On Wed, Nov 11, 2009 at 3:19 PM, William Herrin <[email protected]> wrote:
> Hi folks, > > I couldn't attend but I had two questions about the FIB aggregation > draft (http://tools.ietf.org/html/draft-zhang-fibaggregation-02): > > 1. The level 3 and 4 algorithms disregard the implicit default, right? > Yes. > > A destination that falls through the routing table without matching a > route is unreachable. You can think of this in terms as an implicit > route for 0.0.0.0/0 with a next hop of: local process, compose ICMP > unreachable. If I understood the paper, some or all of the address > space within 0.0.0.0/0 which would otherwise hit that implicit default > will be assigned an essentially random next hop, with the system > depending on the TTL to eventually drop the packet. > Or, the packets may be dropped if the next router does not assign any next hop to this "extra routable space", as different routers aggregate differently. > > Have level 3 and level 4 been tested after adding an explicit default > that has to be honored to see what difference it makes in the numbers? > > No, we didn't add any explicit default route. We can give it a try to see what numbers come out. But intuitively, adding a default route means taking away all extra route space, so the best aggregation can be achieved by the ORTC algorithm mentioned by John in an early email. It should be close to what we have for Level-2 aggregation, which is about 50% table size. > > 2. If I understand figure 6 correctly, the numbers are the percentage > of original size the FIB reduces to. So, 2008 level 4b, if you started > with a 1000 entry FIB, after aggregation the FIB still contains 363 > entries. Did I read it correctly? > Yes. Regards, --- beichuan > > Thanks, > Bill Herrin > > > -- > William D. Herrin ................ [email protected] [email protected] > 3005 Crane Dr. ...................... Web: <http://bill.herrin.us/> > Falls Church, VA 22042-3004 > _______________________________________________ > GROW mailing list > [email protected] > https://www.ietf.org/mailman/listinfo/grow > >
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