PMC unveils OTN framer for IP core and edge routers

PMC-Sierra’s latest Optical Transport Network (OTN) framer chip for IP core and edge routers doubles throughput to 240 gigabit.

The Meta-240G frames IP router traffic using OTN before passing the traffic to the transport network. Line-rate encryption is included on-chip to secure traffic between data centres and traffic in the cloud.

Source: PMC-Sierra

Adding OTN to a router delivers several benefits, says PMC. OTN helps identify networking faults more quickly and simplifies the monitoring and enforcement of service-level agreements. OTN also includes forward-error correction which benefits optical link performance. 

Ethernet is the default router protocol interface while OTN is the dominant protocol in the transport network, says PMC. By moving OTN onto the router’s line port, the transport network extends its end-point reach to the router, says Stephen Docking, senior product line manager, communications unit at PMC. This leads to faster fault isolation and fault recovery.

“The transport network can now communicate with the router in a standard way, providing an extra level of protection that is faster than just IP layer protection,” says Docking. 

OTN also supports the monitoring of error rates across the link.“By making the router part of the link, the service provider can not only monitor performance within the transport network but across the entire end-to-end link including the router,” says Docking. Such monitoring helps verify service-level agreements.

Meta-240G features     

The Meta-240G is PMC’s third-generation framer for routers. The previous generation device, the 120 gigabit Meta-120G was PMC’s first to support OTU4 100 gigabit frames and was implemented in 40nm CMOS. 

The Meta-240G doubles the total bandwidth: 240 gigabit facing the front panel optics and 240 gigabit interfacing to the network processor on the router’s line card.  The device can thus support two 100 gigabit interfaces, six 40 gigabit interfaces and 24, 10 gigabit interfaces. “You can even have two 100 Gig and one 40 Gig, or two 100 Gig and four 10 Gig but most customers will just use 100 Gig [interfaces],” says Docking.

PMC has doubled the framer’s capacity while keeping overall power consumption fixed, in effect halving the power per port compared to its previous generation Meta-120G framer. Yet the chip also supports new features including a low-latency AES-256 encryption engine and an on-chip gearbox. The Meta-240G achieves the power savings by making the chip in 28nm CMOS and by improving the serdes design. 

The gearbox function translates between 10 gigabit streams and 25 gigabit ones. Many devices use 10 gigabit serdes but to connect to a CFP2 or CFP4 100 gigabit optical modules, 25 gigabit electrical channels are required. 

“Designers have had to use discrete gearbox devices [on the line card] which adds space, power and cost,” says Docking. “With the Meta-240G, the gearbox function is integrated into the device.”

Given IP traffic trends, will a 400 gigabit Meta device be needed in 2017? “It may be a bit longer - two to three years’ time - but we would need to [have such a device] to follow the existing trend,” says Docking.

Further information

PMC advances OTN with 400 Gigabit processor, click here