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New Member

layer 2 data link encapsulation

Hi all, can anyone tell me when we go from a normal lan ethernet network, then cross over ppp, or frame relay networks, what happens to the original layer 2 ethernet frame, does it change ?

7 REPLIES
New Member

Re: layer 2 data link encapsulation

the ethernet frame will terminate on the router .

http://www.cisco.com/univercd/cc/td/doc/cisintwk/ito_doc/introint.htm

New Member

Re: layer 2 data link encapsulation

Hi

what do you mean terminate on the router ?

New Member

Re: layer 2 data link encapsulation

He means that it will terminate at the device that connects to a Frame Relay, ATM, etc, network.

New Member

Re: layer 2 data link encapsulation

hi

so when the ethernet frame goes out the say serial, or ppp, atm interface etc, whay happens to it ? does the ethernet frame get encapsualted or changed ?

New Member

Re: layer 2 data link encapsulation

correct. With frame relay you might see PPP or HDLC encapsulations. With ATM you are going to see cells.

New Member

Re: layer 2 data link encapsulation

so what changes? does the ethernet frame get converted to ppp frame? or is the ethernet frame still exsist but encapsulated in ppp, atm etc?

please explain

Super Bronze

Re: layer 2 data link encapsulation

The original Ethernet frame is discarded. Assuming you're doing IP, the L3 IP packet is encapsulated within the L2 frame for the media it's being sent across.

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