ZyXEL Communications MSC1000G User Manual page 604

Chapter 16 VoIP
Figure 408 SIP and H.248 Network Comparison
SIP
A
B
IP NETWORK
ANALOG ANALOG
SIP ATA SIP ATA
H.248
MGC
MG
ANALOG IP NETWORK
C
D
The IES uses H.248 interfaces that consist of a "Signaling Card" (SC) and at least one "Media Card"
(MC). A VOP1248G-61 or VOP1372G-61 can act as either an SC, an MC, or both. The SC includes
the Media Gateway (MG) and acts as an H.248 signaling gateway. It terminates and processes
H.248 protocol messages from the MGC. A VOP in the MC role terminates RTP packets and converts
the payload into analog for the subscriber's phone. The MCs are also known as an SC's slaves. The
SC and MC can be in the same IES chassis for a centralized deployment or in different chassis for a
decentralized deployment. For increased reliability, the SC can use a second MGC if it cannot reach
the first MGC.
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Management Switch Card User's Guide