Cisco Systems UBR900 specifications Sgcp Protocol Stack, Voice Specifications, Metric Value

Feature Overview

Note To support voice configurations involving Cisco gatekeeper products using RAS, the headend must have IP multicast enabled. The cable interface must be designated as the default for RAS to discover the gatekeeper. The gatekeeper then resolves all dialed destinations sent to the RAS protocol.

SGCP Protocol Stack

The Cisco uBR924 cable access router supports Simple Gateway Control Protocol (SGCP), an out-of-band signaling protocol that interacts with an external call agent (CA) to provide call setup and teardown for VoIP calls made through the Internet or a local intranet. Using the call control agent, SGCP communicates with the voice gateways, allowing you to create a distributed system that enhances performance, reliability, and scalability while still appearing as a single VoIP gateway to external clients. SGCP eliminates the need for a dial plan mapper and static configuration on the router to map IP addresses to telephone numbers because this function is provided by the external call agent.

In architectures using the SGCP protocol stack, the session application implements the gateway functionality defined to support both trunk and residential gateways. The Cisco uBR924 functions in this mode as a residential gateway with two endpoints.

SGCP can preserve Signaling System 7 (SS7) style call control information as well as additional network information such as routing information and authentication, authorization, and accounting

(AAA)security information. SGCP allows voice calls to originate and terminate on the Internet, as well as allowing one end to terminate on the Internet and the other to terminate on a telephone or PBX on the PSTN.

Note The uBR924 cable access router supports both H.323 and SGCP call control, but only one method can be active at a time.

Voice Specifications

Table 2	Cisco uBR924 Cable Access Router Voice Specifications
Metric		Value
Loss (between DCS and BTI gateway)		Nominal: 4 dB ±.5 dB (off hook)
		Nominal: 9 dB ±.5 dB (on hook)
Attenuation distortion:		Nominal:
DCS <> BTI (200Hz-3.5kHz)		+1 dB/-3 dB
BTI<> DCS (304 Hz-3004Hz)		±0.5 dB
DCS -> BTI (204 Hz-3004 Hz)		±0.5 dB0
Idle channel noise		<= 18 dBmC (noise shall not exceed)
Signal to C-notched noise		>= 35 dB
Inter-modulation distortion:
R2		>= 52 dB
R3		>= 52 dB
Single frequency interference:
0 to 12 kHz		<= -28 dBmO
0 to 4 kHz		<= -40 dBmO

14Cisco IOS Release 12.0(7)T