Central Site Remote Access Switch 399
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ONFIGURING
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THER
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DVANCED
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PTIONS
Default Line Protocol
PPP Link Failure Detection can be enabled or disabled within the PPP Options configuration menu.
When enabled, two other configurable parameters then control the mechanism. Upon entrance of
a PPP link into Network Phase (the point at which device data transfer is allowed), Echo-Requests
will be sent at a configured frequency. As long as Echo-Replies are received, the link is deemed to
be functional.
A second parameter specifies the maximum number of Echo-Request attempts which will be
transmitted without a reply. If this limit is reached, a message is logged and the link is reported as
faulty. Thus, the configured frequency multiplied by the configured maximum attempts yields the
approximate time it will take to detect a failed link.
Note:
Within the CyberSWITCH, there are certain accesses which also present the ability to
enable/disable the periodic transmission of link maintenance type packets. For example,
the packet-based Frame Relay access supports the configurable enable/disable of
“Keepalives” in order to avoid the extra per-packet costs which the periodic Echo-Request
frames might incur. The PPP Link Detection Failure feature will honor such access-based
configuration, in addition to the explicit enable/disable configuration status of the PPP
feature itself.
PPP R
EFERENCE
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OCUMENTS
Point-to-Point Protocol (PPP) is also described in more detail in the set of RFCs listed below:
•
RFC 1661 The Point-to-Point Protocol
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RFC 1638 PPP Bridging Control Protocol (BCP)
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RFC 1549 PPP in HDLC Framing
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RFC 1547 Requirements for an Internet Standard Point-to-Point Protocol
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RFC 1334 PPP Authentication Protocols
•
RFC 1332 The PPP Internet Protocol Control Protocol (IPCP)
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EFAULT
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INE
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ROTOCOL
The default values for this feature are adequate for most situations. Instructions are included for
the rare instance that you need to alter the configuration.
Note:
This feature does not apply to analog connections (including digital modem).
C
ONFIGURING
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EFAULT
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INE
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ROTOCOL
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SING
CFGEDIT
1.
Select Default Line Protocol from the Options menu.
2.
Change the action on the frame timeout.
3.
Change the frame timeout value.
