Explanation
Why the waste happens and who it affects.
The Metered plan has a lower monthly port fee and charges every GB of outbound data at a per-GB rate set by the peering location zone. The Unlimited plan has a much higher monthly fee with all outbound data included. The plan is chosen once at circuit creation, usually from an early traffic estimate, and then rarely revisited even as replication, backup, analytics or migration traffic from Azure to on-premises grows or shrinks.
A circuit on Metered whose outbound volume has grown can pay more in per-GB charges than the Unlimited premium would cost, and that gap can be closed in place. The reverse, a circuit on Unlimited that now sends little data, is also common but harder to fix, because Microsoft does not support changing a circuit from Unlimited to Metered. Separately, when all the Azure regions a circuit serves are local to its peering location, ExpressRoute Local includes unlimited data at a lower price than Standard Unlimited.
Billing model
The pricing dimensions that drive this cost.
Inbound data is included on every plan; the data plan decides how outbound data is charged.
- Metered data plan
- A fixed monthly port fee by bandwidth plus a per-GB charge for all outbound data, priced by the zone of the peering location
- Unlimited data plan
- A single higher fixed monthly port fee by bandwidth with all inbound and outbound data included; Global Reach is excluded and billed separately
- ExpressRoute Local
- Includes an Unlimited data plan, is offered from 1 Gbps, and gives access only to one or two Azure regions in or near the peering location's metro
- Plan change rules
- Metered to Unlimited can be changed in place without downtime; Unlimited to Metered is not supported, and bandwidth cannot be downgraded
How to detect
5 checks to find it in your estate.
- In Cost Management, filter to the ExpressRoute service and split each circuit's cost into the port fee and the outbound data transfer meter to get monthly outbound GB and cost per Metered circuit
- For each Metered circuit, compare the monthly port fee plus outbound data charges with the Unlimited fee for the same bandwidth and SKU on the pricing page; circuits where the Metered total consistently exceeds the Unlimited fee are on the wrong plan
- For each Unlimited circuit, chart BitsOutPerSecond (split by PeeringType) over several months to estimate outbound GB and price it under the Metered plan to see how much the included data is actually worth
- Identify circuits whose connected virtual networks are all in the one or two Azure regions local to the peering location, which are candidates for ExpressRoute Local if bandwidth is 1 Gbps or more
- Record the zone of each circuit's peering location, since per-GB rates differ by zone and change the break-even
How to fix
4 ways to remove the waste.
- Switch Metered circuits whose outbound charges regularly exceed the Unlimited premium to the Unlimited plan on the circuit's Configuration page; this change is supported in place
- For Unlimited circuits with low outbound volume, weigh the savings against the cost of replacing the circuit, since moving to Metered requires a new circuit and coordination with the connectivity provider, and plan it with the next bandwidth or provider change
- Where all traffic is to local regions, move Standard or Premium circuits to the Local SKU using Azure PowerShell or Azure CLI (not available in the portal), after confirming no remote-region connectivity is needed
- Review data plan fit at least annually and whenever large replication, backup or migration flows from Azure to on-premises start or end
Documentation
Vendor references for pricing and configuration.