The LD50 of nicotine is 50 mg/kg for rats and 3 mg/kg for mice. 0.5-1.0 mg/kg can be a lethal dosage for adult humans, and 0.1 mg/kg for children.
IPSec is a suite of protocols that provide security services at IP layer of TCP/IP stack i.e. Network Layer in OSI model. As Andy Lemke mentioned, IPSec suite comprises of two protocols to offer security to. 1. AH - Authentication Header Protocol.(Protocol no: 51) 2. ESP - Encapsulation of security payload Protocol.
The Open Systems Interconnection (OSI) model is a protocol used to communicate between different networks. Protocols are nothing but a set of rules used to communicate between two networks. The Open Systems Interconnection (OSI) model is divided in seven layers. Reference from Google. OSI Model divided in two parts upper level and lower level. The OSI Model is also divided in two parts; upper level and lower level. The lower level contains a physical layer, data link layer and network layer.