- play_arrow Overview
- play_arrow Understanding How Class of Service Manages Congestion and Defines Traffic Forwarding Behavior
- Understanding How Class of Service Manages Congestion and Controls Service Levels in the Network
- How CoS Applies to Packet Flow Across a Network
- The Junos OS CoS Components Used to Manage Congestion and Control Service Levels
- Mapping CoS Component Inputs to Outputs
- Default Junos OS CoS Settings
- Packet Flow Through the Junos OS CoS Process Overview
- Configuring Basic Packet Flow Through the Junos OS CoS Process
- Example: Classifying All Traffic from a Remote Device by Configuring Fixed Interface-Based Classification
- Interface Types That Do Not Support Junos OS CoS
-
- play_arrow Configuring Class of Service
- play_arrow Assigning Service Levels with Behavior Aggregate Classifiers
- Understanding How Behavior Aggregate Classifiers Prioritize Trusted Traffic
- Default IP Precedence Classifier
- Default DSCP and DSCP IPv6 Classifiers
- Default MPLS EXP Classifier
- Default IEEE 802.1p Classifier
- Default IEEE 802.1ad Classifier
- Default Aliases for CoS Value Bit Patterns Overview
- Defining Aliases for CoS Value Bit Patterns
- Configuring Behavior Aggregate Classifiers
- Applying Behavior Aggregate Classifiers to Logical Interfaces
- Example: Configuring and Applying a Default DSCP Behavior Aggregate Classifier
- Example: Configuring Behavior Aggregate Classifiers
- Understanding DSCP Classification for VPLS
- Example: Configuring DSCP Classification for VPLS
- Configuring Class of Service for MPLS LSPs
- Applying DSCP Classifiers to MPLS Traffic
- Applying MPLS EXP Classifiers to Routing Instances
- Applying MPLS EXP Classifiers for Explicit-Null Labels
- Manage Ingress Oversubscription with Traffic Class Maps
- play_arrow Assigning Service Levels with Multifield Classifiers
- Overview of Assigning Service Levels to Packets Based on Multiple Packet Header Fields
- Configuring Multifield Classifiers
- Using Multifield Classifiers to Set Packet Loss Priority
- Example: Configuring and Applying a Firewall Filter for a Multifield Classifier
- Example: Classifying Packets Based on Their Destination Address
- Example: Configuring and Verifying a Complex Multifield Filter
- play_arrow Controlling Network Access with Traffic Policing
- Controlling Network Access Using Traffic Policing Overview
- Effect of Two-Color Policers on Shaping Rate Changes
- Configuring Policers Based on Logical Interface Bandwidth
- Example: Limiting Inbound Traffic at Your Network Border by Configuring an Ingress Single-Rate Two-Color Policer
- Example: Performing CoS at an Egress Network Boundary by Configuring an Egress Single-Rate Two-Color Policer
- Example: Limiting Inbound Traffic Within Your Network by Configuring an Ingress Single-Rate Two-Color Policer and Configuring Multifield Classifiers
- Example: Limiting Outbound Traffic Within Your Network by Configuring an Egress Single-Rate Two-Color Policer and Configuring Multifield Classifiers
- Overview of Tricolor Marking Architecture
- Enabling Tricolor Marking and Limitations of Three-Color Policers
- Configuring and Applying Tricolor Marking Policers
- Configuring Single-Rate Tricolor Marking
- Configuring Two-Rate Tricolor Marking
- Example: Configuring and Verifying Two-Rate Tricolor Marking
- Applying Firewall Filter Tricolor Marking Policers to Interfaces
- Policer Overhead to Account for Rate Shaping in the Traffic Manager
- play_arrow Defining Forwarding Behavior with Forwarding Classes
- Understanding How Forwarding Classes Assign Classes to Output Queues
- Default Forwarding Classes
- Configuring a Custom Forwarding Class for Each Queue
