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Recommendation for ONS network

Hi there

I've been asked to provide a design for a SDH based network, consisting of 3 nodes: one cpe and 2 network nodes.

The network would look like this:

CPE --30km-- NODE-1 --15km-- NODE-2

The CPE must provide 1 STM-4, 2 STM-1 and 3 E3.

Node-1 must provide 2 STM-1 and 1 STM-4.

Node-2 must provide 2 STM-1, 1 STM-4 and 3 E3.

Between all units the speed would be STM-16.

For the CPE I've looked at the ONS 15305 with a 6-port E3, a 2-port STM-4 and a 2-port STM-1.

For both nodes I've looked at the ONS 15454E with STM-4, STM-1 and E3 circuits, but I'm not quite sure which interfaces to use as the STM-16.

Could anyone suggest what I'm missing and wich modules to use.

Cheers, Lars


Re: Recommendation for ONS network

Hi Lars

you have to calculate the optical budget for the links. Normally we use 0.4dB/km for 1310nm SH (short haul) laser and 0.3db/km for 1550nm LH (Long Haul). Then you have also to add the additional lost of connectors and slices.

To your setup:


Here you need definitely LH laser. The optical budget for LH laser is about 26dB. I recommend to use for the 15305 the module 15305-L16.2-1-LC, this is a 1-port 1550nm LH STM-16 module. For the 15454E use the 15454E-L16.2-1, this is also 1-port 1550nm LH STM-16 card.


It's possible to use short haul lasers. But to be sure, you should know the optical loss of the fiber. Maybe the fiber was already measured after it was installed. The optical budget for short haul cards is about 13dB. If we take 3dB loss for connections , then we could have 10dB for fiber loss. The distance could be 10dB/0.4dB=25km. I recommend for the 15305 the module 15305-S16.1-1 and for the 15454E the 15454E-S16.1-1.

Cheers, Rene

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