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CoS on SONET/SDH OC48/STM16 IQE PIC Overview

The SONET/SDH OC48/STM16 IQE PIC is a clear-channel PIC that is designed to provide better scaling and improved queuing, buffering, and traffic shaping along with clear-channel functionality. Class of service (CoS) on the SONET/SDH OC48/STM16 IQE PIC supports per data-link connection identifier (DLCI) queuing at egress. The SONET/SDH OC48/STM16 IQE PIC can be used in Juniper Networks M320, MX240, MX960, T640, and T1600 routers.

The SONET/SDH OC48/STM16 IQE PIC supports the following CoS features:

  • Eight queues per logical interface.

    Note:

    Queue configuration in other modes, such as 4 queues per scheduler, is not supported on the SONET/SDH OC48/STM16 IQE PIC.

  • Two shaping rates: a committed information rate (CIR) and peak information rate (PIR) per data-link connection identifier (DLCI).

  • Sharing of excess bandwidth among logical interfaces.

  • Five levels of priorities—three priorities for traffic below the guaranteed rate and two priorities for traffic above the guaranteed rate. By default, a strict-high queue gets the excess high priority and all other queues get the excess low priority.

  • Ingress behavior aggregate (BA) classification.

  • Translation table and egress rewrite.

  • Egress delay buffer of 214ms.

  • Forwarding class to queue remapping per DLCI.

  • Weighted round-robin (WRR), weighted random early detection (WRED).

  • Rate limit on all queues to limit the transmission rate.

  • Per unit scheduling via DLCI at egress, where each DLCI gets a dedicated set of queues and a scheduler. When per unit scheduling is configured, the shaping can be configured at the logical and physical interface levels.

    Note:

    Because the SONET/SDH OC48/STM16 IQE PIC is not an oversubscribed PIC, there is no ingress queuing. Therefore, ingress scheduling or shaping is not supported in SONET/SDH OC48/STM16 IQE PIC.

  • Packet or byte statistics are separately collected for ingress and egress queues. The SONET/SDH OC48/STM16 IQE PIC provides the following statistics:

    • Ingress statistics:

      • Per logical interface transmit and drop bytes/packets statistics (based on Layer 3).

      • Per physical interface traffic bytes/packets statistics (based on Layer 2).

    • Egress statistics:

      • Per queue transmit and drop bytes/packets statistics (based on Layer 2).

      • Per queue per color drop bytes/packets statistics (based on Layer 2).

      • Per logical interface transmit and drop bytes/packets statistics (based on Layer 3).

      • Per physical interface traffic bytes/packets statistics (based on Layer 2).

To configure the features mentioned above, include the corresponding class-of-service (CoS) statements at the [edit class-of-service] hierarchy level. The CoS configuration statements supported on the SONET/SDH OC48/STM16 IQE PIC are the same as the CoS configuration statements supported on the IQ2E PIC except for the following unsupported statements.

Unsupported configuration statements at the [edit chassis] hierarchy level:

  • max-queues-per-interface

  • no-concatenate

  • q-pic-large-buffer

  • red-buffer-occupancy

  • ingress-shaping-overhead

  • traffic manager mode

Unsupported configuration statements at the [edit class-of-service] hierarchy level:

  • input-excess-bandwidth-share

  • input-traffic-control-profile

  • per-session-scheduler

  • simple-filter

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