Brian Gilmore Computing Services, University of Edinburgh

1
Brian GilmoreComputing Services,University of
Edinburgh

• Edinburghs Experiences

2
Edinburgh - The History

• April 98 - University Management Committee
  reverses the expectation of a top-slice.
• Bill must be devolved to Planning Units.
• University Computing Policy Committee refuses to
  accept bills based on number of ports
• Committee also very worried about overheads
  (centrally generated traffic such as email)
• Therefore, UKERNA itemisation service had to be
  used to devolve the bills
• July, then August, gave us the first indication
  of traffic levels to either PUs or central items

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August Traffic from the Transatlantic Links
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Charged Directly

• Direct Departmental Traffic
• Charged to Planning Unit (60 in Univ.) or Dept.
• just over 80 of the total traffic
• Most areas of the University use IP addresses
  that can be reasonably mapped to their PU
• 2 areas have caused difficulties - Medicine
  Administration
• Some aggregation and network re-numbering is
  being done.
• However, over 750 UKERNA itemisation bins are
  in use (about 120 billing points)

5
Open Access Labs

• Open Access Labs under Computing Services
  Management.
• Not Teaching Labs - they are Departmental.
• Academics very reluctant to accept open-ended
  bills from this area
• Very difficult/expensive to tie individual
  student usage to traffic usage.
• Computing Services will bear this charge for the
  time being (figure will grow in term time).
• Intention is to police this area strongly, ie
  force use of national cache, ban real audio,
  video etc.

6
Dialup Traffic

• Dialup is a central service run by the Computing
  Services
• Charging individual usage is again very
  difficult/expensive
• Policy body reluctant to carry the charge as an
  overhead unless small
• So, force use of national cache etc (90 of
  browsers will break!)
• Some detailed monitoring to stop outright abuse
  is being performed
• Or, seriously consider an annual charge for the
  service to cover these costs

7
Central Services

• This item covers
• Central email hubs
• Central time sharing services
• Other centrally managed boxes
• Policy body will carry as overhead (so long as it
  is small!)
• Have instituted policy options on central time
  sharing system which has constrained the traffic

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Charged Proxy Caches

• We decided to install 2 caches (actually 2x2).
  One set would be free (ie use national cache)
  and the other charged.
• Free cache is generating a tiny bill -gt
  overheads
• Charged cache (ie it fetches uncached pages)
• Usual problem what is a fair algorithm for
  charging?
• Fairly arbitrary decision taken
• Count the number of requests and divide into
  the cache bill. Common IP tables used to
  allocate bill.

9
Future Challenges

• National Caches
• When they are no longer free, the itemisation in
  bills will need to be as good as UKERNAs!
• Our strategy, re restraint of the overhead
  portion will need to be revisited
• In particular, students could become a
  substantial part of the total bill.
• Size of the Bill
• We are told that the bill will rise substantially
  - users will question their bills more!
• Will need individual itemisation ?