ExpressRoute Limits
This document outlines the limits and constraints for Azure ExpressRoute. Understanding these limits is crucial for designing and implementing your ExpressRoute connectivity effectively.
General Limits
The following table details general limits that apply to ExpressRoute circuits and configurations.
| Limit Type | Limit Value | Description |
|---|---|---|
| Maximum circuits per subscription | 10 | The default maximum number of ExpressRoute circuits you can create in a single Azure subscription. This can be increased by contacting Azure Support. |
| Maximum peerings per circuit | 3 | A circuit can have a maximum of three peerings: Azure public, Azure private, and Microsoft peering. |
| Maximum VNet connections per circuit | 40 (Standard SKU) / Unlimited (Premium SKU) | The number of virtual networks that can be connected to a single ExpressRoute circuit. Premium SKU offers unlimited connections for VNets within the same region. |
| Maximum ExpressRoute gateways per VNet | 1 | Each virtual network can have at most one ExpressRoute gateway. |
| Maximum concurrent BGP sessions | 4,000 | This limit applies to the total number of BGP sessions across all peerings for a given circuit. |
Bandwidth Limits
ExpressRoute offers various dedicated bandwidths. The maximum bandwidth you can provision depends on your ExpressRoute SKU and connectivity provider.
| SKU | Available Bandwidths (Mbps) |
|---|---|
| Standard | 50, 100, 200, 300, 400, 500, 1000, 2000 |
| Premium | 50, 100, 200, 300, 400, 500, 1000, 2000, 5000, 10000 |
Note: The actual available bandwidths are subject to your service provider's offerings. Always confirm with your connectivity provider.
Peering Limits
Specific limits apply to each peering type.
| Peering Type | Maximum Prefixes Advertised (IPv4) | Maximum Prefixes Advertised (IPv6) | Description |
|---|---|---|---|
| Azure Private Peering | 4,000 | 1,000 | For connecting to Azure services within your VNets. Supports both IPv4 and IPv6. |
| Azure Public Peering | 400 | N/A | For connecting to Azure public services (e.g., Storage, SQL Database). Primarily IPv4. |
| Microsoft Peering | 200 | N/A | For connecting to Microsoft 365 services. Primarily IPv4. |
Tip: For private peering, consider aggregating your address spaces to stay within the prefix limits. The Premium SKU increases these limits.
Service Limits
Limits related to specific ExpressRoute services and features:
- FastPath: Not available for ExpressRoute Global Reach.
- Direct Connection: Service Provider is responsible for terminating the connection.
Azure ExpressRoute Premium Add-on
The Premium add-on significantly increases limits and offers additional features:
- Increased number of VNets per circuit.
- Increased number of peerings per circuit.
- Increased number of routes advertised.
- Global Reach capability.
- Higher SLA guarantees.
Considerations
- Limits can change over time. Always refer to the latest Azure documentation.
- Contact Azure Support for requests to increase subscription-level limits.
- Ensure your network infrastructure and configuration align with these limits to avoid unexpected disruptions.