Introduction

Overview

—The classifier selects a packet in a traffic stream based the content of a part of the packet header. In HP-UX IPQoS, classification is based on filter attributes specified in the active HP-UX IPQoS configuration.

—The meter checks compliance to a defined traffic profile and passes results to shaper/policer to trigger appropriate actions for in- and out-of-profile packets. In HP-UX IPQoS, metering is based on policy attributes specified in the active HP-UX IPQoS configuration.

—The marker can write/rewrite the DSCP and VLAN priority values. In HP-UX IPQoS, marking is based on policy attributes specified in the active HP-UX IPQoS configuration.

—The shaper delays (and the policer drops) some packets, so that traffic maintains compliance with a defined traffic profile. In HP-UX IPQoS, shaping actions result from maintaining accordance with metering specifications in the active HP-UX IPQoS configuration. HP-UX IPQoS does not perform shaping based on marking characteristics. Other nodes, such as DS-aware routers, may perform shaping as a result of marking specifications.

DSCP Marking

Each IP packet has a DS field. For IPv4, this is the leftmost 6-bits of the TOS field; for IPv6, this is the leftmost 6-bits of the Traffic Class field. The DS field can be used to mark a packet so that it receives a particular forwarding behavior. The DiffServ model defines a set of commonly used standard DSCP’s and their corresponding forwarding behaviors. The forwarding behavior assigned to a DSCP is referred to as the per-hop behavior (PHB). The PHB defines the forwarding precedence a packet receives in relation to other traffic on a DiffServ-enabled network.

A common agreement about the use and interpretation of the possible values used in the DS field is needed for interdomain use, multivendor interoperability, and overall consistency of expected aggregate behaviors in a network. The IETF Differentiated Services Working Group has standardized a common layout for the six-bit field of these octets. For more information, refer to RFC 2474 Definition of the Differentiated Service Field (DS Field) in the IPv4 and IPv6 Headers and RFC 2475 An Architecture for Differentiated Services, which define the architecture and the general use of the bits within the DS field.

You can select a DSCP value from a group of well-known codepoints associated with the two key forwarding types defined in the DiffServ model. The PHB types are Expedited Forwarding (EF) for higher priority traffic, and Assisted Forwarding (AF) for other traffic. The well-known codepoints, which would appear in the leftmost 6-bits of the TOS or Traffic Class fields, are 46 (101110) for the EF PHB, and a range of codepoints for the AF PHB. For more information, refer to RFC 2597 Assured Forwarding PHB Group and RFC 2598 An Expedited Forwarding PHB.

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HP UX IPQos Software manual Dscp Marking
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UX IPQos Software specifications

HP-UX IPQoS is a sophisticated software solution designed to enhance the network performance of HP's Unix-based operating system, HP-UX. This software focuses on Quality of Service (QoS) mechanisms that ensure efficient bandwidth utilization and prioritize network traffic to meet the demands of various applications.

One of the main features of HP-UX IPQoS is its ability to define traffic priorities. Administrators can classify traffic into different priority levels, allowing critical applications to receive the bandwidth they need while less important traffic can be deprioritized. This feature is essential in environments where bandwidth is a limited resource, ensuring that business-critical processes maintain their performance even during peak usage times.

The software employs advanced traffic shaping techniques that allow the management of data flow in the network. By controlling the rate of traffic and smoothing out bursts, IPQoS helps prevent network congestion, leading to a consistently reliable user experience. In addition, it can manage both inbound and outbound traffic, ensuring optimal performance in various network scenarios.

Another significant characteristic of HP-UX IPQoS is its integration with other network management tools. It operates seamlessly with HP’s Network Management Suite, providing a holistic view of network performance. This integration facilitates easier troubleshooting and monitoring, as administrators can correlate data from different sources for comprehensive insights.

Moreover, HP-UX IPQoS supports various protocols, including DiffServ and MPLS. By adhering to these standards, it positions itself as a versatile tool that can operate in diverse network environments, providing flexibility and ease of deployment. Additionally, the software supports policy-based management, enabling organizations to implement specific rules tailored to their network requirements.

Security is also a critical focus of HP-UX IPQoS. The software provides mechanisms to enforce traffic policies while safeguarding against potential threats. By ensuring that only authorized traffic flows through the network, it minimizes the risk of attacks and data breaches, contributing to a more secure IT environment.

The user interface of HP-UX IPQoS is designed for ease of use, allowing network administrators to configure settings, monitor performance, and generate reports without extensive training. This user-friendliness accelerates the deployment process and enhances the overall management of network resources.

In summary, HP-UX IPQoS is a robust and versatile network management solution that brings substantial benefits to organizations looking to optimize their network performance. With its traffic prioritization features, integration capabilities, support for industry standards, and focus on security, it stands out as an essential tool for maintaining effective and secure network operations in a dynamically changing IT landscape.
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