CDN Architecture & Components 2 — Questions and Answers
Question 1: What is the primary role of an Anycast network in CDN architecture?
- Route users to the nearest PoP based on network topology (Correct answer)
- Replicate content across all edge nodes simultaneously
- Encrypt data in transit between PoPs
- Balance load across origin servers
Correct answer: Route users to the nearest PoP based on network topology
Anycast assigns the same IP address to multiple PoPs so BGP routing automatically directs users to the topologically nearest node.
Question 2: Which CDN component is responsible for translating a user's hostname into the IP address of the optimal edge server?
- Load balancer
- Global Traffic Manager (GTM) / DNS-based routing (Correct answer)
- Reverse proxy
- Origin shield
Correct answer: Global Traffic Manager (GTM) / DNS-based routing
A Global Traffic Manager uses DNS responses to steer clients to the best-performing edge node at request time.
Question 3: In a multi-tier CDN hierarchy, what distinguishes a 'parent' cache from an 'edge' cache?
- Parent caches serve end users directly while edge caches do not
- Edge caches fill cache misses from parent caches rather than the origin (Correct answer)
- Parent caches only store video content
- Edge caches use RAM while parent caches use disk
Correct answer: Edge caches fill cache misses from parent caches rather than the origin
Parent (mid-tier) caches sit between edge nodes and the origin, absorbing cache-miss traffic so the origin receives far fewer requests.
Question 4: What is 'cache shielding' (also called origin shielding) designed to accomplish?
- Prevent DDoS attacks from reaching edge nodes
- Funnel all cache misses through a single upstream node to protect the origin (Correct answer)
- Encrypt cached objects at rest
- Reduce DNS TTL propagation delays
Correct answer: Funnel all cache misses through a single upstream node to protect the origin
Origin shielding collapses cache misses from many edge nodes into a single shield PoP, drastically reducing origin load.
Question 5: Which protocol feature allows a CDN edge server to maintain a single persistent connection to the origin while serving many concurrent client requests?
- HTTP/2 server push
- Connection multiplexing / HTTP/2 streams (Correct answer)
- WebSocket tunneling
- QUIC 0-RTT handshakes
Correct answer: Connection multiplexing / HTTP/2 streams
HTTP/2 multiplexing lets multiple requests share one TCP connection, so the edge opens fewer connections to the origin.
Question 6: A CDN PoP contains hardware that performs SSL/TLS termination. What is the main benefit of terminating TLS at the edge rather than at the origin?
- It eliminates the need for SSL certificates on origin servers
- It reduces round-trip latency because the TLS handshake completes near the user (Correct answer)
- It prevents the CDN from caching HTTPS responses
- It forces HTTP/1.1 on the last mile
Correct answer: It reduces round-trip latency because the TLS handshake completes near the user
Terminating TLS at the nearest PoP shortens the handshake RTT, since the cryptographic exchange happens close to the end user.
Question 7: What does a CDN 'token authentication' mechanism typically protect against?
- Unauthorized hotlinking or direct URL sharing of protected assets (Correct answer)
- SQL injection attacks on origin databases
- Cache poisoning via manipulated headers
- Anycast route hijacking
Correct answer: Unauthorized hotlinking or direct URL sharing of protected assets
Token authentication embeds a signed, time-limited token in the URL so only authorized requests can retrieve protected content.
CDN Architecture & Components 2
What is the primary role of an Anycast network in CDN architecture?