Ttl

Question

https://gateoverflow.in/?qa=blob&qa_blobid=3365268112291698752

Comments

21

Answer 1

21

TTL field is modified only at Network layer. When a packets routes through Router/Network layer it checks the value of TTL field and accepts the packets and decrements the value of ttl by 1 if it is not 0. In Case if it is 0 then network layer simply discards the packets. LANs (HUbs) work at data link layer. Here packets is passing through 2 routers R1 and R2. so at the router it will be decremented to 24-1-1 = 22. Now t the Receiver end also it will pass through Network layer and there also it will be decremented by 1. Finally at the Receiver end value of TTL field will be 22-1 = 21.

Comments

if the host d recieves it then why u u feel like the value should be decremented?

i think answer should be 22 itself..

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Message is received at Application layer finally. So it have to pass through Network layer at host also to reach finally to application/process. So It will be decremented there also.