[f-nsp] MLX throughput issues

[Jeroen Wunnink | Hibernia Networks]

The FLS switches do something weird with packets. I've noticed they 
somehow interfere with changing the MSS window size dynamically, 
resulting in destinations further away having very poor speed results 
compared to destinations close by.

We got rid of those a while ago.


On 12/02/15 17:37, nethub at gmail.com wrote:
>
> We are having a strange issue on our MLX running code 5.6.00c.  We are 
> encountering some throughput issues that seem to be randomly impacting 
> specific networks.
>
> We use the MLX to handle both external BGP and internal VLAN routing.  
> Each FLS648 is used for Layer 2 VLANs only.
>
> From a server connected by 1 Gbps uplink to a Foundry FLS648 switch, 
> which is then connected to the MLX on a 10 Gbps port, running a speed 
> test to an external network is getting 20MB/s.
>
> Connecting the same server directly to the MLX is getting 70MB/s.
>
> Connecting the same server to one of my customer's Juniper EX3200 
> (which BGP peers with the MLX) also gets 70MB/s.
>
> Testing to another external network, all three scenarios get 110MB/s.
>
> The path to both test network locations goes through the same IP 
> transit provider.
>
> We are running NI-MLX-MR with 2GB RAM, NI-MLX-10Gx4 connect to the 
> Foundry FLS648 by XFP-10G-LR, NI-MLX-1Gx20-GC was used for directly 
> connecting the server. A separate NI-MLX-10Gx4 connects to our 
> upstream BGP providers.  Customer’s Juniper EX3200 connects to the 
> same NI-MLX-10Gx4 as the FLS648.  We take default routes plus full 
> tables from three providers by BGP, but filter out most of the routes.
>
> The fiber and optics on everything look fine.  CPU usage is less than 
> 10% on the MLX and all line cards and CPU usage at 1% on the FLS648.  
> ARP table on the MLX is about 12K, and BGP table is about 308K routes.
>
> Any assistance would be appreciated.  I suspect there is a setting 
> that we’re missing on the MLX that is causing this issue.
>
>
>
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-- 

Jeroen Wunnink
IP NOC Manager - Hibernia Networks
Main numbers (Ext: 1011): USA +1.908.516.4200 | UK +44.1704.322.300
Netherlands +31.208.200.622 | 24/7 IP NOC Phone: +31.20.82.00.623
jeroen.wunnink at hibernianetworks.com
www.hibernianetworks.com

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