22 Jan
2010
22 Jan
'10
10:47 p.m.
Hello,
On 1/22/10 3:31 PM, Ovidiu Sas wrote:
The way that the original module was written did not
allow dynamic
numbers of queues and pipes.
I am using the ratelimit module to control incoming/outgoing traffic
on specific trunks by invoking rate limitation based on pipes (by
forcing a specific pipe).
Choosing a specific pipe is up to the kamailio config designer (any
type of operations ca be applied to the pvar before choosing a
specific pipe, so IMHO it is pretty flexible as is right now - one can
apply any regex operations to a pvar).
Pipes and queues can be dynamically modified via mi commands.
The major limitation of the module is the hard coded number of queues
and pipes and the fact that dynamic changes to pipes and queues are
not saved on restart.
Loading the queues and pipes from a db will require a redesign of how
the pipes and queues are stored internally.
yes, it is a hash table. A benefit of dynamic/dynamic names is you can
simply use ip address as pipe name. Also strings tend to look more
meaningful when coming back to a config after some time :-) .
IIRC, one issue with the old design is using single lock for all pipes.
The advantage was using static indexing, therefore faster access (still
under one lock). The new one has a lock per slot, so there can be quite
some parallelism of updates/checks, therefore overall could be same
results, tending to be faster with old for low number of pipes and not
so heavy traffic, better with lot of pipes and lot of traffic.
On the other hand, I find useful what Marius proposed as new features.
Cheers,
Daniel
Regards,
Ovidiu Sas
On Fri, Jan 22, 2010 at 6:52 AM, marius zbihlei<marius.zbihlei(a)1and1.ro> wrote:
--
Daniel-Constantin Mierla
* http://www.asipto.com/
Daniel-Constantin Mierla wrote:
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Hi Marius,
Hello,
I am in no way a heavy user of ratelimit, only done a couple of tests using
the TAILDROP algorithm. My primary interest was in extending the cfg
framework from ser to k modules. I have dug around the documentation and
the code so I can say I am familiar with some of the insights.
since you did some updates to this module, I am
opening for debate some
needed enhancements I did during 3.0 testing phase and want to get opinions
how to get in the code repo.
I want to clear some documentation issues first. The ratelimit docs says
the queue/pipe use the ipfw nomenclature.
<quote>
Packets belonging to the same flow are then passed to either of two
different objects, which implement
the traffic regulation:
_pipe_ A pipe emulates a link with given bandwidth, propagation
delay, queue size and packet loss
rate. Packets are queued in front of the pipe as they come
out from the classifier, and
then transferred to the pipe according to the pipe's
parameters.
_queue_ A queue is an abstraction used to implement the WF2Q+
(Worst-case Fair Weighted Fair Queue-ing) Queueing)
ing) policy, which is an efficient variant of the WFQ policy.
The queue associates a _weight_ and a reference pipe to each
flow, and then all backlogged
(i.e., with packets queued) flows linked to the same pipe
share the pipe's bandwidth pro-portionally proportionally
portionally to their weights. Note that weights are not
priorities; a flow with a lower
weight is still guaranteed to get its fraction of the
bandwidth even if a flow with a
higher weight is permanently backlogged.
In practice, _pipes_ can be used to set hard limits to the bandwidth that
a flow can use, whereas _queues_
can be used to determine how different flow share the available bandwidth.
The _pipe_ and _queue_ configuration commands are the following:
</quote>
Practically is a new module I named for now
ratelimit2 and my last idea is
to get it named pipelimit in the trunk.
The reason for a new module are some major changes. The module uses the
same algorithm but its core is overhaul.
- definitions of pipes are loaded from database
- there can be unlimited number of pipes
- pipes are identified by string names
- should be possible to reload pipes at runtime (iirc, not yet in)
- new pipes can be added at runtime
- functions accept variables to identify the pipe
I might add the following nice to have features(provided by implementing
and
extending queues):
- Matching of packets to a specific queue should be done by via regexp, not
only method (ratelimit.c find_queue() method). If you remove queues, then
matching to a specific pipe...
- Add support for weighted queue eg. Specify the same pipe for invite and
register but allow a 25%-75% priorities. I yet don't know if we can have
several queues assigned per pipe. As a comment, ATM I guess queues are only
used to match request to pipes(Say REGISTER and SUBSCRIBE requests go to
pipe 1, INVITEs to pipe 2)
- Also it would be nice to modify rates(bandwidth in ipfw terminology) at
runtime. AFAIK one can only modify algorithm parameters, not the rate. I am
looking into it.
Since I never used queues from this module and
haven't spent time to
understand the concept behind, this functionality is completely missing.
The old module might be good to keep in place, probably many people are
using it in this form. So, proposals? What is the way to go on? Common code
(algorithms) can be made lib at some point.
Hm, I would suggest keeping compatibility between the new module and the
old
and mark the old as obsolete. The alg section is just a few hundred lines,
and the queue functionality isn't yet that advanced(no weights and such),
and could be easily duplicated and extended into the new.
Any ideas?!
Cheers,
Marius
Cheers,
Daniel
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