Dell PS4000 Configuration Manual page 50

Blade I/O connection guidelines:

Aggregate at least two 1GbE ports from each blade I/O module stack for redundancy
Configurations will be limited to one active link aggregation group per I/O module stack
o
due to rapid spanning tree protocol restrictions.
Link aggregation groups will typically contain a maximum size permitted by switch and/or
o
I/O module vendor (typically eight 1GbE links).

Distribute links amongst multiple switches within each I/O module stack if supported
When the blade solution consists of more than one M1000e enclosure, the 1GbE ports used for
up-linking should be distributed between multiple enclosures to protect against a complete
enclosure failure.

Distribute links evenly between all switches within the external switch stack if supported
When the external switch stack consists of more than one switch, the 1GbE ports used for up-
linking should be distributed between all switches in the external switch stack to protect
against a switch failure.

Use Switch vendor preferred method for link aggregation (if all switches from same vendor)
Some switch vendors have proprietary or enhanced link aggregation protocols. For example,
Cisco supports Port Aggregation Protocol (PAgP) that contains advanced management features.

Use LACP as method for link aggregation when I/O modules and external switches are from
different vendors
The industry standard link aggregation protocol is IEEE 802.3ad, also known as the Link
Aggregation Control Protocol (LACP). LACP is typically the only method for creating link
aggregation groups that can link switches from multiple vendors.
Figure 19 shows how to link the M1000e enclosures using I/O modules connecting to an external switch
stack consisting of Dell PowerConnect 62XX model switches.
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