Networking Functions Flashcards
(20 cards)
What is the main purpose of networking functions?
To enable communication, data transfer, remote access, traffic prioritization, and system availability across networks.
What is a Content Delivery Network (CDN)?
A system of distributed servers that delivers web content to users based on geographic location to reduce latency and increase speed.
Why is a CDN used instead of a central server?
It reduces the time to access data by serving it from a nearby cached location, improving performance for global users.
What is a VPN and what is its primary benefit?
A Virtual Private Network creates a secure, encrypted connection over an untrusted network like the internet, ensuring private data transfer.
What is a VPN concentrator?
A device or software that manages multiple VPN connections, handling encryption and decryption for secure access.
What is the difference between hardware and software VPN concentrators?
Hardware concentrators are built for high performance and large-scale use, while software versions are better for small-scale or personal use.
What is Quality of Service (QoS)?
A network feature that prioritizes certain types of traffic (e.g., voice, video) to ensure performance under load.
What are some alternative names for QoS?
Traffic shaping or packet shaping.
Why is QoS critical in a business network?
It ensures high-priority services like VoIP or video conferencing work smoothly, even during high network usage.
Where is QoS typically configured?
On networking devices such as routers, firewalls, or managed switches.
What does Time to Live (TTL) refer to in networking?
A counter that limits how long a packet or record remains valid, preventing infinite loops or outdated information.
How does TTL prevent routing loops in IP networks?
Each router decreases the packet’s TTL by 1. If TTL reaches 0, the packet is discarded, ending the loop.
What are the default TTL values for major OSes?
Windows: 128 hops; macOS/Linux: 64 hops.
What is a routing loop and how does TTL help stop it?
A misrouting error where packets endlessly circulate between routers; TTL ends the loop by forcing the packet to expire.
How is TTL used differently in DNS than in IP routing?
In DNS, TTL is measured in seconds and determines how long a DNS response is cached on a system.
Why does a low DNS TTL matter?
It allows faster propagation of DNS changes (e.g., when switching IPs), but may increase lookup traffic.
What does a DNS TTL of 300 mean?
The DNS record should be cached for 300 seconds (5 minutes) before refreshing.
How can you view DNS TTL for a domain?
By using commands like “nslookup” or “dig” to query the DNS server.
What happens when a DNS TTL expires?
The cached entry is removed, and a new DNS lookup is required to retrieve the IP address.
How is TTL managed in the IPv4 packet header?
It’s a specific field in the IP header. Routers decrement this field by 1 each hop until it reaches zero and the packet is dropped.
