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Rec. ITU-T Y.1540 (03/2011) 3
adds information on capacity parameters (including a mapping to prior IETF metrics and items for
further study).
NOTE 4 – The ITU-T Y.1540 parameters may be augmented or modified based upon further study of the
requirements of the IP applications (e.g., interactive, block, stream) to be supported.
NOTE 5 – The ITU-T Y.1540 speed, accuracy and dependability parameters are intended to characterize IP
service in the available state.
NOTE 6 – The parameters defined in this Recommendation can apply to a single end-to-end IP service
between two end hosts identified by their IP addresses. The parameters can also be applied to those IP
packets from a given end-to-end IP service that are offered to a given network or exchange link.
NOTE 7 – The ITU-T Y.1540 parameters are designed to characterize the performance of service provided
by network elements between specified section boundaries. However, users of this Recommendation should
be aware that network elements outside the specified boundaries can sometimes influence the measured
performance of the elements between the boundaries. Examples are described in Appendix V.
NOTE 8 – The parameters defined in this Recommendation can also be applied to any subset of the IP
packets offered to a given set of network equipment. Methods for aggregating performance over a set of
network equipment or over an entire network are outside of the scope of this Recommendation.
NOTE 9 – This Recommendation does not provide the tools for explicit characterization of routing stability.
However, the effects of route instability can be quantified using the loss, delay and severe loss block
parameters defined in this Recommendation.
NOTE 10 – Specification of numerical performance objectives for some of the ITU-T Y.1540 performance
parameters may be found in [ITU-T Y.1541].
NOTE 11 – The word "provisional", as used in this Recommendation, means that there is agreement on the
stability of the value referenced, but that the value may change following further study, or on the basis of real
network operational experience.
2 References
The following ITU-T Recommendations and other references contain provisions which, through
reference in this text, constitute provisions of this Recommendation. At the time of publication, the
editions indicated were valid. All Recommendations and other references are subject to revision;
users of this Recommendation are therefore encouraged to investigate the possibility of applying the
most recent edition of the Recommendations and other references listed below. A list of the
currently valid ITU-T Recommendations is regularly published. The reference to a document within
this Recommendation does not give it, as a stand-alone document, the status of a Recommendation.
[ITU-T I.350] Recommendation ITU-T I.350 (1993), General aspects of quality of service
and network performance in digital networks, including ISDNs.
[ITU-T P.10] Recommendation ITU-T P.10/G.100 (2006), Vocabulary for performance and
quality of service.
[ITU-T Y.1541] Recommendation ITU-T Y.1541 (2006), Network performance objectives for
IP-based services.
[IETF RFC 791] IETF RFC 791 (1981), Internet Protocol.
<http://www.ietf.org/rfc/rfc791.txt>
[IETF RFC 2460] IETF RFC 2460 (1998), Internet Protocol, Version 6 (IPv6) Specification.
<http://www.ietf.org/rfc/rfc2460.txt>
[IETF RFC 4737] IETF RFC 4737 (2006), Packet Reordering Metrics.
<<http://www.ietf.org/rfc/rfc4737.txt>>
[IETF RFC 5136] IETF RFC 5136 (2008), Defining Network Capacity.
<<http://www.ietf.org/rfc/rfc5136.txt>>
[IETF RFC 5481] IETF RFC 5481 (2009), Packet Delay Variation Applicability Statement.
<<http://www.ietf.org/rfc/rfc5481.txt>>