08-08-2012, 12:23 PM
VOIP
VOIP_Honey+Harish.pptx (Size: 341.06 KB / Downloads: 26)
Voice & video transmission over IP network.
Convergence around Internet telephone encompassing fax, data, video, voice.
Voice/video broken into chunks, transmitted using Packet Switching and reassembled at the Rx.
Why VOIP?
Cheaper connection(economically)
Call from anywhere
Less maintenance
Improved and expanded features
eg. caller id, call waiting, call transfer, repeat dial, return call, call forwarding, three way calling.
Call Signaling Protocols
How does the communication path get established ?
Signaling: defined as procedures undertaken to setup, manage, and terminate session btn two end points
Protocols:
SIP, H.323, MGCP, MEGACO/H.248
UDP as Transport Layer Protocol
Lost Packet: lost in n/w or delay>400 ms.
So no need of retransmission.
UDP header 8 bytes, TCP header 20 bytes.
Question: What about Lost Packets ?
Forward Error Control
Interleaving