NetScaler Appliances negotiates to “Half-Duplex” for 100 Mbps Speed only…

Today I’d like to share another interesting gotcha while setting up NetScaler Link-Aggregation (LA) channels with network switches. My customer had all their perimeter network infrastructure “managed” by a 3rd Party Supplier and these “managed” switches in the DMZ, were only capable of doing 100-Full-Duplex ether-channels!!

On the surface, this seemed like a relatively easy task and all I’d to do was to set the NetScaler’s Link-Aggregation channel to 100 Mbps (Speed) and FULL (Duplex) setting. But guess what – NetScaler didn’t play ball! It was negotiating at 100-HALF speed/duplex.

I must admit that this trivial task took me to verge of pulling all my hair out! 🙂

Was it the "dodgy cable", or the "Service Provider's invalid Ether-Channel Config" or "NetScaler"??

Apparently, it was the NetScaler configuration. By default, the NetScaler does “Auto-Negotiation” and even if you explicitly set an interface to FULL DUPLEX and 100 Mbps SPEED Setting – it doesn’t apply unless you pass the parameter (-AUTONEG DISABLED).

> set interface LA/1 -autoneg DISABLED -speed 100 -duplex FULL

Hope this helps in your exciting journey of deploying Citrix NetScalers.

P.S. The AUTONEG parameter can't be passed while using >Set Channel LA/1 commands.


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