Configuring an IPv6 VXLAN Tunnel

Using BGP EVPN to establish an IPv6 VXLAN tunnel between VTEPs involves a series of operations. These include establishing a BGP EVPN peer relationship, configuring an EVPN instance, and configuring ingress replication.

Context

To enable BGP EVPN to establish IPv6 VXLAN tunnels in centralized gateway scenarios, complete the following tasks on the involved gateways:

Configure a BGP EVPN peer relationship. After the gateways on an IPv6 VXLAN establish such a relationship, they can exchange EVPN routes. If an RR is deployed on the network, each gateway only needs to establish a BGP EVPN peer relationship with the RR.
(Optional) Configure an RR. The deployment of RRs simplifies configurations because fewer BGP EVPN peer relationships need to be established. An existing device can be configured to also function as an RR, or a new device can be deployed for this specific purpose. Layer 3 gateways on an IPv6 VXLAN are generally used as RRs, and Layer 2 gateways used as RR clients.
Configure an EVPN instance. EVPN instances are used to receive and advertise EVPN routes.
Configure ingress replication. After ingress replication is configured on a VXLAN gateway, the gateway uses BGP EVPN to construct a list of remote VTEP peers that share the same VNI with itself. After the gateway receives BUM packets, its sends a copy of the BUM packets to each gateway in the list.

Currently, BUM packets can be forwarded only through ingress replication. This means that non-Huawei devices must have ingress replication configured to establish IPv6 VXLAN tunnels with Huawei devices. If ingress replication is not configured, the tunnels fail to be established.

Procedure

Configure a BGP EVPN peer relationship.
1. Run bgp as-number
  BGP is enabled, and the BGP view is displayed.
2. (Optional) Run router-id ipv4-address
  A router ID is set.
3. Run peer ipv6-address as-number as-number
  An IPv6 BGP peer is specified.
4. (Optional) Run peer ipv6-address connect-interface interface-type interface-number [ ipv6-source-address ]
  A source interface and a source IPv6 address used to set up a TCP connection with the BGP peer are specified.
  
  If loopback interfaces are used to establish a BGP connection, you are advised to run the peer connect-interface command on both ends of the link to ensure connectivity. If this command is run on only one end, the BGP connection may fail to be established.
5. (Optional) Run peer ipv6-address ebgp-max-hop [ hop-count ]
  The maximum number of hops allowed for establishing an EBGP EVPN peer relationship is configured.
  
  The default value of hop-count is 255. In most cases, a directly connected physical link must be available between EBGP EVPN peers. If you want to establish EBGP EVPN peer relationships between indirectly connected devices, run the peer ebgp-max-hop command. This command allows the devices to establish a TCP connection across multiple hops.
  
  When loopback interfaces are used to establish an EBGP EVPN peer relationship, the peer ebgp-max-hop command must be run, with hop-count being at least 2. Otherwise, the peer relationship fails to be established.
6. Run l2vpn-family evpn
  The BGP-EVPN address family view is displayed.
7. Run peer { group-name | ipv6-address } enable
  The device is enabled to exchange EVPN routes with a specified peer or peer group.
8. Run peer { group-name | ipv6-address } advertise encap-type vxlan
  The device is enabled to advertise EVPN routes that carry the VXLAN encapsulation attribute to the peer or peer group.
9. (Optional) Run peer { group-name | ipv6-address } route-policy route-policy-name { import | export }
  A route-policy is specified for routes to be received from or advertised to the BGP EVPN peer or peer group.
  
  The route-policy helps the device import or advertise only desired routes. It facilitates route management and reduces the routing table size and system resource consumption.
10. (Optional) Run peer { group-name | ipv6-address } mac-limit number [ percentage ] [ alert-only | idle-forever | idle-timeout times ]
  The maximum number of MAC advertisement routes that can be imported from the peer or peer group is configured.
  
