Configuring Strict High Priority for Queuing with a Configuration Editor
You can configure one queue per interface to have strict-high priority, which causes delay-sensitive traffic, such as voice traffic, to be removed from the queue and forwarded with minimum delay. Packets that are queued in a strict-priority queue are removed from the queue before packets in other queues, including high-priority queues. For more information on strict-high priority, see Configuring Strict-High Priority.
To configure strict-priority queuing and prevent starvation of other queues:
- Navigate to the top of the configuration hierarchy in either the J-Web or CLI configuration editor.
- Perform the configuration tasks described in Table 40.
- If you are finished configuring the router, commit the configuration.
Table 40: Configuring Strict-High Priority Queuing and Starvation Prevention
Task | J-Web Configuration Editor | CLI Configuration Editor |
|---|---|---|
| Configuring a BA Classifier | ||
Use a BA classifier to classify traffic based on the IP precedence of the packet. The classifier defines IP precedence value 101 as voice traffic and 000 as data traffic. |
| From the [edit] hierarchy level, enter edit Class of service classifiers inet-precedence corp-traffic forwarding-class voice-class loss-priority low Enter set code-points 101 From the [edit] hierarchy level, enter edit class-of-service classifiers inet-precedence corp-traffic forwarding-class data-class loss-priority high Enter set code-points 000 |
| Configuring the Forwarding Classes | ||
Assign priority queuing to voice and data traffic. |
| From the [edit] hierarchy level, enter edit class-of-service forwarding-classes queue 0 voice-class enter edit class-of-service forwarding-classes queue 1 data-class |
| Configuring the Scheduler Map and Schedulers | ||
Configure the scheduler map and voice scheduler. |
| From the [edit] hierarchy level, enter edit class-of-service scheduler-maps corp-map forwarding-class voice-class Enter set scheduler voice-sched |
Define the voice and data traffic schedulers, and set the priority. |
| From the [edit] hierarchy level, enter edit class-of-service schedulers voice-sched Enter set priority strict-high From the [edit] hierarchy level, enter edit class-of-service schedulers data-sched Enter set priority low |
| Applying the BA Classifier to an Input Interface and Scheduler Map to an Output Interface | ||
Apply the BA classifier to an input interface—for example, ge-0/0/0. Apply the scheduler map to and output interface—for example, e1-1/0/0. (See the interface naming conventions in JUNOS Software Interfaces Configuration Guide for Security Devices.) |
| From the [edit] hierarchy level, enter edit interfaces ge-0/0/0 unit 0 From the [edit] hierarchy level, enter edit class of service classifiers inet-precedence corp-traffic From the [edit] hierarchy level, enter edit interfaces e1-1/0/0 unit 0 From the [edit] hierarchy level, enter edit class-of-service scheduler-maps corp-map |
| Configuring Two Policers | ||
Configure two policers: one as voice-drop and second as voice-excess. |
| From the [edit] hierarchy level, enter edit firewall policer voice-drop if-exceeding Enter set burst-size-limit 200000 bandwidth-limit 2000000 Enter set then discard From the [edit] hierarchy level, enter edit firewall policer voice-excess if-exceeding Enter set burst-size-limit 200000 bandwidth-limit 1000000 Enter set then out-of-profile |
Create a firewall filter voice-term that includes the new policers. First, add the policer voice-drop to the term. |
| From the [edit] hierarchy level, enter edit firewall filter voice-term term 01 from forwarding-class voice-class then policer voice-drop next term |
Then add the policer voice-excess to the term. |
| Enter edit firewall filter voice-term term 02 from forwarding-class voice-class then policer voice-excess accept |
| Applying the Filter to the Output Interface | ||
Apply filter voice-term to e1-1/0/0 using the CLI. | From the [edit] hierarchy level, enter edit interfaces e1-1/0/1 unit 0 family inet filter output voice-term Enter set family inet address 11.1.1.1/24 | |