ELSA LANCOM Business LC-4X00, Руководство пользователя

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Operating modes and functions
ELSA LANCOM Business
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connection can be made at all using the security procedure, names and passwords
specified.
The reliability of the line can be constantly monitored using the LCP once the connection
has been established. This is achieved within the protocol by the LCP echo request and
the associated LCP echo reply. The LCP echo request is a query in the form of a data
packet which is transferred to the remote station along with the data. The connection is
reliable and stable if a valid response to this request for information is returned (LCP echo
reply). This request is repeated at defined intervals so that the connection can be
continually monitored.
What happens when there is no reply? First a few retries will be initiated to exclude the
possibility of any short-term line interference. The line will be dropped and an alternative
route sought if all the retries remain unanswered. This may be found in the form of a
backup line, for example.
We recommend that you switch off regular LCP queries in the case of remote access from
individual workstation computers using Windows 95, Windows 98 or Windows NT since
these operating systems do not respond to LCP echo requests.
The LCP request behavior is configured in the PPP list for each individual connection. The
intervals at which LCP requests should be made are set by the entries in the 'Time' and
'Retries' fields, along with the number of retries that should be initiated without a
response before the line can be considered faulty. LCP requests can be switched off
entirely by setting the time at '0' and the retries at '0'.
Assigning IP addresses via PPP
In order to connect computers using TCP/IP as the network protocol, all participating
computers require a valid and unique IP address. In the event that a remote station does
not have an IP address of its own (e.g. an individual computer belonging to a teleworker),
the
ELSA LANCOM can assign an IP address for the duration of the connection to permit
communications.
This mode of assigning addresses is run during the PPP negotiation and is used only for
connections over the WAN. The assignment of addresses via DHCP, on the other hand,
is used only within the LAN.
Assignment of an IP address will only be possible if the ELSA LANCOM can identify the
remote sites by its call number or name when the call arrives, i.e. the authentication
process has been successful.
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For example: Remote access
Address assignment is made possible by a special entry in the IP routing table.
255.255.255.255 is specified as the network mask as the IP address to be assigned
to the remote station in the 'Router' field. In this case the router name is the name