packets and frames

carl_townshend · ‎06-21-2007

Hi all, when people talk about packets and frames, are they the same thing ? also what would be classed as normal amount of packets per second on a lan ?

mohammedmahmoud · ‎06-21-2007

Hi,

Frame = Layer 2 header + packet + layer 2 trailer. When talking about layer 2 devices we always refer to frames.

Packet = IP header + datagram. When talking about layer 3 devices we always refer to packets.

They are sometimes used interchangeably but technically they are different.

HTH, please do rate all helpful replies,

Mohammed Mahmoud.

carl_townshend · ‎06-25-2007

So if the frame stays on layer 2 its still a frame, and when it crosses a router it adds ip header info so its then called a packet ??

mohammedmahmoud · ‎06-25-2007

Hi,

We can think of it as the Frame contains the packet inside it as its payload, as long as the frame is layer 2 switched only the frame header is checked, but if the frame paths over a router, the router will need to decapsulate the frame in order to be able to check the packet header.

NOTE: The frame is constructed in the first place after the packet is fully structured with its ip header.

HTH,

Mohammed Mahmoud.

pciaccio · ‎06-21-2007

It is:

S = Segment = Layer 4

P = Packet = Layer 3

F = Frame = Layer 2

Hope this helps...Please rate...

srue · ‎06-21-2007

B = Bit = Layer 1 (1's and 0's)

(just for completeness)