Re: [RRG] Which Side to Control Ingress Link Selection?

In einer eMail vom 16.04.2008 00:10:50 Westeuropäische Normalzeit schreibt brian.e.carpenter@gmail.com:

On 2008-04-16 07:16, Christian Vogt wrote:
>>> Doesn't the issue persist independent of the characteristics based on
>>> which a path gets selected? Independent of *how* a path gets selected,
>>> you need to decide *who* selects it (or who selects which part of it).
>>
>> Well, that's true of course. But nothing can change the fact
>> that the originating host chooses the source address and destination
>> address that the packet starts out with, and all subsequent choices
>> depend on that.
>
> Brian,

I agree with Brian: the orginating host chooses (the source address and) the destination address and the respective first best hop. All subsequent routers are supposed to comply with.

How does the ingress router make this choice, how does it select the right ETR?

I take for granted that the destination user is not supposed at all to influence this choice.

So I can imagine,a good choice for the ingress router might be that particular ETR, which is closest.

(note : for some other ingress router, some other particular ETR will be closest)

But does the ingress router know which ETR is closest ? Does it even know which one it should compare in order to find out the closest? If yes, isn't it a big burden to do so? Or are these potential ETRs mutually like ships in the night?

Heiner