True Resilience It has to be RO2 (formerly RA02)

True Resilience It has to be RO2 (formerly RA02)

BT RO2 (formerly RAO2) MPLS Redundancy & Resilient Access

There is a fair amount of confusion in the market place regarding what is and isn’t possible from a BT RO2 MPLS Redundancy.

In all honesty, there are many clients which believe they have full resiliency between their primary and failover circuits but probably don’t due to design issues. Twin design and deliver resilient communication platforms using a broad range of suppliers. BT’s RO2 solution is probably the gold seal standard when it comes to authenticated, guaranteed redundancy and fail over.

BT RO2 (Resilience Option 2) formally known as RAO2 (Resilient Access Option 2) is BT’s name for complete MPLS Redundancy and diversity between circuits. As part of our work with BT, we design solutions for medium and large Enterprise clients to maximise uptime for products such as MPLS, BTNet and point-to-point or multipoint circuits.

Within the intro statement at the start of this article, I mentioned that some clients may believe they have full resilient access but, in all reality, they may have some single point of failure within their network. When we find examples of this scenario, the design will often include two different tail circuit providers or a failover mechanism which includes a technology such as DSL or EFM.

Using a leased line as an example:


Dual building entry points is dependent on a number of factors. We often find buildings which are listed with only one point of entry. In this scenario, there is not much you are able to do but accept that the listed property will always have the single point of failure issue. Dual entry should always be a question which is asked whenever you move to a new office location.

However, if you do not face the issue of a listed building restriction, an RO2 design will always enter each circuit as required via dual points. If your building does not have dual entry and is not subject to listed status, you will be able to pay a contractor to perform building work to create a second entry point.  The theory is that a fibre break  will only take out one of the circuits.


With every resilient access design,  we will ensure you have dual termination devices. If you are reading this post because you have an MPLS layer 3 solution, you would also want to make sure your design engineer puts in place dual hardware within your solution. There is nothing to stop you involving us in the process to assist you here – Any termination hardware from will be resilient.


The tail circuits from your site will exist from the building entry point through to the local BT Exchange. RO2 will attempt to use dual Exchanges to further add diversity and resilience. If one exchange suffers an issue or problem, your traffic will automatically flow via the failover circuit. How the failover will be achieved will vary depending on design.

It’s important to not overlook cable ducts particularly around building entry points.  If you originally only have one entry point you likely only have one duct.  A new route across your site needs to be found along with BT’s designers ensuring ducts are not shared along the routes.  This is not always possible and sometimes pinch points have to be accepted to avoid expensive groundworks.  However lately we have made use of overhead fibre options OpenReach are able to use to more easily create a second route avoiding existing ducting.


The transmission POP is where your physical circuit will terminate and represents how traffic for most product types back into their transmission network. From the transmission point, the traffic is back hauled to the edge of BT’s network. With both the transmission and Provider Edge, full diversity is again the intent.

Overall, BT RO2, is designed to ensure no single point of failure exists throughout your CPE (Customer Premises Equipment), building entry points, tail circuits, BT exchanges, BT transmission POP’s and through to the edge of their network (e.g. PE – Provider Edge).


MPLS redundancy Tail circuits from 2 providers, good idea? It depends

If we take a design from two  providers, one from BT and another from a secondary supplier which have been ordered via different telco’s. The issue here is that neither provider is able to guarantee there will be no commonality between each circuit through to their respective networks. And, this is by far the most common mistake we see IT Managers make when trying to provide for maximum uptime for their connectivity. On paper, the design looks good since two providers look to offer the best possible resiliency. However, the reality is that both providers may have several points where the circuits might meet.


If you consider that each MPLS redundancy provider is not aware of the internal details of a competitors network and therefore cannot possibly commit to a solution with 100% uptime.

Sometimes, using two providers might be possible from two different geographical locations. As an example, we have put together designs where a LAN extension service exists to bring two offices together.

If you are interested in our company helping you with your communications design  let us know by clicking the contact us button at the top of the page and we will be in touch right away.