This document, titled "Assured Forwarding PHB Group," specifies an Internet standards track protocol for the Internet community. It introduces the Assured Forwarding (AF) Per-Hop-Behavior (PHB) group, which provides four independently forwarded AF classes, each with three levels of drop precedence. The AF PHB group ensures that IP packets within the same microflow are not reordered by DS nodes and offers different levels of forwarding assurances based on the allocated resources, current load, and drop precedence. The document outlines the purpose and overview of the AF PHB group, emphasizing its role in providing assured forwarding of IP packets over the Internet. It details the implementation requirements, including the allocation of forwarding resources, queueing and discard behavior, and traffic conditioning actions. The AF PHB group can be used to implement both end-to-end and domain edge-to-domain edge services. Key aspects covered include the recommended codepoints for the AF classes, interactions with other PHB groups, security implications, and IANA considerations. The document also provides examples of services that can be implemented using the AF PHB group, such as the Olympic service and loss and low latency services. The authors are Juha Heinanen from Telia Finland, Fred Baker from Cisco Systems, Walter Weiss from Lucent Technologies, and John Wroclawski from MIT LCS. The document is copyrighted by the Internet Society and is available for unrestricted copying and distribution, provided that the copyright notice and this paragraph are included.This document, titled "Assured Forwarding PHB Group," specifies an Internet standards track protocol for the Internet community. It introduces the Assured Forwarding (AF) Per-Hop-Behavior (PHB) group, which provides four independently forwarded AF classes, each with three levels of drop precedence. The AF PHB group ensures that IP packets within the same microflow are not reordered by DS nodes and offers different levels of forwarding assurances based on the allocated resources, current load, and drop precedence. The document outlines the purpose and overview of the AF PHB group, emphasizing its role in providing assured forwarding of IP packets over the Internet. It details the implementation requirements, including the allocation of forwarding resources, queueing and discard behavior, and traffic conditioning actions. The AF PHB group can be used to implement both end-to-end and domain edge-to-domain edge services. Key aspects covered include the recommended codepoints for the AF classes, interactions with other PHB groups, security implications, and IANA considerations. The document also provides examples of services that can be implemented using the AF PHB group, such as the Olympic service and loss and low latency services. The authors are Juha Heinanen from Telia Finland, Fred Baker from Cisco Systems, Walter Weiss from Lucent Technologies, and John Wroclawski from MIT LCS. The document is copyrighted by the Internet Society and is available for unrestricted copying and distribution, provided that the copyright notice and this paragraph are included.