Configuring T3 Interfaces

T3 is the physical layer protocol used by the Digital Signal level 3 (DS3) multiplexing method in North America. A T3 interface operates at a bit rate of 44.736 Mbps. The JUNOS software supports payload scrambling and subrate operation on each physical T3 interface. One encapsulation format—Point-to-Point Protocol (PPP), Frame Relay, or High-level Data Link Control (HDLC)—must be configured for the interface. DS3 standards supported include:

• ANSI TI.107, TI.102
• GR 499-core, GR 253-core
• Bellcore TR-TSY-000009
• AT&T Pub 54014
• ITU G.751, G.703, G823

To configure T3-specific physical interface properties, include the t3-options statement at the [edit interfaces interface-name] hierarchy level:

[edit interfaces interface-name]

t3-options {

    bert-algorithm algorithm; 

    bert-error-rate rate; 

    bert-period seconds; 

    (cbit-parity | no-cbit-parity); 

    compatibility-mode (adtran | digital-link | kentrox | larscom | verilink) 

          <subrate value>; 

    fcs (16 | 32);

    (feac-loop-respond | no-feac-loop-respond);

    idle-cycle-flag value; 

    (long-buildout | no-long-buildout);

    (loop-timing | no-loop-timing);

    loopback (local | payload | remote); 

    (payload-scrambler | no-payload-scrambler); 

    start-end-flag value; 

}

You can configure the following T3 interface-specific properties:

• Configuring T3 BERT Properties
• Disabling T3 C-Bit Parity Mode
• Configuring the T3 CSU Compatibility Mode
• Configuring the T3 Frame Checksum
• Configuring the T3 FEAC Response
• Configuring the T3 Idle Cycle Flag
• Configuring the T3 Line Buildout
• Configuring the Channelized T3 Loop Timing
• Configuring T3 Loopback Capability
• Configuring T3 HDLC Payload Scrambling
• Configuring T3 Start and End Flags

See also the following section, which applies to a number of different interfaces:

• Configuring an ISDN Dialer Interface as a Backup Interface

For an example of T3 interface configuration, see Examples: Configuring T3 Interfaces.