With the growth of bandwidth requirements by today’s applications and convergence of voice, video, and data applications over common IP infrastructures (networks), deploying QoS technologies and services is a necessity within modern networks. Although you must manage delay, jitter, available bandwidth, and packet loss, the solution must remain scalable and manageable with respect to both simplicity and cost. Following are some of the challenges that enterprises face:
■ The voice quality of IP Telephony applications must be high.
■ The required bandwidth for mission-critical applications must be guaranteed.
■ QoS must be simple enough to reduce errors, the deployment period, and costs.
Cisco AutoQoS is a QoS deployment automation tool that is suitable for midsize enterprises and branches. Following are the main benefits of Cisco AutoQoS:
■ The built-in intelligence of AutoQoS makes its auto-generated configuration code suitable for most common enterprise QoS requirements.
■ AutoQoS protects mission-critical applications against otherwise less-important applications, providing guaranteed resources and preferential treatments.
■ Using AutoQoS does not require in-depth knowledge of QoS, Cisco IOS commands, or the varied networking technologies involved.
■ AutoQoS-generated configurations are based on modular QoS command-line interface (MQC) and follow the Cisco recommendations for best practices and the DiffServ model.
■ You can examine the results of AutoQoS-generated commands, and modify them if necessary, to suit each particular need.
The first phase or release of AutoQoS, referred to as AutoQoS VoIP, was developed to automate generation of QoS configurations for those who had or planned to deploy IP Telephony in their enterprise but lacked the expertise to do so properly. AutoQoS VoIP operates both on Cisco routers and Catalyst switches. It generates the required access lists, class maps, policy maps, interface configurations, and so on to provide adequate configuration supporting IP Telephony applications. AutoQoS VoIP uses Network Based Application Recognition (NBAR) for classification and marking of packet DiffServ Codepoint (DSCP) fields. It can also trust markings of the packets and not re-mark them.
The second phase or release of AutoQoS, referred to as AutoQoS for Enterprise (or AutoQoS Enterprise for brevity), is available only for routers. AutoQoS Enterprise has added capabilities for voice, video, and data, plus another feature called protocol discovery. AutoQoS Enterprise has two deployment stages:
1. Discovering types and volumes of traffic types using NBAR protocol discovery and generating appropriate policies accordingly
2. Implementing the generated policies
You can review the application types discovered during the auto-discovery stage and the QoS policies generated (suggested) by AutoQoS Enterprise first. After that review, you can implement the AutoQoS-generated policies completely, modify them, or not implement them at all. However, it is noteworthy that AutoQoS Enterprise addresses all of the following five key elements of QoS deployment:
■ Application classification—Utilizing NBAR, AutoQoS Enterprise can perform intelligent classification based on deep packet inspection; using CDP (version 2), an IP phone is recognized as an attached device whose packets will be classified accordingly.
■ Policy generation—AutoQoS Enterprise generates policies based on device and interface settings and the traffic observed in the discovery stage. These policies can be tuned further if desired. For example, on WAN interfaces, auto-generated policies take into account the need for techniques such as fragmentation and compression.
■ Configuration—AutoQoS Enterprise is easily enabled on router interfaces. It automates detection of connected IP phones, which in turn affects the QoS configuration of the interface.
■ Monitoring and reporting—AutoQoS can automate generation of alerts, SNMP traps, system loggings, and summary reports. You can use QPM to monitor, view, and evaluate the statistics and the information (QoS feedback) gathered.
■ Consistency—AutoQoS generates consistent policies and configurations on the Cisco devices on which it is deployed. A user can inspect generated policies, filters, and so on, plus the gathered statistics from the discovery stage.
The discovery stage of AutoQoS Enterprise uses NBAR protocol discovery. NBAR protocol discovery first collects and analyzes packets that are going through the interface of a router; then it generates statistics on the types and numbers of the packets processed. All traffic types that NBAR supports (close to 100 applications and protocols) that go through an interface in either direction (input or output) are discovered and analyzed in real-time. The statistics reported per-interface and per-protocol include 5-minute bit rates (bps), packet counts, and byte counts. NBAR protocol discovery can identify and classify all of the following application types:
■ Applications that target a session to a well-known (UDP/TCP) destination port number, referred to as static port applications
■ Applications that start a control session using a well-known port number but negotiate another port number for the session, referred to as dynamic port applications
■ Some non-IP applications
■ HTTP applications based on URL, MIME type, or host name
