The networking industry is going through an incredibly dynamic time of change and opportunity. Global IP traffic will increase nearly threefold over the next five years and 127-fold from 2005 to 2021.  The number of devices connected to IP networks by 2021 will be three times higher than the global population. On top of that, the diversity of applications has never been greater, with each having its own set of requirements and hurdles.

This unprecedented growth requires Service Providers to transform their networks, and Segment Routing is becoming one of the keys to successfully paving the way to that transformation.

Segment Routing emerged back in 2013 when the first draft was posted under the leadership of our Cisco fellow, Clarence Filsfils. In less than four years, this technology has made major inroads into Service Providers, hyper-scale Web Providers and large Enterprises.

Why are customers adopting Segment Routing?

Many Service Providers are moving to Segment Routing because it allows the network to differentiate the way it delivers applications with unmatched simplicity and scalability.

Network Simplification

Segment Routing definitely contributes to network simplification as it removes protocols and makes network operations easier.

In this video, Walmart’s Global WAN Engineer Mark Pagan explains why simplification is a key driver in Walmart’s decision to roll out Segment Routing.

Bell Canada’s Technical Fellow Daniel Voyer, also advocates simplification:

“Segment Routing is fundamental for today’s reality which requires on-demand services as well as exponential bandwidth growth. Streamlining the IP protocols stack in order to provide a simplified service assurance support model for day-today is the key benefit.” You can listen to a recording of his presentation at MPLS+SDN+NFV 2017 for more insight.

Network Resiliency

Segment Routing inherently embeds mechanisms to make networks highly resilient – if a node or a link fails in the network, connectivity is restored in under 50 milliseconds!

In an earlier blog, I described how Vodafone Germany has been experiencing noteworthy improvements since they rolled out Segment Routing in their core network. They are now able to offer high-level SLAs while removing thousands of legacy protection tunnels.

Orange is the first Service Provider to endorse Segment Routing micro-loop avoidance. With this new capability, Orange solves a long-lasting issue that was a source of customer dissatisfaction. Stephane Litkowski, from Orange Group, commented:

“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 but 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!”

Bell Canada also acknowledges the greater resiliency that Segment Routing provides. Here is what Senior Network Architect-Operations Mitch Paglia said:

“We have evaluated Segment Routing with Topology Independent Loop-Free Alternate (SR TI-LFA) and proved that we can converge under 50 milliseconds for every node in the network without complex artifacts. Segment routing comes with capabilities that improves the 5×9 network reliability and flexibility that contribute to the overall customer experience.”

Higher Network Assets Utilization

Current networks are known to be about 50 percent over-engineered, and ever-changing traffic patterns are making the situation worse. Hyperscale Cloud Providers, who have been at the forefront of optimizing their network infrastructure, have learned that by dynamically rerouting traffic, they succeed in reaching an overall capacity utilization of 80 percent or more.

This is exactly what Microsoft is doing with its SD-WAN architecture (Software-Driven Wide Area Network). In his presentation  at MPLS+SDN+NFVVORLD,  Senior Software Engineer Paul Mattes clearly outlines the role Segment Routing plays in SD-WAN architecture and the benefits Microsoft is getting from it over legacy solutions, such as RSVP-TE.

We believe this type of architecture will move into the broader Service Provider community.

Innovative Network Services

Service Providers are continuously seeking to offer new and differentiated network services. Segment Routing powers two interesting network services: low-latency and disjointness. Low-latency network service ensures that time-sensitive applications are always directed over the optimal low-latency path, while disjointness network service ensures that applications can be directed over two paths,  independent of one another, to provide higher resiliency in case of network failure.

Softbank recently announced its adoption of Segment Routing to optimize network operations and to deliver new services to mobile home and enterprise markets.

Better End-User Experience

Offering best-in-class end-user experience is a top priority for Service Providers as customer churn remains a major concern. Many different elements can contribute to improving customer experience, but it starts with the network infrastructure.

Alibaba Group’s Chief Network Architect Dennis Cai explains at the Sigcomm 2017 conference how Segment Routing is helping them deliver a better end-user experience:

“Alibaba Group’s mission is to make it easy to do business anywhere. We put special focus on having network infrastructures capable of supporting this mission. In that respect, Segment Routing architecture brings us many benefits – first, it can be easily deployed in our existing network infrastructure; second, the ability to have fine-grain control over how the network transports applications while being stateless meets our elasticity requirements. It helps us to deliver a better end-user experience.”

Other customers have also publicly shared plans to implement Segment Routing, such as COLT and Telefonica as well as a US Tier 1 Service Provider, a major US Web Provider and a leading financial institution. Many others are currently testing Segment Routing in their labs, and I’m certain that this list will keep on growing over the coming months.

Segment Routing benefits and ease of implementation make it an essential building block of any network infrastructure transformation. There’s never been a better time to make network infrastructures SDN-ready with Segment Routing.  Cisco is your best innovation partner to help you do it!

If you want to learn more about Segment Routing, visit our website.


Jonathan Davidson

EVP and General Manager

Cisco Networking