Performance assurance in LTE-A and 5G virtual and hybrid networks


      Your mobile backhaul network is working just fine. You very seldom see issues with regards to service delivery and quality, and certainly nothing that can’t be identified and fixed quickly. So, besides a bit of scaling to accommodate more traffic, your network is LTE-A- and 5G-ready, right? Not so fast!

      If you’re still relying on two-way, or roundtrip, latency measurements to monitor delay through your network, you’re leaving yourself exposed to Quality of Experience (QoE) issues caused by emerging service trends and more exacting radio specifications. Emerging mobile services tend to be very asymmetrical with regards to bandwidth with significantly more traffic  downstream.  At the same time, as mobile backhaul providers embrace hybrid and virtualized networks for the flexibility and lower cost structure they offer, the relationship between upstream and downstream routing becomes blurred.  What this means is that upstream and downstream latency are very likely to be different and only using roundtrip measurements will lead to undetected latency violations and, hence, service quality issues.

      Traditional wisdom dictates that you need highly synchronized timestamps at both ends of a path to generate a one-way latency measurement. And getting highly synchronized timestamps requires either an expensive GPS solution everywhere or a network-based packet timing protocol (PTP), such as IEEE 1588v2, to distribute synchronization. So, what if your network doesn’t support either of these solutions? Do you need to make a significant investment to upgrade your infrastructure?

      The good news is no, you don’t. EXFO’s Universal Virtual Sync solution, available on many of their BV family of Active Verifiers as well as it’s Virtual Verifiers, can derive highly accurate one-way latency measurements using industry standard two-way latency tests, such as ITU-T Y.1731 or RFC 5357 TWAMP (Two-Way Active Measurement Protocol).  In fact, the far end reflector can be any device that supports these protocols; no additional capabilities are required.  Side-by-side testing of latency measurements, with one setup using GPS synchronized clocks at both ends and the other using free running clocks with the EXFO Universal Virtual Sync feature on the generator end, demonstrated one-way latency measurements within 200us of each other.  If you would like to learn more about how the EXFO Universal Virtual Sync feature can provide you with greater insight into your network’s performance without breaking the bank, download Measuring one-way delay for optimal delivery of revenue-generating service or visit us at