Subject: [alto] Some questions for alto-xdom-disc

From: xin wang <[email-masked]>
Date: Fri, 1 Dec 2017 04:05:47 +0000

Dear authors of alto-xdom-disc and all,

Do you have any new updates on the draft of alto-xdom-disc? I know that the draft intends to address the IRD discovery issue in the cross-domain setting, but I find that the cross-domain itself arouse my great interest.

Considering that each domain has one ALTO server that can give a useful cost value (not default) between any two endpoints in the domain for the ECS. Then, the ALTO server discovery works when a client asks for the cost value between any two endpoints in the same domain, as it will direct to the right ALTO server which can give cost values for some endpoint-pairs. It might involve multiple ALTO servers to answer a single query of ECS service but the requirement of the client can be satisfied.

However, if a client asks for a cost value between two endpoints which locate in different domains, then who should be able to give the cost value? This should be a common case if we target to deploy ALTO across the public Internet as you listed as one of the requirements for ALTO cross-domain server discovery.

There are basically two approaches for the issue above: one is to depend each ALTO server itself to compute cost values across domains (e.g., recursive sending queries to other servers); the other is to set up a hierarchy structure to relay the query to an upper ALTO server which is able to support ECS across domains. In either way, there need substantial efforts to consider/design a protocol between two ALTO servers (which is discussed a little in the Sec. 1.1.2 in your draft).

Do you think there are potential solutions can resolve the issue without depending too much on the inter-ALTO-server information exchanging? Or design inter-ALTO-server protocol is the best direction?

Best,

X. Tony Wang