code: public static boolean isUDPLower(final Buffer t) {
          try {
              return t.capacity() == 3 && t.getByte(0) == 'u' && t.getByte(1) == 'd' && t.getByte(2) == 'p';
          } catch (final IOException e) {
              return false;
          }
      }
docs: Check whether the buffer is exactly three bytes long and has the
  bytes "udp" in it. Note, in SIP there is a different between transport
  specified in a Via-header and a transport-param specified in a SIP URI.
  One is upper case, one is lower case. Another really annoying thing
  with SIP.
  
  @param t
  @return