isdntest Subtests

D 

Basic Rate HDLC 

256 bytes 

10 packets 

B1 

56-kbps HDLC 

1024 bytes 

10 packets 

B2 

64-kbps HDLC 

1024 bytes 

10 packets 

Local Loopback test 

The local loopback test checks the initial activation state of the Network Termination (NT) and Terminal Equipment (TE) interfaces to make sure they are deactivated. The test then activates each interface using the "force activation" capability of DBRI. Each interface is put into local loopback mode. Data residing in host memory is written to each interface, which loops the data back to itself. The data is then read back into host memory and verified. Each channel--D, B1, and B2--is tested (with the exception of the TE D channel, which cannot be tested in local loopback mode). The local loopback test runs internal to the DBRI chip and does not require an NT-to-TE external loopback connector. 

Activation/Deactivation test  

The Activation/Deactivation test runs through the Activation/Deactivation sequence for the NT and then the activation sequence for the TE. The T101 and T103 timers are set to five seconds. This subtest requires an NT-to-TE external loopback connector.  

Remote Loopback test 

The remote loopback capability is tested next. The TE interface is put into remote loopback mode, and the NT transmits data to the TE on all three channels, D, B1 and B2. The TE loops all data back to the NT and reads a copy of it. Data is then verified. Next, the whole process is repeated with the TE transmitting to the NT, which is placed in remote loopback mode. This subtest requires an NT-to-TE external loopback connector.  

Read/Write test 

Next, the Read/Write test is performed on all six ISDN channels: TE D, TE B1, TE B2, NT D, NT B1, and NT B2. The external loopback connector connects each channel on the TE interface to its corresponding channel on the NT. A unique data pattern is used for each path. Packets read are compared against packets written. The test is repeated with the B1 channels placed in 64-kbps HDLC data mode and the B2 channels in 56-kbps HDLC data mode. This subtest requires an NT-to-TE external loopback connector.  

Packet Size test 

The next subtest is the Packet Size test. A read/write test, similar to the previous one, is performed with a packet count of 100. Each packet transmitted and received is a unique size, computed randomly. This subtest requires an NT-to-TE external loopback connector.  

Data Path test 

The last subtest is the Data Path test. Using the ISDN_SET_CHANNEL ioctl, data is routed through a series of short pipe interconnects within DBRI. This subtest requires an NT-to-TE external loopback connector.