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MVP
Posts: 4,272
Registered: ‎07-20-2011

VLAN Pooling hash vs even

 

 

I was wondering what is the difference between the VLAN Pooling hash / even ?

 

Thanks

 

Vic

Thank you

Victor Fabian
Lead Mobility Engineer @ Integration Partners
AMFX | ACMX | ACDX | ACCX | CWAP | CWDP | CWNA
Guru Elite
Posts: 21,031
Registered: ‎03-29-2007

Re: VLAN Pooling hash vs even

Vlan pooling is load balancing devices into multiple VLANs.  Hashing or pooling is the mechanism that determines who ends up in what VLAN.

 

Pooling will choose the next Vlan a device ends up in, round-robin style.  Hashing is deterministic and ensures that the same device will end up in the same VLAN every time.



Colin Joseph
Aruba Customer Engineering

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Aruba Employee
Posts: 20
Registered: ‎01-23-2012

Re: VLAN Pooling hash vs even

Hi,

 

My understanding is that with very large Wireless LAN infrasturctures, it's better using the hash mechanism. When using the pooling mechanism, this implies building a lookup table to associate each client MAC Address to the VLAN where it is assigned. However, this also implies looking up in this table for every packet... This is not efficient.

 

The hash mechanism is much more efficient. However, you may end up with Wireless LAN clients not evenly distributed between your VLANs as this mechanism depends on the hash algorithm and the client MAC Address. Consequently, you may want to closely whatch IP utilisation for each VLAN and create more VLANs/subnets when required.

 

Best regards,

 

Paul Gallant. Eng.
CWNA, CWSP
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