1.2 Networking Functions

What is Content Delivery Network (CDN)?

Provides a way to get data efficiently from one data point to a user.

Geographically distributed caching server by duplicating the data which leads to

users getting the data from the local server instead of the main one.

What is a Virtual Private Network (VPN)?

Connects to a remote network while sending data encrypted so that it’s secure.

What is a concentrator/head-end?

Encryption/decryption access device so that data is securely sent and returned, often integrated into a firewall.

What is Quality of Service (QoS)?

Controls what applications run based on bandwidth usage or data rates, setting important applications to have higher priorities than other apps.

What is Time to Live (TTL)?

A timer that will have the tasks stop or drop once it hits 0.

What are routing loops?

Router A goes to Router B, which goes back to Router A.

What is used to stop a routing loop?

TTL can be used to stop the loop.

What is a hop?

Each pass through a router.

What is the default TTL for macOS/Linux?

64 hops.

What is the default TTL for Windows?

128 hops.

The router decrease TTL by 1 which leads to a TTl of

zero being dropped by the router.

What is TTL in DNS related to?

Number of seconds.