AWS学习笔记（十五）：CloudFront

###CloudFront vs S3 Cross Region Replication
CloudFront:

• Global Edge network
• Files are cached for a TTL (maybe a day)
• Great for static content that must be available everywhere

S3 Cross Region Replication:

• Must be setup for each region you want replication to happen
• Files are updated in near real-time
• Read only
• Great for dynamic content that needs to be available at low-latency in few regions

###CloudFront Signed URL Diagram

###CloudFront Signed URL vs S3 Pre-Signed URL
CloudFront Signed URL:

• Allow access to a path, no matter the origin
• Account wide key-pair, only the root can manage it
• Can filter by IP, path, date, expiration
• Can leverage caching features

S3 Pre-Signed URL:

• Issue a request as the person who pre-signed the URL
• Uses the IAM key of the signing IAM principal
• Limited lifetime

###Unicast IP vs Anycast IP

• Unicast IP: one server holds one IP address
• Anycast IP: all servers hold the same IP address and the client is routed to the nearest one

###AWS Global Accelerator vs CloudFront
They both use the AWS global network and its edge locations around the world
Both services integrate with AWS Shield for DDoS protection.
CloudFront

• Improves performance for both cacheable content (such as images and videos)
• Dynamic content (such as API acceleration and dynamic site delivery)
• Content is served at the edge

Global Accelerator

• Improves performance for a wide range of applications over TCP or UDP
• Proxying packets at the edge to applications running in one or more AWS Regions.
• Good fit for non-HTTP use cases, such as gaming (UDP), IoT (MQTT), or Voice over IP
• Good for HTTP use cases that require static IP addresses
• Good for HTTP use cases that required deterministic, fast regional failover