ONS system software upgrade

[thisisshanky]

I m looking for ONS software download from the software center. I m looking for 4.0 and 3.3 images. and I also see two images each 25 megs in size, one with a SDH in the image name, and one without an SDH. I want to know which one to download, and also what is the difference between the two.

[konigl · Accepted solution]

I assume you're talking about the ONS 15454, based on the information included in your post.

The software image with SDH in the image name is intended for use on networks adhering to the Synchronous Digital Hierarchy standard. The other software image is for use on SONET, or Synchronous Optical Network, standard networks.

While the two standards are closely related, the biggest difference between them is that SONET is used in North America, and SDH is used in Europe and Asia. (Frame size is different, too: you can fit 3 SONET frames in the same space as one SDH frame.) So if you're doing DS-1 and DS-3 hand-offs from the 15454, go with SONET; if you're doing E1s and E4s, go with SDH.

If you're connected to a carrier's network here in the US, you're probably using SONET.

Hope this helps.

[thisisshanky]

Hi Larry.

Very valuable info. Thanks for the response.

[konigl]

You're welcome. Especially glad to help someone out who has helped so many others.