- Configuring Up to 16 Custom Forwarding Classes
- Classifying Packets by Egress Interface
- Forwarding Policy Options Overview
- Configuring CoS-Based Forwarding
- Example: Configuring CoS-Based Forwarding
- Example: Configuring CoS-Based Forwarding for Different Traffic Types
- Example: Configuring CoS-Based Forwarding for IPv6
- Applying Forwarding Classes to Interfaces
- Understanding Queuing and Marking of Host Outbound Traffic
- Forwarding Classes and Fabric Priority Queues
- Default Routing Engine Protocol Queue Assignments
- Assigning Forwarding Class and DSCP Value for Routing Engine-Generated Traffic
- Example: Writing Different DSCP and EXP Values in MPLS-Tagged IP Packets
- Change the Default Queuing and Marking of Host Outbound Traffic
- Example: Configure Different Queuing and Marking Defaults for Outbound Routing Engine and Distributed Protocol Handler Traffic
- Overriding the Input Classification
- play_arrow Defining Output Queue Properties with Schedulers
- How Schedulers Define Output Queue Properties
- Default Schedulers Overview
- Configuring Schedulers
- Configuring Scheduler Maps
- Applying Scheduler Maps Overview
- Applying Scheduler Maps to Physical Interfaces
- Configuring Traffic Control Profiles for Shared Scheduling and Shaping
- Configuring an Input Scheduler on an Interface
- Understanding Interface Sets
- Configuring Interface Sets
- Interface Set Caveats
- Configuring Internal Scheduler Nodes
- Example: Configuring and Applying Scheduler Maps
- play_arrow Controlling Bandwidth with Scheduler Rates
- Oversubscribing Interface Bandwidth
- Configuring Scheduler Transmission Rate
- Providing a Guaranteed Minimum Rate
- PIR-Only and CIR Mode
- Excess Rate and Excess Priority Configuration Examples
- Controlling Remaining Traffic
- Bandwidth Sharing on Nonqueuing Packet Forwarding Engines Overview
- Configuring Rate Limits on Nonqueuing Packet Forwarding Engines
- Applying Scheduler Maps and Shaping Rate to DLCIs and VLANs
- Example: Applying Scheduler Maps and Shaping Rate to DLCIs
- Example: Applying Scheduling and Shaping to VLANs
- Applying a Shaping Rate to Physical Interfaces Overview
- Configuring the Shaping Rate for Physical Interfaces
- Example: Limiting Egress Traffic on an Interface Using Port Shaping for CoS
- Configuring Input Shaping Rates for Both Physical and Logical Interfaces
- play_arrow Setting Transmission Order with Scheduler Priorities and Hierarchical Scheduling
- Priority Scheduling Overview
- Configuring Schedulers for Priority Scheduling
- Associating Schedulers with Fabric Priorities
- Hierarchical Class of Service Overview
- Hierarchical Class of Service Network Scenarios
- Understanding Hierarchical Scheduling
- Priority Propagation in Hierarchical Scheduling
- Hierarchical CoS for Metro Ethernet Environments
- Hierarchical Schedulers and Traffic Control Profiles
- Example: Building a Four-Level Hierarchy of Schedulers
- Hierarchical Class of Service for Network Slicing
- Configuring Ingress Hierarchical CoS
- play_arrow Controlling Congestion with Scheduler RED Drop Profiles, Buffers, PFC, and ECN
- RED Drop Profiles for Congestion Management
- Determining Packet Drop Behavior by Configuring Drop Profile Maps for Schedulers
- Managing Congestion by Setting Packet Loss Priority for Different Traffic Flows
- Mapping PLP to RED Drop Profiles
- Managing Congestion on the Egress Interface by Configuring the Scheduler Buffer Size
- Managing Transient Traffic Bursts by Configuring Weighted RED Buffer Occupancy
- Example: Managing Transient Traffic Bursts by Configuring Weighted RED Buffer Occupancy
- Understanding PFC Using DSCP at Layer 3 for Untagged Traffic
