NetworkGateway endpoints can be transmitted as DNS names by the remote cluster, in which case the local cluster has to first resolve them to a set of IP addresses before it uses them as routable service endpoints. Transmitting DNS names has the advantage that they're rather stable, but it does mean the receiving end has to resolve them in regular intervals - ideally periodically, everytime their TTL has passed.

ACs:

• network gateway endpoints that are hostnames are resolved by the receiving istiod automatically
• (optional) period is automatically derived from DNS entry's TTL