ASCOM IPBS Installation And Operation Manual page 169

Installation and Operation Manual
IP-DECT Base Station & IP-DECT Gateway (software version 5.0.x)
An example of an SRV record might look like this:
_sip._udp.ascom-rd.com. 86400 IN SRV 0 5 5060 sipserver.ascom-rd.com.
This points to a server named sipserver.ascom-rd.com listening on TCP port 5060 for SIP
protocol connections. The priority given here is 0, and the weight is 5.
SRV records must contain the fully qualified domain name (FQDN) of the host.
How to set priority and weight
SIP clients always use the SRV record with the lowest-numbered priority value first, and
only fall back to other records if the connection with this record's host fails. Thus a service
may have a designated "fallback" server, which will only be used if the primary server fails.
Only another SRV record, with a priority field value higher than the primary server's record,
is needed.
If a service has multiple SRV records with the same priority value, clients use the weight
field to determine which host to use. The weight value is relevant only in relation to other
weight values for the service, and only among records with the same priority value.
In the following example showing five records, both the priority and weight fields are used
to provide a combination of load balancing and backup service.
_sip._udp.ascom-rd.com. 86400 IN SRV 10 60 5060 bigbox.ascom-rd.com.
_sip._udp.ascom-rd.com. 86400 IN SRV 10 20 5060 smallbox1.ascom-rd.com.
_sip._udp.ascom-rd.com. 86400 IN SRV 10 20 5060 smallbox2.ascom-rd.com.
_sip._udp.ascom-rd.com. 86400 IN SRV 20 50 5060 backupbox1.ascom-rd.com.
_sip._udp.ascom-rd.com. 86400 IN SRV 20 50 5060 backupbox2.ascom-rd.com.
The first three records with priority 10 are primary servers and the last two records with
priority 20 are secondary servers.
For each client, a primary server is selected at random with the help of the weight values
60, 20 and 20. This will distribute all clients on the primary servers according to the weight
values.
If a client's primary server goes down, the client will use the secondary server instead, i.e.
backupbox1.ascom-rd.com and backupbox2.ascom-rd.com.
E.2.4 Load Balancing Using Dynamic Connection: Master Settings
1 Select DECT > Master.
2 In the drop-down list, select "SIP" protocol.
3 Enter the SIP server's domain address.
4 A local site proxy server (IP-PBX), e.g. SRST (Cisco), can be used to make emergency
phone call in case that the WAN connection goes down, see
Redundancy
Enter the IP address or host name and optionally port of proxy (e.g. proxy2.ascom-
rd.com:5060) to the local site proxy server in the Alt. Proxy text field.
5 Reset in order to make the changes take effect, see
6 Repeat step 1 to 5 for all exisiting Masters.
15 February 2012 / Ver. H
on page 159.
TD 92579EN
E.2.2 Local Site
8.22 Reset.
161