  If an EVPN instance imports many inapplicable MAC advertisement routes from a peer or peer group and they account for a large proportion of the total number of MAC advertisement routes, you are advised to run the peer { group-name | ipv6-address } mac-limit number [ percentage ] [ alert-only | idle-forever | idle-timeout times ] command. This command limits the maximum number of MAC advertisement routes that can be imported. If the imported MAC advertisement routes exceed the specified maximum number, the device displays an alarm, prompting you to check the validity of the MAC advertisement routes imported to the EVPN instance.
11. (Optional) Run peer peerIpv6Addr graceful-restart static-timer restart-time
  The maximum hold-off time for re-establishing BGP peer relationships, namely, the maximum duration from the time the local device finds that the peer device restarts to the time the local device re-establishes a BGP peer relationship with the peer device, is configured.
  Graceful restart (GR) prevents traffic interruption caused by the re-establishment of BGP peer relationships. To set the maximum hold-off time, run either of the following commands:
  - To set the maximum hold-off time for re-establishing all BGP peer relationships, run the graceful-restart timer restart command in the BGP view. The hold-off time can be set to 3600s at the most.
  - To set the maximum hold-off time for re-establishing a BGP EVPN peer relationship, run the peer graceful-restart static-timer command in the BGP view. Use this command if you want to set a hold-off time longer than 3600s.
  If both the graceful-restart timer restart time and peer graceful-restart static-timer commands are run, the peer graceful-restart static-timer command configuration takes precedence.
  
  This step can be performed only after GR has been enabled using the graceful-restart command in the BGP view.
12. (Optional) Run peer peerIpv6Addr path-attribute-treat attribute-id { id [ to id2 ] } &<1-255> { discard | withdraw | treat-as-unknown }
  A special mode for processing specified path attributes in received BGP EVPN Update messages is configured.
  A BGP EVPN Update message contains various path attributes. If a local device receives Update messages containing malformed path attributes, the involved BGP EVPN sessions may flap. To enhance reliability, you can configure a special mode for processing specified path attributes in received BGP EVPN Update messages. The special mode can be:
  - Discards the specified path attributes.
  - Withdraws the routes with the specified path attributes.
  - Processes the specified path attributes as unknown ones.
(Optional) Configure the Layer 3 gateway as an RR on the IPv6 VXLAN. If an RR is configured, each VXLAN gateway only needs to establish a BGP EVPN peer relationship with the RR. This simplifies configurations because fewer BGP EVPN peer relationships need to be established.
1. Run peer { ipv6-address | group-name } reflect-client
  The device is configured as an RR, and RR clients are specified.
2. (Optional) Run peer { group-name | ipv6-address } next-hop-invariable
  The device is enabled to keep the next hop address of a route unchanged when advertising the route to an EBGP EVPN peer.
3. Run undo policy vpn-target
  The device is disabled from filtering received EVPN routes based on VPN targets. If you do not perform this step, the RR will fail to receive and reflect the routes sent by clients.
4. Run quit
  Exit the BGP-EVPN address family view.
5. Run quit
  Exit the BGP view.
Configure an EVPN instance.
1. Run evpn vpn-instance vpn-instance-name bd-mode
  A BD EVPN instance is created, and the EVPN instance view is displayed.
2. Run route-distinguisher route-distinguisher
  An RD is configured for the EVPN instance.
3. Run vpn-target vpn-target &<1-8> [ both | export-extcommunity | import-extcommunity ]
  VPN targets are configured for the EVPN instance. The import and export VPN targets of the local end must be the same as the export and import VPN targets of the remote end, respectively.
4. (Optional) Run import route-policy policy-name
  The EVPN instance is associated with an import route-policy.
  
  Perform this step to associate the EVPN instance with an import route-policy and set attributes for eligible routes. This enables you to control routes to be imported into the EVPN instance more precisely.
5. (Optional) Run export route-policy policy-name
  The EVPN instance is associated with an export route-policy.
  
  Perform this step to associate the EVPN instance with an export route-policy and set attributes for eligible routes. This enables you to control routes to be advertised more precisely.
6. (Optional) Run mac limit number { simply-alert | mac-unchanged
  The maximum number of MAC addresses allowed in the EVPN instance is set.
  
