Router Interface Concepts; Physical Router Interfaces; Layer 2 Virtual Interfaces - Avaya G250 Administration

Router interface concepts

The router in the Avaya G250/G350 Media Gateway includes the following interface categories:
physical
●
Layer 2 virtual
●
Layer 3 routing
●

Physical router interfaces

The following are the physical interfaces of the G250/G350 router:
WAN Interfaces — When you add a WAN media module to the Avaya G250/G350 Media
●
Gateway, the media module provides a WAN interface. You can add one of the following
types 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 10/2 Fast Ethernet port on the front panel of the G250 and
●
G350 provides a Fast Ethernet interface. This interface is an autosensing 10/100Mbps
Fast Ethernet port. It can be used to connect to a LAN, an external firewall, an external
Virtual Private Network (VPN), or a DeMilitarized Zone (DMZ). This interface can also be
used as a WAN interface when configured for PPPoE. For more information, see
Configuring PPPoE
Switching Interface — An internal 100Mbps connection to the G250 and G350 internal
●
switch provides a switching interface. The switching interface supports VLANs. By default,
the switching interface is associated with the first VLAN (Vlan 1).
When you configure the G250 or G350 without an external VPN or firewall, Vlan 1 is used to
connect the internal G250/G350 router to the internal G250/G350 switch. If an external
firewall or VPN is connected to the Fast Ethernet port, it is important to disable Vlan 1 to
prevent a direct flow of packets from the WAN to the LAN.

Layer 2 virtual interfaces

Loopback — The Loopback interface is a virtual Layer 2 interface over which Loopback IP
●
addresses are configured. The Loopback interface represents the router by an IP address
that is always available, a feature necessary mainly for network troubleshooting.
Since the Loopback interface is not connected to any physical interface, an entry in the
routing 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 of
●
an Internet cloud as its endpoints. GRE tunneling encapsulates packets and sends them
over a GRE tunnel. At the end of the GRE tunnel, the encapsulation is removed and the
packet is sent to its destination in the network at the far end of the GRE tunnel. For more
information, see
on page 139.
Configuring GRE tunneling on page 321.
Issue 1.1 June 2005
Configuring interfaces
313