Specifications

Interfaces Page 30
. For multiaccess channels, allow a network management system to
diagnose some other
system's ability to communicate.
, Minimize processing and memory requirements, particularly in
systems other than the requesting system.
The realization of these goals is
differerii: for multiaccess channels
and point-to-point channels, since multiaccess channels have a broader
communication ability.
On a point-to-point channel, a system using the Loop Test functions on
its own behalf and having all of them available can ascertain its
ability to communicate with the system on the other end of the
channel.
For multiaccess channels, the Loop Test functions are modeled after
the Ethernet standard. See Appendix
E or the Ethernet Specification,
Version 2.0, for a detailed description.
Some multiaccess channels may support the concept of a generic
loopback assistant. These are systems that are willing to assist in
some forms of multiaccess loopback testing. The following
descriptions refer to these systems as the loopback assistant
multicast group.
The amount of the Loop
Test interface
thc~ is implemented can cover
the full ranqe from
none at all to full capability. However, those
systems that
do not provide the full interface capability
proportionately limit their capacity for self diagnosis and become
more dependent
on some centralized test facility.
The followinq functior-,S
are oil calls to the Loop Requester.
Function:
Determine
if direct communication with a remote system is
possible.
Inputs:
Channel-id
- the unique identification of the channel on which the
loop is to
be done.
Destination-address
- the identification of the system that is to
be looped to. Applicable only on multiaccess channels. If
applicable and not included, the loopback assistant group
multicast address is used.