Nokia Scalable IP Networks

Ctrl-z is the correct control command to return directly to the ROOT context in the Nokia 7750SR Service Router Command Line Interface (CLI). This shortcut exits the current context and brings the user back to the ROOT context efficiently.

A repeater is a device that receives a signal and then retransmits it, typically to extend the range of the transmission. It does not perform any analysis or processing of the data, such as checking Layer 2 or Layer 3 addresses. Its primary function is to regenerate and amplify the signal to combat the attenuation and distortion that occurs over long distances. This makes option B, which describes a device that receives and retransmits a signal without analyzing the data, the best description of a repeater.

ATM (Asynchronous Transfer Mode) and Frame-Relay are both circuit-switched protocols. They utilize Virtual Circuits (VCs) to create logical separation of traffic on the same physical wire. Virtual Circuits allow multiple customers or types of traffic to be distinguished and managed independently, ensuring that data intended for one virtual circuit does not interfere with data intended for another. This method effectively segregates traffic and supports the communication needs of various customers or applications over a single physical medium.

Layer 3, also known as the network layer, is responsible for providing an universal addressing scheme which enables the routing of data between different networks. This includes the use of IP addresses to identify devices on the network, allowing for data to be sent from one device to another across different Layer 2 networks. Option A correctly describes this feature of Layer 3.

When subnetting a /24 network using a /26 mask, the subnet mask is extended by 2 bits. This gives you 2^2, or 4 subnets. Each subnet can have 2^(32-26) - 2, which results in 62 usable host addresses per subnet. Thus, the correct answer is 4 subnets and 62 hosts.