Configuring ATM-over-SHDSL Interfaces

The symmetric high-speed digital subscriber line (SHDSL) Physical Interface Module (PIM) is available for J-series Services Routers. The PIM supports multi-rate, high-speed, symmetrical digital subscriber line technology for data transfer between a single customer premises equipment (CPE) subscriber and a central office (CO). Unlike ADSL, which was designed for delivering more bandwidth downstream than upstream, SHDSL is symmetrical and delivers a bandwidth of 2.3 Mbps in both directions. The SHDSL PIM has 2 ports and supports ATM-over-SHDSL mode only.

SHDSL is defined in the following specifications from the ITU and the Internet Engineering Task Force (IETF):

• ITU G.991.2, Single-pair High-speed Digital Subscriber Line (SHDSL) Transceiver.
• ITU G.994.1, Handshake Procedures for Digital Subscriber Line (DSL) Transceivers.
• ITU G.997.1, Physical Layer Management for Digital Subscriber Line (DSL) Transceivers.
• RFC 3276, Definitions of Managed Objects for High Bit-Rate DSL - 2nd generation (HDSL2) and Single-Pair High-Speed Digital Subscriber Line (SHDSL) Lines.

J-series Services Routers with SHDSL Annex A or Annex B PIMs act as a primary WAN link. They use an ATM interface to send network traffic through a point-to-point connection to a DSL-access multiplexer (DSLAM). You can configure Point-to-Point Protocol over Ethernet (PPPoE) over ATM to connect through DSL lines. For more information about configuring PPPoE, see Configuring PPPoE.

ATM-over-SHDSL interfaces are not supported on J2300 Services Routers.

NOTE: You can configure J-series Services Routers with SHDSL PIMs for connections through SHDSL only, not for direct ATM connections.

To configure the ATM mode for SHDSL, include the pic-mode statement at the [edit chassis fpc fpc-number pic 0 shdsl] hierarchy level:

[edit chassis]

    fpc fpc-number {

        pic 0 {

            shdsl {

                pic-mode (1-port-atm | 2-port-atm);

        }

    }

}

For more information about configuring the ATM mode, see the JUNOS System Basics Configuration Guide and the J-series Services Router Advanced WAN Access Configuration Guide.

To configure SHDSL operating mode on the physical ATM interface and set the encapsulation, include the shdsl-options statement and the encapsulation statement at the [edit interfaces at-pim/0/port] hierarchy level:

[edit interfaces at-pim/0/port]

    shdsl-options {

        annex (annex-a | annex-b);

        line-rate line-rate;

        loopback (local remote);

        snr-margin {

            current margin;

            snext margin;

        }

    encapsulation (atm-pvc | ethernet-over-atm)

    }

}

To configure ATM virtual path identifier (VPI) options for the interface, include the vpi statement at the [edit interfaces interface-name atm-options] hierarchy level:

[edit interfaces interface-name] 

    atm-options {

        vpi vpi-identifier {

            maximum-vcs maximum-vcs;

            oam-liveness {

                up-count cells;

                down-count cells;

            }

            oam-period (disable | seconds);

        }

    }

}

For more information about configuring ATM VPI options, see Configuring the 
Maximum Number of ATM1 VCs on a VP.

To configure logical interface properties, include the encapsulation statement, family statement, and vci statement:

unit logical-unit-number {

    encapsulation type;

    family inet{

    vci vpi-identifier.vci-identifier;

    }

}

You can include these statements at the following hierarchy levels:

• [edit interfaces interface-name unit logical-unit-number]
• [edit logical-routers logical-router-name interfaces interface-name unit logical-unit-number]

This chapter includes the following topics:

• Configuring ATM Mode on the PIM
• Configuring SHDSL Operating Mode on an ATM Physical Interface
• Configuring Encapsulation on the ATM Physical Interface
• Configuring Logical Interface Properties
• Example: Configuring an ATM-over-SHDSL Interface
• Verifying an ATM-over-SHDSL Interface Configuration