Prior to NSX Advanced Load Balancer version 21.1.4, the placement of BGP virtual services is limited to a maximum of four distinct peer networks and was not label-aware. In the event of more than four distinct peer networks, the Controller chose any four networks randomly out of the same.

Starting with NSX Advanced Load Balancer version 21.1.4, the virtual service placement is done based on the BGP peer label configuration.

Use Case 1

A virtual service VIP with a label X, for instance, can only be placed on SE’s having BGP peering with peers containing label X.

VRF

BGP Peer Labels

VSVIP BGP Peer Labels

Network 1

Label 1

Label 1

Network 2

Label 2

Label 2

Network 3

Label 3

Label 3

Network 4

Label 4

Label 4

Network 5

Label 5

In this case, the virtual service is placed on Network 1, Network 2, Network 3, and Network 4.

Use Case 2

A virtual service VIP with no labels can be placed on SE’s having BGP peering with peers in any subnet. That is, if the BGP peer has labels but BGP virtual service VIP does not have a label, the virtual service VIP is advertised to be placed on all peer NICs (maximum of four distinct peer networks).

VRF

BGP Peer Labels

VSVIP BGP Peer Labels

Network 1

Label 1

Network 2

Label 2

Network 3

Label 3

Network 4

Label 4

Network 5

Label 5

In this case, the virtual service is randomly placed on any one of the four networks.

Use Case 3

If the virtual service VIP is updated to associate a label later, the SE receives the virtual service SE_List update, the VIP is withdrawn from all the other peers and is placed only on the NIC pertaining to the peer with the matching label (disruptive update). For instance, the initial configuration can be done as below:

VRF

BGP Peer Labels

VSVIP BGP Peer Labels

Network 1

Label 1

Label 1

Network 2

Label 2

Label 2

Network 3

Label 3

Label 3

Network 4

Label 4

Network 5

Label 5
Note:

Updates done on the VS VIP to associate the labels will lead to disruptive update of the virtual service.

The updated configuration is as shown below:

VRF

BGP Peer Labels

VSVIP BGP Peer Labels

Network 1

Label 1

Label 1

Network 2

Label 2

Label 2

Network 3

Label 3

Label 3

Network 4

Label 4

Label 4

Network 5

Label 5

Use Case 4

If the label is removed from the virtual service and the virtual service VIP is left with no label, then the virtual service VIP is placed on all the peer - NICs (maximum of four distinct peer networks).

Use Case 5

  • If the virtual service VIP is created with labels for which there is no matching peer, VS VIP creation is blocked due to invalid configuration, whether it is at the time of creating the virtual service or if the virtual service VIP label is updated later.

    VRF

    BGP Peer Labels

    VSVIP BGP Peer Labels

    Network 1

    Label 1

    Label 5

    Network 2

    Label 2

    Network 3

    Label 3

    Network 4

    Label 4

In this case, since there are no matching VS VIP BGP-peer labels, VS VIP creation is blocked with No BGP Peer exists with matching labels error.