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New Member

CSU-DSU to connect to a SONET ring

What CSU/DSU would work for a SONET using a Cisco 7206. I need this at 8mbps level to be able to upgrade to 45mbps level

3 REPLIES
New Member

Re: CSU-DSU to connect to a SONET ring

I think you mean what CSU/DSU would work for a T3, as the smallest SONET frame starts at 55mbps. As for what part you need, I have no idea.

-Charles

New Member

Re: CSU-DSU to connect to a SONET ring

It really depends on how you are interfacing to your SONET ring. I don't know that the 7200 series supports a SONET port adapter of any type so I am assuming that you are accessing an existing ring at the electrical level.

Most SONET access is designed for the T-Carrier environment. That is to say, T-1, T-3, and so on at the drop side. So there is a big jump from 1.5 Mbps to 45 Mbps. If you need to start at 8 Mbps and scale to 45 Mbsp, you might be in a bit of a bind. You can use a HSSI port adapter on the Cisco box and place a HSSI-capable T3 mux in between that and the SONET box or you can just go with a T3 interface in the Cisco box and go directly into your SONET box (assuming it is equipped at that level). With most any SONET box today, in order to achieve more than 1.5 Mbps - but less than 45 Mbps - you need to IMUX multiple T1s together (or load share accross them). This is done outside of, and transparently to, SONET.

Having said all of that, most SONET vendors today provide at least FastEthernet interfaces, with many now providing Gig-E interfaces. To be honest, I'm not exactly sure how one goes about using these though. I suspect that you have to map an entire STS (approx. a T3 worth of bandwidth), or some multiple thereof, to the ethernet interface (putting you right back where you started). So you will really want to discuss it with the technical folks who represent your SONET hardware vendor.

New Member

Re: CSU-DSU to connect to a SONET ring

I should have known better than to think that Cisco wouldn't have a SONET interface for a higher end router like the 7200. You may want to read through this link:

http://www.cisco.com/warp/public/cc/pd/ifaa/pa/pcsnpa/prodlit/sonet_ds.htm

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