priority must be different, 1 is primary, 1 is backup.
[root@srv02 mirtapbx]# host -t SRV _sip._udp.pbx.netvoxtelecom.biz _sip._udp.pbx.netvoxtelecom.biz has SRV record 10 50 5060 pbx7.netvoxtelecom.biz. _sip._udp.pbx.netvoxtelecom.biz has SRV record 10 50 5060 pbx5.netvoxtelecom.biz. As you can see, the phones registering on pbx.netvoxtelecom.biz will "ping-pong" over these two servers. What happens is the following: - the phone is registered on pbx7 and it is currently in a call - the registration timeout is over and the phone "switch" from pbx7 to pbx5, doing so, it deregisters first from pbx7 - the phone is not "UNAVAILABLE" - the phone registers on pbx5 and now it is "NOT INUSE" - a new call arrives and it is received while the phone is still in use.