| LAPD
(Q.921) is used for |
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| Establishing
data link connections identified by the |
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| Data
Link Connection Identifier
(DLCI = SAPI + TEI) |
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| Frame
delimiting, alignment and transparency, |
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| allowing
recognition of frames transmitted over the |
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| D-channel |
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| Flow
control: (a) to maintain the
sequential order of |
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| frames across
a data link connection, (b) temporarily |
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| stopping
transmission |
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| Error
Control: detection of errors
on a data link |
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| connection, recovery
from errors, and notification to |
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| the management
entity of unrecoverable errors |
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