Description: This object is used to specify the type of test to run for ISDN-BRI ports. There are no results stored locally for a loopback test. Loopback of the whole ISDN-BRI physical user port is supported where all the D, B1 and B2 channels are looped back simultaneously, along with individual loopback of the D, B1 and B2 channels. AAL2 Loopback is also supported on a per sub-channel basis. In order to run these tests, the CO-IWF must first set the value of this object appropriate to the test that needs to be run. The CO-IWF should then set the value of ifAdminStatus in the corresponding ifEntry to 'testing'. The CO-IWF should verify that the test is in progress by checking that the value of ifOperStatus in the corresponding ifEntry is equal to 'testing'. Once testing is complete the CO-IWF must set the ifAdminStatus to a value other than 'testing'. Note that the LES device must not allow a CO-IWF to manipulate the ifAdminStatus of physical user ports that do not belong to its managed CP-IWF.