[Dibbler] dibbler-client and pd

thomson thomson at klub.com.pl
Sat Mar 30 15:59:21 CET 2013


Am 29.03.2013 22:22, Jyrki Soini wrote:
>> Wouldn't it be better to have /64 for each interface as a default?
>> That would maintain easy addition of new interfaces/vllans in case
>> the router configuration changes later. If the prefix is allocated in
>> the beginning to (nearly) same size parts, additional interfaces/vlans
>> would require change of other prefixes as well.

On Sat, 30 Mar 2013 10:09:41 +0100, Jean-Jacques Sarton <jj.sarton at web.de>
wrote:
> I thing that the rules for prefix delegation shall apply for each
> interface separately.
I disagree. These are requirements very specific to a given deployment.

Here's what I think would be the best way forward:

1. Keep downlink-prefix-ifaces directive. It defines a list of downlink
interfaces.
If you don't specify it, dibbler will try to find them out on its own.
Not specifying it should work for people who are concerned about new
interfaces being
added later.

2. Add new parameter prefix-split that will have one parameter. It will
define how the delegated prefix should be split. For now I think the
reasonable
values are:
prefix-split 64  - use /64 prefixes on downlink interfaces, even if
received /48

prefix-split full - try to use as much of the prefix as possible. Example:
If received /48 and have 2 interfaces, assign /49 on each.

3. Dibbler-client can call an external script. See section 4.8 in Dibbler
User's
Guide. Client will call this script every time it adds, updates, releases
or
expires an address or a prefix. Someone mentioned that it does not do that
for PD. This is strange. If the script really is not called, then this is
a
bug and has to be fixed.

4. Pass information about downlink interfaces to the script. People who
want to
do extra fancy things (like Jean-Jacques mentioning adding different
suffixes on
different interfaces) can do this in script. 

5. Dibbler currently sets prefixes on its own. Many like that, because it
is easy
to use. Others would like to do something extra using script. Yet others
would like
the client to not setting anything, just call the script. So we need to
add a new
directive that tells dibbler-client how to use received option:

prefix-application internal|script|both|none

6. This is really minor. Dibbler-client generates radvd.conf when
receiving
PD. It has AdvAutonomous hardcoded to on. Someone (Jean-Jacques?) pointed
out to
a RFC that says that should be configurable. Do you think it would be
useful to
add an option that controls if it should be on or off?

7. Anyone interested in prefix exclude option? (RFC6603).

1. is already done.
2, 4, and 5 is to be implemented.
3 needs investigation and little implementation.

What do you think? Would that work for everyone?

Tomek



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