Amer Networks E5Web GUI - Manual (Page 152)

3.4. Interfaces
3.4.1. Overview
An Interface is an important logical building block in cOS Core. All network traffic that transits
through, originates from or is terminated in the Clavister Security Gateway, does so through one
or more interfaces.
Source and Destination Interfaces
An interface can be viewed as a doorway through which network traffic passes to or from cOS
Core. A cOS Core interface has one of two functions:
• The Source Interface
When traffic arrives through an interface, that interface is referred to in cOS Core as the source
interface (also sometimes known as the receiving or incoming interface).
• The Destination Interface
When traffic leaves after being checked against cOS Core's security policies, the interface
used to send the traffic is referred to in cOS Core as the destination interface (also sometimes
known as the sending interface).
All traffic passing through cOS Core has both a source and destination interface. As explained in
more depth later, the special logical interface core is used when cOS Core itself is the source or
destination for traffic.
Interface Types
cOS Core supports a number of interface types, which can be divided into the following four
major groups:
• Ethernet Interfaces
Each Ethernet interface represents a physical Ethernet interface on a cOS Core-based product.
All network traffic that originates from or enters a Clavister Security Gateway will pass
through one of the physical interfaces.
cOS Core currently supports Ethernet as the only physical interface type. For more
information about Ethernet interfaces, see Section 3.4.2, “Ethernet Interfaces”.
Note: Ethernet interfaces in a virtual environment
When cOS Core runs in a virtual environment such as VMware or KVM, the physical cOS
Core interfaces are not in fact physical but are virtual. However, cOS Core still treats
them as though they were physical.
• Sub-interfaces
Some interfaces require a binding to an underlying physical interface in order to transfer
data. This group of interfaces is called Physical Sub-Interfaces.
cOS Core has support for two types of sub-interfaces:
Chapter 3: Fundamentals
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