Targets of a load balancer, identified by IP address or NIC IP configuration. A pool can't span VNets, and a Standard load balancer won't accept a VM that has a Basic public IP.
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Terms in this definition
- ELT
Extract, load, transform: raw data lands in the target system first and is transformed there. See ETL for the opposite order.
- NIC
Network interface card, the network interface of a VM; NSGs can be associated with it.
- IP configuration
NIC setting that carries a private IP, dynamic or static, and optionally a public one. NAT rules and backend pools on a load balancer refer to it.
- Span
One operation inside a trace, such as a single LLM call or prompt flow node, carrying attributes plus start and end times. Nested spans reveal the order of calls.
- Azure Load Balancer
Layer-4 load balancer operating within a region, with zone redundancy on the Standard SKU; it has no WAF, doesn't terminate TLS and can't route by URL.
- Basic
Low-cost Log Analytics table plan where ingestion is cheap but each query is charged per GB and runs at workspace scope. Full KQL and simple log search alerts are supported; standard log search alerts are not.
Related terms
- Basic Load Balancer
Load Balancer SKU retired on 30 September 2025. It was open by default, worked only with Basic public IPs and lacked zones and HA Ports, and its backend pool was confined to a single availability set, scale set or standalone VM.
- Cross-region load balancer
Global tier of Standard Load Balancer: a single anycast public IP fronts a backend pool made up of regional public Standard load balancers, and traffic goes to whichever healthy region is closest. Basic SKUs can't take part.
- Inbound NAT rule
Forwards one port on a frontend IP to the NIC of a single VM. No backend pool, load-balancing rule or health probe is needed, but the same frontend port cannot be used by two rules on one frontend IP.
- Load-balancing rule
In Azure Load Balancer, the rule that links a frontend IP and port to a backend pool, checked by a health probe. Traffic not covered by a rule is not forwarded.
- Outbound rules
With a Standard Load Balancer, these define explicit outbound SNAT so backend pool VMs reach out via the frontend public IPs.
- Request routing rule
Decides where traffic arriving on an Application Gateway listener goes. A basic rule forwards it to one backend pool with set backend settings; a path-based rule picks the pool from a URL path map.
- SNAT ports
Outbound SNAT relies on these ephemeral ports. About 64,000 come with each public frontend IP and are shared among all backend pool members, so adding frontend IPs or a prefix is the only way to get more.
- URL path-based routing
An Application Gateway rule type that chooses the backend pool from the request's URL path, such as /videos/* versus /images/*.