Azure Route Server

This blog is a part of 2 series blog post on Azure Route Server. In this blog, we will understand what is Azure Route Server, supported Network Design scenarios, its pre-requisites and its benefits. In second blog post, I showcase you how to configure Azure Route Server. 

Azure Route Server is a fully managed new offering from Microsoft (is under Preview) that simplifies routing management in your Azure infrastructure, especially if you have a Network Virtual Appliance or NVA. It simplifies the dynamic routing between your Virtual Network and NVA which support BGP protocol & SD networking.

When we provision Azure Route Server, in the background it creates a VMSS which provides high availability to the service. If it is deployed in an Azure region which supports Zone Redundancy, it places the VM's into the Availability Zone to maintain the high availability of the service. It will pick up the first 2 IP from the subnet as soon as the Azure Route Service is deployed.

 There are multiple Architecture Design Patterns can be used to deploy Azure Route Server.

• Support for typical hub and spoke network topology is available. We can host Azure Route Server along with NVA inside the HUB Network.
• Route Server can also be hosted in the Dual Homed Network. Under Dual Homed Network a spoke virtual network is peered to 2 Hub virtual network. 

It eliminates the need to manually configure or maintain route tables.

Azure Route Server can support route sharing with:

•  Network Virtual Appliance or NVA
• ExpressRoute
• Azure VPN Gateway

You can enable or disable the route exchange on the Azure Route Server. Also, you don't need to manually configure or maintain route tables.

With NVAs, it allows you to exchange routing information directly through Border Gateway Protocol (BGP) routing protocol between any NVA that supports the BGP routing protocol and the Azure Virtual Network.

Pre-requisite

•  Azure Route Server can be deployed to an existing or new Virtual Network within its empty dedicated subnet by the name of "RouteServerSubnet".
• A minimum of /27 or higher subnet is required.
• NVA should allow BGP protocol to leverage the benefits of having the Azure Route Server.

Benefits

• Azure Route Server simplifies the configuration, management, and deployment of your NVA in your virtual network.
• You no longer need to manually update the routing table on your NVA whenever your virtual network addresses are updated.
• You no longer need to update User-Defined Routes manually whenever your NVA announces new routes or withdraw old ones.
• You can peer multiple instances of your NVA with Azure Route Server.
• The interface between NVA and Azure Route Server is based on a common standard protocol i.e. BGP.
• You can deploy Azure Route Server in any of your new or existing virtual networks.

 In the next blog post, we will create an Azure Route Server in the Azure portal.