Data patterns to test Serial links

Unanswered Question
Apr 19th, 2008

What kind of data pattern we can use to test the serial links?

Is there any doument?

please help

I have this problem too.
0 votes
  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 0 (0 ratings)
Loading.
scottmac Sat, 04/19/2008 - 10:53

There's all sorts of patterns, each tests a different part of the network electronics.

But unless you can drive the line directly with something like a BERT tester, there's not much point in it; you won't be able to tell where the errors were picked up.

There are tests like:

barber pole 1 or barber pole 0 (one bit different, traveling across the byte to look for "sticky" bits) (or 1 in 8)

Stings of ones or zeros to test inductive line loading or PLL functionality

Alternating bursts of ones and zeros to check switching speed and leaky components

There are a couple pages of various tests to check a T1 line. They are usually run as a group of five tests or so to check the overall line operation and to look for bit-errors.

To use most of these, you need to be able to monitor the line directly; the Telco can do that, (usually) you can't.

If you want to check the serial lines of the router, then try putting up some loops (local first, then remote) and transmitting known bit-streams .... then capture them on the return and compare.

Good Luck

Scott

lamav Sat, 04/19/2008 - 19:33

Hi:

Here goes...

To test a T1 line, these are typically the tests that are run:

QRSS (quasi) -- random bit pattern meant to simulate real data traffic.

1:7 (sometimes called 1:8) -- stressful pattern meant to test line integrity by maximizing number of zero bits (minimum ones density), without forcing binary eight zero suppression coding.

3:24 -- similar to 1:7 but a bit more stressful.

All Ones -- meant to test riser repeaters by forcing a reproduction of every bit.

All Zeroes -- meant to test for B8ZS configuration.

These are about the only test you will ever need to run. If possible, have the LEC dispatch 2 techs and have them run head to head.

T3 lines use similar tests on a different scale.

HTH

Victor

dhirajgidwani9 Sun, 04/20/2008 - 00:55

Hi,

Th most simple ic connect desktop's at bothe ends at the fa0/0 of the router's give the ip address spo that you can pinthe router of the next hop once that is achievable the do a ping fromteh dsktop with a heavy load of 10000 the sreail link will get util and you will be able to see teh errors on the links this is a standard practice for metro ethernets.

Actions

This Discussion