15540ESPx Cross Connect Drawer

[chinnawo]

Hi,

Can anybody give me the purpose of having this box instead of direct connect cable? I can not find any info on web while in official doc has only a paragraph of how to connect it.My point of view is only breakout box for ease of trobleshooting so I can connect/disconnect the colour I want or don't want.

Regards,

Chinnawoot

[rtappend_2]

Chinnawoot,

Direct connection with MTP cables can be used to connect 2.5G and 10G linecards to the OADM or Mux/Demux modules. This provides a fixed mapping of subslot to channel position in the mux, requiring the transponders to be inserted in increasing channel order. This should suit most requirements.

If more flexibility is required, for instance if you need to insert a wavelength from another shelf (perhaps an ONS15530), or if you need to cross-connect or attenuate specific wavelengths, you can use the cross-connect drawer together with the correct cabling-kit to achieve this as it allows access to each of the 8 fibres within the MTP cables to patch as you please.

Does that help?

Regards

Rob.

[chinnawo]

HI,Rob

Thanks for your advices.So I can

1) Sort of having transponder BAND A and BAND B in the same LCMB,isn't it?

2) If I had a 3 boxes with bus topology.Let say LEFT,MIDDLE and RIGHT.

LEFT box want to talk to RIGHT box with 1 wavelength that MIDDLE doesn't have transponder corresponding to that wavelength but have mux/demux that can add/drop that wavelength,isn't it?

Sorry but I can not picture that in my mind,

Best Regards,

Chinnawoot

[rtappend_2]

Chinnawoot,

1) Yes, you could have mixed bands/channels in the same LCMB.

2) Hmm, if you had a 3-node bus, there could be a couple of ways to pass channels through the middle node.

2.1) Band pass-thru

If the channels between LEFT and RIGHT were in a different band, they could be passed transparently through MIDDLE node, using the THRU ports on the OADM's. You would not need to demux those channels at all, therefore they would only experience the pass-thru loss at each OADM (recommended).

2.2) Channel Pass-thru

If they were part of the same band, yes you could use the cross-connect drawer to patch it through. These channels would experience the drop-loss and add-loss as they go through both EAST and WEST OADM's so would have a much lower optical budget than any added channels. If amplification is required this power divergence could be an issue, so I would use with caution.

I would recommend the Band approach (2.1) for this for simplicity and optical budget, but if cost, or other reasons dictate, the channel approach is technically feasible with the caveats I have mentioned.

Regards

Rob.

[chinnawo]

Rob,

You are so great.We kinda get into trouble with 2.2.

Because of budget,we have to use same band(but differenct colour) between Left and Right.

Actually we use ring topology which should work just fine but in backup scenario our configuration will change to bus topology.So signal will get drop at the middle,then we need crossconnect drawer to add them back again to pass to the other end(This is the one that make me so confuse but clearer after got your explanation)

Furthermore bring us a serious problem with huge loss.

Thank you very much (I really mean it!)

Best Regards,

Chinnawoot