When to set Error 'E' bit in Diameter message?

Question

Hi,

I want to know in which scenario or which diameter messages can set the Error bit ('E') bit in request/response messages.
Also, How 'E' bit is set with Transient failures, Permanent failures and Protocol Errors.

Thanks in advance.

Answer 1

When processing of a Diameter request message fails, response message is sent with setting 'E' bit.
For example: If an AVP is unknown for the node, it sends error code comes under the permanent failure.
Since Diameter Answer message is carrying failure response, Experimental-Result-Code will carry "DIAMETER_INVALID_AVP_VALUE (5004)". 'E' bit is set in answer message when node finds a protocol error while processing request message.

Comments

Thanks Vimal for your answer. But I was confused with the RFC-6733 Section 7.2 it says The 'E' (Error Bit) in the Diameter header is set when the request caused a protocol-related error. So how can we set 'E' bit for transient and permanent failures.

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Chinmoy, you are correct. Error bit is set when failure is related to protocol error. I will correct it. Thanks.