ICMP is known as networking layer protocol. But it requires IP to
transfer its packet to data link layer which is another network layer
protocol. Then icmp should be transport layer protocol. But still its
known as network layer protocol. Could you tell me why, please?


regards,
Sukhdeep Singh.

"Deep" <mail2sukhdeep@gmail.com> wrote:

> ICMP is known as networking layer protocol. But it requires IP to
> transfer its packet to data link layer which is another network layer
> protocol. Then icmp should be transport layer protocol. But still its
> known as network layer protocol. Could you tell me why, please?

Maybe it's because ICMP (and IGMP) are not meant to transport data
packets, but are only meant to report or control stuff at the Network
Layer. I wouldn't obsess over this, though. Uh, unless it's something
you have to answer correctly on an exam, of course.

Bert

Deep <mail2sukhdeep@gmail.com> writes:

> ICMP is known as networking layer protocol. But it requires IP to
> transfer its packet to data link layer which is another network layer
> protocol. Then icmp should be transport layer protocol. But still its
> known as network layer protocol. Could you tell me why, please?

"Transport layer" is functional. Using network layer to transmit
packets is only one very tiny part of what makes something a transport
layer protocol.

ICMP is a part of IP. That's what makes it network layer, pure and
simple. The fact that it uses IP to send packets is entirely
irrelevant to its place in the functional hierarchy.

-don provan