DELL N3000 User Manual

Page of 1460
914
Configuring Link Aggregation
Figure 28-1. LAG Configuration
LAGs can be configured on stand-alone or stacked switches. In a stack of 
switches, the LAG can consist of ports on a single unit or across multiple 
stack members. When a LAG members span different units across a stack, 
and a unit fails, the remaining LAG members on the functional units 
continue to handle traffic for the LAG.
Why Are Link Aggregation Groups Necessary?
The primary purpose of LAGs is to increase the overall bandwidth between 
two switches. This is accomplished by effectively aggregating multiple ports 
together that act as a single, logical connection between the two switches.
LAGs also provide redundancy. If a link fails, traffic is automatically 
redistributed across the remaining links.
What Is the Difference Between Static and Dynamic Link Aggregation?
Link aggregation can be configured as either dynamic or static. Dynamic 
configuration is supported using the IEEE 802.3ad standard, which is known 
as Link Aggregation Control Protocol (LACP). Static configuration is used 
when connecting a Dell Networking N2000, N3000, and N4000 series 
switches to an external Gigabit Ethernet switch that does not support LACP. 
One advantage of LACP is that the protocol enables the switch to confirm 
that the external switch is also configured for link aggregation. When using 
static configuration, a cabling or configuration mistake involving the 
N2000/N3000/N4000 switch or the external switch could go undetected and 
thus cause undesirable network behavior. Both static and dynamic LAGs (via 
LACP) can detect physical link failures within the LAG and continue 
forwarding traffic through the other connected links within that same LAG. 
LACP can also detect switch or port failures that do not result in loss of link.