On a newly-deployed AHV cluster, what is the default virtual switch (vs0) uplink bond type?

Upon initial deployment, a Nutanix AHV cluster configures the default virtual switch (vs0) with an active-backup bond for its uplinks. In this mode, only one physical network interface in the bond is active at a time. If the active interface fails, traffic automatically fails over to a passive (standby) interface in the bond. This configuration is the default because it provides network redundancy and high availability without requiring any special configuration, such as LACP, on the upstream physical switches, ensuring maximum compatibility with various network environments.

A. Balance-SLB: This mode provides load balancing based on the source MAC address but is not the default; it must be configured manually.
C. Balance-TCP: This mode provides advanced load balancing but requires the physical switch ports to be configured for LACP, making it an optional, not default, configuration.
D. No Uplink Bond: An uplink bond is created by default to ensure network high availability for the CVM and host; not having a bond would introduce a single point of failure.

1. Nutanix AHV Administration Guide v6.5, Load Balancing in a Bond, Page 63: "By default, an AHV host configures the active-backup load balancing mode for all bonds. In active-backup mode, one NIC is active and the other NICs are passive."

2. Nutanix University, Nutanix Hybrid Cloud Fundamentals Courseware, Module 4: Networking, Section: "AHV Networking": The course material explicitly states that the default bond mode for a new AHV deployment is active-backup to ensure out-of-the-box compatibility and resilience.

3. Nutanix Networking Best Practices Guide, AHV Bond Modes, Section: "Active-Backup": "This is the default bond mode in AHV. Active-backup provides a simple active/passive configuration that is tolerant of link failure."