Installation guide

Wireless ADSL Modem User’s Manual 37
• MRU: The MRU (Maximum Receive Unit) field indicates the maximum size IP
packet that the peer of PPP connection (this device) can receive. During the PPP
negotiation, the peer of the PPP connection will indicate its MRU and will accept any
value up to that size. The actual MTU of the PPP connection will be set to the smaller
of the two (MTU and the peer’s MRU). In the normal negotiation, the peer will
accept this MRU and will not send packet with information field larger than this value.
Range for MRU field is 0-32767, default value is 1492.
• MTU: Maximum Transmission Unit (MTU) is the largest size packet that can be
sent by the modem. If the network stack of any packet is larger than the MTU value,
then the packet will be fragmented before the transmission. During the PPP
negotiation, the peer of the PPP connection will indicate its MRU and will accept any
value up to that size. The actual MTU of the PPP connection will be set to the smaller
of the two (MTU and the peer’s MRU).
Range for MTU field is 0-32767, default value is 1492.
• MSS: Maximum Segment Size is the largest size of data that TCP will send in a
single, unfragmented IP packet. The LAN client and the WAN host will indicate their
MSS during the TCP connection handshake.
Range for MSS field is 0-32767, default value is 1432.
• Lcp Echo Interval: This is the time interval, in seconds, between PPP session
connection attempts.
Range for Lcp Echo Interval field is 0-32767, default value is 10.
• Lcp Echo Maximum Consecutive Failure: This is the number of times a PPP
session can fail while trying to connect before stopping. If a PPP session fails this
number of times, you must manually reconnect the PPP session.
Range for Lcp Echo Maximum Consecutive Failure field is 0-32767, default value
is 6.
• Authentication: The different types of available authentications are:
o Auto: When auto is selected, PAP mode will run by default. However, if
PAP fails, then CHAP will run as the secondary protocol. This is the
default setting.
o PAP: Password Authentication Procedure. Authentication is done through
username and password.
o CHAP: Challenge-Handshake Authentication Protocol. Typically more
secure than PAP, CHAP uses username and password in combination with
a randomly generated challenge string which has to be authenticated using
a one-way hashing function.
• Automatic Reconnect: When it is checked, the ADSL Bridge/Router will
reconnect a PPP session when it is terminated by the ISP. If a PPP session is
terminated under any other conditions (i.e. by Disconnect Timeout or manual
disconnect), the Automatic Reconnect will not reconnect the session. This box is
unchecked by default.
• PPP Configuration Status: A table will be displayed at the bottom of this page
to show all the Session Names with its Adapter (PVC number), Mode (PPPoA or
PPPoE), Service Name, Account to Use (PPP Account ID), Disconnect Timeout
configuration, MRU, MTU, MSS, Authentication Mode (Auto, CHAP or PAP), and
Auto Reconnect configuration.