Regarding alternate endpoint

[Sunil Chandra]

Hi,

In the explaination of endpointAlias field in URQ message (Section 7.10.1 of
H.225.0), it is said that if the E.164 address is assigned, it should be
mentioned.
Why this is mandatory for E.164 address?
Why it is mandatory for E.164 addresses only?

With regards,
Sunil