Questions related to SAMLv2.0

Hi All,

I am reading the SAMLv2.0 standard and I am unable to find the answers of some of my questions. I need some help.

1- How persistent name identifier will be established between IDP and multiple SPs when using SAML webSSO profile?

2- When SAML assertion is received by SP. Does it validate the SAML assertion locally or it calls the IDP for SAML assertion validation?

3- In which request form SAML assertions pass from one SP to another and so on in order to achieve webSSO?

Thanks for your time.