Trafalgar Square Authority in conjunction with the charity Unicef, who began ticketing the event to control crowd numbers. A Christmas ceremony has been held in the square every year since 1947. A Norway spruce (or sometimes a fir) is presented by Norway's capital city, Oslo as London's Christmas tree, a token of gratitude for Britain's support during World War II. (Besides war-time support, Norway's Prince Olav and the country's government lived in exile in London throughout the war.) The Christmas tree is decorated with lights that are switched on at a seasonal ceremony. It is usually held twelve days before Christmas Day.
Christmas tree packet of Christmas tree packets can also be used to conduct a DoS attack by exploiting the fact that Christmas tree packets require much more processing by routers and end-hosts than the "usual" packets do. Christmas tree packets can be easily detected by intrusion-detection systems or more advanced firewalls. From a network security point of view, Christmas tree packets are always suspicious and indicate a high probability of network reconnaissance activities. Christmas tree packet In information technology, a Christmas tree packet is a packet with every single option set for whatever protocol is in use. The term derives from a fanciful