checksum

The Stream Control Transmission Protocol (SCTP) uses a 32-bit checksum in the common header of each packet to provide some level of data integrity. If another method used by SCTP already provides the same or a higher level of data integrity, computing this checksum does not provide any additional protection but does consume computing resources.

This document provides a simple extension allowing SCTP to save these computing resources by using zero as the checksum in a backwards-compatible way. It also defines how this feature can be used when SCTP packets are encapsulated in Datagram Transport Layer Security (DTLS) packets.

This document describes a protocol and new DNS Resource Record that provides a cryptographic message digest over DNS zone data at rest. The ZONEMD Resource Record conveys the digest data in the zone itself. When used in combination with DNSSEC, ZONEMD allows recipients to verify the zone contents for data integrity and origin authenticity. This provides assurance that received zone data matches published data, regardless of how the zone data has been transmitted and received. When used without DNSSEC, ZONEMD functions as a checksum, guarding only against unintentional changes.

ZONEMD does not replace DNSSEC: DNSSEC protects individual RRsets (DNS data with fine granularity), whereas ZONEMD protects a zone's data as a whole, whether consumed by authoritative name servers, recursive name servers, or any other applications.

As specified herein, ZONEMD is impractical for large, dynamic zones due to the time and resources required for digest calculation. However, the ZONEMD record is extensible so that new digest schemes may be added in the future to support large, dynamic zones.

The One-Way Active Measurement Protocol (OWAMP) and the Two-Way Active Measurement Protocol (TWAMP) are used for performance monitoring in IP networks. Delay measurement is performed in these protocols by using timestamped test packets. Some implementations use hardware-based timestamping engines that integrate the accurate transmission time into every outgoing OWAMP/TWAMP test packet during transmission. Since these packets are transported over UDP, the UDP Checksum field is then updated to reflect this modification. This document proposes to use the last 2 octets of every test packet as a Checksum Complement, allowing timestamping engines to reflect the checksum modification in the last 2 octets rather than in the UDP Checksum field. The behavior defined in this document is completely interoperable with existing OWAMP/TWAMP implementations.

The Network Time Protocol (NTP) allows clients to synchronize to a time server using timestamped protocol messages. To facilitate accurate timestamping, some implementations use hardware-based timestamping engines that integrate the accurate transmission time into every outgoing NTP packet during transmission. Since these packets are transported over UDP, the UDP Checksum field is then updated to reflect this modification. This document proposes an extension field that includes a 2-octet Checksum Complement, allowing timestamping engines to reflect the checksum modification in the last 2 octets of the packet rather than in the UDP Checksum field. The behavior defined in this document is interoperable with existing NTP implementations.

This document specifies an IP-based encapsulation for MPLS, called MPLS-in-UDP for situations where UDP (User Datagram Protocol) encapsulation is preferred to direct use of MPLS, e.g., to enable UDP-based ECMP (Equal-Cost Multipath) or link aggregation. The MPLS- in-UDP encapsulation technology must only be deployed within a single network (with a single network operator) or networks of an adjacent set of cooperating network operators where traffic is managed to avoid congestion, rather than over the Internet where congestion control is required. Usage restrictions apply to MPLS-in-UDP usage for traffic that is not congestion controlled and to UDP zero checksum usage with IPv6.

This document updates the IPv6 specification (RFC 2460) to improve performance when a tunnel protocol uses UDP with IPv6 to tunnel packets. The performance improvement is obtained by relaxing the IPv6 UDP checksum requirement for tunnel protocols whose header information is protected on the "inner" packet being carried. Relaxing this requirement removes the overhead associated with the computation of UDP checksums on IPv6 packets that carry the tunnel protocol packets. This specification describes how the IPv6 UDP checksum requirement can be relaxed when the encapsulated packet itself contains a checksum. It also describes the limitations and risks of this approach and discusses the restrictions on the use of this method.

This document provides an applicability statement for the use of UDP transport checksums with IPv6. It defines recommendations and requirements for the use of IPv6 UDP datagrams with a zero UDP checksum. It describes the issues and design principles that need to be considered when UDP is used with IPv6 to support tunnel encapsulations, and it examines the role of the IPv6 UDP transport checksum. The document also identifies issues and constraints for deployment on network paths that include middleboxes. An appendix presents a summary of the trade-offs that were considered in evaluating the safety of the update to RFC 2460 that changes the use of the UDP checksum with IPv6.

This document describes a framework for defining encryption and checksum mechanisms for use with the Kerberos protocol, defining an abstraction layer between the Kerberos protocol and related protocols, and the actual mechanisms themselves. The document also defines several mechanisms. Some are taken from RFC 1510, modified in form to fit this new framework and occasionally modified in content when the old specification was incorrect. New mechanisms are presented here as well. This document does NOT indicate which mechanisms may be considered "required to implement". [STANDARDS-TRACK]

This draft describes an optional extension to IS-IS protocol, used

today by several ISPs for routing within their clouds. IS-IS is an

interior gateway routing protocol developed originally by OSI and

used with IP extensions as IGP. IS-IS originally does not provide

CSNP and PSNP checksums, relying on the underlying layers to verify

the integrity of information provided. Experience with the protocol

shows that this precondition does not always hold and scenarios

can be imagined that impact protocol functionality. This document

introduces a new optional TLV providing checksums.

This specification defines a lossless compressed data format. This memo provides information for the Internet community. This memo does not specify an Internet standard of any kind.

This memo presents a techniques for efficiently implementing the Internet Checksum in hardware. It includes PLD code for programming a single, low cost part to perform checksumming at 1.26 Gbps. This memo provides information for the Internet community. This memo does not specify an Internet standard of any kind.

This memo describes an updated technique for incremental computation of the standard Internet checksum. It updates the method described in RFC 1141. This memo provides information for the Internet community. This memo does not specify an Internet standard of any kind.

This memo correctly describes the incremental update procedure for use with the standard Internet checksum. It is intended to replace the description of Incremental Update in RFC 1071. This is not a standard but rather, an implementation technique.

This RFC summarizes techniques and algorithms for efficiently computing the Internet checksum. It is not a standard, but a set of useful implementation techniques.