What is ExtendMM™?

ExtendMM™ is a Siklu licensed feature that easily and seamlessly combines a high-capacity EtherHaul™ link with an inexpensive, unlicensed, low capacity and lower frequency link, leveraging on the supervising intelligence and a built-in switch in the EtherHaul™ radios.

With ExtendMM you can:

• Improve link availability
• Deploy longer links
• Achieve 100% link availability
• Upgrade existing sub-6GHz links to Gigabit throughputs

How does Extend MM work?

When all is well in the world and the weather is good our Siklu link will deliver Gigabit or more throughput (model dependent).

At times you may experience heavy rain which causes the link to degrade and the link throughput may decrease. The Siklu EtherHaul™ radios automatically reduce the modulation and coding, consequently the receiver sensitivity decreases Adaptive Coding Modulation (ACM).

The ACM is shown by the negative step, indicated by the Red Line. This reduction prevents the fade margin (Green Line) from becoming negative, and the link remains in operation, albeit at a lower throughput.

As the rain intensifies even more, ACM initiates another reduction in sensitivity, and in throughput. Only when the rain becomes violent and the ACM is exhausted, does the link finally fail.

As the rain subsides we will see the ACM initiate a step up in the modulation and sensitivity, resulting in increased throughput, with continued weather conditions improving the ACM will continue to increase the throughput and modulation until the Siklu radio link is again providing maximum throughput.

While ACM in most cases is good enough for maintaining link availability, some instances require up to 100% link availability or may have a minimal throughput SLA. This is where the ExtendMM™ feature will make this possible, using any low-frequency radio as backup radio, ideally sub 6GHz.

We can use any spare port on the Siklu EtherHaul™ radio to connect to the backup radio. On some models we can also make use of the PoE-out to power the backup radio. Enabling us to run a single ethernet cable or reusing existing cabling in scenarios where we are upgrading and existing lower capacity radio link.

The EtherHaul™ radio configured as the Master will automatically prevent a Layer 2 loop by shutting down the designated backup Ethernet port. Implemented using the Ethernet Ring Protection protocol (ITU-T G.8032)

In the event of the Siklu link completely going down due to rain or if the configured throughput threshold is met, traffic is automatically routed via the backup link.

Link availability is maintained while throughput is reduced according to capability of the backup radio link. The ExtendMM™ hitless switching time is less than <100ms.

When the Siklu link is restored and the throughput is above the configured threshold, traffic remains routed via backup link for a further 60 seconds (ERP WTR timer), this delay ensures switch stability.

After the 60 seconds (ERP WTR timer) has expired and provided that the Siklu link has been stable throughout this period, traffic is then rerouted via Siklu link.

If you would like to get in touch with any further questions about this article or any other technical enquiry, please contact us on +44 (0) 1488 647 647

Author: Byron Frederiksen – Solutions Support Engineer at Purdicom. To read this article and more by Byron on LinkedIn check here: https://www.linkedin.com/in/byron-frederiksen-56b76936/detail/recent-activity/posts/