Azure Express Route considerations

Hi peers,

we currently have an office in Amsterdam that has a fiber connection to a DataCenter (ELAN 1GB link). The datacenter runs ESX clusters VMs.

We also have a couple of regional offices (ASIA, US, Europe).

The regional offices all have a DMVPN router, there is also a DMVPN router in our dutch office and one in the DC running the VMs. So we have an Internet & I-WAN site-to-site type of network with regional links speed of 100Mbps for the most part. It works well for us.

All client VLANS are replicated with EIGRP so all client vlans can access each other and can access also the servers running in the dutch DC.

Since the dutch ESX cluster is shrinking in size and getting old, we want to migrate the VMs (around 40 VMs) to Azure and terminate our DC agreement and close the ELAN connection.

I have contacted a network provider that can offer us a fiber 1Gb port and quoted us for Express Route at different bandwith (100Mb,200,500,1GB,...). They don't offer BGP, NAT as a managed service so we'll need help from network advisors with that. I am not a network engineer so I am just busy now trying to compare the price involved with keeping stuff on-premises or running in Azure. This is really preliminary work and I understand that I need to work with network professionals but for this reason I want to do some homework before so I ask the correct questions.

• Since Express Route offers site-to-site topologies I was wondering if there would be any gotchas setting up an Express Route link directly from our Amsterdam Office to Azure and have regional offices reach azure via the DMVPN network via our dutch office, then via Express route...? it's very low traffic anyways we have an accounting application that 1 or 2 colleagues access with a VPN client, connect to a VM in Amsterdam via RDP then run the accounting client on that VM. We are a small shop (15 people in Amsterdam, regional offices from 5 to 30 people in our biggest office in Asia). Occasionally some people in Asia or US require access to a file server VM but thats about it.

• I saw an option for Express Route premium but I cannot wrap my head around the design implementation for improving regional access (in Asia for instance). Moving forward if we want to build VMs in Asia for our Asian's colleagues we may want to get Express Route links in Asia too, how does it plays out with Premium, do we get premium on our Europe link so we can extend our regional presence or do we need ER links for each regions we want to work with in Azure.

EDIT: they dont offer BGP as managed service