IP protocol is not to communicate between computers in a LAN. Is that true?

[Muhammad Thanveer]

I heard somebody saying that there is a misconception in people that they think I am running IP protocols to allow communication between Computers, NO, we have some other protocols which allow communicate people locally.

IP protocols are used to communicate between networks.

I am clear about the statement  "IP protocols are used to communicate between networks."

but I am not clear about

"there is a misconception in people that they think I am running IP protocols to allow communication between Computers, NO, we have some other protocols which allow communicate people locally"

I am trying to understand, How computers can communicate without a layer 3 protocol lets say IP for an example and what are the protocols that allow people to communicate between themselves between computers with in their local area network?

Hope you understood my question.

Thanks in advance.

BR

Mohammad Thanveer

[Reza Sharifi]

Hi,

Have a look at this link for some good info on layer-2 and layer-3 forwarding with pictures.

https://documentation.meraki.com/MS/Layer_3_Switching/Layer_3_versus_Layer_2_Switch_for_VLANs

HTH

[Muhammad Thanveer]

Thanks 

[Muhammad Thanveer]

Hello,

Thanks for the link provided, here what I understood is at Layer 2 we need a MAC address for the hosts to communicate which is provided by ARP. Now without an IP address how can we get a MAC address, it means for a host to request or respond we use IP. 

So we are using IP, how can we deny this. It was said by a big shot in networks that we don't need an IP address to communicate in LAN, there are some other protocols which are there for it.

Please correct me if I am wrong.

[Jon Marshall]

Your initial post talked about not needing IP protocols but your latest reply talks about not needing an IP address .

So we need to understand what he actually said ie. -

1) when he said IP protocols (plural) does he mean the IP protocol itself or other protocols such as a routing protocol that sits within the IP layer

2) when he says you don't need an IP address presumably he is talking about a network not running IP because it wouldn't make sense otherwise ie. the original statement about using IP but then not needing an IP address are clearly contradictory.

Jon

[Muhammad Thanveer]

Hi Jon

I understand that we need Ip to communicate between PC in a land since we are using ARP. 

As per the person whom I am referring he said we don't need Ip protocol to communicate between PC in a lan. There are some other protocols to do this.he also said we need Ip to communicate between networks not in lan. Is that correct.

Hope its clear now.

[Jon Marshall]

There are some older protocols that can be used for clients within the same vlan that do not use IP but then, as far as I know, these protocols are not routable.

The general statement is you use IP and L3 IP addresses to deliver traffic to the remote subnet and then you use mac addresses, for example, to deliver the traffic to the end device.

So mac addresses are only used to deliver traffic within the same vlan/IP subnet.

But it is obviously not as clear cut as that because a computer needs to -

1) determine if the destination device is on the same IP subnet or not and it uses the IP protocol together with the IP addresses and it's subnet mask to work that out

and

2) it needs to arp for the mac address of the IP address whether that IP address is the end device on the same IP subnet or the clients default gateway.

So if he is talking about a standard TCP/IP network ie. no weird protocols, then IP is needed on the end computers because they have to make decisions.

If he is talking about a TCP/IP network then just ask him to disable the IP stack on the end computers and see how well the connectivity works.

Not on your network obviously :-)

Jon