bit errors in case of BERT test

I have a Cisco WS-C2960-24TC-L(c2960-lanbase-mz.122-50.SE1.bin) switch, which has a JDSU SmartClass Ethernet tester connected to SFP port Gi0/1 and another JDSU SmartClass Ethernet tester connected to SFP port Gi0/2. Those two ports are in VLAN 10:

Gi0/1 -> tester1 connected 10 full 1000 1000BaseLX SFP
Gi0/2 -> tester2 connected 10 full 1000 1000BaseLX SFP

In addition I have following SPAN configuration:

monitor session 1 source vlan 10
monitor session 1 destination interface Fa0/1

..and Fa0/1 in connected to PC NIC. Other than this, switch has default configuration. In the PC, there is a tcpdump(1) running.

The problem is, that if I make L2 traffic test between the JDSU testers, there are no bit errors with Acterna payload, but if I use BERT payload, there is constantly bit errors increasing. I have tried with different BERT patterns(all zero, all ones, 2^23-1 etc) but nothing helps. On the other hand, with Acterna payload, there are no errors. I know, it's not directly Cisco related question, but maybe somebody here has experience with different Ethernet testers and their payloads?

In addition, where should one prefer BERT over Acterna?

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Comments

kryolla

BERT bit error rate test is usually for testing T1

m4rtin

kryolla wrote: »

BERT bit error rate test is usually for testing T1

However, it's suitable for Ethernet testing as well, isn't it? In addition, I quite don't understand, what is the main difference for example between Acterna payload filled with zeros and BERT payload filler with zeros?

kryolla

BERT is a stress test for T1 testing, not sure what you are trying to accomplish with testing ethernet, we only test when we run have a patch panel ran between rooms and have to test the punch downs and making sure its wired correctly but we never stress tested an ethernet port on a switch.