內建VoIP網路介面
將PSTN與Internet Telephoney整合於同一系統內,不改變使用者撥號習慣,可以透過VoIP達到語音VPN聯網功能,不僅藉由VoIP達到IP
Remote office,也可節省電信費用之開銷。
VoIP網路通信協定:
SIP call signaling
RFC3261 with backward compatible with
RFC2543
RTP (RFC1889),
RTCP (RFC1890)
SDP (RFC2327)
NAPTR for
SIP URI lookup (RFC2915)
DHCP
PPPoE
TFTP/HTTP
for Auto Provisioning
IEEE 802.1Q
VLAN
SNTP for
network time synchnization
Media Encription
– AES, HMAC MD5, HMAC SHAI
VoIP語音處理技術:
Codec: G.711 (a-law
and u-law), G.723.1/A, and G.729A/B.
Line Echo Cancellation
VAD (Voice Activity
Detection)
CNG (Comfort Noise
Generation)
Packet Lost Concealment
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