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Content Delivery Networks - Coggle Diagram
Content Delivery Networks
Overview
A geographically distributed group of servers
Provides Internet content as quickly, cheaply, reliably, and securely as possible
A majority of web traffic at present is served through CDNs
Does not host Internet content
Security risks
Distributed Denial of Service (DDOS)
attacks
On-path attacks
Data breaches
Improving
reliability
and
redundancy
Benefits
Minimizing
downtime
Handling hardware failures
Intelligent
failover
Providing uninterrupted service when one or more servers go offline
Anycast
routing
Transferring traffic to an available data center when an entire data centre fails
Handling spikes in traffic with
load balancing
Distributing traffic evenly across multiple servers
Reducing
latency
Benefits
Reducing
wait time
and
bounce rate
Reducing hosting costs
Optimizations
Using
SSDs
instead of
HDDs
Faster disk reads and writes
Reduced disk failure
Efficient access of
fragmented
data
Optimizing
TLS/SSL
connections
Connection reuse
TLS false start
Reducing data transfer to and from
origin servers
Caching
content at the nearest edge server to the client after the initial request
Reducing file sizes using
minification
and
compression
GZip
Distance reduction
Placing servers at
Internet eXchange Points (IXPs)
Locations where Internet providers connect and allow each other access to their networks
Distributing content closer to visitors by using a nearby CDN server
Placing data centres in high-traffic and strategic locations
Factors affecting latency
Number and size of unique Internet assets requested
Round trip time
(RTT)
Time taken for a client to send an
HTTP
request to an
origin server
or an
edge server
and receive a response
Components
TCP/IP handshake
Determined by the number of
hops
between client and server
Can be diagnosed with
traceroute
Overhead of establishing a
TCP/IP
connection
Request time and response time
Determined by the physical distance between client and server
TLS (Transport Layer Security)
Overview
A protocol for encrypting data sent over the Internet
Succeeded
SSL (Secure Sockets Layer)
Used by the
HTTPS
protocol to establish encrypted connections
Prevents intermediaries from reading and tampering intercepted data
Components
Authentication
Verifying validity of identities
Encryption
Obfuscating information
Integrity
Detecting forgery and tampering
SSL certificate
Contains information about the owner of a site and the public half of an
asymmetric key pair
Certificate authority (CA)
Digitally signs SSL certificates to certify correctness
Implicitly trusted when trusting an SSL certificate
Operating systems and browsers have a list of trusted certificate authorities
Visitors are warned of untrusted certificate authorities
Rating
Certificates can be independently rated based on strength and protocol support
Can change over time as newer and better implementations emerge