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I have a confusion about where the data packet goes if its not sent to any computer on the network.Is is sent back or is it absorbed by the terminator?

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— the confusion comes from mixing two different things: what the physical wire/signal does and what the protocol stacks do. touched on topology differences; here’s a concise, practical breakdown so the behavior makes sense in each case.

On a physically shared medium (old coax or a hub) the transmitter puts a voltage wave on the cable that every NIC can see. Each NIC examines the frame’s MAC address and checksum; if it’s not for them they simply ignore it. Proper line terminators absorb the energy so the signal stops cleanly; an unterminated cable causes reflections and corruption. On modern switched Ethernet the switch either forwards a frame to the single port where the destination MAC is known or it temporarily floods the frame to all ports if the MAC is unknown — still, frames aren’t “sent back” to the sender in normal operation.

Ring topologies behave differently: a frame is passed node-to-node and the originator watches for its own frame to return. If no node accepts it, the frame completes the loop and the sender removes it — that’s why a ring can look like the packet “came back.”

Higher layers add other outcomes: if the IP address isn’t reached the ARP process will fail or a router may reply with an ICMP error; transport protocols react differently (TCP will retry and eventually report failure; UDP won’t). To see exactly what’s happening, capture traffic with a packet sniffer (Wireshark), watch for ARP/ICMP messages, and check the switch MAC table and interface error counters — those traces will show whether the frame was ignored, forwarded, absorbed by the medium, or removed after a ring circulation.

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Member Avatar for techsheaven

Sounds like something a professor/teacher would ask... Tell him/her it doesn't matter as long as they do not gather in your network! (just joking)

IPv4 calls it TTL, or Time To Live... but that is a bit a misnomer since it is not actually counting time, but hops. IPv6 sets this straight by calling it -- what else, "Hop Limit."

Of course a packet can't change itself, so routers do the job. They decrement the TTL/Hop Limit bits until the limit is reached and the packet is terminated. If the packet reaches the final router and the IP/MAC address is not available, it is terminated by the router.

There's only 8 bits available for TTL, so the max hops possible is 255. This keeps rogue packets from flooding networks.

http://www.rfc-editor.org/rfc/rfc5082.txt

Good Luck

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I was told that the packet is absorbed by the terminator connected at the end of the connection wire.But i saw in a video that the packet returns back if its not accepted by any of the computer.
You dint explained what actually happens with the packet.You said that the packets counts are decreased,please explain a bit more .Thanks :)

Member Avatar for techsheaven

Are you talking about a tolken ring topology?

Member Avatar for Member #727902

I am very new to networks.My teacher told me that the packet is absorbed by the terminator whereas i saw in a video that if the packet is not accepted it is sent back.Dont know about topologies

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Check this out:

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Thank you.Also If its a ring connection,token will be generated and if a computer absorbs the token and sends a packet but none of the computer recieves the packet what will happen?

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Remember, I was just using a Token Ring Network as an example. There are other network types (like a Bus Network) that MUST be terminated. An unterminated signal reflects on the network until it degrades (at which point we call it "noise").

If you get a ticket to a sold-out play, and your ticket says Row C, Seat 5, you go sit there. You pass a lot of seats on the way, but you get to your seat. Well, let's say that you arrive at your seat only to discover that it has been un-bolted from the floor. You wonder around causing a disruption, because there is no place for you. At the play, An usher may help resolve the issue, but in the world of networking there are no second chances! If packets arrive at a network and don't have a place to be, there is no usher -- only a terminator (its death for the packet)! Why? Can you imagine if no one sat in there seat at a play? There would be no play! The same holds true for networks. . . If all packets reflected on the network, no communication could take place!

So to answer your question, it is terminated. On Ethernet networks, we do not terminate with a separate terminator, but termination is built into the network equipment. Don't be confused by Tokens, they are just a way for networks to take turns. We don't have those in Ethernet -- If packets bump into each-other, they are just re-sent ( and a little light on the switch flashes). Packets with no home get termnated... On token-ring it would have to by terminated by the MAU. On Ethernet(star topology), I don't know if network adapters, routers, or but handle the termination (let us know if you find out). Bus Networks always us a physical terminator as far as I know.

Good Luck

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