Cisco Crosswork Planning Design 7.2.x User Guide

QoS bound and QoS violations

Updated: August 14, 2026

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Introduces the concepts of QoS bound and QoS violations, explaining how policies and interface queue properties define capacity limits, how violations are detected, and how these calculations facilitate network service planning and monitoring in the Network Summary table.

Cisco Crosswork Planning uses the concepts of QoS bound and QoS violation to identify whether QoS parameters are being met or surpassed. This helps you plan for service requirements across the network. Policies and queue properties determine the QoS bound calculation. In turn, this calculation determines whether there is a violation.

QoS bound

The QoS bound is the maximum interface capacity available without violating these QoS requirements. Separate QoS bounds are calculated for both policy and interface queue properties.


QoS bound for...	Calculated based on...
Interface queues	Combination of interface queue properties, or in live networks, it is the capacity percentage that is discovered.
Service class	Policy
Service class mapped to queues	The lower of these two calculations is used: Policy for service class Queue properties for queues
Undifferentiated traffic	Policy

In the Network Summary table, these columns convey the QoS bound information: QoS bound meas, QoS bound meas (%), QoS bound sim, and QoS bound sim (%).

QoS bound calculations involve determining how to increase traffic on the queues until it reaches the maximum allowable amount. This capacity, or the reason the traffic cannot be increased further, is defined both by the QoS parameters and the amount of traffic. For example, when traffic arrives at Queue X, Cisco Crosswork Planning fixes the traffic on all other queues and then determines how it can increase the traffic on Queue X until some other traffic blocks it.

For those queues that do not reach full capacity, unused queue capacity is made available for other queues.

QoS violation

QoS violation is the total traffic minus the capacity permitted for the queue (QoS bound). A violation occurs if the maximum QoS capacity allotted through policies and interface queue properties is exceeded. If the number appearing in the QoS violation column is positive, the allotted capacity has been surpassed. If the number is negative, the allotted capacity has not been reached.

Policies and QoS bound calculations

If you do not set other QoS parameters such as Priority, Weight, or Police limit in the Interface queue properties, the QoS bound equals the policy that you configure.

This table provides examples of how interface capacity, traffic type, and policy settings affect QoS bound calculations and whether violations occur.

Table 1. Example policies and QoS bound calculations
Example configuration	QoS bound	QoS violation (Positive # = Violation)
Interface capacity = 10,000 Mbps Undifferentiated traffic = 5000 Mbps Normal operation policy = 60%	6000 Mbps (60%)	–1000 Mbps (–10%) Because this number is negative, there is no capacity violation.
Interface capacity = 10,000 Mbps Undifferentiated traffic = 8000 Mbps Normal operation policy = 60%	6000 Mbps (60%)	2000 Mbps (20%) Because this number is positive, there is a capacity violation.
Interface capacity = 10,000 Mbps Voice traffic = 6000 Mbps Video traffic = 2000 Mbps Voice normal operation policy = 90% Video normal operation policy = 60%	Voice = 9000 Mbps (90%) Video = 6000 Mbps (60%)	Voice = –3000 Mbps (30%) Video = –4000 Mbps (40%)

Interface queue properties and QoS bound calculations

Cisco Crosswork Planning simultaneously calculates QoS bound for each queue in the interface. Cisco Crosswork Planning uses the Interface queue parameters (Priority, Weight, and Police limit) and measured or simulated traffic for all queues in the interface. Priority is always considered first. If there are queues of equal Priority, then Weight is applied next.

Queues with priority 1 share all available interface capacity. Their weight and police limits further refine how much each priority 1 queue can use (their QoS bound). Each priority 1 queue can borrow available capacity from other priority 1 queues up to the limit of their QoS bound.
The available capacity for priority 2 queues is the total interface capacity minus all capacity consumed by priority 1 queues. The process then begins again for all priority 2 queues. Their weight and police limits determine their QoS bound, and priority 2 queues can borrow capacity from each other up to the limits set by the QoS bound.
This process continues for each successive priority level. Traffic that is outside any QoS bound is dropped to the lowest priority of all traffic on the interface.

For discovered networks with measured traffic, if no Cisco Crosswork Planning QoS parameters are set, the QoS bound is based on whatever capacity percentages the live network has for each queue.

Priority

If policies are not set that further affect the QoS bound, a queue’s QoS bound is calculated using this pattern:

Priority 1 QoS bound = 100% of the interface capacity.
Priority 2 QoS bound = Total interface capacity – amount of traffic consumed by priority 1 queues.
Priority 3 QoS bound = Total interface capacity – amount of traffic consumed by (priority 1 + priority 2 queues).
QoS bound for each succeeding priority follows this same pattern where the traffic consumed by all higher priority queues is subtracted from the total interface capacity.

