Specifications

6.3 Case II: Two-site configuration

This case describes the typical settings of a two-site configuration; say Company B headquarters

B-HQ and its branch B-BR located in another country. Assume each site has a DSL connection for

Internet access. B-HQ has 4 PSTN subscriber lines and B-BR has 2 lines as shown in Figure 6-2. The

provisioning tasks include:

․ Both sites have staff phones in cubes and offices and utility phones in public areas.

․ Each phone has one extension. A utility phones can call extensions within the site it is in only,

while the staff phones can call any extension in both sites without limitation. B-HQ has extensions

1XX and B-BR has extensions 2XX.

․ Calls between B-HQ and B-BR use private SIP trunks across Internet. IP PBX at B-HQ has a

static IP address, 64.1.0.1 and IP PBX at B-BR has a static IP address, 222.44.0.1.

․ Only staff phones can call out to PSTN with a prefix 9.

․ B-HQ staff phones call out starting with 90118621 will relay to B-BR through the SIP trunk and

then hop off to PSTN in B-BR. Similarly, B-BR staff phones call out starting with 9001408 will

relay to B-HQ for PSTN hop-off.

․ Incoming PSTN calls are answered by auto attendant and could be transferred to any extension.