Hi Nabeel,
Use below code to set SIP registration port:
LinphoneProxyConfig proxyConfig = linphoneCore.createProxyConfig(identity, linphoneAddress.asStringUriOnly(), null, true);
...
proxyConfig.setProxy("sip:" + domain + ":" + port);
...
...
linphoneCore.addProxyConfig(proxyConfig);
Create address and set transport port:
LinphoneAddress linphoneAddress = LinphoneCoreFactory.instance().createLinphoneAddress(identity);
linphoneAddress.setTransport(LinphoneAddress.TransportType.LinphoneTransportTcp);
linphoneAddress.setPort(port);