Segment routing for low-latency enterprise Ethernet

Arelion has always innovated our network to benefit our global customers that depend on low-latency, cost-effective connectivity. Our early adoption of a multi-vendor network architecture allowed us to integrate optimally priced equipment to reduce costs for our customers. But what about the need for low latency? We recently set a new standard with the availability of 40Gbps Ethernet Virtual Private Line (EVPL) for our enterprise customers.

As more enterprises depend on diverse, low-latency Ethernet services to operate their global businesses, the network must be dynamically innovated down to the routers to handle those demands. Network diversity must be a primary focus because many of our enterprise customers in the banking, automotive and related sectors cannot afford even a second of downtime caused by a network outage nor can they afford noticeable delays in their connectivity.

To satisfy the need for low-latency, diverse Ethernet services on a global scale, we’ve implemented segment routing based on the lowest latency paths across our multi-vendor network at no added cost to our enterprise customers.

A brief history of routing: from link metrics to low latency

Traditional MPLS networks typically have a routing table based on link metrics, including link speed or hop count. Then Dijkstra’s algorithm was implemented in the 1980s, helping networks route traffic according to the shortest path between many routers. Amid these numerous approaches, Arelion strives to offer our customers transparency in our own approach to Ethernet services.

There can be minor latency variances in sea cable connectivity since our network has a global reach spanning multiple geographies. We typically addressed this by stitching our customers hop by hop in our network to achieve the lowest latency at that moment. But manual processes to achieve low latency are unsustainable as our global network expands. This pushed us to implement an innovative approach to segment routing that allows us to find the lowest latency path dynamically and automatically without manual intervention.

Segment routing and Flex-Algo based on low latency

Segment routing is a protocol that runs on top of our Intermediate System to Intermediate System (IS-IS) routing protocol. With segment routing, you can create different Flex-Algos (routing planes) based on criteria that differs from normal IGP metrics. All links in Arelion’s network have a latency metric which we use to create a low-latency Flex-Algo, enabling us to route traffic based on the lowest latency. This dynamic, low-latency approach to segment routing provides extremely fast rerouting times to benefit the enterprise customers that rely on the diverse Ethernet services running over our #1 ranked global Internet backbone.

Segment routing provides the long overdue benefit of eliminating the Label Distribution Protocol while improving network redundancy and providing lower failover time (below 250 milliseconds). This means that our routers dynamically know what’s happening in the network and rapidly respond to outages by swapping the traffic to the next best low-latency link when one link goes down, providing diversity benefits coupled with latency benefits.

We use segment routing in conjunction with Topology Independent Loop-Free Alternate (TILFA) to achieve this faster failover time while reducing packet loss. Segment routing also improves the regional diversity of our Ethernet services, providing our customers with more choice in which countries they route their traffic through. As we expand our network, our routers automatically adjust to eliminate the manual implementation of this protocol.

Taking the route less traveled

Arelion’s innovative approach to segment routing is what sets us apart in our implementation of this protocol. Our low-latency network is the core of our approach, allowing us to implement segment routing and low-latency Flex-Algo on a carrier-level scale in a multi-vendor network environment. Amid inflationary pressures, we understand the importance of global services that are cost-effective without sacrificing quality, so we are happy to offer low-latency segment routing as a premium, free service.

By offering segment routing in addition to running enterprise traffic in the highest quality-of-service class, we ensure our enterprise customers are unaffected by congestion or latency as they depend on our global Ethernet services to operate their businesses.

If you’re an enterprise business interested in the benefits of Arelion’s low-latency Ethernet services, please contact us here.


Anders Samuelsson
Senior Network Specialist