Network device and method of measuring upstream bandwidth employed thereby

A network device for measuring upstream bandwidth of a communication network, the communication network comprising a server and a plurality of communication nodes configured between the network device and the server, the network device comprising a processor, a memory, and one or more programs, wherein the one or more programs are stored in the memory and operable to be executed by the processor, the programs comprising:

• a first transmission module operable to transmit a sequence of Internet control message protocol (ICMP) request datagrams corresponding to a sequence of time to live (TTL) to the server via the communication nodes, wherein the sequence of the TTL is increased by degrees from a first value to a second value and when one of the ICMP request datagrams reaches one of the communication nodes, the TTL of the ICMP request datagram is decreased by 1, when one of the communication nodes receives an ICMP request datagram with TTL of 1, the communication node transmits an overtime datagram to the network device;
• a determination module operable to determine whether one of the communication nodes transmit the overtime datagram to the network device, and designate the communication node that transmits the overtime datagram first as the best communication node;
• a second transmission module operable to transmit a plurality of ICMP detection datagrams to the best communication node;
• a receiving module operable to receive response datagrams corresponding to the plurality of ICMP detection datagrams from the best communication node and record receiving time of the response datagrams;
• and
• a calculation module operable to calculate an upstream bandwidth according to size of the plurality of ICMP detection datagrams and the recorded receiving time of the response datagrams corresponding to the plurality of ICMP detection datagrams;
• wherein the first transmission module is further operable to increase the second value and transmit another sequence of ICMP request datagrams with another sequence of TTL from the first value to the increased second value when the network device does not receive the overtime datagram.