic to be processed by vUGWs and vMSEs and transmitted over a DCN through E2E SR tunnels as well as being transmitted within a DCN in load balancing mode.
Usage Scenario
The NFVI telco cloud solution uses the DCI+DCN networking. A large amount of mobile phone traffic is sent to vUGWs and vMSEs on the DCN. After being processed by the vUGWs and vMSEs, the mobile phone traffic is forwarded over the DCN to destination devices on the Internet. The destination devices send traffic to mobile phones in similar ways. To achieve these functions and ensure traffic load balancing on the DCN, you need to deploy the NFVI distributed gateway function.
Figure 3-155 shows the networking of an NFVI distributed gateway (BGP EVPN over E2E SR tunnels). DC-GWs, which are the border gateways of the DCN, exchange Internet routes with external devices over PEs. L2GW/L3GW1 and L2GW/L3GW2 are connected to VNFs. VNF1 and VNF2 that function as virtualized NEs are deployed to implement the vUGW functions and vMSE functions, respectively. VNF1 and VNF2 are each connected to L2GW/L3GW1 and L2GW/L3GW2 through IPUs.
Establish BGP VPN peer relationships between VNFs and DC-GWs so that the VNFs can advertise mobile phone routes (UE IP) to DC-GWs.
On L2GW/L3GW1 and L2GW/L3GW2, configure static VPN routes with the IP addresses of VNFs as the destination addresses and the IP addresses of IPUs as next-hop addresses.
- Deploy EVPN RRs which can be either a standalone device or a DC-GW. In this section, BGP EVPN peer relationships are established between all L2GW/L3GWs, PEs, and DC-GWs, DC-GWs are deployed as RRs to reflect EVPN routes, and other devices function as RR clients. The functions of a BGP EVPN RR are as follows:
DC-GWs can reflect the mobile phone routes learned by VNFs to L2GW/L3GWs and PEs so that mobile phone routes can be transmitted outside the DCN and the traffic sent to mobile phone users can be introduced to the DCN. Route-policies need to be configured DC-GWs so that the mobile phone routes sent by DC-GWs to L2GW/L3GWs and PEs carry the gateway addresses which are VNFs' loopback addresses.
DC-GWs receive the IP prefix routes destined for VNFs from an L2GW/L3GW based on BGP EVPN peer relationships and reflect the IP prefix routes to PEs and other L2GWs/L3GWs. The EVPN RR can also be used to synchronize the MAC or ARP routes of IPUs and the IP prefix routes destined for VNFs between L2GW/L3GWs.
Configure static default routes on PEs and use the EVPN RRs to reflect the static default routes to L2GW/L3GWs.
Deploy SR tunnels between PEs and L2GW/L3GWs and between DC-GWs and L2GW/L3GWs to carry service traffic.
The traffic transmitted between mobile phones and the Internet over VNFs is north-south traffic. The traffic transmitted between VNF1 and VNF2 is east-west traffic. To achieve load balancing of east-west traffic and north-south traffic, deploy the load balancing function on DC-GWs and L2GW/L3GWs.
The NFVI distributed gateway function supports both IPv4 and IPv6 services. If a step does not differentiate IPv4 and IPv6 services, this step applies to both IPv4 and IPv6 services.
Pre-configuration Tasks
Before configuring the NFVI distributed gateway function, complete the following tasks:
Allow the routes between PEs and DC-GWs and between DC-GWs and L2GW/L3GWs to be reachable.
Deploy SR tunnels between PEs and L2GW/L3GWs and between DC-GWs and L2GW/L3GWs.
Configure the BD EVPN function on DC-GWs and L2GW/L3GWs. The configuration includes creating EVPN instances and L3VPN instances, establishing BGP EVPN peer relationships, and configuring VBDIF interfaces. On DC-GWs, the configuration involves only creating L3VPN instances and establishing BGP EVPN peer relationships.
Configure the static routes destined for VNF1 and VNF2 on L2GW/L3GWs by referring to Static VPN IPv4 Routes or Static VPN IPv6 Routes.
Configuring Route Recursion over SR Tunnels
By default, routes are recursed to a BD EVPN or BGP VPNv4/VPNv6 network over MPLS LDP tunnels. If SR tunnels are used to carry service traffic, the function to recurse routes over SR tunnels must be configured.
Context
You can configure a tunnel policy or an SR-MPLS BE tunnel-preferred policy to recurse routes over SR tunnels.
Procedure
- Configure a tunnel policy on PEs, DC-GWs, and L2GW/L3GWs and apply the tunnel policy. You can choose to recurse routes over SR-MPLS BE or SR-MPLS TE tunnels. For configuration details, see Configuring and Applying a Tunnel Policy.
