[Asterisk-Dev] TDMoE explanation/documentation/implementation ?

[Anton Tinchev]

Paul Cadach wrote:

> Hello,
> 
> 
>>Anybody can provide TDMoE documentation ?
> 
> 
> I don't think this exists... Most powerful documentation is sources...
> 
> 
>>Is TDMoE similar to some telco's standart, especially for forming frames.
> 
> 
> Not sure. ztd-eth does encapsulation to real ethernet frames, while for example RAD devices (as documented) uses TCP and
> could run over WAN, not LAN only as ztd-eth.
> 
> 
>>Is TDMoE really a kind of TDM (how/algorithm ?) encapsulated in Ethernet
>>frame.
> 
> 
> Mostly looks like... TDMoE is point-to-point connection, single end is "master" device which located on host provides
> real clocking (i.e. have installed Zaptel hardware device(s)), other end is "slave" which gets timing from "master" one.
> Zaptel hardware generates host interrupts every 1 ms and passes audio/etc frames to the host system. ztd-eth driver
> delivers data over Ethernet at the same times (+/- something due to processing audio frames within interrupt handler
> while networking code requires to operate outside interrupt routines), so TDMoE could be treated as real TDM structure
> (and, Ethernet link must not be overloaded to minimize jitter and eliminate packet drops on network side, best if TDMoE
> runs over point-to-point Ethernet link made with cross-over cable).
> 
> Also, ztd-eth doesn't handle CAS signalling as it done with E1/T1 hardware (i.e. there is no timeslot #0, but emulation
> for CAS bits is available), so not all features are possible (for example, V5.2 uses/requires manipulation of Sa? bit at
> TS #0, and it WILL NOT passed over TDMoE).
What signalisation is handling? CSS, ESF ...
> 
> I'm using TDMoE to pass PRI trunk (30 B + 1 D channels), all works more-or-less fine for me.
> 
> 
> WBR,
> Paul.
> 
> 
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