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EEs use this service to download a local policy file.

PORT8892
PATH/download/policy/local
HTTP MethodGET
HTTP Request BodyEmpty
HTTP Request Headers

Optionally, the request may include the standard HTTP Header 'If-None-Match' containing the filename of the local policy file that the EE currently possesses, excluding any path. For example:

If-None-Match: "local_policy_0001_0001.oer"

This is used to prevent the same policy file from being downloaded by the device multiple times.

HTTP Response Body

File containing the local policy represented by an OER encoded ASN.1 serialized SignedLocalPolicyFile. The file name returned is of the form: local_policy_<X>_<Y>.<Z>

Where:

  • X is the global version number
  • Y is the local policy version
  • Z is one of the permitted encoding formats (oer) from the file name in the request message

OR

An HTTP code of 304 (Not Modified), if the provided file name in the 'If-None-Match' header matches the current version available on the RA server.

Preconditions

None

Postconditions

  1. Returned file contains policy that the device will use

Error Handling

See "RA-EE Errors" in Overview of Used Error Codes

Quality of Service

Estimated values are per logical unit, meaning multiple individual nodes can contribute to achieve the desired level of service. The number of vehicles that potentially invoke this service in a week is a function of the number of years in service:

 

Quality Metric
Rationale
1 Year
3 Years
5 Years
10 Years
Throughput

Assuming half of all new cars plus all existing vehicles need to download local policy in the same week.

8,500,000 new vehicles / 604,800 seconds/week

14 requests / second

(8,500,000 new vehicles + 34,000,000 existing vehicles) / 604,800 seconds/week

70 requests / second

(8,500,000 new vehicles + 68,000,000 existing vehicles) / 604,800 seconds/week

126 requests / second

(8,500,000 new vehicles + 153,000,000 existing vehicles) / 604,800 seconds/week

267 requests / second

Quality of Protection

  • RA protects access with HTTPS (TLS V1.2)
  • Supports at a minimum OpenSSL cipher suite ECDHE-ECDSA-AES128-SHA256

2 Comments

  1. Anonymous

    Currently the name used to download the file differs from the naming convention of the local policy file here: Step 18.2: Generate Local Policies for EEs. Is there a plan to reconcile these differences and create a consistent naming scheme?

    1. Good catch, thank you! It is fixed now.