User's Manual

ISG50 User’s Guide 87
CHAPTER 6
Configuration Basics
This information is provided to help you configure the ISG50 effectively. Some of it is helpful when
you are just getting started. Some of it is provided for your reference when you configure various
features in the ISG50.
• Section 6.2 on page 91 introduces the ISG50’s object-based configuration.
• Section 6.3 on page 92 introduces zones, interfaces, and port groups.
• Section 6.4 on page 94 introduces some terminology and organization for the ISG50.
• Section 6.5 on page 94 covers the ISG50’s packet flow.
• Section 6.6 on page 97 identifies the features you should configure before and after you
configure the main screens for each feature. For example, if you want to configure a trunk for
load-balancing, you should configure the member interfaces before you configure the trunk. After
you configure the trunk, you should configure a policy route for it as well. (You might also have to
configure criteria for the policy route.)
• Section 6.7 on page 103 identifies the objects that store information used by other features.
• Section 6.8 on page 104 introduces some of the tools available for system management.
6.1 PBX Features Overview
This chapter is an overview of different logical components and how they work together to route
calls on the ISG50.
6.1.1 Call Routing
The two main functions of any IP-PBX are routing internal calls and handling calls to and from the
outside world.
The following sections explain how these functions are performed on the ISG50.
6.1.1.1 Call Routing Terms
The following are some terms related to ZyXEL’s IP-PBX implementation.
• Extension - This is a unique number assigned to each telephone connected to the ISG50.
Extensions are used to make calls between phones connected to the ISG50 and to route calls
from the outside world to their correct target. Extensions fall into the following two groups:
• SIP Extension - This is an extension assigned to a SIP (Session Initiation Protocol) based IP
phone connected to the ISG50. Alternatively this could be an extension assigned to an analog
phone which connects to the ISG50 via a VoIP gateway device.