Does anyone know of a really good document that takes you through all the data patterns you can use for an extended ping (in detail). I am currently troubleshooting a Leased Line connection and when I use a data pattern of 0x0000 I see some packet loss.
Try the web sites of testing equipment manufacturers.
Different patterns will test for different faults. Each pattern has an analog equivelant. This is important when checking for 'bridge tap'. Each tap acts like a bandpass filter. All data not within the pass band will be transported error free. Data within the pass band will be corrupted. So when searching for bridge tap, a series of data patterns must be used in order to test all frequency bands.
A test pattern of 'all ones' (0xffff) is useful for testing repeaters. It requires a lot more effort for a repeater to create a one than it does for a zero. A high ones density will test the repeater's ability to function under difficult situations.
A data pattern of 'all zeros' (0x0000) is useful in testing the clocking of a circuit. Ones in the data stream are used to reset the clock. After each reset, the clock drifts toward it's free run frequency until another 'one' resets it. If the ones density is too low and the oscillator is too far off, the clock will drift beyond the pulse width. When this occurs, the receiver does not detect a pulse within the pulse period and data is lost.
In response to you post. I am currently experiencing abort errors clocking up very slowly on one end of a 2MB LL. This is associated with the odd CRC error and interface reset. Could this be a result of a clocking problem or line code mismatch on the CSU/DSU at each end?
Aborts are caused by an illegal series of ones. Usually this indicates a clocking problem between the DTE and the DCE.
Interface resets can be caused by quite a few things, one of which is a clocking problem between the DTE and the DCE.
I would say you should look at the CSU/DSU and the serial cable first. Is the serial cable secure to the router and the CSU? I have seen a lot of trouble caused by people not tightening the connectors properly
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