Concept Guide

Link Aggregation
Unlike IOA Automated modes (Standalone and VLT modes), the IOA Programmable MUX (PMUX) can support multiple uplink LAGs. You
can provision multiple uplink LAGs. The I/O Aggregator auto-congures with link aggregation groups (LAGs) as follows:
• All uplink ports are automatically congured in a single port channel (LAG 128).
• Server-facing LAGs are automatically congured if you congure server for link aggregation control protocol (LACP)-based NIC
teaming (Network Interface Controller (NIC) Teaming).
No manual conguration is required to congure Aggregator ports in the uplink or a server-facing LAG.
NOTE: Static LAGs are not supported on the SMUX Aggregator.
NOTE: In order to avoid loops, only disjoint VLANs are allowed between the uplink ports/uplink LAGs and uplink-to-uplink
switching is disabled.
Supported Modes
Standalone, VLT, PMUX, Stacking
Topics:
• How the LACP is Implemented on an Aggregator
• Link Aggregation Control Protocol (LACP)
• Conguring Auto LAG
• Conguring the Minimum Number of Links to be Up for Uplink LAGs to be Active
• Optimizing Trac Disruption Over LAG Interfaces On IOA Switches in VLT Mode
• Preserving LAG and Port Channel Settings in Nonvolatile Storage
• Enabling LACP link-fallback
• Enabling the Verication of Member Links Utilization in a LAG Bundle
• Monitoring the Member Links of a LAG Bundle
• Verifying LACP Operation and LAG Conguration
• Multiple Uplink LAGs with 10G Member Ports
How the LACP is Implemented on an Aggregator
The LACP provides a means for two systems (also called partner systems) to exchange information through dynamic negotiations to
aggregate two or more ports with common physical characteristics to form a link aggregation group.
NOTE
: A link aggregation group is referred to as a port channel by the Dell Networking OS.
A LAG provides both load-sharing and port redundancy across stack units. An Aggregator supports LACP for auto-conguring dynamic
LAGs. Use CLI commands to display LACP information, clear port-channel counters, and debug LACP operation for auto-congured LAG
on an Aggregator.
The Dell Networking OS implementation of LACP is based on the standards specied in the IEEE 802.3: “Carrier sense multiple access with
collision detection (CSMA/CD) access method and physical layer specications.”
LACP functions by constantly exchanging custom MAC protocol data units (PDUs) across local area network (LAN) Ethernet links. The
protocol packets are only exchanged between ports that you congure as LACP-capable.
31
468 Link Aggregation