CoS on ACX Series Routers Features Overview

CoS on ACX routers running Junos OS

The following key CoS features are supported on ACX Series Universal Metro Routers:

• Physical interface-based classifiers at the [edit class-of-service interfaces interfaces-name] hierarchy level

• Fixed classification for all ingress packets traversing a logical interface to a single forwarding class. Fixed classification is supported on all interface types.

• EXP bits located in each MPLS label and used to encode the CoS value of a packet as it traverses a label-switched path (LSP). To configure global EXP bits, include the exp statement at the [edit class-of-service system-defaults classifiers] hierarchy level.

• Rewrite rules at the physical and logical interface levels including the following: IP type-of-service (ToS), DSCP, MPLS EXP bit value, and IEEE 802.1p bit value.

• Attachment of the following rewrite rules to the physical interface at the [edit class-of-service interfaces interface-name rewrite-rules] hierarchy level: IP ToS, DSCP, and IEEE 802.1p bit value.

• Rewrite rules for MPLS EXP bits on the logical interface at the [edit class-of-service interfaces interface-name unit unit-number rewrite-rule] hierarchy level.

  Note:

  Fine-grained rewrite is not possible, even when you use multifield filters, because of the application-specific integrated circuit (ASIC) limitation.

Queuing and scheduling features include:

• Support for up to eight forwarding classes.

• Support for up to eight egress queues per port.

• Internal buffer of 2 MB with per-egress queue buffer management.

• Three weighted random early detection (WRED) curves for TCP and one WRED curve for non-TCP. There are two fill levels and two drop probabilities per WRED curve; the drop probability corresponding to the first fill must be zero.

• Strict-priority and weighted deficit round-robin scheduling.

• Multiple strict-priority queues per port.

• Per-queue committed information rate (CIR) and peak information rate (PIR).

• Per-physical-port shaping.

• Up to four levels of hierarchical scheduling, depending on the platform.

Queue statistics features include:

• Per-egress-queue enqueue statistics in packets, bytes, packets per second (pps), and bits per second (bps).

• Per-egress-queue transmit statistics in packets, bytes, pps, and bps.

• Per-egress-queue drop statistics in packets and pps.

CoS on ACX routers running Junos OS Evolved

ACX7000 Series routers support the following CoS features:

• Behavior aggregate (BA) classifiers (Inet-Prec/DSCP/DSCP-v6/EXP/IEEE-802.1p/IEEE-802.1ad) at the logical interface level

• Fixed and multifield classifiers

• Maximum of eight forwarding classes

• Eight virtual output queues (VOQ) per port

• Two scheduling priority levels - strict-high and low

• Multiple strict-high priority queues with round robin (RR) scheduling

• Multiple low priority queues with weighted fair queue (WFQ) scheduling

• CIR and PIR for low priority queues

• PIR at the port level

• Rewrite rules (Inet-Prec/DSCP/DSCP-v6/EXP/IEEE-802.1p/IEEE-802.1ad) at the logical interface level

• Hierarchical class of service (HCoS) features including:

  • Three levels of hierarchical scheduling (physical interfaces, logical interfaces, queues)

  • Support for Layer 3 VPN, Layer 2 VPN, Layer 2 Circuit, VPLS, and EVPN services

  • Per-queue buffer configuration

  • HCoS on aggregated Ethernet (ae-) interfaces

Note:

ACX routers running Junos OS Evolved do not support the following CLI show commands:

• show class-of-service forwarding-table
• show class-of-service routing-instance
• show class-of-service system-defaults