Route advertisement received from EVPN peer is not installed on the T0-VRF routing table
Article ID: 374319
Updated On:
Products
Issue/Introduction
After a dataplane restart or an edge reboot, you may notice that EVPN traffic is being dropped. Upon inspecting the VRF VNI on the service router, you might observe that the interface is displayed as either "downlink" or "uplink" rather than br-interface.
Example of Non-Working Configuration:
edge(tier0_sr[2])> get vrf vni
VRF VNI VxLAN IF L3-SVI State Rmac
VRF-100 1000 vxlan-1000 br-1000 Up 02:50:56:00:00:0b
VRF-101 1001 vxlan-1001 downlink-89 Up 02:50:56:56:44:42
VRF-102 1002 vxlan-1002 br-1002 Up 02:50:56:00:00:0b
VRF-103 1003 vxlan-1003 br-1003 Up 02:50:56:00:00:0b
VRF-104 1004 vxlan-1004 br-1004 Up 02:50:56:00:00:0b
In a working EVPN VRF configuration, all SVI entries should be displayed as br-id.
Example of Working Configuration:
VRF VNI VxLAN IF L3-SVI State Rmac
VRF-100 1000 vxlan-1000 br-1000 Up 02:50:56:00:00:0b
VRF-101 1001 vxlan-1001 br-1001 Up 02:50:56:56:44:42
VRF-102 1002 vxlan-1002 br-1002 Up 02:50:56:00:00:0b
VRF-103 1003 vxlan-1003 br-1003 Up 02:50:56:00:00:0b
VRF-104 1004 vxlan-1004 br-1004 Up 02:50:56:00:00:0b
Environment
VMware NSX
Cause
The issue occurs because the SVI interfaces of the T0-VRF are expected to use a bridge interface, such as br-1001. However, the SVI interface has been incorrectly updated to "uplink" or "downlink." This typically happens when there is a collision between the interface indexes of kni-lport-eth0 and a bridge interface.
In this scenario, kni-lport-eth0 and br-1001 have the same interface index. Interface indexes are generated by the Linux Kernel and are unique within their own namespace but not across different namespaces. kni-lport-eth0 is created in the default namespace, while user interfaces like downlinks, uplinks, VXLAN, and bridge interfaces are created in the plr_sr namespace. Since the EVPN control plane is only aware of the plr_sr namespace, it incorrectly updates the SVI interface to "downlink-89," a sub-interface of kni-lport-eth0.
To validate the issue, use the following command:
#show evpn vni detail
The SVI interface should point to a bridge interface. In cases where it points to an uplink interface, as shown below, the configuration is incorrect.
Example of Non-Working VNI Interface:
VNI: 1001
Type: L3
Tenant VRF: VRF-101
Local Vtep IP: 10.196.103.130
VxLAN Intf: vxlan-358021
SVI If: uplink-downlink-89 -----> This should be br-1001 Interface
Example of Working VNI Interface:
VNI: 1001
Type: L3
Tenant VRF: VRF-101
Local Vtep IP: 10.196.103.130
VxLAN Intf: vxlan-358091
SVI If: br-1001 -----> Correct Interface
State: Up
VNI Filter: none
Router MAC: 02:50:56:00:74:00
L2 VNIs:
Resolution
Although a dataplane restart or edge reboot may resolve the issue, this is not the recommended solution. Instead, it is advisable to place the edge into maintenance mode and then exit maintenance mode. This issue has been addressed and fixed in the following releases:
3.2.4.0, 4.2.0 and 4.1.2.4
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