  A device consumes more system resources as it learns more MAC addresses, meaning that the device may fail to operate when busy processing services. To limit the maximum number of MAC addresses allowed in an EVPN instance and thereby improving device security and reliability, run the mac limit command. After this configuration, if the number of MAC addresses exceeds the preset value, an alarm is triggered to prompt you to check the validity of existing MAC addresses.
7. (Optional) Run mac-route no-advertise
  The device is disabled from sending local MAC routes with the current VNI to the EVPN peer.
  
  In Layer 3 VXLAN gateway scenarios where Layer 2 traffic forwarding is not involved, perform this step to disable local MAC routes from being advertised to the EVPN peer. This configuration prevents the EVPN peer from receiving MAC routes, thereby conserving device resources.
8. (Optional) Run local mac-only-route no-generate
  The device is disabled from generating an EVPN MAC route when the local MAC address exists in both a MAC address entry and an ARP/ND entry.
  
  If a MAC address entry and an ARP/ND entry on the device both contain the local MAC address, the device generates both an EVPN MAC/IP route and an EVPN MAC route by default. To optimize memory utilization, perform this step so that the device generates only the EVPN MAC/IP route. To ensure normal Layer 2 traffic forwarding, also run the mac-ip route generate-mac command on the peer device to enable the function to generate MAC address entries based on MAC/IP routes.
9. (Optional) Run mac-ip route generate-mac
  The function to generate MAC address entries based on MAC/IP routes is enabled.
  
  If the peer device is configured not to advertise MAC routes (using the mac-route no-advertise command) or not to generate MAC routes (using the local mac-only-route no-generate command), the local device cannot generate MAC address entries by default. To ensure normal Layer 2 traffic forwarding, perform this step on the local device to enable the function to generate MAC entries based on MAC/IP routes.
10. Run quit
  Exit the EVPN instance view.
11. Run bridge-domain bd-id
  The BD view is displayed.
12. Run vxlan vni vni-id split-horizon-mode
  A VNI is created and associated with the BD, and split horizon is specified for packet forwarding.
13. Run evpn binding vpn-instance vpn-instance-name [ bd-tag bd-tag ]
  A specified EVPN instance is bound to the BD. By specifying different bd-tag values, you can bind multiple BDs to the same EVPN instance. In this way, VLAN services of different BDs can access the same EVPN instance while being isolated.
14. Run quit
  Return to the system view.
Configure ingress replication.
1. Run interface nve nve-number
  An NVE interface is created, and the NVE interface view is displayed.
2. Run source ipv6-address
  An IPv6 address is configured for the source VTEP.
3. Run vni vni-id head-end peer-list protocol bgp
  Ingress replication is configured.
  
  With this function, the ingress of an IPv6 VXLAN tunnel replicates and sends a copy of any received BUM packets to each VTEP in the ingress replication list (a collection of remote VTEP IPv6 addresses).
4. Run quit
  Return to the system view.
(Optional) Enable the device to add its router ID (a private extended community attribute) to locally generated EVPN routes.
1. Run evpn
  The global EVPN configuration view is displayed.
2. Run router-id-extend private enable
  The device is enabled to add its router ID to locally generated EVPN routes.
  
  If both IPv4 and IPv6 VXLAN tunnels need to be established between two devices, one device's IP address is repeatedly added to the ingress replication list of the other device while the IPv4 and IPv6 VXLAN tunnels are being established. As a result, each device forwards two copies of BUM traffic to its peer, leading to duplicate traffic. To address this problem, run the router-id-extend private enable command on each device. This enables the device to add its router ID to EVPN routes. After receiving the EVPN routes, the peer device checks whether they carry the same router ID. If they do, the EVPN routes are from the same device. In this case, the peer device adds only the IP address of the device whose EVPN routes carry the IPv4 VXLAN tunnel identifier to the ingress replication list, thereby preventing duplicate traffic.
Run commit
The configuration is committed.