Chapter 13 Interfaces

13.1.2 What You Need to Know

Interface Characteristics

Interfaces generally have the following characteristics (although not all characteristics apply to each type of interface).

•An interface is a logical entity through which (layer-3) packets pass.

•An interface is bound to a physical port or another interface.

•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 ZyWALL.

•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 ZyWALL 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 ZyWALL. 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 ZyWALL. There are three types: virtual Ethernet interfaces, virtual VLAN interfaces, and virtual bridge interfaces.

•The auxiliary interface, along with an external modem, provides an interface the ZyWALL can use to dial out. This interface can be used as a backup WAN interface, for example. The auxiliary interface controls the AUX port.

•Trunks manage load balancing between interfaces.

Port groups, trunks, and the auxiliary interface have a lot of characteristics that are specific to each type of interface. See Section 13.2 on page 280, Chapter 14 on page 337, and Section 13.8 on page 327 for details. The other types of interfaces--Ethernet, PPP, cellular, VLAN, bridge, and virtual--have a lot of similar

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ZyWALL USG 2000 User’s Guide