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I am new to Android. Actually I am an iPhone Developer. Currently, I am trying to develop an Internet-based application.

Can anyone tell me that what is TTL, and why its necessary?

isNaN1247
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Tom
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    The internet is a wonderful place [Time to live - Wikipedia](http://en.wikipedia.org/wiki/Time_to_live) – isNaN1247 Dec 22 '11 at 12:40

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Actually TTL is stepped down by 1 each time the Packet enters a new L3 node. Each OS may generate different initial TTL values. After a number of hops when the TTL is reduced to 0 the packet is discarded. In some complex routers (i.e. GGSN/PGW - telecom nodes for mobile broadband) traffic can be identified and handled based on the TTL value. For example TTL value is used for tethering detection etc

Konstantinos pF
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TTL is a value in data packet of Internet Protocol. It communicates to the network router whether or not the packet should be in the network for too long or discarded. Usually, data packets might not be transmitted to their intended destination within a stipulated period of time. The TTL value is set by a system default value which is an 8-bit binary digit field in the header of the packet. The purpose of TTL is, it would specify certain time limit in seconds, for transmitting the packet header. When the time is exhausted, the packet would be discarded. Each router receives the subtracts count, when the packet is discarded, and when it becomes zero, the router detects the discarded packets and sends a message, Internet Control Message Protocol message back to the originating host.

mina
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