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Dedicated Queue Scaling for CoS Configurations on MIC and MPC Interfaces Overview
Queuing Ethernet Modular Port Concentrators (MPCs) provide a set of dedicated queues for subscriber interfaces configured with hierarchical scheduling or per-unit scheduling.
The dedicated queues offered on these MPCs enable service providers to reduce costs through different scaling configurations. These queuing MPCs enable service providers to reduce the cost per subscriber by allowing many subscriber interfaces to be created with four or eight queues.
This topic describes the overall queue, scheduler node, and logical interface scaling for subscriber interfaces created on these MIC and MPC combinations.
Queue Scaling for MPCs
Beginning with Junos OS Release 15.1, MPC2E-3D-NG-Q, MPC3E-3D-NG-Q, MPC5EQ-40G10G, and MPC5EQ-100G10G MPCs support up to five levels of hierarchical queuing. Beginning with Junos OS Release 16.1R1, MPC7 line cards also support five levels of hierarchical queuing. Table 1 lists the number of dedicated queues and nodes supported per MPC.
MPC |
Dedicated Queues |
Level 4 Nodes |
Level 3 Nodes |
Level 2 Nodes |
Level 1 Nodes (Ports) |
|---|---|---|---|---|---|
MPC2E-3D-NG-Q MPC3E-3D-NG-Q |
512,000 |
64,000 |
16,000 |
4000 |
384 |
MPC5EQ-40G10G MPC5EQ-100G10G |
1 million |
128,000 |
32,000 |
4000 |
384 |
MPC7 |
512,000 |
64,000 |
16000 |
8000 |
252 |
MPC10E on MX10K series platforms |
256,000 | 32,000 | 8,000 | 4,000 | 128 |
The maximum scaling targets provided in Table 1 are based on system level design specifications. Actual realized subscriber or session scale is highly dependent upon the configuration and can be influenced by configuration variables including: the number of routes, the number of enabled services, the number of policy and firewall filters, policers, counters, statistics and access model type. Once you define a configuration, your Juniper account team can help characterize the expected system level scale or scale range for your live deployment.
MPCs vary in the number of Packet Forwarding Engines on board. MPC2E-3D-NG-Q and MPC3E-3D-NG-Q MPCs each have one Packet Forwarding Engine, allowing all 64,000 level 4 (subscriber) nodes to be allocated to a single MIC. MPC5EQ MPCs have two Packet Forwarding Engines, one for each possible MIC, each supporting 64,000 level 4 (subscriber) nodes. MPC7 MPCs also have two Packet Forwarding Engines, one for each possible MIC, each supporting 256,000 dedicated queues and 32,000 level 4 (subscriber) nodes.
The nonqueuing MPCs MPC2E-3D-NG, MPC3E-3D-NG, MPC5E-40G10G, and MPC5E-100G10G provide up to eight queues per port in standard configuration. However, each of these MPCs can be configured to provide limited-scale hierarchical class of service (HCoS) and up to 32,000 queues.
Managing Remaining Queues
In Junos OS releases earlier than Release 15.1R4, SNMP traps generate system log messages to notify you:
When the number of available dedicated queues on the MPC drops below 10 percent. For example:
Mar 15 14:55:22.977 host cosd[1963]: COSD_OUT_OF_DEDICATED_QUEUES: Queue usage count for interface xe-3/0/0 is at 90 percent
When the maximum number of dedicated queues on the MPCs is reached. For example,
Mar 15 18:01:59.344 host cosd[3848]: COSD_OUT_OF_DEDICATED_QUEUES: Queue usage count for interface xe-3/0/0 is at 100 percent.
When the maximum number of dedicated queues is allocated, the system does not provide subsequent subscriber interfaces with a dedicated set of queues. For per-unit scheduling configurations, there are no configurable queues remaining on the MPC.
For hierarchical scheduling configurations, remaining queues are available when the maximum number of dedicated queues is reached on the MPC. Traffic from these logical interfaces is considered unclassified and attached to a common set of queues that are shared by all subsequent logical interfaces. These common queues are the default port queues that are created for every port. You can configure a traffic-control profile and attach that to the interface to provide CoS parameters for the remaining queues. These subscriber interfaces remain with this traffic-control profile, even if dedicated queues become available.
Starting in Junos OS Release 15.1R4, the COSD_OUT_OF_DEDICATED_QUEUES functionality is not available for QoS-enabled dynamic subscribers. Starting in Junos OS Release 17.4R1, CoS resource monitoring enables you to set a per-FPC queue threshold of up to 90 percent of resources bound to a scheduling hierarchy; subscriber logins are not allowed when the threshold is reached. However, this threshold applies to all queues, not dedicated queues alone. See Resource Monitoring for Subscriber Management and Services Overview for more information.
Change History Table
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