@make[report]
@device[x2700]
@majorheading[Telematics]
@section[General]
Telematics offer a range of X.25 networking products called the Net 25 Product
Family including concentrator switches, primary switches, backbone switches,
PADs and supervisory nodes.  The equipment is sold in the UK by Telematics and
also by ICL and other companies including IAL who sell it under their own label.
Telematics is certified for use on most public data networks.  The maximum
packet size supported is 1024 bytes.
@section[Hardware Description]
The Net 25 switches are based on a proprietary 32 bit bus that is stated to
run at 32 Megabytes/sec.  
There are three models available, the P500, P1000 and P2000.  The main
difference being the number of slots available.  The particular switch
confgurations, described as Net 25/XXX are constructed from the appropriate
model.
The Net 25/100 switch consists of the bus and a
general purpose M68000 processor card, a memory controller and memory, either
a floppy or a hard disk, and an Network Communications Processor NCP.
A Net 25/200 is formed by adding a
'communications accelerator' which is a two part cache, one part a cache for the general processor
and the other part a cache for the NCP.

The Net 25/400 is formed by the further addition of one or two extra general
processors and the Net 25/800 by an additional two processors.  At any stage
(!) extra memory can be added up to a maximum of 16 Mb (?) in increments of
2 Mb(?)

The NCP supports a TDM based bus with a scanner with a maximum capacity of
2 M bits/sec.  The scanner can support up to 60 'line modules', each
supporting up to 8 lines (depending on speed).  In addition our new module
in the field, although no BT approval as yet, with 120 Kbytes of on board
RAM can support up to two expander cards to which either 8 V24 or 4 V35
cards can be supported
@section[Software Description]
The basic operating system, caled TRAX, is used to support a number of
tasks which implement the switch software.  In addition it is possible to
run differnet complexities of Network Management tasks or 'user' written
tasks. (A 'user' task is any not written by Telematics.)  TRAX is written
in M68000 assembler code.

The switch software, consisting of a number of tasks to - handle call set up,
handle data transfer and an Interface 6 Network Management (INF).
The data transfer task is writtin in assembler
and the call set up task is written in C.  'User' tasks can be written in
either C, Pascal or assembler.

@section[Configuration Options]

The maximum number of line which can be supported by each
model is as follows:
@begin[verbatim]
                  Net 25/100     ?
                  Net 25/200     ?
                  Net 25/400     ?
                  Net 25/800     ?
@end[verbatim]

@section[Line Speeds/Interface Options]
Telematics support 64 kb/s as well as the line speeds in the specification.
V24 is used up to 19.2 kb/s and V35 above that.  In addition X.21 is
supported (at any speed?). Both internal and external clocking can be sent
at any of these speeds.
@section[Throughput]
The following throughput is claimed for the Telematics range.  The figures are
for data packets only through the switch.  There is no dependance of packet
size.
@begin[verbatim]
                   Net 25/100    100 dpp/s
                   Net 25/200    200 dpp/s
                   Net 25/400    400 dpp/s
                   Net 25/800    800 dpp/s
@end[verbatim]
? section on proof of above.
@section[Costs]
The following costs have been quoted by Telematics for the 4 configurations.
@begin[verbatim]
                  10 line:   ?
                  18 line:   ?
                  48 line:   ?
                 100 line:   ?
@end[verbatim]
The hardware quoted for the 10 line switch is about to be replaced by a new
option and reference should be made to the ICL section for details of it.

In addition to the above, various items can be added to the configuration -
@begin[verbatim]
                  Comms accelerator (to net 25/100)
                  Extra processor        (all)     10,500
                  Additional line cards  (all)
@end[verbatim]
Any one of the configurations can be field upgraded to the large configuration.
@section[Addressing]
Telematics allows multiple entries in the address table.  The table size is
only limited by the overall store size.  An individual entry can be either a
single address or can be made to match and address, eg. 1234 would match any
address from 12340000000 to 12349999999.  This is not quite as flexible as
a 'range of addresses' but by using multiple entries, the differences are
fairly minor.
@section[Network Management]
Network Management can be performed on a separate machine or the software
can be integrated with the software of one of the switches in a network.
If it is integrated then there could be a performance cost although it is
possible to run the management package at a priority level less than that
of the switching functions on a separate processor with the switch system.

No explicit charging is done by the current software though the information
is present to do charging for calls, for example, to PSS.

The management protocols are @u[not] in the public domain, although
Telematics would sell us listings etc., to allow community hosts to perform
some of the management.  It appears that they would @u[not] allow other
switch manufacturers to implement the protocols.
@section[Statistics]
Telematics meet the JNT spec except for the percentage utilisation ?????
@section[Status Monitoring]
Telematics do not report in real-time the number of active calls on a link
or the respective address, otherwise the spec is met.
@section[Control]
It is @u[not] possible to clear a call to a selected address, the rest of
the spec is met with the ability to change network addresses on a line
link.

It is possible to use any network terminal (password protected) for switch
control.

There are two levels of Network Management/Control Software - 'A' and 'C'.
'C' is a partial form that only allows the operation of a particular switch
to control that switch.  'A' adds the ability to look at and control a remote
switch.  At lease one node in each university would require either the 'A'
level or a support management machine.
@section[Date/Time Stamp]
Complies.
@section[PSS Compatibility]
Telematics say that they are currently compatible with PSS.  However, if in
the future (?) there is a divergance between PSS and CCITT then Telematics
will guarantee compatibility only with CCITT.
@section[Performance - Packet Transmission]
@begin[verbatim]
                   Call Request            30ms
                   Data Packate           4-6ms
                   Clear                  <30ms

@section[Availability and Reliability]
It was claimed that the Net 25 series would meet the reliability
part of the specification.  It was noted that line cards could
be replaced on live systems, so that only a failure in a central
module would force an entire operating system to go down.
Redundant systems, ie line cards shared between two nodes could be
constructed if necessary.
Only figures for hardware reliability are stated - in terms of
7000 hours MTBF for the kernel system.  An availability for an
entire node is quoted at 99.9%.

@section[Operations]
It is not possible with the current software to automatically
dump the store to backing disk in the case of a complete failure.  If
failures of individual tests occur details of the
failure are printed out on the system console.

There is not a separate handler for each link in a system
and consequently it is not possible for an individual link to
fail, and require a reload, that occurs on the
GEC switches.

@section[?????]
All configurations, including the initial set up, is done by
using the INF software.  This can be achieved by either
inputting commands that directly change the configuration or by
editing a file and then 'executing' the file.  In the case of the
file, only the differences between the file and the running system are
actioned.

@section[X25 )1984)]
Work is currently on hand to implement X25 (1984).  Features will
start to appear in early 1986 and there will be a comprehensive
implementation (backing ?) by the end of 1986.  The OSI copies
document has not been studied.

@section[Academic Community Special Requirements]
The TRAX system together with the X25 system has been designed and built
with the specific criteria that it is easy
to add 'user' modules to the system to tailor it for non standard
requirements.  However, Telematics state that they have 
enough to do and would not wish
to take on 'specials' for the academic community.  They stated
that various software houses could do specials
but they were not prepared to take prime contractor status for
the work.

The advantages and disadvantages of the comments 'doing it itself'
would need to be carefully weighed up.

@section[Product History]

@section[Company Information]

@section[Confidentiality]

@section[Summary]