Why does username is considered as part of the identity ?

[TianHong Zhao]

Hi,

In EAP_TTLS/MSCHAPV2, the username is taken from identity (excluding the
realm part), but why ?

In the project I'm working on, when using EAP_TTLS/MSCHAPV2, "identity"
in phase1 is MAC address, "identity" in phase2 is the username,
is there any easy way to make eap_ttls code choose the right one ?

Tianhong