Specify Network Settings
45
N300 WiFi Cable Modem Router Model C3000
MTU only if you are sure that it is necessary for your ISP connection. See Change the
MTU Size on page 45.
•Disable SIP ALG. Some VoIP applications do not work well with the SIP ALG.
Selecting this check box to turn off the SIP ALG might help your VoIP devices to
create or accept a call through the modem router.
6. Click the Apply button.
Your changes are saved.
Change the MTU Size
The maximum transmission unit (MTU) is the largest data packet a network device transmits.
When one network device communicates across the Internet with another, the data packets
travel through many devices along the way. If a device in the data path has a lower MTU
setting than the other devices, the data packets must be split or “fragmented” to
accommodate the device with the smallest MTU.
The best MTU setting for NETGEAR equipment is often the default value. In some situations,
changing the value fixes one problem but causes another. Leave the MTU unchanged unless
one of these situations occurs:
•You experience problems connecting to your ISP or other Internet service, and the
technical support of either the ISP or NETGEAR recommends changing the MTU setting.
These web-based applications might require an MTU change:
-A secure website that does not open, or displays only part of a web page
-Yahoo email
-MSN portal
-America Online’s DSL service
•You use VPN and have severe performance problems.
•You used a program to optimize MTU for performance reasons, and now you have
connectivity or performance problems.
Note: An incorrect MTU setting can cause Internet communication
problems. For example, you might not be able to access certain
websites, frames within websites, secure login pages, or FTP or
POP servers.
To change the MTU size:
1. Launch a web browser from a computer or wireless device that is connected to the
network.
2. Type http://routerlogin.net or http://192.168.0.1.
A login screen displays.