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INTERNATIONAL TELECOMMUNICATION |
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TELECOMMUNICATION STUDY PERIOD 2001-2004 |
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Question(s): |
5 - |
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Source: |
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Title: |
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LIAISON STATEMENT |
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To: |
IETF ippm WG chairs (Merike Kaeo,
Matthew Zehauskas) IETF Area Directors for Operations and
Management (Scott Bradner, Allison Mankin) IETF email address for liaison
statements |
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Approval: |
ITU-T SG4 meeting, Geneva, 5 – 14
February 2003 |
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For: |
Information/Action |
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Deadline: |
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Contact: |
Wolfgang Miller Acterna |
Tel: +49 7121 861328 Fax: +49 7121 862029 Email:wolfgang.miller@acterna.com |
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ITU-T SG4 is pleased to inform the IETF that a new topic is discussed with regard to performance measurements of IP networks and services.
Question 4 of Study Group 4 is standardizing test and measurement equipment. In February 2003 SG4 discussed a new draft Recommendation, O.iptest , focusing on the standardization of a test packet format to perform tests of IP based networks and services.
Regarding this topic, ITU-T SG4 would like to cooperate with the related WG of the IETF, such as the IPPM WG.
The framework of the draft Recommendation is described below:
1 – Scope
In order to support provisioning and maintenance of IP-based networks, in order to measure the performance of IPv4 and IPv6 networks and services for different Type-P [RFC2330], a common standard IP Test Packet format is desirable such that interoperability between heterogeneous test equipment and comparison of measurement results can be achieved.
2 – Requirements
A standard IP test packet should meet the following requirements:
v Network level: It is
necessary to define a test packet suitable for performing the measurement of
existing IP performance metrics and flexible enough to permit proprietary
extension and new format definition in the future. The format should be
compatible with all SUB-IP media on IP versions and should allow accurate
measurements in the Gbit range.
v Application level:
The concern is not only the performance measurement of IP networks, but of
numerous application services. To permit IP test packets to be transported in
the same manner as regular application packets, it is necessary to use test
packets with the same behaviour as regular packets of the tested IP service.
The IP test packet format defined should accept the header of any regular IP
application.
v Interoperability:
There is a need for interoperability between instruments of different
manufacturers to monitor consistently network performance and QoS. That will
offer measurement results comparison against SLAs and correlation between
measurement points and instruments.
v Inter-domain
interoperability: This is motivated by the need to perform end-to-end tests
across administrative areas and composite networks.
It is necessary to increase
operational interoperability by promoting the sharing of the same measurement
identification mechanism in the test packet to permit the managers of the
measurement systems to exchange results among administrative domains.
3 – Test packet format
It is proposed to adopt a standard format for IP test
packets. The currently proposed test packet consists of Sub-IP header and
trailer, IP header, data block and an IP measurement signature (IMS).
Signature format
The signature block is
explained below, showing the various fields of IMS.
ID: Identifier to differentiate test packets from regular packets
Ver: Version number
Type: permits to categorize measurement packet types
Ext: Proprietary extension size
SN: Sequence number
Timestamp: Wire time the packet was sent
Measure ID: Identifier of the measure in the initiator scope
Owner ID: Initiator of the measure
Specific: Proprietary extension
The signature is flexible enough to define several classes of measurement packets, mainly transport and application classes.
Signature classes
Some examples of signature classes are given hereafter, for illustration purpose only:
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Classes |
Length data |
Extension |
Type |
Signature length (bytes) |
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Applications |
VoIP |
RTP SDU- Signature |
0 |
1 |
20 |
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HTTP |
variable |
1 |
1 |
28 |
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Transport |
UDP |
variable |
0 |
1 |
20 |
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TCP |
variable |
1 |
1 |
28 |
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Network |
IPv4 |
variable |
0 |
1 |
20 |
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IPv6 |
variable |
0 |
1 |
20 |
We would appreciate any comments or remarks on the framework of this new Recommendation O.iptest.
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