[c-nsp] SPAN destination on oversubscribed module

[Sigurbjörn Birkir Lárusson]

It¹s a given the load coming from other modules would go through the
fabric, whether inter module traffic does depends on which ports you are
using and how SPAN is handled with distributed-forwarding, must admit I¹ve
never given that much thought.

On the 6708 there are two ASICS ,one for port 1,3,5,7 and the other for
2,4,6,8 as I understood it.  Traffic traveling between the ASICs needs to
go through the Fabric, Fabric within the ASIC does not.

I¹m assuming the situation on the 6716 is similar except then probably
with 4 asics instead of 2, so if the mirroring port and the monitoring
ports are all on the same asic, that bandwidth might be freed from going
over the fabric.  I¹d try this in a lab before committing it though, these
cards are a bit dangerous.  Should and does are not the same thing with
the 7600 platform (ever).

Kind regards,
Sibbi

On 9.1.2014 15:10, "Ben Hammadi, Kayssar (NSN - TN/Tunis)"
<kayssar.ben_hammadi at nsn.com> wrote:

>Thanks Phil, 
>
>   The last question is about the effect of the SPAN on fabric load , the
>monitored traffic from other module will cross the fabric on its way to
>the replication engine of module WS-X6716-10T  and contribute on fabric
>load right ? 
>
>Br.
>
>BEN HAMMADI Kayssar
> 
>NOKIA SOLUTION NETWORKS
>Lead Engineer -BroadBand Connectivity
>JNCIE-M (#471), JNCIE-SP (#1147), CCIP
>Mobile : +216 29 349 952  /  +216 98 349 952
>Skype : kayssar ben hammadi
>
>
>-----Original Message-----
>From: cisco-nsp [mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of
>ext Phil Mayers
>Sent: Thursday, January 09, 2014 3:57 PM
>To: cisco-nsp at puck.nether.net
>Subject: Re: [c-nsp] SPAN destination on oversubscribed module
>
>On 09/01/14 14:47, Ben Hammadi, Kayssar (NSN - TN/Tunis) wrote:
>> Dears ,
>>
>> We have two 6509 interconnected via port-channel of two 10Ge port
>> carrying about 3Gb. the module used is WS-X6716-10T and only the two
>> mentioned port are used on this module for the moment . We are now
>> adding a monitoring probe that will be connected on this module , the
>> estimated monitored traffic is about 8Gb . Since this module has an
>> oversubscription rate of 4:1 , i need to check :
>
>You need to be really careful with this on a 6716. As you have hinted,
>you absolutely can blow away production traffic.
>
>>
>> *       On witch port it is recommended to connect the new probe
>> without affecting the port channel
>
>An unused port-group, or one with <2Gb/sec of TX traffic.
>
>> *       can one port on this module reach 8Gb of monitored traffic
>
>Yes, but only if the 4-port port-group has 8Gbit/sec of TX capacity.
>
>> *       the monitored traffic will be added to the actual Swicth load
>> or it is transparent ?
>
>Not sure what this means.
>_______________________________________________
>cisco-nsp mailing list  cisco-nsp at puck.nether.net
>https://puck.nether.net/mailman/listinfo/cisco-nsp
>archive at http://puck.nether.net/pipermail/cisco-nsp/
>
>_______________________________________________
>cisco-nsp mailing list  cisco-nsp at puck.nether.net
>https://puck.nether.net/mailman/listinfo/cisco-nsp
>archive at http://puck.nether.net/pipermail/cisco-nsp/