Configuring Multi-Site

This chapter contains the following sections:

About VXLAN EVPN Multi-Site

The VXLAN EVPN Multi-Site solution interconnects two or more BGP-based Ethernet VPN (EVPN) sites/fabrics (overlay domains) in a scalable fashion over an IP-only network. This solution uses border gateways (BGWs) in anycast or vPC mode to terminate and interconnect two sites. The BGWs provide the network control boundary that is necessary for traffic enforcement and failure containment functionality.

In the BGP control plane, BGP sessions between the BGWs rewrite the next hop information of EVPN routes and reoriginate them.

VXLAN Tunnel Endpoints (VTEPs) are only aware of their overlay domain internal neighbors, including the BGWs. All routes external to the fabric have a next hop on the BGWs for Layer 2 and Layer 3 traffic.

The BGW is the node that interacts with nodes within a site and with nodes that are external to the site. For example, in a leaf-spine data center fabric, it can be a leaf, a spine, or a separate device acting as a gateway to interconnect the sites.

The VXLAN EVPN Multi-Site feature can be conceptualized as multiple site-local EVPN control planes and IP forwarding domains interconnected via a single common EVPN control and IP forwarding domain. Every EVPN node is identified with a unique site-scope identifier. A site-local EVPN domain consists of EVPN nodes with the same site identifier. BGWs on one hand are also part of the site-specific EVPN domain and on the other hand a part of a common EVPN domain to interconnect with BGWs from other sites. For a given site, these BGWs facilitate site-specific nodes to visualize all other sites to be reachable only via them. This means:

  • Site-local bridging domains are interconnected only via BGWs with bridging domains from other sites.

  • Site-local routing domains are interconnected only via BGWs with routing domains from other sites.

  • Site-local flood domains are interconnected only via BGWs with flood domains from other sites.

Selective Advertisement is defined as the configuration of the per-tenant information on the BGW. Specifically, this means IP VRF or MAC VRF (EVPN instance). In cases where external connectivity (VRF-lite) and EVPN Multi-Site coexist on the same BGW, the advertisements are always enabled.

Guidelines and Limitations for VXLAN EVPN Multi-Site

VXLAN EVPN Multi-Site has the following configuration guidelines and limitations:

  • VXLAN EVPN Multi-Site is not supported on Cisco Nexus 9500 platform switches with -R line cards.

  • Support for VXLAN EVPN Multi-Site functionality on the Cisco Nexus N9K-C9336C-FX and N9K-C93240YC-FX2 is added. N9K-C9348GC-FXP does not support VXLAN EVPN Multi-Site functionality.

  • VXLAN EVPN Multi-Site and Tenant Routed Multicast (TRM) is supported between source and receivers deployed in the same site.

  • The Multi-Site border gateway allows the co-existence of Multi-Site extensions (Layer 2 unicast/multicast and Layer 3 unicast) as well as Layer 3 unicast and multicast external connectivity.

  • The following switches support VXLAN EVPN Multi-Site:

    • Cisco Nexus 9300-EX, 9300-FX, and 9500 platform switches with X9700-EX line cards


      Note

      The Cisco Nexus 9348GC-FXP switch does not support VXLAN EVPN Multi-Site functionality.

    • Cisco Nexus 9396C switch and Cisco Nexus 9500 platform switches with X9700-FX line cards

    • Cisco Nexus 9336C-FX2 switch

  • In a VXLAN EVPN multisite deployment, when you use the ttag feature, make sure that the ttag is stripped (ttag-strip ) on BGW's DCI interfaces that connect to the cloud. To elaborate, if the ttag is attached to non-Nexus 9000 devices that do not support ether-type 0x8905, stripping of ttag is required. However, BGW back-to-back model of DCI does not require ttag stripping.

  • The number of border gateways per site is limited to four.

  • Beginning with Cisco NX-OS Release 9.2(1), Border Gateways (BGWs) in a vPC topology are supported.

  • Support for Multicast Flood Domain between inter-site/fabric border gateways is not supported.

  • Multicast Underlay between sites is not supported.

  • iBGP EVPN Peering between border gateways of different fabrics/sites is not supported.

  • The peer-type fabric-external command configuration is required only for VXLAN Multi-site BGWs (this command must not be used when peering with non-Cisco equipment).


    Note

    The peer-type fabric-external command configuration is not required for pseudo BGWs.

  • Anycast mode can support up to four border gateway's per site.

