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UK based Global Manufacturer needed Guaranteed Connectivity to US Data Centre


Business Problem

Global manufacturer needed reliable and robust links to US data center and domestic sites.

Exmos Solution

Install Stonegate firewalls at each UK site with multiple ADSL Broadband lines. Use Stonegate mesh VPN, routing engine and traffic shaping capabilities to connect each office to the US data centre through the new leased line in the UK's head office.

Tools used

  • Stonegate Management Centre
  • Stonegate Firewalls
  • Exmos Managed Firewall Service
  • Exmos Managed Internet Connectivity Service


New applications in the US data centre can be accessed reliably from any UK office.


This UK based global manufacturing company was acquired by a US based corporation.

As part of that acquisition they were required to move onto the corporate ERP system, running from a data centre in the US. The application was hosted under Citrix.

Standard access to the data centre was via VPN over 2Mbit leased line.

Business Problem

From the UK the connectivity would be expensive doubly so due to the two locations the company has - one in Scotland and one in England.

The cost of a leased line for their English based operation was prohibitive due to the relatively small number of people who were required to use the ERP applications. However, their requirement for a robust, reliable link was as imperative as the larger user base in their head office.

Although their existing ADSL based VPN link between sites was adequate, it was starting to suffer saturation and was also not reliable enough for the new requirements.

They were also very keen to avoid the scenario where all their internet traffic would be carried to the US for egress via the data centre public internet link. This would put additional strain on the leased line and have it carrying traffic which was predominantly European based.

ERP Application Performance

As well as the reliability of the connection to the ERP system, the performance was also critical. Being Citrix based, poor performance of the link would be immediately noticeable by the users and quickly impact their ability to work efficiently or at all. This could have a direct impact on the ability of the company to transact and ultimately deliver their products.

Exmos Solution

Exmos proposed a Stonegate firewall along with the installation of an additional ADSL line at each UK office. This would utilise Exmos' managed firewall service and managed internet connection service.

Mesh VPN

Once these were installed Exmos configured mesh VPN's between each UK site. This allows the site to site VPN traffic to be routed across any combination of ADSL link at either end. Traffic across the mesh is also load balanced over all the links. The firewalls also have the capacity to increase the bandwidth through installation of additional ADSL lines if required.

Traffic Routing

Traffic routing was also implemented and this effectively forced all US data centre traffic, from all the remote UK sites, through all the meshed VPN's to the UK head office and then out through the leased line to the data centre. All the rest of the internet traffic (web, email etc..) all used the local load-balanced ADSL lines. This kept the amount of bandwidth used at the data centre by the UK offices to a minimum. Premium traffic was carried on the premium cost link and commodity traffic was carried on the low cost broadband.

Traffic Prioritisation

Finally Exmos proposed that by using Stonegate's traffic shaping engine, all Citrix traffic would be guaranteed and prioritised (two separate options!), at the same time, all the standard bandwidth hogs would be restricted (SMTP, FTP, HTTP......). The advantage of Stonegate's traffic shaping engines is that the restrictions are only applied when the line is saturated. This allows for email or web to use as much bandwidth as possible until a more important protocol (e.g. Citrix) starts being used.

Either site could suffer the outage of one broadband line without impact. Even although they were struggling for bandwidth on a single line before, the traffic shaping/prioritisation ensures that the all important Citrix traffic always has bandwidth available to it.

Business Benefits

After the implementation of the Exmos solution several business benefits were immediately introduced:

  • Individual ADSL line failure does not stop access to the US data centre from any UK site
  • Single leased line covers both UK sites
  • Performance of the Citrix applications is more than acceptable and very stable
  • Heavily used ADSL lines are not a problem as the Stonegate traffic shaping manages bandwidth
  • clever routing ensures only the essential traffic is sent down the leased line to the data centre
  • General web access across all UK offices improved
  • Access to file servers at other UK offices improved too
  • Use of Exmos' Managed Services, Internet and Firewall, ensure maximum potential of their UK network