📄 rfc1431.txt
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award [2] marks if the query found the author's entry successfully.
The expensiveness of each query should be measured using the
following formula, which introduces the notion of SearchStones! The
SearchStone rating is calculated by adding together the total
operations used in attempting to resolve a query, weighted thus:
o Bind [5]
o Read operation [1]
o List operation [2]
o Search single level for countries, organisations or
localities [3]
Barker [Page 13]
RFC 1431 DUA Metrics February 1993
o Search single level for organisational units, people or roles [3]
o Search subtree [5]
Note: The single level searches have been separated into two
categories in acknowledgement that certain types of search are
much more likely to span multiple DSAs than others. The
weightings are the same for the moment because of the
pervasiveness of the Quipu implementation, which replicates all
sibling entries in a single DSA, whatever the level in the DIT.
The notion of SearchStones merits some further explanation and the
statement of some caveats.
The idea is to give some broad brush view of the work being
undertaken by a DUA to retrieve an entry. There will be some
correspondence between a low SearchStone rating and a DUA responding
quickly, and vice-versa, although this correlation is not consistent,
for reasons given below. It would be desirable to be able to have
some timing information for the resolution of queries, but such
results would only be meaningful if the tests were for target entries
widely distributed throughout the DIT. Maybe this is something for
the future? In the meantime it is worth noting some of the factors
which militate against simple minded interpretation of the
SearchStones.
o The DIT is not uniform, with the depth varying considerably
o While the DIT is currently mastered mostly by DSAs of a single
implementation, this will be decreasingly the case, and other DSAs
may have very different performance profiles.
o Different directory domains are already adopting different
strategies on information replication with profound performance
implications.
o No weighting is given to different search filters, or to boolean
combinations of filters.
While acknowledging the difficulty of the exercise, there are counter
arguments:
o Some DUAs are better than others at finding the required results
o Some DUAs will get the required results more quickly than most
o DUA designers have to build DUAs in the knowledge that the DIT is
heterogeneous with respect to DSA implementation and DIT structure
Barker [Page 14]
RFC 1431 DUA Metrics February 1993
One possible way forward would be to refine the test queries such
that they better represented the diversity of the DIT. However, as a
first step, the tests are restricted to queries which could
reasonably be constructed as searches for the author's entry. The
author's entry is held in part of the DIT which is representative of
much of the current DIT. It is suggested that in order to normalise
the tests as much as possible, that testing be performed by
connecting to the target DSA directly. The DSA's name is "cn=Vicuna,
c=GB", and the addresses of the DSA may be found in the presentation
address attribute for that entry. Note that the SearchStone rating
should be shown even for queries which cannot be resolved.
First, the straightforward queries:
50. NAME=Paul Barker, OU=Computer Science, O=University College
London, C=GB
51. NAME=Paul Barker, OU=Computer Science, O=UCL, C=GB
52. NAME=Barker, OU=Computer, O=UCL, C=GB
53. NAME=Barker, O=UCL, C=GB
54. NAME=p barker, O=university college, C=GB
55. NAME=paul b, OU=cs, O=university college, C=GB
More difficult queries:
56. NAME=p b, O=university college, C=uk
57. NAME=Paul Barker, OU=Computer Networking, O=london college, C=GB
58. NAME=Paul Baker (sic), OU=cs, O=ucl, C=Britain
59. NAME=p baker (sic), O=UCL, C=England
60. NAME=Paul Barker, OU=Directories, O=london, C=United Kingdom
Other general questions:
61. Will the DUA attempt a query of the form "Find all the Smiths in
Britain"? .....................................................
If so, does it do it by:
(a) A single query under the country node? .....................
Barker [Page 15]
RFC 1431 DUA Metrics February 1993
(b) Multiple queries under all organisation nodes? .............
62. Does the DUA allow "hands-off" querying whereby the details of a
query may be entered in one go, and the DUA attempts to resolve
the query without any further user intervention? ...............
13. International Languages
63. Does the DUA offer multi-lingual support. If so: ..............
(a) State which languages are already supported [1 per language up
to a maximum of 3] ..........................................
................................................................
64. Can the DUA handle national language characters not found in
PrintableString? [2 if yes] ....................................
14. User Friendliness
65. Is run-time help available? [2 if yes] .........................
If so:
(a) Is context-sensitive help available? [1 if yes] ............
(b) How many screens/windows? ..................................
(c) How many bytes of help information? [2 if more than 5 Kbytes
of text, 1 if more than 3 Kbytes] ...........................
