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Sync Data across Routers

I am trying to replace a TDM with routers, the problem I have is that the mux channels are transparent to any framing Tx/Rx by the connected device, in my case Telemetry units running MODBUS. I can't find a way of running Sync data on a router where the router is transparent to layer 2 or above. Even STUN Basic needs a 7e flag.

The analogy would be replacing two leased line synchronous modems with routers, where, like the modems, the routers operate at layer 1transfering data but retaining a timing relationship at each sync port

The ultimate test would be to run a BERT test with 511 pattern between sync ports on two routers connected together via an IP cloud.(The two routers would slave to the same master clock source)

Any suggestions on how I can achieve this .............!!

Cisco Employee

Re: Sync Data across Routers

This really isn't going to be possible unless you use a TDM-enabled router interface, and even then it may not be possible. You're not going to be able to transport any TDM-type circuits across a packet network if you need to maintain strict clocking between the 2 devices.

In the voice world, we have TDM "drop and insert" interfaces such as the PA-MCX-xTE1 where you can do a cross-connect between ports on the card, but you can't leverage a packet network with this approach, you're simply doing switching at this point. Without looking at our SONET products, I believe that's the closest you're going to get to a layer2-independent solution.

Also, bear in mind that routers today are not able to reference an accurate (stratum1/2) clock source to maintain end to end clock accuracy.



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