ZyXEL Communications ISG50 User Manual
Chapter 27 Global PBX Settings
ISG50 User’s Guide
437
Each field is described in the following table.
27.6.1 How the Peer-to-Peer SIP Connection Works
The following is a basic explanation of how the ISG50 creates a peer-to-peer SIP connection
between two IP phones within the same host range.
between two IP phones within the same host range.
1
The first phone (A) sends an invite for the other phone to the ISG50. This invite includes its IP
address and which codecs it can use.
address and which codecs it can use.
2
Next, the ISG50 accepts the invite on behalf of the second phone (B) and sends an
acknowledgement back to A.
acknowledgement back to A.
3
The ISG50 sends an new invite to B. This invite includes the ISG50’s IP address and the codecs it
has in common in with A.
has in common in with A.
For example, if A says it can use the G.723, Speex, and GSM codecs but the ISG50 is set to G.723,
then the ISG50 lets B know that only the G.723 codec is available for the telephone call.
then the ISG50 lets B know that only the G.723 codec is available for the telephone call.
4
When B accepts the invite from the ISG50, it sends back an acknowledgement. The ISG50 has now
received confirmation from both phones of their IP addresses and an mutually agreed upon codec.
received confirmation from both phones of their IP addresses and an mutually agreed upon codec.
5
The ISG50 sends out a re-invite to both A and B that includes both IP addresses and the codec to
be used. This allows the two phones to create a bridge directly with one another. The ISG50 then
removes itself from the communication chain.
be used. This allows the two phones to create a bridge directly with one another. The ISG50 then
removes itself from the communication chain.
Table 145
Configuration > PBX > Global > Peer to Peer
LABEL
DESCRIPTION
Enable Peer to
Peer
Peer
Select this to have the ISG50 to set up direct connections between two IP phones on the
same subnet. If you enable it, you should set up the Local Net for Peer to Peer.
same subnet. If you enable it, you should set up the Local Net for Peer to Peer.
Local Net for Peer to peer
Add
Click this to add a new entry to the local net list.
Remove
Click this to delete the selected item(s) in this list.
#
This field is a sequential value and is not associated with a specific entry.
Local Net for Peer
to Peer
to Peer
This displays the network on which Peer to Peer connections may be made. For example,
if the Local Net IP address is 192.168.1.0/24, then any device with an IP from
192.168.1.1 to 192.168.1.254 can make a peer connection to any other device in the
same host range.
if the Local Net IP address is 192.168.1.0/24, then any device with an IP from
192.168.1.1 to 192.168.1.254 can make a peer connection to any other device in the
same host range.
Apply
Click this to save your changes.
Reset
Click this to set every field in this screen to its last-saved value.