MPLS+SDN+NFV World Congress is already two months away. Time goes really fast! Once again, it was an awesome week with spot on content and great speakers – can’t wait attending the next one! As every year, Cisco had a booth with some nice demos and the ones related to Segment Routing clearly hit the mark! Demo staffers relentlessly showcased Segment Routing demos to enthusiastic customers.

2016 is clearly an inflexion point in Segment Routing adoption. Enterprise and Service Providers have tested and validated the technology and are ready to roll out the technology in live networks. Customers now fully understand the benefits of the technology – it’s all about bringing simplicity and scalability to the network. No RSVP, no midpoint state, no tunnel to configure!

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Some noteworthy innovations were disclosed during the Segment Routing track:

On-Demand Next Hop and SR PCE (Path Computation Engine)

Provisioning multi-domain services (L2VPN & L3VPN) comes with complexity and scalability issues notably when routing information need to be redistributed across domains … With the On-Demand Next Hop (ODN) feature, no need to do any redistribution. ODN does trigger delegation of computation of an end-to-end LSP to a PCE controller, including constraints and policies. It then installs the replied multi-domain LSP for the duration of the service into the local FIB.

TI-LFA (Topology Independent Loop Free Alternate) node/SRLG (Shared Risks Link Groups) protection

TI LFA Fast ReRoute has been enhanced to not only protect from Link but also from Node or SRLG failure now! It increases significantly network availability.

Micro-loop avoidance

When a link or a node fails, traffic is being switched over to a backup LSP. Now, depending on the time it takes for each node to update their routing tables, loops can occur causing drops in traffic. Even if these loops are transient (as routing protocols end up converging), they could put some applications into severe troubles. Think of IoT applications such as remote surgery for a moment … If you were to be the patient going for such a surgery, I bet you would feel better off knowing the network is fully reliable!

Stephane Litkowski, from Orange Group, did some in-depth testing of micro-loop avoidance code provided by Cisco and shared great insights during his presentation at MPLS World Congress.

See below what Stephane has to say about it:

“Customer expectations in term of quality of experience are growing with the criticality of their applications. As MPLS transport is the foundation of our services, we must make it the most efficient and robust, also because bad things can happen in a network and network must dynamically adapt without disrupting customer applications. In this area, micro-loops have always been a pain for networks by breaking fast-reroute or creating micro-congestions. Orange was interested in micro-loop prevention for many years by investigating, evaluating, implementing multiple solutions. But all those past solutions were only partial or too complex to be deployed in a live network. Now, thanks to the Segment Routing building blocks, we have the technology to easily build loop-free paths in the network in a simple way. We consider Segment Routing as an enabler to prevent micro-loops in IP/MPLS networks. We already evaluated Segment Routing micro-loop avoidance in our labs, showing impressive results: we will deploy it for sure!”

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If you’ve missed this event and want to know more about these innovations, go and watch these videos:

And for those willing to do some hands-on, check out dCloud: https://dcloud.cisco.com/


Frederic Trate

Marketing Manager

Service Provider Business Architecture, France