[f-nsp] Packetloss on MLX-4

[Justin Keery]

Do you have any broadcast limiting (storm control) applied?

On other vendors' switches we find that excessive broadcast filtering can
cause this kind of thing.

Also it could be an inconsistency between MAC and ARP timeouts


*Justin Keery, Director*
Venus Business Communications Ltd
*FAST FIBRE INTERNET AND ETHERNET PRIVATE NETWORKS*
24 Denmark St, London WC2H 8NJ

 VENUS
020 7240 5858
07976 153 984
www.venus.co.uk




On 12 February 2014 14:56, Rogier van Eeten <rogier at virtunix.nl> wrote:

> Greetings,
>
> We've got the following setup:
>
>
> [ other AS ]
>     |
> [ mlx-4 ] -- [ icx6430 ] -- (cloud) -- [ customer ]
>     |
> [ server ]
>
>
> The mlx has a bgp session with the other AS and with the customer. The
> server and other AS can reach each other, the customer and the server can
> reach each other and the other AS and customer can reach each other.
> This setup is duplicated many times, with different servers and different
> customers.
>
> From time to time a server gets unreachable from the customer and vice
> verse. The other AS can still reach the server and the customer.
>
> I made a port-mirror of the ports on the mlx-4 and the icx6430 that face
> each other and captured the data going through. Although there's nothing
> between the two devices, except for a direct patch, I see packets on the
> icx, that I don't see on the mlx. The packetloss is not random, so it's not
> a problem in the cable. When I ping the customer from the other AS and the
> server, I see the reply packets for both on the icx, but only for the other
> AS on the mlx.
>
> So, the problem isn't at the customer, the routing on their side still
> works. Somehow the mlx is dropping packets, but I have no idea why. It's
> not always the same customer where the problem occurs and we couldn't find
> anything that triggers this event.
>
> Now the weirdest part. To "fix" the problem, it helps to change the
> mac-address of the server. In some cases it also helped to do 'show
> mac-address' on the mlx.
>
> Does anyone have an idea where to look?
>
>
> Thanks in advance,
> Rogier
>
> _______________________________________________
> foundry-nsp mailing list
> foundry-nsp at puck.nether.net
> http://puck.nether.net/mailman/listinfo/foundry-nsp
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://puck.nether.net/pipermail/foundry-nsp/attachments/20140212/40b2852d/attachment.html>