- and malware like viruses, Trojan horses, and worms.
- IPS - An intrusion prevention system (IPS) is a computer security device that monitors network and/or system activities for malicious or unwanted behaviour and can react, in real time, to block or prevent those activities.
- For example, a network-based IPS will operate inline to monitor all network traffic.
# Knowledge check
- If a node has a wireless connection to the Internet, does that node have to be mobile? Suppose that a user with a laptop walks around her house with her laptop, and always accesses the Internet through the same access point. Is this user mobile from a Network standpoint? explain your answer?
- No. A mobile node is one that changes its point of attachment into the network over time. Since the user is always accessing the Internet through the same access point, she is not mobile.
- Consider a TCP connection going over Mobile IP. True or False : The TCP connection phase between the correspondent and the mobile host goes through the mobiles home network, but the data transfer phase is directly between the correspondent and the mobile host, bypassing the home network.
- False
- In mobile IP, what effect will mobility have on end-to-end delays of datagram between the source and destination?
- Because datagrams must be first forwarded to the home agent, and from there to the mobile, the delays will generally be longer than via direct routing.
- Note that it is possible, however, that the direct delay from the correspondent to the mobile (i.e., if the datagram is not routed through the home agent) could actually be smaller than the sum of the delay from the correspondent to the home agent and from there to the mobile.
- Consider two mobile devices in a foreign network having a foreign agent. Is it possible for the two mobile nodes to use the same care-of-address in mobile IP? Explain your answer.
- Two mobiles could certainly have the same care-of-address in the same visited network. Indeed, if the care-of-address is the address of the foreign agent, then this address would be the same. Once the foreign agent decapsulates the tunneled datagram and determines the address of the mobile, then separate addresses would need to be used to send the datagrams separately to their different destinations (mobiles) within the visited network.
- What are the differences between the following types of wireless channel impairments : path loss, multipath propagation, interference from other sources?
- Path loss is due to the attenuation of the electromagnetic signal when it travels through matter.
- Multipath propagation results in blurring of the received signal at the receiver and occurs when portions of the electromagnetic wave reflect off objects and ground, taking paths of different lengths between a sender and receiver.
- Interference from other sources occurs when the other source is also transmitting in the same frequency range as the wireless network.
