Feedback
Table Of Contents
Routing Protocol Service Class
Business-Data-1 and Best Effort Service Classes
Interface-Based Aggregated Rate Limiters
QoS Service Model Overview
A QoS policy is a set of parameters that control and condition the traffic flowing through a service provider network.
The Cisco IP Solution Center (ISC) configures QoS at the access circuit, which involves the PEs in the service provider network and the CPEs in the customer network. A QoS policy is applied to the selected set of access circuits using a QoS service request. The ISC provisioning engine generates the QoS configuration from the service request and downloads the configuration to the specified CPE and PE devices.
A QoS service request can be integrated with VPN provisioning accomplished through ISC or deployed on its own if VPN services are not provisioned through ISC.
In ISC, the IP QoS service model is comprised of:
•
IP QoS Link—contains device (CPE and PE) interface information.
•
–
–
•
Note
This chapter provides an overview of the IP QoS service model in ISC.
The chapter contains the following sections:
QoS Link
A QoS Link can contain two interfaces (for both the CPE and PE) or one interface (CPE only or PE only). For QoS provisioning, you can select both interfaces in the CPE-PE link. A typical device interface selection is as follows:
•
–
–
Note
•
–
The interfaces selected as link endpoints can be provisioned with QoS parameters such as policing, traffic shaping, congestion management, congestion avoidance, link efficiency, and CAR. You apply these parameters later in the provisioning process.
See Defining QoS Link Candidates for information on defining QoS link candidate interfaces in the ISC user interface.
Service Level IP QoS Policy
The service level portion of the QoS policy corresponds to service classes. A QoS service class provides a method for classifying traffic flows into classes so that you can apply the appropriate QoS parameters to a class of traffic instead of applying them to all traffic. For example, all TCP traffic might be grouped into a single class so that bandwidth is allocated for the class and not for individual traffic flows.
A QoS service class can include:
•
•
•
•
•
•
A typical service provider network might create different QoS policies, and each QoS policy might contain three to five service classes. For example, a service provider might have a gold, silver, and bronze QoS policies, each specifying different service level agreements (SLA), and each of those QoS policies might contain one or more service classes. Most networks require at least a voice, a management, and a data service class.
ISC provides five default or template service classes for you to modify and use for a service level QoS policy:
•
•
•
•
•
See Creating the Service Level IP QoS Policy for information on defining the service level QoS policy in the ISC user interface.
The following section describes the five service classes provided with ISC.
QoS Service Classes
A QoS service class defines how each QoS parameter is applied.
Network traffic can be categorized into voice traffic, data traffic, and control traffic. Voice and data traffic are common in enterprise networks. Control traffic refers to routing protocol traffic and management traffic, which are commonly used in the service provider portion of the network.
The five default service classes provided with ISC cover most networks, which require at least one for interactive voice traffic, one for management traffic, and at least one service class for data traffic.
You can either remove or add more service classes if required. ISC supports the number of service classes defined by the Cisco differentiated services (DiffServ) architecture; up to 64 classes for DSCP traffic, and up to 8 service classes for IP Precedence traffic.
See Adding a Data Service Class for more information.
VoIP Service Class
Interactive voice traffic in ISC refers to any voice traffic (telephone calls, faxes) that is IP-encapsulated and sent over the network, such as Voice-over-IP (VoIP).
Mandatory QoS components for this service class:
•
•
•
•
Routing Protocol Service Class
Routing protocol traffic refers to traffic control messages, such as route update messages, hellos, database descriptors, keepalives, and database refresh messages.We recommended the minimum bandwidth, one percent, for your routing protocol service class.
Mandatory QoS components for this service class:
•
•
Management Service Class
Management traffic refers to the traffic between the management station at the provider core and the access routers. We recommended the minimum bandwidth, one percent, for your management service class.
Mandatory QoS components for this service class:
•
•
•
QoS parameters for the VoIP, Routing Protocol, and Management service classes are described in VoIP, Routing Protocol, and Management Service Classes.
Business-Data-1 and Best Effort Service Classes
The two data service classes, Business-Data-1 and Best Effort, are nearly identical. The only difference between them is the Traffic Classification parameter. For Business-Data-1, traffic is classified by protocol. Best-Effort classifies all traffic.
The QoS requirements for data applications can vary. Each data application should be profiled before you determine the appropriate classification and scheduling treatment.
Mandatory QoS components for this service class:
•
•
•
Optional components:
•
•
Note
QoS parameters for the Business-Data-1 and Best-Effort service classes are described in Business-Data-1 and Best Effort Service Classes.
Link Level QoS Policy
The link level portion of the QoS policy corresponds to QoS parameters that are sensitive to link bandwidth and the CPE-PE link's encapsulation type. A link level QoS policy, called link QoS settings in the ISC user interface, provides a method for defining policies specific to the CPE-PE link. For example, you might require different policies for Frame Relay and ATM links because of the different encapsulation involved.
Link level QoS parameters in ISC include:
•
•
Note
•
•
Note
Aggregated Traffic Shapers
Aggregated traffic shaping allows you to control the traffic leaving an interface. You can select an aggregated traffic shaper for each CPE-PE link.
Aggregated traffic shapers are optional. ISC supports the following aggregated traffic shapers:
•
•
•
•
•
•
•
See Aggregated Traffic Shapers for more information on defining the aggregated traffic shapers parameters in the ISC user interface.
Link Efficiency
Link efficiency settings are based on the bandwidth of the CPE-PE link itself and are used to minimize serialization delay on the link. ISC uses methods of fragmentation and compression to minimize this delay.
ISC supports the following link efficiency settings:
•
•
•
See Link Efficiency Settings for information on defining the link efficiency parameters in the ISC user interface.
Interface-Based Aggregated Rate Limiters
Interface-based aggregated rate limiters allow you to control the maximum rate of traffic sent or received on an interface for the CPE-PE link. You can also specify traffic handling policies for when the traffic conforms or exceeds the specified rate limit.
Aggregate rate limits match all packets or a subset of packets on an interface or subinterface. To specify class-based rate limiting parameters, see Creating the Service Level IP QoS Policy.
ISC supports the following interface-based rate limiter parameters:
•
•
•
•
•
See Interface-Based Aggregated Rate Limiters for information on defining the interface-based rate limiters in the ISC user interface.
IP QoS Service Requests
An IP QoS service request contains one or more QoS links. Each link can optionally be associated with a link QoS setting. A QoS policy can be associated with a QoS service request.
An IP QoS service request should:
•
•
To apply IP QoS policies to network devices, you must deploy the QoS service request. When you deploy a QoS service request, ISC compares the device information in the Repository (the ISC database) with the current device configuration and generates a configlet.
See Creating the QoS Service Request for information on creating the QoS service request using the ISC user interface.
See Cisco IP Solution Center Infrastructure Reference, 4.0 the for more information on the ISC Repository.
