Supported Platforms
Example: Configuring Forwarding Class Sets
A forwarding class set (fc-set) is a priority group for enhanced transmission selection (ETS) traffic control. Each fc-set consists of one or more forwarding classes (output queues).
ETS enables you to configure link resources (bandwidth and bandwidth sharing characteristics) for a priority group, and then allocate the priority group’s resources among the forwarding classes that belong to the priority group. This is called two-tier, or hierarchical, scheduling. Traffic control profiles control the scheduling for the priority group, and schedulers control the scheduling for individual forwarding classes.
Requirements
This example uses the following hardware and software components:
- A Juniper Networks QFX3500 Switch
- Junos OS Release 11.1 or later for the QFX Series
Overview
You can configure up to three unicast fc-sets and one multicast fc-set. A common way to configure unicast priority groups is to configure separate fc-sets for local area network (LAN) traffic, storage area network (SAN) traffic, and high-performance computing (HPC) traffic, and then assign the appropriate forwarding classes to each fc-set.
![]() | Note: If you configure strict-high priority queues, you must create an fc-set that is dedicated only to strict-high priority traffic. Only one fc-set can contain strict-high priority queues. Queues that are not strict-high priority cannot belong to the same fc-set as strict-high priority queues. The multidestination fc-set cannot contain strict-high priority queues. |
To apply ETS, you map one or more fc-sets to a physical egress port. You can map up to three forwarding class sets to each port. When you map an fc-set to a port, the port uses hierarchical scheduling to allocate port resources to the priority group (fc-set) and to allocate the priority group resources to the queues (forwarding classes) that belong to the priority group.
This example describes how to:
- Configure three fc-sets called lan-pg, san-pg, and hpc-pg.
- Assign forwarding classes to each of the fc-sets.
- Apply the fc-sets and their output traffic control profiles to an egress interface.
This example does not describe how to configure the forwarding classes assigned to the fc-sets or how to configure traffic control profiles. Table 1 shows the configuration components for this example:
Table 1: Components of the Forwarding Class Sets Configuration Example
Component | Settings |
---|---|
Hardware | QFX3500 switch |
LAN traffic priority group | Forwarding class set: lan-pg |
SAN traffic priority group | Forwarding class set: san-pg |
HPC traffic priority group | Forwarding class set: hpc-pg |
Egress interface | xe-0/0/7 |
Configuring Forwarding Class Sets
Step-by-Step Procedure
- Define the lan-pg priority group (fc-set) and
assign to it the forwarding classes best-effort-1 and best-effort-2:
[edit class-of-service]
user@switch# set forwarding-class-sets lan-pg class best-effort-1
user@switch# set forwarding-class-sets lan-pg class best-effort-2 - Define the san-pg priority group and assign to
it the forwarding classes fcoe and fcoe-2:
[edit class-of-service]
user@switch# set forwarding-class-sets san-pg class fcoe
user@switch# set forwarding-class-sets san-pg class fcoe-2 - Define the hpc-pg priority group and assign to
it the forwarding classes nc and high-perf:
[edit class-of-service]
user@switch# set forwarding-class-sets hpc-pg class nc
user@switch# set forwarding-class-sets hpc-pg class high-perf - Map the three forwarding class sets to an interface (the
output traffic control profiles associated with the forwarding class
sets determine the class of service scheduling for the priority groups):
[edit class-of-service]
user@switch# set interfaces xe-0/0/7 forwarding-class-set lan-pg output-traffic-control-profile lan-tcp
user@switch# set interfaces xe-0/0/7 forwarding-class-set san-pg output-traffic-control-profile san-tcp
user@switch# set interfaces xe-0/0/7 forwarding-class-set hpc-pg output-traffic-control-profile hpc-tcp
Verification
To verify the priority group configuration, perform these tasks:
Verifying Forwarding Class Set Membership
Purpose
Verify that you configured the lan-pg, san-pg, and hpc-pg priority groups with the correct forwarding classes.
Action
List the forwarding class set member configuration using the operational mode command show configuration class-of-service forwarding-class-sets:
user@switch> show configuration class-of-service
forwarding-class-sets
lan-pg { class best-effort-1; class best-effort-2; } san-pg { class fcoe; class fcoe-2; } hpc-pg { class high-perf; class nc; }
Verifying the Egress Interface Configuration
Purpose
Verify that egress interface xe-0/0/7 is associated with the lan-pg, san-pg, and hpc-pg priority groups and with the correct output traffic control profiles.
Action
Display the egress interface using the operational mode command show configuration class-of-service interfaces xe-0/0/7:
user@switch> show configuration class-of-service
interfaces xe-0/0/7
forwarding-class-set { lan-pg { output-traffic-control-profile lan-tcp; } san-pg { output-traffic-control-profile san-tcp; } hpc-pg { output-traffic-control-profile hpc-tcp; } }