Cloud Connectivity: Linking Offices Across Two Continents
  • Cloud connectivity: connecting transatlantic offices through the public cloud
  • Forgoes expensive purchasing of capacity on monthly basis
  • Offers flexibility in scale and highly cost-efficient
  • Hentsu used Azure backbone network to connect offices across the Atlantic, saving thousands a month for our client

It’s no secret that running a business across continents has its challenges. Now imagine having to connect two office networks, only with an ocean in between. Traditionally, purchasing capacity on submarine cables would have been the only way to connect the two, but thanks to the cloud connectivity with Azure, Hentsū has come up with a more cost-effective and flexible way of conquering the ocean in between.

Cloud Connectivity across an Ocean

As part of some of the public cloud infrastructure work Hentsū provided for one of our clients recently, we connected their London and New York offices without the use of leased transatlantic links. These services, which are usually used to connect networks in different locations, are expensive and often leased on a one or three-year basis. Depending on factors such as bandwidth, a transatlantic link can cost roughly £8000 a month. A big financial commitment for most firms.

Instead, Hentsū’s experienced consultants were able to come up with a more cost-efficient solution to spending thousands of pounds a month on connecting offices through cloud connectivity.

How it Works

By exploiting the fact that public cloud providers already have high capacity and highly resilient connections between regional datacentres, Hentsū connected the two offices through the public cloud provider’s own international backbone network. Essentially, Hentsū could reuse the link between the customer’s UK and US public cloud data centres, in order to create a wider area network (WAN) between the New York office and London offices.

Once an office is connected to a local public cloud network point of presence, or site-to-site VPNs over internet, clients can reuse the public cloud provider’s backbone network to connect offices.

While it’s possible to build a route between offices via the public internet, Hentsū connected the client’s offices through Microsoft Azure’s backbone network, as demonstrated in the below diagram.

Azure’s VPN gateway service supports transit routing, and Border Gateway Protocol (BGP) enabled gateways will automatically learn routes to other sites via Azure.

Although Microsoft ExpressRoute doesn’t natively support transit routing and will drop packets not destined for a vNet on Azure, it’s possible to build “transit VPNs” to a network appliance on Azure and tunnel traffic across ExpressRoute, known as an overlay network. As demonstrated in the diagram below.


The benefits of an ExpressRoute Premium are that it can be metered (pay for what you use) or unmetered (fixed cost of unlimited usage). Not only is this cheaper than buying capacity on a transatlantic link, but it also offers flexibility as to when and where the link is no longer needed.

Overall, this is another great example of yet another service the public cloud is able to offer to users.

How Hentsu can help

Want to know more about cloud connectivity and Azure? Come talk to us… You can contact us at: