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Zur Information ueber das, was bezueglich IP in England
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1

               Technical Aspects of the Use of Internet Protocols

                   to Support UK Academic Community Networking

                   Interim Report of the JNT DoD Advisory Group

                                    Edited by

                                   Phil Jones
                                      (JNT)

                                 Alistair Munro
             (Centre for Communications Research, Bristol University)

                                Management Summary


        This report has been prepared for the JNT by the Advisory Group on
        Department  of  Defense  and  Associated  Protocols  (DoDAG).  The
        Group's remit is to advise the JNT on  the  technical  aspects  of
        Internet,  and  associated,  protocols  and services, (referred to
        generically as the Internet Suite of Protocols, some of which have
        been  standardised by the US DoD), and related issues. The calling
        notice and the Group's terms of reference are appended [A.1, A.2]

        There is a strong  belief  that  UK  Academic  Community  (UK  AC)
        research  effort  is  being  hampered  by  limited  access  to the
        Internet - in America, Europe and elsewhere.  While mail  services
        are   adequate,   terminal   connection   and   file-transfer  are
        particularly  weak  and  in  increasing   demand.   Gateways   and
        converters  are  in  service  or  being  developed, (e.g. 1Q91 for
        file-transfer), but terminal connection will not be well  provided
        for.

        There are also requirements from users in the UK AC for networking
        facilities  which  could be offered now over IP, but which are not
        immediately available now using Coloured Books products or,  (with
        rare  exceptions  in  the  fullness  of time), OSI products. These
        include windowing,  certain  screen  mode  terminal  access,  file
        serving, file access and interactive facilities in ARPA-FTP.

        In a national context these services offer some benefits;  but  it
        is  the  demand  for  international  access that appears to be the
        overriding concern. This is strong enough that  some  institutions
        will  be  prepared  to  connect  to  commercially  offered  WAN IP
        services to achieve connectivity. This will endanger  the  unified
        transparent  interworking  capability  that has been JANET's major
        achievement and it will fragment the Community.

        IP is non-proprietary, widely implemented  and  available,  is  as
        reliable  as other comparable services, is cheap, respectable, and
        has at least one OSI transition target  -  the  primary  candidate
        being  a  connectionless  network  service  supporting  a  class 4
        transport protocol providing a connection-mode transport  service,
        [3.14]


                            Tuesday, November 6, 1990 1 - ii -

        The DoDAG's conclusions and technical recommendations are  in  the
        following areas:

        IP Services

        Concerning services, the DoDAG's  technical  evaluation  concluded
        [7.2, 8.2]:

        (a)  a service of WAN IP should be offered  to  institutions  with
             permission  to  use  X-Windows,  ARPA-FTP and TELNET (in both
             line mode and IBM 3270 mode);

        (b)  the demand  for  SMTP  is  higher  than  expected.  Computing
             service  mail managers favour it and focus on deficiencies in
             the quality  of  current  mail  relaying  services.   Several
             issues were raised:

             1.   the quality of relaying between SMTP and Grey Book mail;

             2.   the quality of the e-mail services  between   the  JANET
                  community and the Internet;

             3.   the vulnerability of the mail community to fragmentation
                  into non-interworking sectors.

             The Group concluded that these issues require  further  study
             by working groups responsible for mail. For the meantime SMTP
             should be permitted but discouraged.

        (c)  NNTP be permitted for  distribution  of  news.  A  transition
             target  for  OSI  might  be provided by developments in X.400
             group communication services and further study is required;

        (d)  technical   difficulties   in   managing   user   and   group
             identifications  indicate  that  file serving and file access
             (e.g. using NFS), should be discouraged until more  is  known
             about  management  tools such as Kerberos. However, given the
             value of the facilities for obtaining archives  it  might  be
             possible  to permit these services for read-only access under
             published, multilaterally agreed, user identifiers;

        (e)  services based on RPC should be permitted but discouraged;

        (f)  use of transport level facilities (e.g. UDP and  TCP)  should
             be permitted but discouraged;

        (g)  the Berkeley r-services should  be  actively  discouraged  on
             security grounds.

        Naming, Addressing and Routing

        The DoDAG notes, [3.8, 3.9], the problems of naming and addressing
        raised  by  provision of WAN IP. The integration of the NRS and IP
        name and address spaces is a particular concern (in respect of the
        unification/fragmentation   aspects).   Many   institutions   have
        obtained Internet network addresses already and the opportunity of

                            Tuesday, November 6, 1990 1 - iii -

        allocating  all  addresses  centrally,  by the NE for example, has
        passed.  However the NE may obtain a block of addresses  from  the
        Internet authorities and allocate them itself for new networks.

        The DoDAG draws attention to the classes of IP address  and  their
        respective  technical  merits. The allocation of a class A address
        for JANET would have  some  administrative  advantages  but  would
        cause  serious  problems with sub-network routing. Furthermore, as
        referred to above, many institutions have already  obtained  class
        B/class   C   licences   and  a  change  would  cause  significant
        disruption. The class B/class C approach, with existing  addresses
        being retained, is recommended.

        It is recommended that the JNT  study  the  practical  aspects  of
        supporting  DNS  nationally  and the international distribution of
        addressing and routing information for IP  networks  connected  to
        JANET.

        IP Provision

        Concerning the means by  which  IP  be  implemented,  the  DoDAG's
        technical conclusion [3.13, 3.14, 7.1, 8.1] is that it is feasible
        to offer a wide area IP service over X.25 on  JANET.   Performance
        considerations indicate that it is advisable for an institution to
        await  a  JANET  Mark  II  (i.e.  2  megabit)  connection   before
        connecting to the WAN IP service.

        A participating institution must connect to the service through  a
        purpose-built   router.   Direct   host   connection  is  strongly
        discouraged: the means to prevent this is available but permission
        to do it may be granted for individual systems in special cases.

        Backbone Routing

        The use of backbone routers  allows  an  incremental  approach  to
        traffic  management. The IP traffic can be routed onto connections
        that are independent of those carrying CONS traffic if  necessary.
        The  DoDAG  noted that this may incur a performance penalty due to
        extra transit and switching delays.  This support is not essential
        for  an initial service which can be supported by the site routers
        alone.

        The DoDAG has not been able  to  obtain  quantitative  information
        that would allow it to make recommendations concerning the traffic
        levels at which backbone routers should be used.  The  JNT  should
        study  this and the relationship, in terms of performance, between
        it and the point-to-point connection.

        However, the DoDAG  considers  that  it  has  identified  the  key
        factors  that affect the performance of the proposed service, [3.1
        - 3.7], and expects traffic levels to rise beyond the level  where
        a  detailed examination of these parameters has much importance in
        comparison with the congestion at site routers.  Thus,  the  Group
        recommends  that a backbone network be installed at the outset, if
        only to avoid the disruption that would be caused by changing over
        later on.  This also simplifies the management problem, [3.8, 3.9,

                            Tuesday, November 6, 1990 1 - iv -

        3.10].

        The backbone network will be implemented by routers sited  at  the
        NOCs.  At  least one is required for the initial service rising to
        an estimated eight as traffic increases. A  new  class  B  address
        should be obtained for this network.

        The  backbone  topology  should  be  static,  with  site   routers
        forwarding  external  requests  to  a  nominated  backbone router.
        Dynamic routing and the protocol to support  it  are  for  further
        study.

        IP Network Management

        The case for the ability to manage the IP network is very  strong,
        [3.10].   The  SNMP  protocol  should  be permitted for diagnostic
        purposes, with updates installed manually via TELNET for  security
        reasons.

        The DoDAG recommends that management  of  routing  information  is
        wholly  under  Network Executive control. Obtaining and allocating
        new addresses should be done by the NE which should  take  overall
        responsibility for the JANET community.

        Support and Funding Implications

        It will be necessary to budget for routing equipment, and  funding
        will  be  required  for  staff on the Network Executive and at the
        NOCs. The DoDAG  estimates  that  up  to  eight  routers  will  be
        required,  located  at  the NOCs. The staff requirement depends on
        the detailed model of the IP service and the level  of  management
        and  support.  It  is  a  matter for further study but the initial
        advice obtained by the DoDAG indicates that one man-year per  year
        effort  is required in the steady state. It is also noted that the
        Internet authorities define the support functions that  the  JANET
        community would have to provide.

        Institutions wishing to take up the option of this  service  would
        need  to adequately convincing in their application for permission
        to connect to this service. They would  need  to  satisfy  certain
        criteria,  including  those  imposed by membership of the Internet
        and by RIPE, and demonstrate their willingness to fund and acquire
        appropriate  equipment  (including  a  router)  and to provide the
        appropriate support (including staff).






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