Reference Guide
S-Series Stacking Commands | 1443
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S-Series Stacking Commands
Overview
All commands in this chapter are specific to the S-Series s,  , and   
platforms as indicated by the characters that appear under each of the command 
headers. 
The commands are always available and operational, whether or not the S-Series has 
a stacking module inserted. You can use the commands to pre-configure a switch, so 
that the configuration settings are invoked when the switch is attached to other 
S-Series units. 
For details on using the S-Series stacking feature, the chapter “Stacking S-Series 
Switches” in the
 FTOS Configuration Guide. 
The Dell Force10 operating software (FTOS) commands for data center bridging features include 
802.1Qbb
 priority-based flow control (PFC), 802.1Qaz enhanced transmission selection (ETS), and the 
Data Center Bridging Exchange (DCBX) protocol. CLI commands for individual DCB features are as 
follows:
Switch Stacking an DCB Caveats for the S4820T
The following is a list of behaviors and limitations regarding the use of DCB over S4820T ports 
involved in switch stacking:
• You can enable DCB only on 40 Gig (QSPF+) ports.
• DCB is not supported over any of the 48 RJ-45 10 Gig ports while they are configured in stacking 
mode.
• You cannot configure stacking on any of the 48 RJ-45 10 Gig ports, if DCB is enabled on any of 
the 40 Gig stacking ports.
• If DCB is enabled, it will disable the ability to use any of the 48 10 Gig ports for stacking.
Caution: S4810 and S4820T Stacking cannot be enabled simultaneously with VLT. If both 
are enabled at the same time, unexpected behavior will occur.










