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New Member

VoIP broadcast


1)I want to know what protocols are used by VoIP.

2)When using VoIP with products other than Cisco, those uses Auto Discovery, do they do ARP broadcast or what? How should that broadcast be relayed over the WAN??

Thanks & Regards,

Saurabh Garg


  • WAN Routing and Switching
New Member

Re: VoIP broadcast


I think you need to clearify what exectly you wanna do.

VOIP signaling protocol H323,SIP and MGCP

Audio stream goes into RTP.

RAS Gatekeeper Discovery

There are two processes by which H.323 terminals/gateways discover their zone gatekeepers:

Unicast Discovery (manual method)?Uses UDP port 1718. In this process, endpoints are configured with the gatekeeper IP address and can attempt registration immediately. The gatekeeper replies with a gatekeeper confirm (GCF) or gatekeeper rejection (GRJ) message.

Multicast Discovery (auto-discovery)?Uses UDP multicast address Auto discovery enables an endpoint to discover its gatekeeper through a multicast Gatekeeper Request (GRQ) message. Because endpoints do not have to be statically configured for gatekeepers, this method has less administrative overhead. A gatekeeper replies with a GCF or GRJ message. A gatekeeper can be configured to respond only to certain subnets

for more info check here

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