Questions in: Network & Telecom

Right Answer:
Log retention refers to the policies and practices for storing and managing log data over a specified period of time, ensuring that logs are kept for compliance, security, and troubleshooting purposes before being deleted or archived.

Right Answer:
The two servers can communicate through the firewall by allowing specific traffic based on defined rules. This is typically done by configuring the firewall to permit certain ports and protocols that the servers use to communicate, such as HTTP (port 80), HTTPS (port 443), or other necessary services. Additionally, using VPNs or tunneling can secure the communication between the servers through the firewall.

Right Answer:
A Bastion Host is a secure server that acts as a gateway between an external network (like the internet) and an internal network, providing a controlled access point for remote users to connect to the internal network while minimizing security risks.

Right Answer:
A virus is a type of malicious software (malware) that attaches itself to legitimate programs or files, replicates itself, and spreads to other computers, often causing harm to systems and data.

Right Answer:
Host-based security refers to security measures that are implemented on individual devices or hosts, such as computers or servers, to protect them from threats. This includes using antivirus software, firewalls, and intrusion detection systems to monitor and control access to the host.

Right Answer:
To deploy the employee assistance program (EAP) application, ensure it is hosted on a secure server, configure firewall rules to allow necessary traffic, implement access controls, and conduct thorough testing before going live.

Right Answer:
IP spoofing is a technique where an attacker sends IP packets from a false (or "spoofed") source address to disguise their identity or impersonate another device on a network.

Right Answer:
A screening router is a type of router that filters incoming and outgoing traffic based on predefined security rules, allowing or blocking data packets to enhance network security.

Right Answer:
Using just one NMOS or PMOS transistor as a transmission gate would result in poor performance because NMOS transistors conduct well for strong '0' (low voltage) but poorly for strong '1' (high voltage), while PMOS transistors do the opposite. This leads to signal degradation and increased resistance in one direction, making it inefficient for bidirectional signal transmission. A transmission gate, which combines both NMOS and PMOS transistors, allows for better signal integrity and lower resistance in both directions.

Right Answer:
To model a SRAM at RTL level, you can use a combination of a memory array and control logic. The memory array can be represented as a 2D array of flip-flops or registers, where each cell stores a bit. The control logic includes address decoding for read and write operations, enabling signals for word lines and bit lines, and a data bus for input and output. You can use Verilog or VHDL to describe the behavior, specifying read and write operations based on control signals.

Right Answer:
Increasing the number of contacts or vias from one metal layer to the next can improve electrical connectivity and reduce resistance, but it may also increase capacitance and lead to potential issues with signal integrity, power consumption, and layout complexity.

Right Answer:
Intrusion Detection is the process of monitoring network or system activities for malicious actions or policy violations, and it typically involves identifying and alerting on potential security breaches.

Right Answer:
To design a Desktop Publishing application, focus on user-friendly layout tools, customizable templates, text and image editing features, and support for various file formats. Ensure it has collaboration options and integrates with other software for a seamless workflow.

Right Answer:
A screened subnet, also known as a DMZ (Demilitarized Zone), is a network segment that sits between an internal network and an external network (like the internet). It contains servers that need to be accessible from the outside, such as web servers or email servers, while protecting the internal network from direct exposure to external threats.

Right Answer:
When the input square pulse goes from 0 to VDD, the NMOS transistor will turn on, allowing current to flow from the drain to the source. The output will follow the input, so it will also go from 0 to VDD.

Right Answer:
A transistor-level two-input NAND gate can be drawn using four transistors: two NMOS transistors in series and two PMOS transistors in parallel.

**Sizing:**

(a) **Considering Vth (Threshold Voltage):**
- Size the NMOS transistors (M1, M2) to have a width (W) that is larger than the PMOS transistors (M3, M4) to compensate for the lower mobility of electrons compared to holes. A common ratio is W_NMOS = 2 * W_PMOS, ensuring that the NMOS transistors can pull the output low effectively.

(b) **For Equal Rise and Fall Times:**
- To achieve equal rise and fall times, size the PMOS transistors (M3, M4) to be wider than the NMOS transistors (M1, M2). A typical sizing could be W_PMOS = 2 * W_NMOS, which balances the drive strengths, allowing both the pull

Right Answer:
Noise Margin is the measure of a circuit's ability to tolerate noise without affecting its performance. It is defined as the difference between the actual voltage levels of a logic high (V_OH) and logic low (V_OL) and the minimum required voltage levels for those states (V_IH and V_IL).

To determine Noise Margin, follow these steps:

1. Identify the output high voltage (V_OH) and output low voltage (V_OL) from the datasheet of the device.
2. Identify the input high voltage (V_IH) and input low voltage (V_IL) thresholds for the receiving device.
3. Calculate the Noise Margin for high (NM_H) and low (NM_L) as follows:
- NM_H = V_OH - V_IH
- NM_L = V_IL - V_OL
4. The Noise Margin is considered acceptable if both NM_H and NM_L are positive values.

Right Answer:
A screened host is a type of firewall configuration where a single host acts as a gateway between an internal network and the external network, filtering traffic based on predefined security rules. It typically includes a packet-filtering firewall and may also have additional security measures like intrusion detection.

Right Answer:
Testing is the process of executing a system to identify defects, while verification is the process of evaluating work products to ensure they meet specified requirements.

Right Answer:
No, the traceout command typically cannot work across a firewall because firewalls often block ICMP packets, which are used by traceout to determine the path to a destination.