OTN layer
Posted by Geoff on October 26, 2005
Since G.709 standards do NOT include GbE interfaces, an OTN layer will always need a sub-layer to aggregate the GbE to a higher rate interfaces (as STM64, STM16), is that right?
Short answer is yes, sort of. But let me try to add some clarity.
G.709 today is being implemented primarily at two speeds. OTU1 is defined at 2.7 Gbps and OTU2 is defined at 10.7 Gbps. Both are fully capable of carrying multiple types of traffic streams as payload, just like SONET/SDH. So, for example, an OTU1 frame can transparently carry OC48/STM16 a 2.4 Gbps signal, such that the SONET/SDH overhead is protected while still offering OAM&P for OTU1.
This same frame can carry 2 Gigabit Ethernet circuits and a few other circuit types all the way up to the full ~2.4Gbps payload. Our implementation of OTU1 and OTU2 utilize OC3/STM1 frame sizes for aggregation. So a GigE circuit would require 7x155Mbps or 1.085Gbps to carry a GigE.
