Testing at the T1 Layer

The T1 channel testing commands enable you to specify testing parameters for a single channel, multiple individual channels, ranges of channels, or any combination of the three types of specifications. For example:

To enable testing at the T1 layer:

1. Configure one of the following loopback tests.
   • Set the loopback to local to test the line without connecting to the network.

     host1(config-controll)#t1 2 loopback local

   • Set the loopback to network to test the line connected to the network.

     host1(config-controll)#t1 2 loopback network line

   • Set the loopback to remote-loopback to enable acceptance of loopback commands issued from a remote router.

     host1(config-controll)#t1 2 remote-loopback

2. Configure the line to run bit error rate tests.

   host1(config-controll)#t1 2 bert pattern 2^11 time 10 unframed

t1 bert

• Use to enable bit error rate tests using the specified pattern on a T1 interface.
• Unlike other configuration commands, bert is not stored in NVRAM.
• Specify one of the following test patterns:

  Note: The CT3/T3-F0 line module supports only the 2^11, 2^15, and 2^20-O153 options.

  • 0s—Repetitive test pattern of all zeros, 00000...
  • 1s—Repetitive test pattern of all ones, 11111...
  • 2^11—Pseudorandom test pattern, 2047 bits in length
  • 2^15—Pseudorandom test pattern, 32,767 bits in length
  • 2^20-O153—Pseudorandom test pattern, 1,048,575 bits in length
  • 2^20-QRSS—Pseudorandom QRSS test pattern, 1,048,575 bits in length
  • 2^23—Pseudorandom test pattern, 8,388,607 bits in length
  • alt-0-1—Repetitive alternating test pattern of zeros and ones, 01010101...

    Note: The BERT patterns supported when testing the T1 layer vary depending on the line module and I/O module assembly you are using.

• Specify the duration of the test in the range 1–1440 minutes.
• Optionally, specify the unframed keyword to overwrite the framing bits.
• Example

  host1(config-controll)#t1 2 bert pattern 2^11 interval 10 unframed

• Use the no version to stop the test that is running.
• See t1 bert.

t1 loopback

• Use to configure a loopback.
• Specify one of the following options:

  Note: The CT3/T3-F0 line module does not support the remote line inband option.

  • local—Loops the router output data back toward the router at the T1 framer; on supported line modules, also sends an alarm indication signal (AIS) out toward the network
  • network { line | payload }—Specify the line keyword to loop the data back toward the network before the T1 framer and automatically set a local loopback at the HDLC controllers. Specify the payload keyword to loop the payload data back toward the network at the T1 framer and automatically set a local loopback at the HDLC controllers.
  • remote line fdl ansi—Sends a repeating 16-bit ESF data link code word (00001110 11111111) to the remote end requesting that it enter into a network line loopback. Specify the ansi keyword to enable the remote line facilities data link (FDL) ANSI bit loopback on the T1 channel, according to the ANSI T1.403 Specification.
  • remote line fdl bellcore—Sends a repeating 16-bit ESF data link code word (00010010 11111111) to the remote end requesting that it enter into a network line loopback. Specify the bellcore keyword to enable the remote line facilities data link (FDL) Bellcore bit loopback on the T1 channel, per the Bellcore TR-TSY-000312 Specification.
  • remote line inband—Sends a repeating 5-bit inband pattern (00001) to the remote end requesting that it enter into a network line loopback
  • remote payload [ fdl ] [ ansi ]—Sends a repeating, 16-bit, ESF data link code word (00010100 11111111) to the remote end requesting that it enter into a network payload loopback. Enables the remote payload facilities data link (FDL) ANSI bit loopback on the T1 channel. You can optionally specify fdl and ansi.
• If you do not specify an option, the router will set a local loopback for the channel.
• Example

  host1(config-controll)#t1 2 loopback local

• Use the no version to deactivate loopback. If you specify the remote keyword, the no version sends the 16-bit ESF data link code word or inband pattern to deactivate the loopback at the remote end based on the last activate request sent to the remote end. If you do not specify the remote keyword, the no version clears the local loopback configuration.
• See t1 loopback.

t1 remote-loopback

• Use to enable the acceptance of loopback commands issued from a remote router.
• Example

  host1(config-controll)#t1 2 remote-loopback

• Use the no version to restore the factory default, which is to reject loopback commands issued from a remote router.
• See t1 remote-loopback.

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