User's Manual

Chapter 12 Interfaces
ISG50 User’s Guide
234
• Many interfaces can share the same physical port.
• An interface belongs to at most one zone.
• Many interfaces can belong to the same zone.
• Layer-3 virtualization (IP alias, for example) is a kind of interface.
Types of Interfaces
You can create several types of interfaces in the ISG50.
• Setting interfaces to the same port role forms a port group. Port groups create a hardware
connection between physical ports at the layer-2 (data link, MAC address) level.
• Ethernet interfaces are the foundation for defining other interfaces and network policies. RIP
and OSPF are also configured in these interfaces.
• VLAN interfaces receive and send tagged frames. The ISG50 automatically adds or removes
the tags as needed. Each VLAN can only be associated with one Ethernet interface.
• Bridge interfaces create a software connection between Ethernet or VLAN interfaces at the
layer-2 (data link, MAC address) level. Unlike port groups, bridge interfaces can take advantage
of some security features in the ISG50. You can also assign an IP address and subnet mask to
the bridge.
• PPP interfaces support Point-to-Point Protocols (PPP). ISP accounts are required for PPPoE/PPTP
interfaces.
• Cellular interfaces are for 3G WAN connections via a connected 3G device.
• Virtual interfaces provide additional routing information in the ISG50. There are three types:
virtual Ethernet interfaces, virtual VLAN interfaces, and virtual bridge interfaces.
• Trunk interfaces manage load balancing between interfaces.
Port groups and trunks have a lot of characteristics that are specific to each type of interface. See
Section 12.2 on page 236 and Chapter 13 on page 281 for details. The other types of interfaces--
Ethernet, PPP, cellular, VLAN, bridge, and virtual--have a lot of similar characteristics. These
characteristics are listed in the following table and discussed in more detail below.
Table 61 Ethernet, PPP, Cellular, VLAN, Bridge, and Virtual Interface Characteristics
CHARACTERISTICS ETHERNET ETHERNET PPP CELLULAR VLAN BRIDGE VIRTUAL
Name* wan1, wan2 lan1, lan2,
dmz
pppx cellularx vlanx brx **
Configurable Zone No No No No
Yes Yes No
IP Address Assignment
Static IP address
Yes Yes Yes Yes Yes Yes Yes
DHCP client Yes No Yes Yes Yes Yes No
Routing metric Yes Yes Yes Yes Yes Yes Yes
Interface Parameters
Bandwidth
restrictions
Yes Yes Yes Yes Yes Yes Yes
Packet size (MTU) Yes Yes Yes Yes Yes Yes No
DHCP
DHCP server No
Yes No No Yes Yes No
DHCP relay No Yes No No Yes Yes No
Connectivity Check Yes No Yes No Yes Yes No