Best practices

Although Akamai provides secure transmission and environments for a scalable, zero rate billing network, it does not guarantee end-to-end package security and integrity. It is the auto manufacturer's responsibility to guarantee the safety of all communications.

Akamai provides best practices for the following areas:

UID support
Firmware files storage
Efficient files distribution
Burst rate limiting
Integrity and safety checking
Certificates
Domain flexibility

The following table shows the recommendations for the proper use of UID, firmware files storage, efficient files distribution, burst rate limiting, integrity and safety checking, certificates, and domain flexibility.

Recommendation	Non-compliance Result
UID Support
To keep individual vehicle reporting consistent, the UID of an individual vehicle must remain unique and static over the course of a reporting cycle.	May result in receiving invalid or erroneous results in the reports.
Firmware Files Storage
To prevent downloading a wrong or corrupted file, each firmware file must have a unique URL. To avoid collision of firmware files, you can use a naming convention. For example: `my-domain://<make or head unit>/<model>/patch-name/version`. If you find a corrupted firmware file at the origin, in NetStorage, or in the cache, remove and replace it with a different URL.	May result in the delivery of invalid files, excess download costs, or delayed delivery of files.
Efficient Files Distribution
For efficient downloads, data and burst rates reduction, cost reduction, and contract compliance, consider the following solutions in your OTA Updates system. Compressing files at the origin or NetStorage and decompressing in head units. Implementing a download management system in head units that manages offsets by reconnecting to limit download traffic and aborts downloads as early as possible. Leveraging a different domain for Wi-Fi connections to reduce load on the zero rate billing (ZRB) network.	May result in excess download costs and delayed delivery of files.
Burst Rate Limiting
To manage the download rates of all cars within a billable region so they comply with your contract-specified burst rate, consider the following solutions in your OTA Updates system: Spreading out downloads (campaigns) in even distribution. Prioritizing smaller more urgent files over larger maintenance files.	May significantly higher download costs.
Integrity and Safety Checking
To keep communications secure between the OTA Updates system and head units, use an authentication and integrity mechanism for all data delivered over the system. Consider the following solutions in your OTA Updates system: Signing all messages and including the vehicle’s UID and the request number in messages to head units to ensure authority and integrity. Including manifest information in download files to ensure correctness for all critical payloads and messages. Verifying the signatures, UIDs, and request numbers of campaign server responses in head units.	May result in accidental or malicious application of invalid or dangerous files.
Certificates
To keep communications secure between the OTA Updates system and head units, consider the following solutions in your OTA Updates system: Changing the Certification Authority (CA) that signs client certificates. Rotating client certificates regularly. Note: Head units must allow for changes to both the certificates and the CA/Trusted Root certificates.	May result in long-term supportability issues.
Domain Flexibility
For flexibility in removing vehicles from the OTA Updates system or shifting vehicles from the OTA Updates system to other networks, head units must be able to change the domains they use to connect to the OTA Updates system. Consider the following solutions in your OTA Updates system: Allowing for head units to change domains for groups of vehicles or the entire fleet.	May prevent head units with older software from receiving firmware updates from the OTA Updates system.