  • Anycast mode can only support Layer 3 services attached to local interfaces.

  • In Anycast mode, BUM is replicated to each border-leaf and DF election, between border leafs of a particular site decides which border leaf would forward the traffic inter-site traffic (Fabric to DCI and vice versa) for that site.

  • In Anycast mode, all the Layer 3 services are advertised in BGP via EVPN Type-5 routes with their physical IP as the next hop.

  • vPC mode can support only two border gateways.

  • vPC mode can support both Layer 2 hosts and Layer 3 services on local interfaces.

  • In vPC mode, BUM is replicated to either of the border-gateway’s for traffic coming from external site and hence both the border gateways are forwarders for site external to site internal (DCI to Fabric) direction.

  • In vPC mode, BUM is replicated to either of the border gateways for traffic coming from the local site leaf for a VLAN using Ingress Replication (IR) underlay. Both border gateways are forwarders for site internal to site external ( Fabric to DCI) direction for VLANs using the IR underlay.

  • In vPC mode, BUM is replicated to both border gateways for traffic coming from the local site leaf for a VLAN using the multicast underlay. Therefore, a decapper/forwarder election happens and the decapsulation winner/forwarder only forwards the site-local traffic to external site border-gateways for VLANs using the multicast underlay.

  • In vPC mode, all the Layer 3 services/attachments are advertised in BGP via EVPN Type-5 routes with their virtual IP as next hop. If the VIP/PIP feature is configured, they are advertised with PIP as the next hop.

  • If different Anycast Gateway MAC addresses are configured across sites, ARP suppression must be enabled for all VLANs that have been extended.

  • Bind NVE to a loopback address that is separate from loopback addresses that are required by Layer 3 protocols. A best practice is to use a dedicated loopback address for the NVE source interface (PIP VTEP) and Multi-Site source interface (anycast and virtual IP VTEP).

  • PIM BiDir is not supported for fabric underlay multicast replication with VXLAN Multi-Site.

  • PIM is not supported on multisite VXLAN DCI links.

  • FEX is not supported on a vPC BGW and Anycast BGW.

  • To improve the convergence in case of fabric link failure and avoid issues in case of fabric link flapping, ensure to configure multi-hop BFD between loopbacks of spines and BGWs.

    In the specific scenario where a BGW node becomes completely isolated from the fabric due to all its fabric links failing, the use of multi-hop BFD ensures that the BGP sessions between the spines and the isolated BGW can be immediately brought down, without relying on the configured BGP hold-time value.

  • For SVI-related triggers (such as shut/unshut or PIM enable/disable), a 30-second delay was added, allowing the Multicast FIB (MFIB) Distribution module (MFDM) to clear the hardware table before toggling between L2 and L3 modes or vice versa.

Enabling VXLAN EVPN Multi-Site

This procedure enables the VXLAN EVPN Multi-Site feature. Multi-Site is enabled on the BGWs only. The site-id must be the same on all BGWs in the fabric/site.

Procedure

  Command or Action Purpose

Step 1

configure terminal

Example:

switch# configure terminal

Enters global configuration mode.

Step 2

evpn multisite border-gateway ms-id

Example:

switch(config)# evpn multisite border-gateway 100

Configures the site ID for a site/fabric. The range of values for ms-id is 1 to 2,814,749,767,110,655. The ms-id must be the same in all BGWs within the same fabric/site.

Step 3

interface nve 1

Example:

switch(config-evpn-msite-bgw)# interface nve 1

Creates a VXLAN overlay interface that terminates VXLAN tunnels.

Note

 

Only one NVE interface is allowed on the switch.

Step 4

source-interface loopback src-if

Example:

switch(config-if-nve)# source-interface loopback 0

The source interface must be a loopback interface that is configured on the switch with a valid /32 IP address. This /32 IP address must be known by the transient devices in the transport network and the remote VTEPs. This requirement is accomplished by advertising it through a dynamic routing protocol in the transport network.

Step 5

host-reachability protocol bgp

Example:

switch(config-if-nve)# host-reachability protocol bgp

Defines BGP as the mechanism for host reachability advertisement.

Step 6

multisite border-gateway interface loopback vi-num

Example:

switch(config-if-nve)# multisite border-gateway interface loopback 100

Defines the loopback interface used for the BGW virtual IP address (VIP). The border-gateway interface must be a loopback interface that is configured on the switch with a valid /32 IP address. This /32 IP address must be known by the transient devices in the transport network and the remote VTEPs. This requirement is accomplished by advertising it through a dynamic routing protocol in the transport network. This loopback must be different than the source interface loopback. The range of vi-num is from 0 to 1023.

