multiple routing tables review patch ready for simple testing.

Bruce M Simpson bms at
Wed Apr 30 18:08:13 UTC 2008

Julian Elischer wrote:
> what's SSM?

Source-specific multicast, where multicast flows (channels) are 
identified by both their original source address, and group address. 
Multicast addresses have no meaning on their own beyond the scope of a 
single link.

> I haven't changed any of that.. Basically I've kept clear of
> M/Cast. The way I see it, if you don't define ROUTETABLES=2 (or more)
> or don;t define it at all in your config then you get what you had
> before and I shouldn't have broken anything.

Cool! Doing multicast "right" is Hard. Doing it "right" in ad-hoc 
topologies is Harder.

It makes sense to steer clear of it for now. It can no doubt benefit 
from the hierarchy offered by multiple FIBs, but again, the policy 
routing mechanisms don't really exist just now, and things like PIM need 
changes to encompass it.

They will need to come into existence for the model to work on a macro 
scale, for the same reason SSM was put on the table.

> I take it from this that you don't have any major complaints
> as far as what I've done.

No problems here... I haven't tried testing.

I would say though if we are going to be renaming rtalloc() and friends, 
that names should really change to be descriptive of what it does.
It doesn't "allocate a route", it tries to look up a forwarding table 
entry, and returns a reference to it.


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