String branch = via.getBranch();
if (branch == null || branch.length() == 0) {
via.setBranch(sipRequest.getTransactionId());
}
}
MessageChannel messageChannel = null;
if (this.listeningPoints.containsKey(hop.getTransport()
.toUpperCase()))
messageChannel = sipStack.createRawMessageChannel(
this.getListeningPoint(hop.getTransport()).getIPAddress(),
this.getListeningPoint(hop.getTransport()).getPort(), hop);
if (messageChannel != null) {
messageChannel.sendMessage((SIPMessage) sipRequest,hop);
} else {
throw new SipException(
"Could not create a message channel for "
+ hop.toString());
}