Table 2. Examples of priority QoS bound calculations
Example configuration	QoS bound	QoS violation (Positive # = Violation)	QoS bound calculations
Interface capacity = 20,000 Mbps EF traffic = 6000 Mbps; priority = 1 BE traffic = 3000 Mbps; no priority set	EF = 20,000 Mbps BE = 14,000 Mbps	EF = –14,000 Mbps BE = –11,000 Mbps	EF = Total interface capacity because it is the only priority 1 queue BE = 20,000 (interface capacity) – 6000 (consumed by higher priority queues)
Interface capacity = 10,000 Mbps EF Traffic = 6000 Mbps; priority = 1 BE Traffic = 5000 Mbps; priority = 2	EF = 10,000 Mbps BE = 4000 Mbps	EF = –4000 Mbps BE = 1000 Mbps	EF = Total interface capacity because it is the only priority 1 queue BE = 10,000 (interface capacity) – 6000 (consumed by higher priority queues

Weight

The weight identifies the forwarding precedence for queues of equal priority. If weights for queues of the same priority do not add up to 100%, weights are converted proportionally so they do add up to 100%.

Table 3. Examples of weight QoS bound calculations
Example configuration	QoS bound	QoS violation (Positive # = Violation)	QoS bound calculations
Interface capacity = 10,000 Mbps AF1 traffic = 3000 Mbps; priority = 1; weight = 100% AF2 traffic = 6000 Mbps; priority = 1; weight = 100%	AF1 = 5000 Mbps AF2 = 7000 Mbps	AF1 = –2000 Mbps AF2 = –1000 Mbps	AF1 = Half of capacity for priority 1 queues because both queues have equal weights AF2 = 5000 (half of capacity) + 2000 (unused AF1 capacity)
Interface capacity = 10,000 Mbps AF1 = 5000 Mbps; priority = 1; weight = 60% AF2 traffic = 6000 Mbps; priority = 1; weight = 40%	AF1 = 6000 Mbps AF2 = 5000 Mbps	AF1 = –1000 Mbps AF2 = 1000 Mbps	AF1 = 60% of capacity for all priority 1 queues AF2= 10,000 (interface capacity) – 5000 (consumed by AF1 queue)

Police limits

Priority 1 queues have 100% of the interface traffic, and thus starve out the remaining queues. To prevent this queue starvation, use police limits to configure how much of the maximum percentage should be available for a given priority level.

Table 4. Examples of police limit QoS bound calculations
Example configuration	QoS bound	QoS violation (Positive # = Violation)	QoS bound calculations
Interface capacity = 10,000 Mbps EF traffic = 1000 Mbps; priority = 1; police limit = 50% BE traffic = 2000 Mbps; priority = 2	EF = 5000 Mbps BE = 9000 Mbps	EF = –4000 Mbps BE = –7000 Mbps	EF = 50% of total interface capacity BE = 10,000 (interface capacity) – 1000 (capacity consumed by EF)
Interface capacity = 10,000 Mbps EF traffic = 1000 Mbps; priority = 1; police limit = 5% BE traffic = 2000 Mbps; priority = 2	F = 500 Mbps BE = 9500 Mbps	EF = 500 Mbps BE = –7500 Mbps	EF = 5% of total interface capacity BE = 10,000 (interface capacity) – 500 (capacity consumed by EF)
Interface capacity = 10,000 Mbps EF = 3000 Mbps; priority = 1; police limit = 20% AF1 traffic = 4000 Mbps; priority = 2; police limit = 75% AF2 traffic = 2500 Mbps; priority = 2; police limit 25%	EF = 2000 Mbps AF1 = 6000 Mbps AF2 = 4000 Mbps	EF = 1000 Mbps AF1 = –2000 Mbps AF2 = –1500 Mbps	EF = 20% of total interface capacity AF1 = 75% of (10,000 [interface capacity] – 2000 [capacity consumed by EF]) AF2 = 10,000 (interface capacity) – 2000 (capacity consumed by EF) – 4000 (capacity consumed by AF1)

Interface QoS bound calculations using multiple QoS parameters

Cisco Crosswork Planning calculates a QoS bound for interface queues based on three parameters—priority, weight, and police limit—when all are configured.

Table 5. Examples of interface QoS bound calculations using multiple QoS parameters
Example configuration	QoS bound	QoS violation (Positive #= Violation)	QoS bound calculation
Interface capacity = 10,000 Mbps EF = 3000 Mbps; priority = 1; police limit = 20% AF1 traffic = 4000 Mbps; priority = 2; weight = 75% AF2 traffic = 2500 Mbps; priority = 2; weight = 25%	EF = 2000 Mbps AF1 = 6000 Mbps AF2 = 4000 Mbps	EF = 1000 Mbps AF1 = –2000 Mbps AF2 = –1500 Mbps	EF = 20% of total interface capacity AF1 = Maximum of these two values. 75% of (10,000 [interface capacity] – 2000 [capacity consumed by EF]) 8000 (available capacity) – 2500 (AF2 traffic) AF2 = Maximum of these two values. 25% of (10,000 [interface capacity] – 2000 [capacity consumed by EF]) 8000 (available capacity) – 4000 (AF1 traffic)

Service class QoS bound calculations using multiple QoS parameters

When service classes have defined policies and are mapped to queues, Cisco Crosswork Planning calculates a QoS bound for both. The system then uses the lowest value of the two so as to enforce restrictions in the strictest possible manner.

Example calculation

Interface capacity = 10,000 Mbps
QoS bound for service class = 50%, or 5000 Mbps based on policy
QoS bound for EF queue = 7500 Mbps based on combined parameters of priority, weight, and police limit

The QoS bound for this service class is 5000 Mbps because the policy QoS bound calculation is lower.

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