I posted this question in the Network+ forum with no resolve. Everyone has conflicting information. So I'll give it a try here...

While studying with my Sybex Network+ Study Guide by David Groth, I read (on page 58) that the Data Link Layer is responsible for "creating, transmitting and receiving packets." It continues: "At the Data Link layer, data coming from upper layer protocols are divided into logical chunks called packets."

Then while answering the review questions (page 85), the following question was asked:

15. Which OSI layer is responsible for building and tearing down pakets?
A. Network
B. Transport
C. Data Link
D. Physical

So...like the good student I am, I regurgitated the material by answering "C".

However, the correct answer (on page 88) is stated as: "A. The network layer is responsible for packaging data into packets. The other layers use different terms for data packages, such as frames."

So, I am confused. Which is right and why?

Any help would be appreciated. Thanks in advance.

Christian

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Cisco and Sun both say it's network. I've read many books on the subject as well and all say network. The OSI standard defines that packets are at the network layer.

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Frame = Data Link
Packet = Network
Segment = Transport

These terms are often used loosely, but when formally asked remember the above.

---
Ron Steedman CCNP, CCNA, MCP, BS Computer Science
Free CCNA Practice Tests, Study Guides, & Message Boards!
http://www.congonetworking.com/

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All the sources I have used so far (Sybex, CiscoPress, Learnkey CCNA and various web pages) have stated that the responsibility of the network layer is to form packets (containing an IP address, among other things, in the header) which routers can use for the end-to-end delivery of the datagram.

The datalink layer address (ie MAC address) is only responsible for providing delivery of the datagram across a SINGLE media segment/link.

A simple statement I use to remember what OSI layer deals with what is....

Application - Do -------> Data
Presentation " "
Session " "
Transport - Some -----> Segment
Network - People ---> Packet
Data-Link - Fry ------> Frame
Physical - Bacon? ---> Bits

Stupid I know, but hey it works for me....

Hope this helps

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cthesoup,

UKCCNA and rsteedma are on the money. This is the correct answer. The only thing I added is that UKCCNA did not mention that "Packets" are also referred to as "Datagrams" also.

Application = The user data
Presentation = ""
Session = ""
Transport = "Segments"
Network = "Packets" or "Datagrams"
Datalink = "Frames"
Physical = "Bits"

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I ditto that

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network works for me also

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