- Configuring DSCP-based PFC for Layer 3 Untagged Traffic
- PFC Watchdog
- CoS Explicit Congestion Notification
- Example: Configuring Static and Dynamic ECN
- play_arrow Altering Outgoing Packet Headers Using Rewrite Rules
- Rewriting Packet Headers to Ensure Forwarding Behavior
- Applying Default Rewrite Rules
- Configuring Rewrite Rules
- Configuring Rewrite Rules Based on PLP
- Applying IEEE 802.1p Rewrite Rules to Dual VLAN Tags
- Applying IEEE 802.1ad Rewrite Rules to Dual VLAN Tags
- Rewriting IEEE 802.1p Packet Headers with an MPLS EXP Value
- Setting IPv6 DSCP and MPLS EXP Values Independently
- Configuring DSCP Values for IPv6 Packets Entering the MPLS Tunnel
- Setting Ingress DSCP Bits for Multicast Traffic over Layer 3 VPNs
- Applying Rewrite Rules to Output Logical Interfaces
- Rewriting MPLS and IPv4 Packet Headers
- Rewriting the EXP Bits of All Three Labels of an Outgoing Packet
- Defining a Custom Frame Relay Loss Priority Map
- Example: Per-Node Rewriting of EXP Bits
- Example: Rewriting CoS Information at the Network Border to Enforce CoS Strategies
- Example: Remarking Diffserv Code Points to MPLS EXPs to Carry CoS Profiles Across a Service Provider’s L3VPN MPLS Network
- Example: Remarking Diffserv Code Points to 802.1P PCPs to Carry CoS Profiles Across a Service Provider’s VPLS Network
- Assigning Rewrite Rules on a Per-Customer Basis Using Policy Maps
- Host Outbound Traffic IEEE802.1p Rewrite
- play_arrow Altering Class of Service Values in Packets Exiting the Network Using IPv6 DiffServ
- Resources for CoS with DiffServ for IPv6
- System Requirements for CoS with DiffServ for IPv6
- Terms and Acronyms for CoS with DiffServ for IPv6
- Default DSCP Mappings
- Default Forwarding Classes
- Juniper Networks Default Forwarding Classes
- Roadmap for Configuring CoS with IPv6 DiffServ
- Configuring a Firewall Filter for an MF Classifier on Customer Interfaces
- Applying the Firewall Filter to Customer Interfaces
- Assigning Forwarding Classes to Output Queues
- Configuring Rewrite Rules
- DSCP IPv6 Rewrites and Forwarding Class Maps
- Applying Rewrite Rules to an Interface
- Configuring RED Drop Profiles
- Configuring BA Classifiers
- Applying a BA Classifier to an Interface
- Configuring a Scheduler
- Configuring Scheduler Maps
- Applying a Scheduler Map to an Interface
- Example: Configuring DiffServ for IPv6
-
- play_arrow Configuring Line Card-Specific and Interface-Specific Functionality
- play_arrow Feature Support of Line Cards and Interfaces
- play_arrow Configuring Class of Service for Tunnels
- play_arrow Configuring Class of Service on Services PICs
- CoS on Services PICs Overview
- Configuring CoS Rules on Services PICs
- Configuring CoS Rule Sets on Services PICs
- Example: Configuring CoS Rules on Services PICs
- Packet Rewriting on Services Interfaces
- Multiservices PIC ToS Translation
- Fragmentation by Forwarding Class Overview
- Configuring Fragmentation by Forwarding Class
- Configuring Drop Timeout Interval for Fragmentation by Forwarding Class
- Example: Configuring Fragmentation by Forwarding Class
- Allocating Excess Bandwidth Among Frame Relay DLCIs on Multiservices PICs
- Configuring Rate Limiting and Sharing of Excess Bandwidth on Multiservices PICs
- play_arrow Configuring Class of Service on IQ and Enhanced IQ (IQE) PICs
- CoS on Enhanced IQ PICs Overview
- Calculation of Expected Traffic on IQE PIC Queues
- Configuring the Junos OS to Support Eight Queues on IQ Interfaces for T Series and M320 Routers
- BA Classifiers and ToS Translation Tables
- Configuring ToS Translation Tables
- Configuring Hierarchical Layer 2 Policers on IQE PICs
- Configuring Excess Bandwidth Sharing on IQE PICs