Step 7

no shutdown

Example:

switch(config-if-nve)# no shutdown

Negates the shutdown command.

Step 8

exit

Example:

switch(config-if-nve)# exit

Exits the NVE configuration mode.

Step 9

interface loopback loopback-number

Example:

switch(config)# interface loopback 0

Configures the loopback interface.

Step 10

ip address ip-address

Example:

switch(config-if)# ip address 198.0.2.0/32

Configures the IP address for the loopback interface.

Multi-Site with vPC Support

About Multi-Site with vPC Support

The BGWs can be in a vPC complex. In this case, it is possible to support dually-attached directly-connected hosts that might be bridged or routed as well as dually-attached firewalls or service attachments. The vPC BGWs have vPC-specific multihoming techniques and do not rely on EVPN Type 4 routes for DF election or split horizon.

Guidelines and Limitations for Multi-Site with vPC Support

Multi-Site with vPC support has the following configuration guidelines and limitations:

  • 4000 VNIs for vPC are not supported.

  • For BUM with continued VIP use, the MCT link is used as transport upon core isolation or fabric isolation, and for unicast traffic in fabric isolation.

  • The routes to remote Multisite BGW loopback addresses must always prioritize the DCI link path over the iBGP protocol between vPC Border Gateway switches configured using the backup SVI. The backup SVI should be used strictly in the event of a DCI link failure.

Configuring Multi-Site with vPC Support

This procedure describes the configuration of Multi-Site with vPC support:

  • Configure vPC domain.

  • Configure port channels.

  • Configuring vPC Peer Link.

Procedure

  Command or Action Purpose

Step 1

configure terminal

Example:

switch# configure terminal

Enters global configuration mode.

Step 2

feature vpc

Example:

switch(config)# feature vpc

Enables vPCs on the device.

Step 3

feature interface-vlan

Example:

switch(config)# feature interface-vlan

Enables the interface VLAN feature on the device.

Step 4

feature lacp

Example:

switch(config)# feature lacp

Enables the LACP feature on the device.

Step 5

feature pim

Example:

switch(config)# feature pim

Enables the PIM feature on the device.

Step 6

feature ospf

Example:

switch(config)# feature ospf

Enables the OSPF feature on the device.

Step 7

ip pim rp-address address group-list range

Example:

switch(config)# ip pim rp-address 100.100.100.1 group-list 224.0.0/4

Defines a PIM RP address for the underlay multicast group range.

Step 8

vpc domain domain-id

Example:

switch(config)# vpc domain 1

Creates a vPC domain on the device and enters vpn-domain configuration mode for configuration purposes. There is no default. The range is from 1 to 1000.

Step 9

peer switch

Example:

switch(config-vpc-domain)# peer switch

Defines the peer switch.

Step 10

peer gateway

Example:

switch(config-vpc-domain)# peer gateway

Enables Layer 3 forwarding for packets destined to the gateway MAC address of the vPC.

Step 11

peer-keepalive destination ip-address

Example:

switch(config-vpc-domain)# peer-keepalive destination 172.28.230.85

Configures the IPv4 address for the remote end of the vPC peer-keepalive link.

Note

 

The system does not form the vPC peer link until you configure a vPC peer-keepalive link.

The management ports and VRF are the defaults.

Step 12

ip arp synchronize

Example:

switch(config-vpc-domain)# ip arp synchronize

Enables IP ARP synchronize under the vPC domain to facilitate faster ARP table population following device reload.

Step 13

ipv6 nd synchronize

Example:

switch(config-vpc-domain)# ipv6 nd synchronize

Enables IPv6 ND synchronization under the vPC domain to facilitate faster ND table population following device reload.

Step 14

Create the vPC peer-link.

Example:

switch(config)# interface port-channel 1
switch(config)# switchport
switch(config)# switchport mode trunk
switch(config)# switchport trunk allowed vlan 1,10,100-200
switch(config)# mtu 9216
switch(config)# vpc peer-link
switch(config)# no shut

switch(config)# interface Ethernet 1/1, 1/21
switch(config)# switchport
switch(config)# mtu 9216
switch(config)# channel-group 1 mode active
switch(config)# no shutdown

Creates the vPC peer-link port-channel interface and adds two member interfaces to it.

