Switching fabric capabilities

Switching fabric capabilities

The following table summarizes requirements for the switching fabric capabilities:

Switch fabric capabilities summary
Name of requirement Description
LACP TCP/UDP hash balance mode Level 4 LACP hash balance mode is recommended to support services that employ TCP sessions. This helps to avoid fragmentation and asymmetry in traffic flows.
Multihome server connection support

There are two major options to support multihomed server connections:

  • Switch stacking

    Stacked switches work as a single logical unit from configuration and data path standpoint. This allows you to configure IP default gateway on the logical stacked switch to support multi-rack use case.

  • Multipath Link Aggregation Groups

    MLAG support is recommended to allow cross-switch bonding across stacked ToR switches. Using MLAG allows you to maintain and upgrade the switches separately without network interruption for servers. In case of PXE networks, the LACP fallback must be enabled on the switch so that servers can PXE boot without having LACP configured.

LAG/port-channel links The number of supported LAGs/port-channel links per switch must be twice the number of ports. Take this parameter into account so that you can create the required number of LAGs to accommodate all servers connected to the switch.


LACP configurations on access and server levels must be compatible with each other. In general, it might require additional design and testing effort in every particular case, depending on the models of switching hardware and the requirements to networking performance.