Network Working Group                                           P. Jones
Request for Comments: 1346                        Joint Network Team, UK
                                                               June 1992


             Resource Allocation, Control, and Accounting
                    for the Use of Network Resources

Status of this Memo

   This memo provides information for the Internet community.  It does
   not specify an Internet standard.  Distribution of this memo is
   unlimited.

0. MANAGEMENT SUMMARY

   This paper gives reasons for wanting better sharing mechanisms for
   networks.  It concludes that the challenge of sharing network
   resources (and for example intercontinental link resources) between
   groups of users is neither well understood, nor well catered for in
   terms of tools for those responsible for managing the services.  The
   situation is compared with other fields, both inside and outside IT,
   and examples are cited. Recommendations for further work are made.

   The purpose of this RFC is to focus discussion on particular
   challenges in large service networks in general, and the
   International IP Internet in particular.  No solution discussed in
   this document is intended as a standard.  Rather, it is hoped that a
   general consensus will emerge as to the appropriate solutions,
   leading eventually to the adoption of standards.

   The structure of the paper is as follows:

      1. Findings
      2. Conclusions
      3. Recommendations

1. FINDINGS

   Issues arising from contention in the use of networks are not
   unusual.  Once connectivity and reliability have been addressed to a
   reasonable level, bandwidth becomes (or appears to become?) the main
   issue.  Usage appears to have a strong tendency to rise to fill the
   resources available (fully in line with the principles of Parkinson's
   Law).  Line-speed upgrades have an effect, but with no guarantee of
   permanently alleviating the problem.  Line-speeds are increasing as
   technology improves over time, but the variations on matters like
   availability and funding are wide, and users remain avaricious.

   Often the situation can appear worse than having to survive in a
   jungle, in the sense that the strong (even if "good") seem to have
   little advantage over the weak.  It may seem that it is the
   determined person rather than the important work that gets service.

   Most people will have experienced poor service on an overloaded
   network at some time. To help the end-users, it seems on the face of
   it that one must help the IT Service Manager he relates to.  Examples
   relating to the relationship between the network manager and his
   customers, IT Service Managers at institutions connecting to his
   network, include the following:

   (a) If the IT Service Manager finds his link to the Network Manager's
   network overloaded, he may be offered a link upgrade, probably with a
   cost estimate.  He might prefer control mechanisms whereby he can say
   that department X deserves more resources than department Y, or that
   interactive terminal use takes preference over file transfers, or
   that user U is more important than user V.

   (b) Where an IT Service Manager is sharing a link, he will commonly
   get more than his institution's share of the link, and often get very
   good value-for-money compared to using a dedicated link, but he has
   no guarantee that his end-users' usage won't get swamped by the use
   of other (perhaps much larger) partners on the shared link.  This
   could be seen as wishing to have a guaranteed minimum share according
   to some parameter(s).

   (c) On a shared link as under (b), the Network Manager may wish to
   ensure that usage of the link (which might be a high-performance
   trunk line on a network or an international link for example) by any
   one partner is "reasonable" in relation perhaps to his contribution
   to the costs.  In contrast to (b), the Network Manager is wishing to
   impose a maximum value on some parameter(s).  He may be happy if the
   width of the IT Service Manager's access link is not greater than his
   share of the shared link (assuming the measure agreed on is "width"),
   but this will commonly not be the case.  To be able to reach
   agreement, the Network Manager and the IT Service Manager may need
   options on the choice of parameters, and perhaps a choice on the
   means of control, as well as being able to negotiate about values.

   In circumstances where the Network Manager can exercise such controls
   over his customers, the IT Service Managers may say with some feeling
   and perhaps with justification, that if they are going to be
   controlled can the Network Manager please provide tools whereby they
   can arrange for the onward sharing of the resource they have, and
   thence onwards down the hierarchy to the end-users.

   (d) It may be Network Manager A has a link that Network Manager B
   would like to use on occasion, perhaps as back-up on access to a
   third network.  Network Manager A might well wish to be
   accommodating, perhaps as examples because of financial benefit or
   perhaps because of the possibility of a reciprocal arrangement.
   However, the fear of overload affecting normal use and the lack of
   control over the usage militates against arrangements that the
   parties could be quite keen to make.

   Such challenges are very far from being unique to networking.
   Government and both public and private organisations and companies
   allocate budgets (and resources other than money), control and
   account for usage, recognising the possibility of overdrawing and
   borrowing.  In times of shortage, food is rationed.  I haven't
   checked this out, but it would surprise me if Jerry Hall wasn't
   guaranteed a ticket for any Rolling Stones concert, should she wish
   to attend.

   The charging factor influences use but does not control it (except
   perhaps in unusual circumstances where say payment was expected in
   advance and usage was cut off when the money ran out).

   In the IT world, multi-user hosts have filestore control systems; one
   that I use has an overdraft facility with no penalty for not having a
   prior arrangement!  There are also system designs and implementations
   for sharing host processor time with more sophistication than just
   counting seconds and chopping people off; this problem seems to me to
   be reasonably well understood.  (Library catalogue searches under
   author "John Larmouth" should provide some references for those who
   require convincing.)  Some multi-user hosts have controls of sorts on
   terminal connections.  On the other hand, I am not aware of any
   control system in operation that can guarantee multi-user host
   response time even outside the network context among directly
   connected terminals.

   The various roles bring different interests to bear.  A provider will
   not necessarily see it in his interests to control usage, or (perhaps
   even more likely) to provide customers with control tools, since the
   lack of these may encourage - or even oblige - the customer to buy
   more.  Even if the IT Service Manager can deal with the issue of who
   or what is important, and the issues of the relative importance of
   allocating resources against requests, other issues like social
   acceptability may arise to complicate his life.  For example it may
   be generally agreed (and perhaps the network manager instructed) that
   "everyone" must be able to do a small amount of work at any time,
   perhaps to do some housekeeping or seek information.

   Time is an important factor.  Network resources, like computer
   processor time and unlike filestore, vanish if they are not used.
   People will in general prefer resources during prime shift to those
   in the middle of their night; however, in global terms the middle of
   their night can be during prime shift somewhere along their path of
   usage.

   What's to do?  Splitting lines with multiplexers is rather
   inflexible, and may well militate against the benefits of resource-
   sharing that give rise commonly to link-sharing arrangements.  Some
   technologies:

      - have the ability to treat (or at least mark) traffic as of high
        priority, for example where it gives emergency or status
        information;

      - (in the case of X.25(84), I understand from my JNT colleague Ian
        Smith,) have throughput class (section 6.13) and transit delay
        (section 6.27).  (Ian tells me that it is in his view far from
        clear how practical these facilities are);

      - may be able to discriminate between traffic on grounds of
        network source address;

      - may be able to discriminate between traffic on grounds of
        network destination address;

      - may be able to discriminate between traffic on grounds of
        application protocol, perhaps giving preference to interactive
        terminal traffic, or making a choice between preference for
        email and for file transfer traffic;

      - may be able to discriminate between traffic on grounds of other
        facets of network protocol or traffic.

   In practice, one may well not have adequate tools in these or other
   terms, and one may well have to ignore the challenges of resource
   control, and either ignore the issue or refuse service.

2. CONCLUSIONS

      2.1 There seems to be a lack of tools to enable the controlling
      and the sharing of networks and links.  This is militating against
      the cooperative sharing of resources, and restricting the ability
      of organisations to do business with one another.

      2.2 Further, the definition of what constitutes a share, or what
      parameter of service one would try to measure and control (or what

      the choices are if any), is not clear.

      2.3 Following from that, it is then not clear whether what is
      needed is new or enhanced protocols/services, new or enhanced
      procurement specifications or profiles, or new or enhanced
      networking products or tools.

      2.4 Service providers (more likely the public carriers or but also
      some Network Managers) may see it as against their interests to
      provide controlling tools if they see them as tending to constrain
      usage and hence reducing income.  If so, they may not support, and
      may even oppose, progress in the area.  However, they might be
      persuaded that the provision of such tools might give them
      competitive edge over their rivals, and therefore to support
      appropriate projects and developments.

3. RECOMMENDATIONS

   There seems scope for one or more studies to:

      - restate and refine the definition of the problems;

      - collect, catalogue and relate relevant experience in both the
        networking and non-networking fields;

      - make recommendations as to what areas (e.g., among those
        suggested in 2.3 above) projects should be undertaken;

      - outline possible projects, indicating the timescale on which
        improved sharing of production network service resources is
        likely to be achieved, and recommending an order of priority
        among the suggested projects.

FOOTNOTES:

   Gender issues - where appropriate, the male embraces the female and
   vice versa.

   Dramatis Personae:

      Jerry Hall is a close associate of Mr. M. Jagger, formerly of the
      London School of Economics in the University of London, and now
      Chairman and Chief Executive of an internationally prominent and
      successful commercial musical operation.

      Others mentioned in this paper are assumed to prefer to remain
      anonymous, although the standard is to give contact information
      for the author (see Author's Address section).

Security Considerations

   Security issues are not discussed in this memo.

Author's Address

   Phil Jones
   JNT
   RAL, Chilton, Didcot, OXON  OX11 0QX

   Voice: +44-235-446618
   Fax:   +44-235-446251

   Email: p.jones@jnt.ac.uk  or c=gb;a= ;p=uk.ac;o=jnt;i=p;s=jones;