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New Member

IGX 84xx clock problem over satellite, but not in lab.

Hello,

Between 3 IGX 84xx node network (triangle) there seems to be a problem with the clock on one switch. The network is very unstable and is more busy with itself than passing traffic. There are lots of failures on the trunk as a result. Is this a SCM problem or..... All trunks go via satellite.

Thanks for helping!

Mike

3 REPLIES
Silver

Re: IGX 84xx clock problem over satellite, but not in lab.

I found this on Cisco's site.. might be useful to you: http://www.cisco.com/warp/public/74/topissues/wan_sw/clocking.html

New Member

Re: IGX 84xx clock problem over satellite, but not in lab.

Mike,

Passing clocks across a satellite link is typically challenging. The reasons are that though the satellites appear to be stable platforms, they move constantly relative to a point on the earth. As a result, there is a degradation of the clocking information due to Doppler shift.

To better answer your exact situation I need some more information:

1. What is the clock reference for your three nodes? each node? (dspcurclk and dspclksrcs)

2. Are you attempting to pass clocks across the satellites (i.e. pass sync = Y on cnftrk)?

3. Are you using your own v-sat terminals or are these links provided thru a commercial telco? If your own - what satellite modem and does it have built-in buffers? Which telco?

........Mike

New Member

Re: IGX 84xx clock problem over satellite, but not in lab.

Hi Mike,

Thanks for the info. The clocks are set to be correct, so that should not be that problem. The info on the equipment on the trunks is as follows:

These are our own ComTech EFdata modems type SDM 300A with the options Reed Solomon and Drop & Insert. The channel is configured as E1-CCS with HDB3 G703 unbalanced.

Mike

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