Polycom MGC Administrator Administrator's Manual page 579

Router
H.323
Required
A router is a device that allows the communication between devices located
on different subnetworks. Network devices transmit packets to the default
router when the destination IP address is on a different subnetwork and no
static route is configured.
Static Routes
H.323
Optional
A static route defines the router to be used to access another subnetwork.
When a network device transmits packets to another device on a different
subnetwork, it checks whether a static route is defined.
NAT Traversal
H.323
Optional
NAT Traversal (Network Address Translation) is an application used by
firewalls to allow multiple devices located in a local (referred to also as
private) network to share a small number of public IP addresses. The devices
in the local network use IP addresses that are unique only to the local
network. The NAT application maps the local IP addresses with the public IP
addresses. The mapping can be either dynamic or static. Static mapping is
when a device behind the firewall has a permanent public IP address mapped
to its internal (local) IP address. Dynamic mapping is when a public IP
address from the available public addresses is mapped to the internal address
of a device that needs to communicate across the firewall for the session
duration.
SIP
Required
SIP
Optional
SIP
Optional
MGC Administrator's Guide
E-5