[Serusers] SER RADIUS Accounting and B2BUA

[Alistair Cunningham]

Maxim Sobolev wrote:
> Alistair Cunningham wrote:
> 
>> Matt,
>>
>> Because SER handles SIP messages, not RTP streams, it cannot 100% 
>> accurately record CDRs. For instance, if the BYE message is lost 
>> because a client crashed, SER has no way of knowing when the call 
>> ended or how much it cost. A BTBUA gets round this problem by having 
>> the RTP packets come to it, so if a client crashes, the RTP stream 
>> stops and the BTBUA knows the call has finished. The disadvantage of a 
>> BTBUA is that it adds latency and doesn't scale well, because it needs 
>> to handle all the RTP traffic.
> 
> 
> This is not necessarily true. SIP permits building signalling-only 
> B2BUA, which if designed correctly will be able to handle up to 50-100 
> call setups/teardowns per second on any modern x86 hardware. This will 
> provide capacity sufficient for any mid-level ITSP - allowing to bill 
> more than 10 millions per month. If this is not sufficient then several 
> of such B2BUA can be installed in parallel to provide more scalable 
> solution. The problem with using either Cisco or Asterisk as SIP B2BUA 
> is that they handle both signalling (SIP) and media (RTP), which makes 
> them less scalable and introduces the problem with increased latency, 
> losses and jitter.

Maxim,

You're quite correct. I was generalising too much.

-- 
Alistair Cunningham,
Integrics Ltd,
Telephony, Database, Unix consulting worldwide
+44 (0)7870 699 479
http://integrics.com/