- Configuring Rate-Limiting Policers for High Priority Low-Latency Queues on IQE PICs
- Applying Scheduler Maps and Shaping Rate to Physical Interfaces on IQ PICs
- Applying Scheduler Maps to Chassis-Level Queues
- play_arrow Configuring Class of Service on Ethernet IQ2 and Enhanced IQ2 PICs
- CoS on Enhanced IQ2 PICs Overview
- CoS Features and Limitations on IQ2 and IQ2E PICs (M Series and T Series)
- Differences Between Gigabit Ethernet IQ and Gigabit Ethernet IQ2 PICs
- Shaping Granularity Values for Enhanced Queuing Hardware
- Ethernet IQ2 PIC RTT Delay Buffer Values
- Configuring BA Classifiers for Bridged Ethernet
- Setting the Number of Egress Queues on IQ2 and Enhanced IQ2 PICs
- Configuring the Number of Schedulers per Port for Ethernet IQ2 PICs
- Applying Scheduler Maps to Chassis-Level Queues
- CoS for L2TP Tunnels on Ethernet Interface Overview
- Configuring CoS for L2TP Tunnels on Ethernet Interfaces
- Configuring LNS CoS for Link Redundancy
- Example: Configuring L2TP LNS CoS Support for Link Redundancy
- Configuring Shaping on 10-Gigabit Ethernet IQ2 PICs
- Configuring Per-Unit Scheduling for GRE Tunnels Using IQ2 and IQ2E PICs
- Understanding Burst Size Configuration on IQ2 and IQ2E Interfaces
- Configuring Burst Size for Shapers on IQ2 and IQ2E Interfaces
- Configuring a CIR and a PIR on Ethernet IQ2 Interfaces
- Example: Configuring Shared Resources on Ethernet IQ2 Interfaces
- Configuring and Applying IEEE 802.1ad Classifiers
- Configuring Rate Limits to Protect Lower Queues on IQ2 and Enhanced IQ2 PICs
- Simple Filters Overview
- Configuring a Simple Filter
- play_arrow Configuring Class of Service on 10-Gigabit Ethernet LAN/WAN PICs with SFP+
- CoS on 10-Gigabit Ethernet LAN/WAN PIC with SFP+ Overview
- BA and Fixed Classification on 10-Gigabit Ethernet LAN/WAN PIC with SFP+ Overview
- DSCP Rewrite for the 10-Gigabit Ethernet LAN/WAN PIC with SFP+
- Configuring DSCP Rewrite for the 10-Gigabit Ethernet LAN/WAN PIC
- Queuing on 10-Gigabit Ethernet LAN/WAN PICs Properties
- Mapping Forwarding Classes to CoS Queues on 10-Gigabit Ethernet LAN/WAN PICs
- Scheduling and Shaping on 10-Gigabit Ethernet LAN/WAN PICs Overview
- Example: Configuring Shaping Overhead on 10-Gigabit Ethernet LAN/WAN PICs
- play_arrow Configuring Class of Service on Enhanced Queuing DPCs
- Enhanced Queuing DPC CoS Properties
- Configuring Rate Limits on Enhanced Queuing DPCs
- Configuring WRED on Enhanced Queuing DPCs
- Configuring MDRR on Enhanced Queuing DPCs
- Configuring Excess Bandwidth Sharing
- Configuring Customer VLAN (Level 3) Shaping on Enhanced Queuing DPCs
- Simple Filters Overview
- Configuring Simple Filters on Enhanced Queuing DPCs
- Configuring a Simple Filter
- play_arrow Configuring Class of Service on MICs, MPCs, and MLCs
- CoS Features and Limitations on MIC and MPC Interfaces
- Dedicated Queue Scaling for CoS Configurations on MIC and MPC Interfaces Overview
- Verifying the Number of Dedicated Queues Configured on MIC and MPC Interfaces
- Scaling of Per-VLAN Queuing on Non-Queuing MPCs
- Increasing Available Bandwidth on Rich-Queuing MPCs by Bypassing the Queuing Chip
- Flexible Queuing Mode
- Multifield Classifier for Ingress Queuing on MX Series Routers with MPC
- Example: Configuring a Filter for Use as an Ingress Queuing Filter
- Ingress Queuing Filter with Policing Functionality
- Ingress Rate Limiting on MX Series Routers with MPCs
- Rate Shaping on MIC and MPC Interfaces
- Per-Priority Shaping on MIC and MPC Interfaces Overview
- Example: Configuring Per-Priority Shaping on MIC and MPC Interfaces
- Configuring Static Shaping Parameters to Account for Overhead in Downstream Traffic Rates
