code: public void processTimeout(TimeoutEvent timeoutEvent) {
          Transaction transaction = null;
          if(timeoutEvent.isServerTransaction()) {
              transaction = timeoutEvent.getServerTransaction();
              if(logger.isDebugEnabled()) {
                  logger.debug("timeout => " + transaction.getRequest().toString());
              }
          } else {
              transaction = timeoutEvent.getClientTransaction();
              if(logger.isDebugEnabled()) {
                  logger.debug("timeout => " + transaction.getRequest().toString());
              }
          }
          String callId = ((CallIdHeader)transaction.getRequest().getHeader(CallIdHeader.NAME)).getCallId();
          register.unStickSessionFromNode(callId);
      }
docs: /*
  (non-Javadoc)
  @see javax.sip.SipListener#processTimeout(javax.sip.TimeoutEvent)