Step 15

system nve infra-vlans range

Example:

switch(config)# system nve infra-vlans 10

Defines a non-VXLAN-enabled VLAN as a backup routed path.

Step 16

vlan number

Example:

switch(config)# vlan 10

Creates the VLAN to be used as an infra-VLAN.

Step 17

Create the SVI.

Example:

switch(config)# interface vlan 10
switch(config)# ip address 10.10.10.1/30
switch(config)# ip router ospf process UNDERLAY area 0
switch(config)# ip pim sparse-mode
switch(config)# no ip redirects
switch(config)# mtu 9216
switch(config)# no shutdown

Creates the SVI used for the backup routed path over the vPC peer-link.

Step 18

(Optional) delay restore interface-vlan seconds

Example:

switch(config-vpc-domain)# delay restore interface-vlan 45
(Optional)

Enables the delay restore timer for SVIs. We recommend tuning this value when the SVI/VNI scale is high. For example, when the SCI count is 1000, we recommend that you set the delay restore to 45 seconds.

Step 19

evpn multisite border-gateway ms-id

Example:

switch(config)# evpn multisite border-gateway 100

Configures the site ID for a site/fabric. The range of values for ms-id is 1 to 281474976710655. The ms-id must be the same in all BGWs within the same fabric/site.

Step 20

interface nve 1

Example:

switch(config-evpn-msite-bgw)# interface nve 1

Creates a VXLAN overlay interface that terminates VXLAN tunnels.

Note

 

Only one NVE interface is allowed on the switch.

Step 21

source-interface loopback src-if

Example:

switch(config-if-nve)# source-interface loopback 0

Defines the source interface, which must be a loopback interface with a valid /32 IP address. This /32 IP address must be known by the transient devices in the transport network and the remote VTEPs. This requirement is accomplished by advertising the address through a dynamic routing protocol in the transport network.

Step 22

host-reachability protocol bgp

Example:

switch(config-if-nve)# host-reachability protocol bgp

Defines BGP as the mechanism for host reachability advertisement.

Step 23

multisite border-gateway interface loopback vi-num

Example:

switch(config-if-nve)# multisite border-gateway interface loopback 100

Defines the loopback interface used for the BGW virtual IP address (VIP). The BGW interface must be a loopback interface that is configured on the switch with a valid /32 IP address. This /32 IP address must be known by the transient devices in the transport network and the remote VTEPs. This requirement is accomplished by advertising the address through a dynamic routing protocol in the transport network. This loopback must be different than the source interface loopback. The range of vi-num is from 0 to 1023.

Step 24

no shutdown

Example:

switch(config-if-nve)# no shutdown

Negates the shutdown command.

Step 25

exit

Example:

switch(config-if-nve)# exit

Exits the NVE configuration mode.

Step 26

interface loopback loopback-number

Example:

switch(config)# interface loopback 0

Configures the loopback interface.

Step 27

ip address ip-address

Example:

switch(config-if)# ip address 198.0.2.0/32

Configures the primary IP address for the loopback interface.

Step 28

ip address ip-address secondary

Example:

switch(config-if)# ip address 198.0.2.1/32 secondary

Configures the secondary IP address for the loopback interface.

Step 29

ip pim sparse-mode

Example:

switch(config-if)# ip pim sparse-mode

Configures PIM sparse mode on the loopback interface.

Configuring Peer Link as Transport in Case of Link Failure

This procedure describes the configuration of an SVI interface configured with a high IGP cost to ensure it is only used as a backup link.


Note

This configuration is required to use the peer link as a backup link during fabric and/or DCI link failures.

Procedure

  Command or Action Purpose

Step 1

configure terminal

Example:

switch# configure terminal

Enters global configuration mode.

Step 2

system nve infra-vlans vlan-range

Example:

switch(config)# system nve infra-vlans 10

Specifies VLANs used by all SVI interfaces for uplink and vPC peer-links in VXLAN as infra-VLANs. You should not configure certain combinations of infra-VLANs. For example, 2 and 514, 10 and 522, which are 512 apart.

Step 3

interface vlan-id

Example:

switch(config)# interface vlan10

Configures the interface.

Step 4

no shutdown

Example:

switch(config-if)# no shutdown

Negates the shutdown command.

Step 5

mtu value

Example:

switch(config-if)# mtu 9216

Sets the maximum transmission unit (MTU).

