Specifications

15xx-A1 Family Router Users Guide 38
users who are charged with online time. It should be noticed that some programs
automatically link to Internet. Computer will send data to network when infected by virus.
Connection will not be disconnected under these data streams.
 Inactivity Timeout: When Dial on demand is selected, this input box indicates that after
how long the connection will be disconnected in the absence of traffic. If the value is 0,
connection will not be disconnected.
 MTU: the Maximum transmission unit (MTU) value may be set for your needs. Higher
MTU can provide for a more efficient link because each packet will carry more data while
the overhead in the packet such as header information does not get larger with the size
of the packet. So the bulk throughput on the link will go up. Generally a large packet size
can occupy the time on the link, so the higher MTU can increase lag time and minimum
latency which is not appropriate for all applications.
 Manual Connect: connect/disconnect PPPoE connection manually
 PPP IP extension: Allows only one PC on the LAN. The public IP address assigned by
the remote using the PPP/IPCP protocol is actually not used on the WAN PPP interface.
Instead, it is forwarded to the PC's LAN interface through DHCP.
Only one PC on the LAN can be connected to the remote since the DHCP server within
the ADSL gateway has only a single IP address to assign to a LAN device. NAT and
firewall are disabled when this option is selected. The ADSL gateway becomes the
default gateway and DNS server to the PC through DHCP using the LAN interface IP
address. The ADSL gateway extends the IP subnet at the remote service provider to the
LAN PC. That is, the PC becomes a host belonging to the same IP subnet. The ADSL
gateway bridges the IP packets between WAN and LAN ports, unless the packet is
addressed to the gateway's LAN IP address.
 Enable NAT: To define NAT services in the Advanced Setup | NAT screens, NAT must
be enabled.
 NAT Public Address (available if NAT is enabled). Automatic means the modem will
use pubic IP addresses provided by the network; Menu IP addresses means that the
modem will use the addresses you specify.
 Enable Firewall: Enables Firewall.
 Use Static IPv4 Address: Defines a static IP address (v4) which you enter in the IPv4
Address text box which is displayed when the Use Static IPv4 Address check box is
selected.
 Enable PPP Debug Mode: Used to debug PPPoE issues. Use only when instructed by
your ISP.
 Enable KeepAlive: Enables/disables TCP keep alive packets.
 Bridge PPPoE Frames Between WAN and Local Ports: By default the bridge PPPoE
frame between WAN and local ports is on. This allows a PC behind the modem to be the
PPPoE termination point. PPPoE authentication is passed on to the PC instead of to the
router. If there are multiple PCs then, each one will have a PPPoE authentication. Note
that this option is not applicable for PPPoA.
 Enable IGMP Multicast Proxy: Configures the router for IGMP snooping so the router
can keep limit multicast traffic.
7. Click Next.
8. On the Routing — Default Gateway page set the priority of WAN interfaces used as default
gateways then click Next
If multiple WAN interfaces are configured, you can define the priority by their position in the
Selected Default Gateway Interfaces window. Top is the highest priority; bottom the
lowest.
Change the priority order by removing all items from the Selected Default Gateway
Interfaces window by selecting them, then clicking the right arrow button. Select the items in