Panasonic UF-E1 Service Manual page 168

UF-E1
b. Link Establishment Phase
In this phase, LCP configuration packets (configuration request, acknowledge packet) are
exchanged in both directions. When the transmitting and receiving ends transmit and receive the
Configure-Ack packet, link is established (LCP Open). In this phase, only the LCP packet can be
used. Other packets are ignored.
When the Configure-Request packet is received in the Protocol phase or Acknowledge phase in the
Network Layer, the phase shifts to the Link Establishment phase.
c. Authentication Phase
Before the protocols of the network layer, the authentication protocol can be executed. Although the
Authentication phase can be omitted, if it is to be executed, it should be executed as soon as the
link is established. LCP setting option configures which authentication protocols are to be used. As
an authentication protocol, there is one in the data link control protocol shown in Table 6.5.2.2.
In this phase, LCP, authentication protocol, and link quality monitoring packet can be executed.
Packets other than these will be discarded.
d. Network Layer Protocol Phase
In this phase, individual NCP's corresponding to network layer protocols are executed. The network
protocols are not effective until NCP's are executed. At this point, the packets of the protocols sup-
ported are discarded and packets of the protocols not supported are made subject to Protocol
Reject.
The packets usable in this phase are LCP, NCP, and Network protocol packets.
e. Link Termination Phase
Transition to the Link Termination phase is made when modem is down with CD (CD OFF), failure in
authentication and link quality, time out in idle time, and termination request. LCP sends Terminate
Request packet. When Terminate Ack packet is received for it, link shifts to closed state and a signal
is sent to physical layer for termination. When closing the link, the network layer is notified for con-
ducting necessary procedure. At this point, there is nothing for NCP to do. When the counterpart
PPP receives the Terminate Request packet, it sends the Terminate Ack packet. After elapse of cer-
tain time (by the Restart Timer for which default is 3 seconds and can be configured), link is termi-
nated. Then, the phase is shifted to Link Terminate phase.
In this phase, only LCP packet can be received.
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