Step 6

no ip redirects

Example:

switch(config-if)# no ip redirects

Prevents the device from sending redirects.

Step 7

ip address ip-address/length

Example:

switch(config-if)# ip address 35.1.1.2/24

Configures an IP address for this interface.

Step 8

no ipv6 redirects

Example:

switch(config-if)# no ipv6 redirects

Disables the ICMP redirect messages on BFD-enabled interfaces.

Step 9

ip ospf cost cost

Example:

switch(config-if)# ip ospf cost 100

Configures the OSPF cost metric for this interface.

Step 10

ip ospf network point-to-point

Example:

switch(config-if)# ip ospf network point-to-point

Specifies the OSPF point-to-point network.

Step 11

ip router ospf instance area area-number

Example:

switch(config-if)# ip router ospf 1 area 0.0.0.0

Configures the routing process for the IP on an interface and specifies an area.

Step 12

ip pim sparse-mode

Example:

switch(config-if)# ip pim sparse-mode

Configures sparse-mode PIM on an interface.

Verifying the Multi-Site with vPC Support Configuration

To display Multi-Site with vPC support information, enter one of the following commands:

show vpc brief

Displays general vPC and CC status.

show vpc consistency-parameters global

Displays the status of those parameters that must be consistent across all vPC interfaces.

show vpc consistency-parameters vni

Displays configuration information for VNIs under the NVE interface that must be consistent across both vPC peers.

Output example for the show vpc brief command: 

switch# show vpc brief
Legend:
                (*) - local vPC is down, forwarding via vPC peer-link
 
vPC domain id                     : 1  
Peer status                       : peer adjacency formed ok     (<--- peer up)
vPC keep-alive status             : peer is alive                
Configuration consistency status  : success (<----- CC passed)
Per-vlan consistency status       : success                       (<---- per-VNI CCpassed)
Type-2 consistency status         : success
vPC role                          : secondary                    
Number of vPCs configured         : 1  
Peer Gateway                      : Enabled
Dual-active excluded VLANs        : -
Graceful Consistency Check        : Enabled
Auto-recovery status              : Enabled, timer is off.(timeout = 240s)
Delay-restore status              : Timer is off.(timeout = 30s)
Delay-restore SVI status          : Timer is off.(timeout = 10s)
Operational Layer3 Peer-router    : Disabled
[...]

Output example for the show vpc consistency-parameters global command: 

switch# show vpc consistency-parameters global
 
    Legend:
        Type 1 : vPC will be suspended in case of mismatch
 
Name                        Type  Local Value            Peer Value            
-------------               ----  ---------------------- -----------------------
[...]
Nve1 Adm St, Src Adm St,    1     Up, Up, 2.1.44.5, CP,  Up, Up, 2.1.44.5, CP,
Sec IP, Host Reach, VMAC          TRUE, Disabled,        TRUE, Disabled,      
Adv, SA,mcast l2, mcast           0.0.0.0, 0.0.0.0,      0.0.0.0, 0.0.0.0,    
l3, IR BGP,MS Adm St, Reo         Disabled, Up,          Disabled, Up,        
                                  200.200.200.200        200.200.200.200
[...]

Output example for the show vpc consistency-parameters vni command: 

switch(config-if-nve-vni)# show vpc consistency-parameters vni
 
    Legend:
        Type 1 : vPC will be suspended in case of mismatch
 
Name                        Type  Local Value            Peer Value            
-------------               ----  ---------------------- -----------------------
Nve1 Vni, Mcast, Mode,      1     11577, 234.1.1.1,      11577, 234.1.1.1,    
Type, Flags                       Mcast, L2, MS IR       Mcast, L2, MS IR      
Nve1 Vni, Mcast, Mode,      1     11576, 234.1.1.1,      11576, 234.1.1.1,    
Type, Flags                       Mcast, L2, MS IR       Mcast, L2, MS IR
[...]

Configuring VNI Dual Mode

This procedure describes the configuration of the BUM traffic domain for a given VLAN. Support exists for using multicast or ingress replication inside the fabric/site and ingress replication across different fabrics/sites.


Note

If you have multiple VRFs and only one is extended to ALL leaf switches, you can add a dummy loopback to that one extended VRF and advertise through BGP. Otherwise, you'll need to check how many VRFs are extended and to which switches, and then add a dummy loopback to the respective VRFs and advertise them as well. Therefore, use the advertise-pip command to prevent potential user errors in the future.

