[asterisk-users] Types of bridging

Phil Frost phil at macprofessionals.com
Thu Mar 29 08:59:10 CDT 2012

On Mar 29, 2012, at 08:43 , Deepesh D wrote:
> What are the different type of bridging used by asterisk in a SIP
> call? What is the difference between Packet2Packet bridging, Remote
> bridging and Native bridging?

Packet2Packet bridging is when RTP datagrams are forwarded by Asterisk without modification. This imposes little load on the CPU. Obviously this can only happen if both ends are using the same codec, and likely there are likely other less obvious conditions that must be met.

Remote bridging happens when Asterisk can direct both ends to send media (RTP probably) to each other directly, by a SIP reINVITE, for example. Only works if both ends have a route to each other, Asterisk is configured to do it, each end shares a codec, and probably a dozen other more subtle conditions are true. In this case there is no load on Asterisk as it's not even in the media path. It also means it can't do things like intercept and act on DTMF or monitor the call.

Native bridging is when media is forwarded with Asterisk, but for whatever reason (different codecs, maybe) Asterisk must inspect or modify the stream. Could mean a significant CPU load.
Phil Frost
office 248-893-0738
direct 248-662-0809

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