Microsoft Azure ExpressRoute Redundancy Modes

PurposeMicrosoft Azure ExpressRoute is designed to support high availability (HA) network architectures that provide more resilient connectivity to Microsoft resources. With Equinix Fabric, you can implement various options for HA or non-HA network architectures.

For more details from Microsoft, see Designing for high availability with ExpressRoute.

The following diagram shows the recommended architecture for the maximum network availability of an ExpressRoute circuit, as described in Options 4 and 4a below.

Azure ExpressRoute Concepts

An Azure ExpressRoute (ER) Service Key (SK) can be used for provisioning all the VLANs (also known as Fabric Virtual Connections) that are associated with the configured ExpressRoute Circuit.

Active or provisioned SKs can be modified to increase bandwidth and support changes between metered and unmetered plans.

Between one and four VLANs can be deployed, depending on the customer’s redundancy requirements and interest in an Azure ExpressRoute Service Level Agreement (SLA).

There are currently two peering types (routing domains) available for ExpressRoute:

  • Azure Private

  • Microsoft Peering

Note: Azure Public Peering has been deprecated and is not accounted for in the VLAN count above. Some existing customers might still have Azure Public peering VLANs for up to six VLANs (VCs) total.

For more information on Azure ExpressRoute peering types, see ExpressRoute circuits and peering.

Service Level Agreement

Azure ExpressRoute customers must have redundant BGP sessions within each peering type to receive the Azure ExpressRoute SLA.

Microsoft Azure does not require ExpressRoute customers to maintain redundant BGP sessions unless the customer wants Microsoft Azure to honor the Azure ExpressRoute Service Level Agreement.

A customer can receive the Azure ExpressRoute SLA even if there is a single Fabric port connected to their router, but the SLA is provided only if they have redundant BGP sessions. For more details, see SLA for Azure ExpressRoute.

Note: A single port, with both primary and secondary are configured on the same port, means that failure of the port impacts both connections.

Customer Fabric Port Configuration

The NNIs (Z-side) between the Azure ER Microsoft Enterprise Edge (MSEE) routers and the Fabric routers are configured for 802.1ad (QinQ) port encapsulation. Equinix Fabric customer-facing UNI ports (A-side) can be configured as 802.1ad (QinQ) or 802.1Q encapsulation.

QinQ Equinix Fabric Ports

If a customer has QinQ port encapsulation, up to two Virtual Connections (S-tagged VLANs) can be created per service key. However, we recommend that a customer take advantage of both S-tag and C-tag VLANs if they have QinQ ports. This means that only two VLANs (Virtual Connections) are required and billed for by Equinix.

If one or more 802.1ad (QinQ) ports are configured on the A-side, each peering type, Azure Private and Microsoft Peering, requires a unique S-Tag when using one Fabric port. If two ports are deployed, S-Tags can be the same or unique. (C-Tags are not visible to the Equinix Fabric, and are passed transparently to Microsoft). Customers define the S-Tags when creating VCs on Equinix Fabric. C-Tags much match the VLANs configured on the Azure side when ExpressRoute was ordered. Z-side S-Tags are dynamically created by Azure.

Dot1Q Equinix Fabric Ports

If one or more 802.1Q ports are configured on the A-side, each VLAN must be unique when using only one Fabric port. If two ports are deployed, VLANs can be the same for Primary and Secondary VCs or they can all be unique. This means that a single ExpressRoute Circuit (primary and secondary connections) will have up to four unique VLANs if both peering types are required.

If the customer port is Dot1Q encapsulation, a user must specify the desired peering type (Microsoft or Private). The user must also sync BGP in the Fabric portal once the Layer 2 connectivity has been established and the BGP peering configurations have been entered in the Azure Resource Manager portal.

After completing BGP peering on the Microsoft portal, your connection status will become Provisioned in the Equinix Fabric portal in approximately 15-20 minutes. This process can be accelerated if you select your connection in the Connections Inventory, then select Sync BGP peering for immediate provisioning.

Billing Policy on Fabric

Only two Local (metro) VCs are billed, even if a customer has one or more .1Q ports with both peering types configured with the same Service Key.

Remote VCs are always billed, regardless of port encapsulation. For example:

  • .1Q port(s) with 2 peering types = 4 VCs = 2 billing VCs

  • QinQ port(s) with 2 peering types = 2 VCs = 2 billing VCs

  • .1Q port(s) with 2 peering types (remote connections) = 4 VCs = 4 billing VCs

    (That is, 4 remote VC charges + 2 metro/local VC charges)

Deployment Options Through the Equinix Fabric Portal

Option 1 – Single Peering Type – dot1Q Fabric Port

This diagram shows a Service Key (SK) used to create one VC.

Fabric billing summary – 1 Fabric Port + 1 VC

Option 1a – Single Peering Type – dot1Q Fabric Port

In this diagram, an SK is used to create two VCs.

Fabric billing summary – 1 Fabric Port + 2 VCs

Option 1b – Single Peering Type – QinQ Fabric Port

This diagram shows an SK used to create two VCs (S-Tag VLANs).

Fabric billing summary – 1 Fabric Port + 2 VCs

Option 2 – Two Peering Types – dot1Q Fabric Port

In this diagram, an SK is used to create four VCs (VLANs).

Fabric billing summary – 1 Fabric Port + 2 VCs

Option 3 – Single Peering Type – dot1Q Fabric Ports

Here, an SK is used to create two VCs (VLANs) for high availability.

Fabric billing summary – 2 Fabric Ports + 2 VCs

Option 3a – Single Peering Type – QinQ Fabric Ports

In this diagram, an SK is used to create 2 VCs (S-Tag VLANs) for high availability.

Fabric billing summary – 2 Fabric Ports + 2 VCs

Option 4 – Two Peering Types – dot1Q Fabric Ports

This diagram shows an SK used to create four VCs (VLANs) for high availability.

Fabric billing summary – 2 Fabric Ports + 2 VCs

Option 4a – Two Peering Types – QinQ Fabric Ports

Here, an SK is used to create two VCs (S-Tag VLANs) for high availability.

Fabric billing summary – 2 Fabric Ports + 2 VCs