TCP operates at Layer 4 which is Transport of the OSI Model!
IP operates at the bottom of layer 3. Layer distinctions, however, are fuzzy because things have changed since the OSI model was conceived and implementors combined things together.
Transport, page 48 in Network+ Guide to Networks 5th edition
IP operates at layer 3, this is the NETWORK LAYER in the OSI Model.
Network+ Guide to Networks
Fifth Edition
Ch02, pg56, Figure 2-7
Network Layer
Network Layer of the OSI model
NETWORK
Network layer
IP addresses are used primarily by layer 3 (network layer) of the OSI model for routine purposes.
Layer 3 of the OSI model. An ICMP header follows the IP header of the IP packet.
Layer 3 i.e, network layer of the OSI model is used to IP addressing.
DHCP runs at the application layer of the OSI model.
TCP/IP because the osi model has seven layer but in tcp/ip only four layers and most important is that the tcp/ip model is reduce the function of osi model.
transport
IP operates at layer 3, this is the NETWORK LAYER in the OSI Model. Network+ Guide to Networks Fifth Edition Ch02, pg56, Figure 2-7
The TCP/IP model was adopted and condensed into 4 Layers.1. Link layer ( Layer 1and 2 of the OSI model)2. Internet Layer (Layer 3 of the OSI model)3. Transport ( Layer 4, 5 and 6 of the OSI model)4. Application ( Layer 7 of the OSI model)http://en.wikipedia.org/wiki/TCP/IP_model#Link_Layer
The Network Interface layer
IP is a layer 3 (network layer) protocol used for routing
Routers and layer 3 switches work at Layer 3 of OSI model.
Transport layer and Network layer.