Nortel Networks 1000S - Manual (Page 30)

Page 30 of 44 System architecture
553-3031-010 Standard 3.00 August 2005
The MG 1000S supports a Small System Controller (SSC) card and four slots
for flexible configurations of line, trunk, and application cards.
Note: You can configure the SSC in the MG 1000S for survivability to
assume local call processing if the Call Server cannot be accessed. If the
MG 1000S is not configured as survivable, then the MG 1000S is
out-of-service until the Call Server is again accessible.
Voice Gateway Media Cards are installed in the MG 1000S. A Voice
Gateway Media Card provides transcoding between IP and circuit-switched
protocol.
Each MG 1000S can support one MG 1000S Expander.
Ethernet switch (customer-supplied)
The customer-supplied Layer 2 Ethernet switch transmits data packets to
interconnected Ethernet-attached devices. The switch directs the data only to
the targeted device, rather than to all attached devices. See Data Networking
for Voice over IP (553-3001-160) for details.
Power over LAN (optional)
An optional Power over LAN unit adds power and data communication over
standard Category 5 LAN drops for powering IP Phones. The Power over
LAN unit eliminates the need to connect each telephone to an AC power
outlet. This saves in desktop wiring and enables the use of a centralized
Uninterruptible Power Supply (UPS) for power backups.
Infrastructure
Various infrastructure components are required to support VoIP. These
components include switches, routers, and MG 1000S. The data network
infrastructure’s engineering and provisioning is critical to achieve
satisfactory telephony voice quality. For more information, see Data
Networking for Voice over IP (553-3001-160).