TTL and Intermediary network devices

DrSic · Jan 10, 2012

thread581-759360
Hey Ye'all,

I'm currently taking ccna classes to get prepaired for certification. Today we were discussing the TTL topic and we wondered at what end of a (let's say) router the ttl is decremented, at the incoming interface, the routerprocess or it's outgoing interface? just for the sake of having something to talk about over a cup of coffee...

DrB0b · Jan 11, 2012

"When a router forwards a packet, it MUST reduce the TTL by at least one. If it holds a packet for more than one second, it MAY decrement the TTL by one for each second. This way, Time-to-Live is used as a time count."

(Emphasis mine)

Source:

http://www.maxi-pedia.com/time+to+live

(that line is towards the bottom of the page in the paragraph titled "Time-to-Live: Does it measure time or hops?"

"You don't know what you got, till its gone..
80's hair band Cinderella or ode to data backups???

DrSic · Jan 11, 2012

Thanks DrBOb, The 'time'-thing hadn't come up but will surely be discussed. IT Gives a new dimension to the topic in class.

DrB0b · Jan 11, 2012

No Problem DrSic,
I got a Bachelors from SIU here in IL and I don't remember ever going over the Time aspect of it, only the Hops. Maybe I wasn't paying attention that day...........

If you get stumped or looking for a good discussion topic, just bounce a post here as there are many good minds here willing to help.

"You don't know what you got, till its gone..
80's hair band Cinderella or ode to data backups???

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TTL and Intermediary network devices

DrSic

Technical User

DrB0b

IS-IT--Management

DrSic

Technical User

DrB0b

IS-IT--Management

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