- Example: Configuring Static Shaping Parameters to Account for Overhead in Downstream Traffic Rates
- Traffic Burst Management on MIC and MPC Interfaces Overview
- Understanding Hierarchical Scheduling for MIC and MPC Interfaces
- Configuring Ingress Hierarchical CoS on MIC and MPC Interfaces
- Configuring a CoS Scheduling Policy on Logical Tunnel Interfaces
- Per-Unit Scheduling and Hierarchical Scheduling for MPC Interfaces
- Managing Dedicated and Remaining Queues for Static CoS Configurations on MIC and MPC Interfaces
- Excess Bandwidth Distribution on MIC and MPC Interfaces Overview
- Bandwidth Management for Downstream Traffic in Edge Networks Overview
- Scheduler Delay Buffering on MIC and MPC Interfaces
- Managing Excess Bandwidth Distribution on Static Interfaces on MICs and MPCs
- Drop Profiles on MIC and MPC Interfaces
- Intelligent Oversubscription on MIC and MPC Interfaces Overview
- Jitter Reduction in Hierarchical CoS Queues
- Example: Reducing Jitter in Hierarchical CoS Queues
- CoS on Ethernet Pseudowires in Universal Edge Networks Overview
- CoS Scheduling Policy on Logical Tunnel Interfaces Overview
- Configuring CoS on an Ethernet Pseudowire for Multiservice Edge Networks
- CoS for L2TP LNS Inline Services Overview
- Configuring Static CoS for an L2TP LNS Inline Service
- CoS on Circuit Emulation ATM MICs Overview
- Configuring CoS on Circuit Emulation ATM MICs
- Understanding IEEE 802.1p Inheritance push and swap from a Transparent Tag
- Configuring IEEE 802.1p Inheritance push and swap from the Transparent Tag
- CoS on Application Services Modular Line Card Overview
- play_arrow Configuring Class of Service on Aggregated, Channelized, and Gigabit Ethernet Interfaces
- Limitations on CoS for Aggregated Interfaces
- Policer Support for Aggregated Ethernet Interfaces Overview
- Understanding Schedulers on Aggregated Interfaces
- Examples: Configuring CoS on Aggregated Interfaces
- Hierarchical Schedulers on Aggregated Ethernet Interfaces Overview
- Configuring Hierarchical Schedulers on Aggregated Ethernet Interfaces
- Example: Configuring Scheduling Modes on Aggregated Interfaces
- Enabling VLAN Shaping and Scheduling on Aggregated Interfaces
- Class of Service on demux Interfaces
- Example: Configuring Per-Unit Schedulers for Channelized Interfaces
- Applying Layer 2 Policers to Gigabit Ethernet Interfaces
-
- play_arrow Configuration Statements and Operational Commands
Schedulers Overview for ACX Series Routers
You use schedulers to define the properties of output queues. These properties include the amount of interface bandwidth assigned to the queue, the size of the memory buffer allocated for storing packets, the priority of the queue, and the random early detection (RED) drop profiles associated with the queue.
You associate the schedulers with forwarding classes by means of scheduler maps. You can then associate each scheduler map with an interface, thereby configuring the hardware queues, packet schedulers, and RED processes that operate according to this mapping.
In ACX Series routers, you can configure more than one strict-priority queue per port.
The hardware services the queues in the descending order of queue numbers marked as
strict priority. All the strict-priority queues are given preferential treatment by the
scheduler as long as their shaping rates (or peak information rates) are not met. Unlike
MX Series routers, the ACX Series routers configured with queues as
strict-high at the [edit class-of-service schedulers scheduler-name priority strict-high] statement hierarchy, the service is based
on queue number and not based on sharing the strict-high queues.
