Resilient PDH Access Rings with 50 ms Restoration Protection

Ring topology is deployed in networks where it is vital to guarantee delivery of mission-critical traffic. If a link is broken anywhere in the network, traffic can travel in both directions to reach all nodes on the ring.

RAD offers several options for cost-effective ring connectivity with protection capabilities of under 50 milliseconds.

DXC multiservice access nodes provide backup of under 50 milliseconds for E1/T1 radio links in a ring topology, using drop-and-insert of E1/T1 lines at each site. The DXC can groom fractional E1/T1 lines and cross connect them to any timeslot to fill E1/T1 lines. This enables the network owner to lease fewer lines from the carrier.

In the example below, the DXC ensures reliable backhaul of cellular traffic. The DXC-30 placed in the base station controller (BSC) duplicates up to 10 full E1 links (320 timeslots) or up to 13 full T1 links, which it then transmits to the ring in both directions for 1+1 redundancy. The DXC-offers carrier-class redundancy in a compact, cost-effective unit that is ideal for crowded base stations (BTSs).

This protection solution requires the RAD DXC only. Alternative solutions require costly investments in additional radio transmitters, transceivers and licenses.

RAD’s unique Optimux-T3 multiplexer creates an extremely cost-effective resilient ring for transparent delivery of E1 and T1 traffic in campus or cellular environments. It is the only PDH multiplexer on the market that offers drop-and-insert and ring connectivity. It presents an attractive alternative to SDH ADMs in small access ring applications.

The Optimux-T3 maximizes the capacity of the network by carrying up to 21 E1 or 28 T1 lines over a fiber or wireless link. Optimux-T3 transmits E1 and T1 services using a T3 format, which are gaining popularity in Europe and elsewhere, since it provides better utilization of SDH containers and offers higher capacity over fiber and wireless links.