Configuring E3 Interfaces

E3 is a high-speed WAN digital communication technique designed to operate over copper facilities at a rate of 34.368 Mbps. Widely used outside North America, it is the time-division multiplexing scheme used to carry 16 E1 circuits. The following standards apply to E3 interfaces:

• ITU-T Recommendation G.703, Physical/electrical characteristics of hierarchical digital interfaces, describes data rates and multiplexing schemes for the E series.
• ITU-T Recommendation G.751, General Aspects of Digital Transmission Systems: Terminal Equipment, describes framing methods.
• ITU-T Recommendation G.775, Loss of Signal (LOS) and Alarm Indication Signal (AIS) Defect Detection and Clearance Criteria, describes alarm reporting methods.

The JUNOS software supports the E3 Physical Interface Card (PIC) and the E3 Intelligent Queuing (IQ) PIC. The E3 IQ PIC supports transmission scheduling on logical interfaces. For more information, see the JUNOS Class of Service Configuration Guide.

NOTE: In unframed mode, the E3 IQ PIC does not detect yellow or loss-of-frame alarms.

To configure E3-specific physical interface properties, include the e3-options statement at the [edit interfaces interface-name] hierarchy level:

[edit interfaces interface-name]

e3-options {

    bert-algorithm algorithm; 

    bert-error-rate rate; 

    bert-period seconds; 

    compatibility-mode (digital-link | kentrox | larscom) <subrate value>; 

    fcs (16 | 32);

    idle-cycle-flag value; 

    loopback (local | remote); 

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

    start-end-flag value; 

    (unframed | no-unframed);

}

You can configure the following E3-specific properties:

• Configuring E3 BERT Properties
• Configuring the E3 CSU Compatibility Mode
• Configuring the E3 Frame Checksum
• Configuring the E3 Idle Cycle Flag
• Configuring E3 Loopback Capability
• Configuring E3 HDLC Payload Scrambling
• Configuring the E3 Start and End Flags
• Configuring E3 IQ Unframed Mode

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

• Configuring an ISDN Dialer Interface as a Backup Interface