4: Setting up the GSM (3G) modem for a primary WAN link
Configuring a GSM (3G) modem on a GW2040 Series Router
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Issue: 1.5
Page 19 of 34
4.2.7
Select asynchronous PPP operation
All PPP interfaces by default are configured for synchronous data transfer. The GSM (3G)
modem however uses asynchronous data transfer so you must configure the PPP
interface to operate asynchronously.
In the Expert View menu, select
interfaces -> ppp-1 -> ppp -> ppp.
The PPP Interface
page appears. Click
Advanced
to view advanced options.
Figure 15: The PPP interface page
Set Enabled to
yes
, and set Asychronous Link Enabled to
yes
. You can leave all other
settings at their default values.
Field name
Configuration
Command line
Enabled
Enables the ppp-2 interface.
Set Ppp Interface
Enabled
Maximum Receive
Unit (MRU)
The SMG sends the MRU to the end
device or peer to inform it that the
router can receive larger packets, or to
request that the peer send smaller
packets. Enter the MRU for the
specified PPP interface. Minimum value
is 512 bytes. Default/Maximum value is
1524 bytes.
Set Ppp Interface
Maximum Receive Unit
Maximum Remote
Receive Unit
The peer sends the Maximum Remote
Receive Unit (MRRU) to the SMG to
inform it that the remote router can
receive larger packets, or to request
Set Ppp Interface
Maximum Remote Receive
Unit
