[ntp:questions] Re: Need ntpdc command to recreate sockets

mayer at gis.net mayer at gis.net
Tue Jan 11 14:31:16 UTC 2005


John DeDourek wrote:

> The interesting question is whether a change in the
> local IP address indicates a change in the characteristics
> of the path to the server.  The statistics in the
> "smoothing filter", e.g. the delay to the server,
> presumably are designed on the assumption that the
> path doesn't change.
>
> Now, if I am on my DSL connection and the ISP changes
> the IP address, I am presumably still connected to the
> same DSLAM and probably have the same path to the router,
> presuming the ISP is not doing selective routing based on
> IP addresses.
>
> However, if I am on my laptop attached to one network,
> then detach, walk down the hall, and reattach to the
> other network in the building (taking the interface
> down then up) the path to the server may well change.
> Two cases: I switch interfaces, e.g. from wired to
> wireless; or I switch from one network to another
> on the same interface, e.g. on wireless.
>
> I won't mention the issues of Mobile IP, as that is
> rather controversial as to whether it will be widely
> deployed.  But this introduces the issues of the
> home IP address and the "care of" IP address.
>
> But the essential question is whether a change in the
> local IP address should cause the server to go
> "not synchronized" and then reaccumulate sufficient
> measurements to the other servers before going
> "synchronized" again.

It could be a settable option to specify whether or not
this is a fixed system with DHCP changing it's address
or it's mobile and the address change is due to it being
plugged into a different network (wireless or fixed).
Laptops are the primary candidate for regularly changing
IP addresses and network.

Danny




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