Diameter : In which scenario Error-Reporting-Host AVP is added in Diameter answer message ?

Question

I was going through rfc3588 and could not understand when a Diameter Server/Agent adds Error-Reporting -Host AVP within the answer message.

Answer 1

If an intermediate Diameter Agent/Relay node found any error then set error in the Result-Code AVP and add an extra AVP known as Error-Reporting-Host AVP. There is one more condition adhere, if Diameter Agent/Relay node receives answer from another node and answer message carrying Result-Code AVP set to other than 2001 then Diameter Agent/Relay nodes log the error locally and does not modify the Result-Code of received message.