Administrator Guide

Stacking 233
significant portion of the stack capacity will transit stacking links. One
technique for achieving this is to distribute uplinks evenly across the stack vs.
connecting all uplinks to a single stack unit or to adjacent stacking units.
NOTE: Beginning with the 6.5.1 release, any stack containing any N3000 Series switch
(other than the N3048EP-ON) is limited to a maximum of eight units.
Dell EMC Networking N2100-ON Series switches have two fixed stacking
ports in the rear that accept mini-SAS cables. Dell EMC Networking
N3100-ON Series switches support an optional 2x21G or 2x40G stacking
module in the rear slot.
Dell EMC Networking N4000 Series switches support high performance
stacking over front-panel ports, allowing increased capacity to be added as
needed, without affecting network performance and providing a single point
of management. Up to twelve Dell EMC Networking N4000 Series switches
can be stacked using any port as long as the link bandwidth for parallel
stacking links is the same. In other words, all the port types on the Dell EMC
Networking N4000 Series switches can be used for stacking. Additional
stacking connections can be made between adjacent switch units to increase
the stacking bandwidth provided that all redundant stacking links have the
same port speed. It is strongly recommended that the stacking bandwidth be
kept equal across all stacking connections; that is, avoid mixing single and
double stacking connections within a stack. Up to eight redundant stacking
links operating at the same speed can be configured on a Dell EMC
Networking N4000 Series stack unit (four in each direction).
A stack of twelve Dell EMC Networking N4000 Series switches has an
aggregate front panel capacity of 5.760 terabits (not including the 40G ports).
Provisioning for 5% inter-stack capacity requires 280 Gigabit of bandwidth
dedicated to stacking or all four 40G ports plus another twelve 10G ports.
Therefore, it is recommended that operators provision large stacking
topologies such that it is unlikely that a significant portion of the stack
capacity will transit stacking links. One technique for achieving this is to
distribute downlinks and transit links evenly across the stack vs. connecting
all downlinks/transit links to a single stack unit or to adjacent stacking units.
If Priority Flow Control (PFC) is enabled on any port in a Dell EMC
Networking N4000 Series stack, stacking is supported at distances up to 100
meters on the stacking ports. If PFC is not enabled, stacking is supported up