66. Are the error messages terse renderings of the X.500 service
errors, or user-friendly!? As an example, provide the error
message displayed to the user if an administrative limit is
exceeded. [2 if user-orientated, 1 if administrator-orientated, 0
if no message at all] ...........................................
....................................................................
....................................................................
67. If modify operations are provided, is there support for editing
the attributes correctly with the appropriate syntax (e.g., does
the DUA guide the user that addresses are of up to 6 lines of up
to 30 characters; what support is given for entering distinguished
names) [2 for postal address support, 2 for DN support, 1 for any
other support] ..................................................
68. Is the user allowed to see what sort of entries are in the
Directory if they are unable to find the entry they are looking
for? [1 if yes] ................................................
Barker [Page 16]
RFC 1431 DUA Metrics February 1993
69. Does the DUA allow automatic following of attributes with DN
values, such as seeAlso and roleOccupant? [1 if yes]............
15. Operational Use
The DUA exists. But is there any evidence to suggest that it is a
usable tool?
70. Is this DUA widely in use? [5 if used by more than 20 orgs, 3 if
by more than 10 orgs, 2 if by more than 5 orgs, 1 if used
operationally to provide a service anywhere] ....................
(a) Is this DUA in use anywhere in the COSINE/Internet Pilot? ..
................................................................
(b) Is this DUA in use in any other major pilot? ...............
(c) Is this DUA in use anywhere else operationally? ............
71. Has this DUA been assessed by groups outside of the software
developers or providers? .......................................
72. If so, are the assessments public? Please provide copies of these
assessments if they are available ...............................
Barker [Page 17]
RFC 1431 DUA Metrics February 1993
__________________________________________________________
|_____Section_____|_____Points____|______________________|
|No._|Description_|Maximum_|Scored|______________________|
| | | | | |
|__2_|Gen_Info____|__10____|...___|__________n/a_________|
| | | | | |
|__3_|Conf_to_OSI_|__15____|...___|__________n/a_________|
| |Conf to Res | | | |
|__4_|Comm_stds___|__10____|...___|__________n/a_________|
| | | | | |
|__5_|Gen_Style___|__10____|_...__|__________n/a_________|
| | | | | |
|__9_|Disp_Res____|__10____|_...__|__________n/a_________|
| | | | | |
|_10_|Assoc_hand._|__15____|_...__|__________n/a_________|
| | | | | |
|_11_|Man_cap_____|__10____|_...__|__________n/a_________|
| 12 |Query res | | |Search |No. of other |
| | | | |Stones |entries found |
|____|Q._50_______|__2_____|_...__|_...___|:_...._....___|
| | | | | | |
|____|Q._51_______|__2_____|_...__|_...___|:_...._....___|
| | | | | | |
|____|Q._52_______|__2_____|_...__|_...___|:_...._....___|
| | | | | | |
|____|Q._53_______|__2_____|_...__|_...___|:_...._....___|
| | | | | | |
|____|Q._54_______|__2_____|_...__|_...___|:_...._....___|
Barker [Page 18]
RFC 1431 DUA Metrics February 1993
__________________________________________________________
|_____Section_____|_____Points____|______________________|
|No._|Description_|Maximum_|Scored|______________________|
| | | | | | |
|____|Q._55_______|__2_____|_...__|_...___|:_...._....___|
| | | | | | |
|____|Q._56_______|__2_____|_...__|_...___|:_...._....___|
| | | | | | |
|____|Q._57_______|__2_____|_...__|_...___|:_...._....___|
| | | | | | |
|____|Q._58_______|__2_____|_...__|_...___|:_...._....___|
| | | | | | |
|____|Q._59_______|__2_____|_...__|_...___|:_...._....___|
| | | | | | |
|____|Q._60_______|__2_____|_...__|_...___|:_...._....___|
| | | | | |
|_13_|Int_Lang____|__5_____|_...__|__________n/a_________|
| 14 |User-fr | | | |
| | | | | |
| |Query DUA | 10 | .... | n/a |
| | | | | |
|____|Modify_DUA__|__15____|_...__|__________n/a_________|
| | | | | |
|_15_|Op_use______|__5_____|_...__|__________n/a_________|
Table 1: DUA Metrics
16. Security Considerations
Security issues are not discussed in this memo.
17. Author's Address
Paul Barker
Department of Computer Science
University College London
Gower Street
London
WC1E 6BT
United Kingdom
Phone: +44 71 380 7366
Fax: +44 71 387 1397
Email: P.Barker@cs.ucl.ac.uk
Barker [Page 19]
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