A standard load balancer continuously uses the data path from within a region to the load balancer frontend, to the network that supports your VM. As long as healthy instances remain, the measurement follows the same path as your application's load-balanced traffic. The data path in use is validated. The measurement is invisible to your application and doesn't interfere with other operations.

A value of 100% indicates that the data path is very stable for the load balancer operations. A value of 0% indicates that the data path is unstable.

A standard load balancer uses a distributed health-probing service that monitors your application endpoint's health according to your configuration settings. This metric provides an aggregate or per-endpoint filtered view of each instance endpoint in the load balancer pool. You can see how load balancer views the health of your application, as indicated by your health probe configuration.

A very high value is desired for this measure.

A standard load balancer reports the data processed per front end. You may notice that the bytes aren’t distributed equally across the backend instances. This is expected as the Azure Load Balancer algorithm is based on flows.

A high value for this measure indicates that the data transmission is high.

A standard load balancer reports the packets processed per front end.

A standard load balancer doesn't terminate Transmission Control Protocol (TCP) connections or interact with TCP or User Data-gram Packet (UDP) flows. Flows and their handshakes are always between the source and the VM instance. To better troubleshoot your TCP protocol scenarios, you can make use of SYN packets counters to understand how many TCP connection attempts are made. The metric reports the number of TCP SYN packets that were received.

A standard load balancer reports the number of outbound flows that are masqueraded to the Public IP address frontend. SNAT ports are an exhaustible resource. This metric can give an indication of how heavily your application is relying on SNAT for outbound originated flows. Counters for successful and failed outbound SNAT flows are reported. The counters can be used to troubleshoot and understand the health of your outbound flows.

The values reported by this measure and its numeric equivalents are mentioned in the table below:

Note:

By default, this measure reports the Measure Values listed in the table above to indicate the current Provisioning state of Load Balancer.

The IP address of the Azure Load Balancer. It's the point of contact for clients. These IP addresses can be either public IP Address or private IP Address.

Use the detailed diagnosis of this measure to know the Name, IP address, Rules count and Rules (Name:Type).

The group of virtual machines or instances in a virtual machine scale set that is serving the incoming request.

Use the detailed diagnosis of this measure to know the Backend pool, Resource name:Resource status:IP address:Network interface:Availability zone, Rules count and Rules (Name:Type).

A health probe is used to determine the health status of the instances in the backend pool. This health probe will determine if an instance is healthy and can receive traffic.

Use the detailed diagnosis of this measure to know the Name, Protocol, Port, Path, Used by and Rules (Name:Type).

A load balancer rule is used to define how incoming traffic is distributed to all the instances within the backend pool. A load-balancing rule maps a given frontend IP configuration and port to multiple backend IP addresses and ports. Load Balancer rules are for inbound traffic only.

Use the detailed diagnosis of this measure to know the Name, Load balancing rule, Backend pool and Health probe.

An inbound NAT rule forwards incoming traffic sent to frontend IP address and port combination. The traffic is sent to a specific virtual machine or instance in the backend pool. Port forwarding is done by the same hash-based distribution as load balancing.

Use the detailed diagnosis of this measure to know the Name, Frontend IP, Frontend port and Service.

An outbound rule configures outbound Network Address Translation (NAT) for all virtual machines or instances identified by the backend pool. This rule enables instances in the backend to communicate (outbound) to the internet or other endpoints.