- Configure an SR-MPLS BE tunnel-preferred policy on PEs, DC-GWs, and L2GW/L3GWs so that users can choose to recurse routes over SR-MPLS BE tunnels.
Configuring Route Advertisement on PEs
The route advertisement function allows PEs to advertise default static routes to L2GW/L3GWs through BGP EVPN RRs.
Procedure
- Run system-view
The system view is displayed.
- Create a route-policy to filter and modify the advertised and received routes. For configuration details, see Configuring a Route-Policy. You can run the apply gateway-ip none or apply ipv6 gateway-ip none command to delete gateway addresses from the VNF routes received from L2GW/L3GWs so that the routes sent from PEs to VNFs can be recursed over SR tunnels, instead of being forwarded based on gateway addresses.
- Configure default static VPN routes.
Run the ip route-static vpn-instance vpn-instance-name 0.0.0.0 { 0.0.0.0 | 0 } { nexthop-address | interface-type interface-number [ nexthop-address ] } [ tag tag ] command to create a default static VPN IPv4 route.
Run the ipv6 route-static vpn-instance vpn-instance-name :: 0 { nexthop-ipv6–address | interface-type interface-number [ nexthop-ipv6-address ] } [ tag tag ] command to create a default static VPN IPv6 route.
- Run ip vpn-instance vpn-instance-name
The VPN instance view is displayed.
- Enter the IPv4 or IPv6 address family view of the VPN instance.
Run the ipv4-family command to enter the IPv4 address family view of the VPN instance.
Run the ipv6-family command to enter the IPv6 address family view of the VPN instance.
- Run import route-policy policy-name evpn
The L3VPN instance is bound to an import route-policy. This route-policy is used to filter the routes received by the L3VPN instance so that the gateway addresses are deleted from the routes received from L2GW/L3GWs.
- Run quit
Exit from the IPv4 or IPv6 address family view of the VPN instance.
- Run quit
Exit from the VPN instance view.
- Run bgp { as-number-plain | as-number-dot }
The BGP view is displayed.
- Enter the IPv4 or IPv6 address family view of a BGP-VPN instance.
Run the ipv4-family vpn-instance vpn-instance-name command to enter the IPv4 address family view of a BGP-VPN instance.
Run the ipv6-family vpn-instance vpn-instance-name command to enter the IPv6 address family view of a BGP-VPN instance.
- Run network { 0.0.0.0 0 | :: 0 }
Default static VPN routes are imported to the IPv4 or IPv6 address family of the BGP-VPN instance.
- Run advertise
l2vpn evpn
The function to advertise IP routes from the VPN instance to the EVPN instance is enabled.
- Run quit
Exit from the IPv4 or IPv6 address family view of the BGP-VPN instance.
- Run quit
Exit from the BGP view.
- Run commit
The configuration is committed.
Configuring Route Advertisement on DC-GWs
Route advertisement can be configured on DC-GWs to allow the DC-GWs to construct their own forwarding entries based on the received EVPN routes.
Procedure
- Configure DC-GWs to advertise the VPN loopback routes and the mobile phone routes received from VNFs through EVPN.
- Establish BGP VPN peer relationships between DC-GWs and VNFs.
- Configure RRs in BGP EVPN so that EVPN routes can be synchronized between L2GW/L3GWs and the EVPN routes sent by L2GW/L3GWs can be reflected to PEs.
- Run commit
The configuration is committed.
Configuring Route Advertisement on L2GW/L3GWs
Route advertisement can be configured on L2GW/L3GWs to allow the L2GW/L3GWs to construct their own forwarding entries based on the received EVPN or BGP routes.
Verifying the Configurations of the NFVI DistributedGateway Function
After configuring the NFVI distributed gateway function, verify the configurations. On DC-GWs, you can view the VPN peer relationships between DC-GWs and VNFs and the information about the mobile phone routes received from VNFs.
Procedure
- Run the display bgp { vpnv4 | vpnv6 } vpn-instance vpn-instance-name peer command on DC-GWs to check whether the VPN peer relationships have been established between DC-GWs and VNFs.
- Run the display bgp vpnv4 vpn-instance vpn-instance-name routing-table or display bgp vpnv6 vpn-instance vpn-instance-name routing-table command on DC-GWs to check whether DC-GWs can receive mobile phone routes from VNFs and whether the next-hop addresses of the mobile phone routes are VNF addresses.
- Run the display ip routing-table vpn-instance vpn-instance-name or display ipv6 routing-table vpn-instance vpn-instance-name command on DC-GWs to check whether the VPN routing tables of DC-GWs include mobile phone routes and whether the outbound interfaces of the mobile phone routes are VBDIF interfaces.