Administration of the Avaya G350 Media Gateway - Avaya Support

Configuring interfacesRouter interface conceptsThe router in the Avaya G350 Media Gateway includes the following interface categories:●●●physicalLayer 2 virtualLayer 3 routingPhysical router interfacesThe following are the physical interfaces of the G350 router:●●●WAN Interfaces — When you add a WAN media module to the Avaya G350 MediaGateway, the media module provides a WAN interface. You can add one of the followingtypes of WAN media modules:- The Avaya MM340 media module provides an E1/T1 WAN interface.- The Avaya MM342 media module provides a USP WAN interface.Fast Ethernet Interface — The 10/3 Fast Ethernet port on the front panel of the G350provides a Fast Ethernet interface. This interface is an autosensing 10/100Mbps FastEthernet port. It can be used to connect to a LAN, an external firewall, an external VirtualPrivate Network (VPN), or a DeMilitarized Zone (DMZ). This interface can also be used asa WAN interface when configured for PPPoE. For more information, see ConfiguringPPPoE on page 91.Switching Interface — An internal 100Mbps connection to the G350 internal switchprovides a switching interface. The switching interface supports VLANs. By default, theswitching interface is associated with the first VLAN (Vlan 1).When you configure the G350 without an external VPN or firewall, Vlan 1 is used to connectthe internal G350 router to the internal G350 switch. If an external firewall or VPN isconnected to the Fast Ethernet port, it is important to disable Vlan 1 to prevent a direct flowof packets from the WAN to the LAN.Layer 2 virtual interfaces●●Loopback — The Loopback interface is a virtual Layer 2 interface over which Loopback IPaddresses are configured. The Loopback interface represents the router by an IP addressthat is always available, a feature necessary mainly for network troubleshooting.Since the Loopback interface is not connected to any physical interface, an entry in therouting table can not have the Loopback interface’s subnet as its next hop.GRE tunnel — A GRE tunnel is a virtual point-to-point link using two routers at two ends ofan Internet cloud as its endpoints. GRE tunneling encapsulates packets and sends themover a GRE tunnel. At the end of the GRE tunnel, the encapsulation is removed and thepacket is sent to its destination in the network at the far end of the GRE tunnel. For moreinformation, see Configuring GRE tunneling on page 166.Issue 3 January 2005 161