Cisco SPA2102-AN - Single Port Router Administration Manual page 77

Configuring Voice Services
SIP Trunking and Hunt Groups on the SPA8000
Cisco Small Business ATA Administration Guide
The following figure shows a simplified logical block diagram of the SPA8000 with
the SIP Trunking feature.
Figure 1 Logical Block Diagram of SIP Trunking
Phone 1
L1
Phone 2
L2
Phone 3
L3
Phone 4
L4
Phone 5
L5
Phone 6
L6
Phone 7
L7
Phone 8
L8
RTP Path
SIP Path
•
SIP Path: As a standalone line, the SIP User Agent (SIP UA) exchanges signaling
directly with the ITSP equipment. As a trunk line, the Line UA exchanges
signaling with the internal proxy server only. The Internal Proxy Server handles
all SIP signalling between both ends of the call, from call establishment to
termination.
•
RTP Path: Whether the line is standalone or a member of a trunk group, the Line
UA exchanges RTP packets directly with the ITSP equipment.
T1
Internal
T2
Proxy
Server
T3
T4
4
ITSP
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