Q:
Good stuff....I consider ARP a layer two protocol. It basically reside between layer 2 and layer 3, but for all intense and purposes, it is considered a L2 protocol by the standards bodies.
Just my opinion. I love this question though and I like to ask it about once a year or so as it sparks some very good debates and makes people puruse the RFC's and such. It's a great learning enabling question...
Thanks for the great input from both of your two !.....Bob
A:
You are so diplomatic. I agree the, the layer to which some protocols reside is contoverssial as there is no clear line. Outside of protocols like TCP, UDP and IP whose purpose and use is very clear there are several protocols that do not fit easily into a layered model. I once asked someone, If RIP is considered to be a Layer 3 protocol then why does it use TCP port 520. Obviuosly, it has to do with the interworking of the algorithm itself, anyway the response was something to the affect of, ethertype numbers, IP protocol numbers, and TCP/UDP port numbers should not be the sole determnant of protocol placement in a layered model. Although that is the way many of us learn the models and the interactions of protocols (e.g. encapsulation). He used the example of SNMP, it has both UDP and TCP port numbers, an IP protocol number and an ethertype, so where would this protocol be placed? A very good point. Maybe I should have prefaced my original comment with this story. I guess as you eluded with many protocols there is no clear cut way to box their activities in one layer or another. Which in essence is the reason you asked the question. Have an excellent weekend.
|
ITpassZone is keeping researching the official cisco CCNA test note certification training certification
exam pool to guarantee that ITpassZone cisco CCNA test note certification training study guide
covers 100% of the cisco CCNA test note certification training IT test knowledge and contain
extremely similar question style and content. 