For more information about configuring multicast or ingress replication for a large number of VNIs, see Example of VXLAN BGP EVPN (EBGP).

Procedure

  Command or Action Purpose

Step 1

configure terminal

Example:

switch# configure terminal

Enters global configuration mode.

Step 2

interface nve 1

Example:

switch(config)# interface nve 1

Creates a VXLAN overlay interface that terminates VXLAN tunnels.

Note

 

Only one NVE interface is allowed on the switch.

Step 3

member vni vni-range

Example:

switch(config-if-nve)# member vni 200

Configures the virtual network identifier (VNI). The range for vni-range is from 1 to 16,777,214. The value of vni-range can be a single value like 5000 or a range like 5001-5008.

Note

 

Enter one of the Step 4 or Step 5 commands.

Step 4

mcast-group ip-addr

Example:

switch(config-if-nve-vni)# mcast-group 255.0.4.1

Configures the NVE Multicast group IP prefix within the fabric.

Step 5

ingress-replication protocol bgp

Example:

switch(config-if-nve-vni)# ingress-replication protocol bgp

Enables BGP EVPN with ingress replication for the VNI within the fabric.

Step 6

multisite ingress-replication

Example:

switch(config-if-nve-vni)# multisite ingress-replication

Defines the Multi-Site BUM replication method for extending the Layer 2 VNI.

Configuring Fabric/DCI Link Tracking

This procedure describes the configuration to track all DCI-facing interfaces and site internal/fabric facing interfaces. Tracking is mandatory and is used to disable reorigination of EVPN routes either from or to a site if all the DCI/fabric links go down.

Procedure

  Command or Action Purpose

Step 1

configure terminal

Example:

switch# configure terminal

Enters global configuration mode.

Step 2

interface ethernet port

Example:

switch(config)# interface ethernet1/1

Enters interface configuration mode for the DCI or fabric interface.

Note

 

Enter one of the following commands in Step 3 or Step 4.

Step 3

evpn multisite dci-tracking

Example:

switch(config-if)# evpn multisite dci-tracking

Configures DCI interface tracking.

Step 4

(Optional) evpn multisite fabric-tracking

Example:

switch(config-if)# evpn multisite fabric-tracking
 (Optional)

Configures EVPN Multi-Site fabric tracking.

The evpn multisite fabric-tracking is mandatory for anycast BGWs and vPC BGW fabric links.

Step 5

ip address ip-addr

Example:

switch(config-if)# ip address 192.1.1.1

Configures the IP address.

Step 6

no shutdown

Example:

switch(config-if)# no shutdown

Negates the shutdown command.

Configuring Fabric External Neighbors

This procedure describes the configuration of fabric external/DCI neighbors for communication to other site/fabric BGWs.

Procedure

  Command or Action Purpose

Step 1

configure terminal

Example:

switch# configure terminal

Enters global configuration mode.

Step 2

router bgp as-num

Example:

switch(config)# router bgp 100

Configures the autonomous system number. The range for as-num is from 1 to 4,294,967,295.

Step 3

neighbor ip-addr

Example:

switch(config-router)# neighbor 100.0.0.1

Configures a BGP neighbor.

Step 4

remote-as value

Example:

switch(config-router-neighbor)# remote-as 69000

Configures remote peer's autonomous system number.

Step 5

peer-type fabric-external

Example:

switch(config-router-neighbor)# peer-type fabric-external

Enables the next hop rewrite for Multi-Site. Defines site external BGP neighbors for EVPN exchange. The default for peer-type is fabric-internal .

Note

 

The peer-type fabric-external command is required only for VXLAN Multi-Site BGWs. It is not required for pseudo BGWs.

Step 6

address-family l2vpn evpn

Example:

switch(config-router-neighbor)# address-family l2vpn evpn

Configures the address family Layer 2 VPN EVPN under the BGP neighbor.

Step 7

rewrite-evpn-rt-asn

Example:

switch(config-router-neighbor)# rewrite-evpn-rt-asn

Rewrites the route target (RT) information to simplify the MAC-VRF and IP-VRF configuration. BGP receives a route, and as it processes the RT attributes, it checks if the AS value matches the peer AS that is sending that route and replaces it. Specifically, this command changes the incoming route target’s AS number to match the BGP-configured neighbor’s remote AS number. You can see the modified RT value in the receiver router.