Scheduling on ACX Routers Running Junos OS
Unlike other ACX Series routers, ACX5048 and ACX5096 router supports CIR among
strict-priority queues. There is no implicit queue number-based priority among the
strict-priority queues. Unlike other ACX Series routers, ACX5048 and ACX5096 router
supports configuring drop profiles for loss-priority low,
medium-high, and high for non-TCP protocols as
well.
The options buffer-partition multicast percent
<0-100> at the [edit
class-of-service schedulers scheduler-name
buffer-size] hierarchy level and multicast
<0-100> at the [edit
class-of-service schedulers scheduler-name
shared-buffer-maximum] hierarchy level are supported only on
ACX5048 and ACX5096 routers. For more information, see Shared and Dedicated Buffer Memory Pools on ACX Series Routers.
ACX5448 routers support port-based queueing, scheduling, and shaping. You can
configure up to eight queues (virtual output queues) per physical interface (port).
Scheduling properties can be applied at both physical as well as logical interface
levels. The egress scheduler supports two priority levels
(strict-high and low). Multiple strict-high
priority queues and multiple low (default) priority queues can be configured.
By default a port on an ACX5448 router gets a dedicated buffer of 100 microseconds and shared buffer from DRAM. Delay buffer controls the latency of the queue during congestion and maximum number of packets that can be held in a queue. Default buffer size per port is 100 microseconds.
On all ACX Series routers running Junos OS, the strict priority
queues cannot have transmit-rate configured.
On ACX710 routers, class-of-service commit changes, particularly for schedulers on a physical interface, cause very short (less than one second) pauses in forwarding packets. This can cause packet loss. For some protocols that use very short keepalive intervals, such as BFD, we recommend you disable or enlarge the keepalive interval before you apply scheduler changes. We also recommend you configure scheduling before you enable live traffic.
On ACX 4000 routers, whenever the scheduling and shaping parameters of a port or any of its queues are changed, the entire scheduling configuration on the port is erased and the new configuration is applied. During this window, the traffic pattern does not adhere to user parameters. We recommend you configure scheduling before you enable live traffic.
Scheduling on ACX Routers Running Junos OS Evolved
All ACX7000 routers run Junos OS Evolved.
Scheduling Priorities
ACX7000 routers support eight scheduler priority levels for port-level scheduling and six levels for hierarchical scheduling. ACX7000 routers also support multiple queues with the same priority.
Priority | Port Scheduling | Hierarchical Scheduling |
|---|---|---|
low-latency | Yes | Yes |
strict-hight | Yes | Yes |
high | Yes | Yes |
medium-high | Yes | Yes |
medium-low | Yes | Yes |
low-high | Yes | No |
low-medium | Yes | No |
low | Yes | Yes |
ACX routers do not guarantee round-robin distribution between same priority queues.
On all ACX routers running Junos OS Evolved, you can only configure
transmit-rate on low priority queues.
Low Latency Queuing (LLQ)
ACX7000 routers support low latency queuing (LLQ). LLQ enables delay-sensitive
data to have preferential treatment over other traffic. A
low-latency queue has the highest priority over any other
priority queues, including strict-high queues, as well as a low
delay scheduling profile.
For port scheduling of virtual output queues (VOQs), low latency VOQs receive their own dedicated egress queue. High priority VOQs receive a second dedicated egress queue, and low priority VOQs receive a third dedicated egress queue.
Due to the scheduling hierarchy of hierarchical class of service (HCoS), a hierarchical scheduling can use a maximum of two egress queues. Therefore for hierarchical scheduling of VOQs, low latency VOQs and high priority VOQs receive a common dedicated egress queue, and low priority VOQs receive the second dedicated egress queue.
We recommend the following when configuring low-latency VOQs:
Use policers to normalize the burstiness of traffic before it reaches a low-latency VOQ.
Configure a maximum of two low-latency VOQs on a physical or logical interface.
Classify and schedule traffic (that is, reserve bandwidth) for low-latency VOQs so that there is no congestion for those queues.
Low-latency queues receive the same buffers as other queues to efficiently use the limited hardware VOQ buffer profiles.
Change History Table
Feature support is determined by the platform and release you are using. Use Feature Explorer to determine if a feature is supported on your platform.
