Re: [OSL | CCIE_RS] Native vlan from router to switch

Another way to look at it is via the layer definitions themselves.

Layer 3 provides logical addressing. In other words an address that is
independent of physical hardware containing some mechanism to provide a
network and host portion thereby enabling it to be routed. Arp does not do
that.

Layer 2 provides physical addressing as well as services to communicate
with higher layers (i.e. layer 3). That is a better fit for arp.

There are many examples of protocols that do not fit perfectly by
definition into a single layer and you can make that arguement for arp at
layer 2, however, as discussed above it is certainly not a layer 3
protocol. So in my eyes that debate is null and void due to the absence of
any other suitable contenders.

Hope that helps,

Andres

On 13/12/2011 7:31 PM, "CCIE KID" <eliteccie_at_gmail.com> wrote:

Hey guys,

I guess they say its a Layer 2 or Layer 3 on the basis of encapsulation.
ARP is encapsulated in Layer 2 header. So its a Layer 2 protocol
But OSPF, EIGRP and ICMP are encapsulated in Layer 3. So thats why it is a
Layer 3 Protocol.
So on the basis of encapsulation, they would have brought out that the
protocol is a Layer 2 or Layer 3.

BGP,RIP are encapsulated in TCP and UDP respectively. So they are
application layer protocol.

Where does it encapsulate depends upon where it sits in OSI Layer,

ARP sits above Layer 2 but layer 3. So thats why Scott would have called it
as a Layer 2.5 Protocol

OSPF,ICMP,EIGRP are all payloads of IP . They are all present above IP but
below Layer 4. So they r all Layer 3.5 protocol.

So it all depends upon where does the protocol actually sits in the OSI
layer.

I guess this topic would have opened up many logics in networking

I thank everyone who contributed

I also enjoy working on this topic

On Tue, Dec 13, 2011 at 1:55 PM, Michael Davis - Webquor <
mdavis_at_webquor.com.au> wrote:

> Sorry...

Blogs and organic groups at http://www.ccie.net
Received on Wed Dec 14 2011 - 07:28:35 ART