Amer Networks E5Web GUI - Manual (Page 153)

• Virtual LAN (VLAN) interfaces as specified by IEEE 802.1Q. When routing IP packets over a
Virtual LAN interface, they will be encapsulated in VLAN-tagged Ethernet frames. For
more information about Virtual LAN interfaces, see Section 3.4.4, “VLAN”.
• PPPoE (PPP-over-Ethernet) interfaces for connections to PPPoE servers. More information
about this topic can be found in Section 3.4.5, “PPPoE”.
• Tunnel Interfaces
Tunnel interfaces are used when network traffic is being tunneled between the system and
another tunnel end-point in the network, before it gets routed to its final destination. VPN
tunnels are often used to implement virtual private networks (VPNs) which can secure
communication between two security gateways.
To accomplish tunneling, additional headers are added to the traffic that is to be tunneled.
Furthermore, various transformations can be applied to the network traffic depending on the
type of tunnel interface. For example, when routing traffic over an IPsec interface, the
payload is usually encrypted to achieve confidentiality.
cOS Core supports the following tunnel interface types:
i. IPsec interfaces are used as end-points for IPsec VPN tunnels. More information about
this topic can be found in Section 9.3, “IPsec Components”.
ii. PPTP/L2TP interfaces are used as end-points for PPTP or L2TP tunnels. More information
about this topic can be found in Section 9.5, “PPTP/L2TP”.
iii. GRE interfaces are used to establish GRE tunnels. More information about this topic can
be found in Section 3.4.6, “GRE Tunnels”.
• Loopback Interfaces
A loopback interface is a special type of interface that will take all packets sent through it and
pass them on out through the loopback interface configured as the one to loop to. These are
almost exclusively used for Virtual Routing scenarios.
More information about loopback interfaces can be found in Section 3.4.7, “Loopback
Interfaces”.
All Interfaces are Logically Equivalent
Even though the different types of interfaces may be very different in the way they function, cOS
Core treats all interfaces as logically equivalent. This is an important and powerful concept and
means that all types of interfaces can be used interchangeably in the various cOS Core rule sets
and other configuration objects. This results in a high degree of flexibility in how traffic can be
examined, controlled and routed.
Interfaces have Unique Names
Each interface in cOS Core is given a unique name to be able to identify and select it for use with
other cOS Core objects in a configuration. Some interface types, such as physical Ethernet
interfaces, are already provided by cOS Core with relevant default names that are possible to
modify if required. New interfaces defined by the administrator will always require a
user-provided name to be specified.
Chapter 3: Fundamentals
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