About NAROS

[marcelo bagnulo <marcelo@it.uc3m.es>]

Hi Cedric,

About NAROS for TE, i was wondering if  policy table defined in RFC 3484
could provide the capabilities needed for performing TE?
I mean, RFC 3484 defines a policy table that is to be used for defining
policies, such as which source address to prefer when reaching a given
destination address, which i think is what the NAROS TE application
achieves.
So i was thinking why not just complete the table with the sites
policies to achieve this goal.
The problem is that currently there is no way to dynamically configure
the policy table, so NAROS could be used for this. In this way, once the
hosts obtains the policy information, it configures its policy table and
uses it for following packets.

An alternative option would be to define a new dhcp option to configure
the policy table, so that when the hosts boots it obtains the policy
table configuration from the dhcp server. The problem with this solution
would be if the policy table is too large or too dynamic, in which case,
i guess that using NAROS would provide better performance. Another
option would be to use the NAROS server a single point for specifying
policy and that the dhcp server obtain the policy table configuration
from it. Have you considered any of these options?

About fault tolerance capabilities. As defined in the draft NAROS server
would only be aware of direct providers outages. However, i guess that
NAROS server capabilities to select the appropriate address could be
improved if the NAROS server had additional information, such as the BGP
routing table, moreover, i guess that it would be interesting that the
NAROS server had the bgp routing table view from each of the borders
routers connected to different isps. With this information, it would be
capable of knowing which addresses are reachable from each provider and
perform a better address selection. However, i would say that some
failures would remain undetected by the NAROS server, essentially due to
aggregation. This implies that an additional mechanism for failure
detection is needed, probably and e2e mechanism.

Thanks, marcelo