HP auroraTempo User Manual page 234

aurora Tempo - User Guide
•
Header:
This is the same as the standard header but contains
a DLCI of zero to signify its an LMI frame.
•
Unnumbered frame indicator:
This indicates that the frame does not contain a
sequence number. This field is always set to the
value '0 0 0 0 0 0 1 1'.
•
Protocol discriminator:
This is included for compatibility with ISDN Frame
Relay procedures only and is always set to the value
'0 0 0 0 1 0 0 0'.
•
Call reference:
This field is only used for SVCs; when not used for
SVCs it contains the value
'0 0 0 0 0 0 0 0'.
•
Message type:
This describes the type of management message in
the LMI frame. There are three main types of LMI
message:
•
Information elements:
There will be at least one information element in an
LMI message. The information element comprises
of an identifier, a length indicator and one or more
octets containing the message details.
STATUS and STATUS ENQUIRY messages are passed
between the user and the network. The following diagram
shows the flow of these messages:
8-20
• call establishment messages
• call clearing messages
• miscellaneous messages
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