SipHeaderFieldName viaName = new SipHeaderFieldName(RFC3261.HDR_VIA);
respHeaders.add(viaName, reqHeaders.get(viaName));
SipHeaderFieldName toName = new SipHeaderFieldName(RFC3261.HDR_TO);
String to = reqHeaders.get(toName).getValue();
SipHeaderFieldValue toValue = new SipHeaderFieldValue(to);
toValue.addParam(new SipHeaderParamName(RFC3261.PARAM_TAG),
Utils.randomString(10));// TODO 19.3
respHeaders.add(toName, toValue);
return sipResponse;
}