Describe how traceroute is implemented give an exampleSoluti

Describe how traceroute is implemented.

give an example.

Solution

Trace route is implemented by a smart trick involving the TTL header in IP. This is the \"Time To Live\" of an IP packet. It\'s not a time measure but rather a number representing the number of hops a packet can take earlier than it is dropped. In many applications, an IP packet is originate with a TTL of 255. Each router that the packet transits subtract 1 from the TTL. It seems a suitable path across the Internet that comes close to 255 hops, so that number should be satisfactory for normal activity. However, if a direction-finding loop has occurred, the TTL keeps packets from active forever and jam up links. Once a packet has bounced around long enough, its TTL will fall to zero and it will be dropped.

Example:

When you enter the traceroute command, the value initiates the sending of a packet (using the Internet Control Message Protocol), including in the packet a time limit value (known as the TTL) that is considered to be exceed by the first router that receives it, which will return a Time exceed message. This enables traceroute to resolve the time essential for the hop to the first router. rising the time limit value, it resends the packet so that it will reach the second router in the path to the target, which returns another Time exceed message, and so forwards. Traceroute determines when the packet has reached the target by with a port number that is outside the normal range. When it received, a Port inaccessible message is returned, enabling traceroute to calculate the time length of the last hop. As the tracerouting progresses, the proceedings are displayed hop by hop.