Re: Troubleshoot UDP out-of-sequence

Pavel,

we have a POS OC12, it is a protected SDH circuit, but as far as I am
concerned it's a single path. As for the queues, they all do have the same
marking (and actually are not being QoS anywhere else).

Persio

On Mon, Sep 12, 2011 at 10:05 AM, Pavel Bykov <slidersv_at_gmail.com> wrote:

> With a path that long, I find it unlikely that there isn't more than one
> link at one point or another. How do you figure that there is only one link?
> Do you have back-to-back dark fiber or lambda? Because if you have
> virtualized packet transport, it will most definitely be carried over
> multiple paths. E.g. One mpls vpn link does not mean that mpls transport is
> not redundant somewhere.
>
> If there is really ony one L1/L2 path, it could be caused by the packets
> falling into different queues, yet this is also unlikely, because all
> packets should have the same markings and same L3/L4 information.
>
> What type of transport do you have between Sao Paulo and NY?
>
> On 12.9.2011, at 14:54, Persio Pucci <persio_at_gmail.com> wrote:
>
> > Hi folks,
> >
> > I am having some problems trying to figure out what could be causing UDP
> > packets get out-of-sequence on some multicast streams (market data)
> between
> > Sao Paulo and New York.
> >
> > There is no part of this path with parallel, load-balanced connections,
> > which could be a obvious cause. What else could I check? The packets do
> > arrive, so they are not being dropped on the way, but they arrive out of
> > sequence, being useless to the application.
> >
> > Also, we are monitoring on both ends sniffed data so I know I receive
> them
> > in order in Sao Paulo, but not in New York. This is affecting a really
> small
> > percentage of the data (less than 0,001%), but I believe this should be
> 0,
> > and so do my customers (with reason).
> >
> > Any ideas or tips?
> >
> >
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Received on Mon Sep 12 2011 - 10:25:08 ART