Aggregating Ports - Dell PowerConnect 5316M User Manual

Aggregating Ports

Port Aggregation optimizes port usage by linking a group of ports together to form a single Link
Aggregated Groups (LAGs). Port Aggregation multiplies the bandwidth between the switch
modules, increases port flexibility, and provides link redundancy. The switch module supports up to
six LAGs per system, and six ports per LAG per switch module.
Each LAG is composed of ports of the same speed, set to full-duplex operations. Ports in a LAG,
can be of different media types (UTP/Fiber, or different fiber types), provided they operate at the
same speed. Fiber ports refer only to internal ports.
Aggregated Links can be assigned manually or automatically by enabling Link Aggregation Control
Protocol (LACP) on the relevant links. The switch module provides LAG Load Balancing based on
both source MAC addresses and destination MAC addresses.
Aggregated Links are treated by the system as a single logical port. Specifically, the Aggregated Link
has similar port attributes to a non-aggregated port, including auto-negotiation, speed, Duplex
setting, etc.
The Ethernet Switch Module supports both static LAGs and Link Aggregation Control Protocol
(LACP) LAGs. LACP LAG negotiate Aggregated Port links with other LACP ports located on a
different switch module. If the other ports are also LACP ports, the Ethernet Switch Module
establish a LAG between them.
NOTE:
Internal Ports cannot be aggregated.
NOTE:
To enable LACP, LACP must be defined for external ports.
Follow these guidelines when adding ports to a LAG:
• There is no Layer 3 interface defined on the port.
• The port does not belong to any VLAN.
• The port does not belong to any other LAG.
• The port is not a mirrored port.
• GVRP is not enabled.
NOTE:
Ports can be configured as LACP ports only if the ports are not part of a previously configured
LAG.
The switch module uses a hash function to determine which frames are carried on which
aggregated-link member. The system uses a hash function to forward frames to aggregated link
members. This hash function statistically load-balances aggregate link member use, and guarantees
no frame reordering. The switch module considers an Aggregated Link as a single logical port.
Each Aggregated Link has an Aggregated Link Port Type, including Gigabit Ethernet ports. Ports
can be added to an Aggregated Link only if they are the same port type. When ports are removed
from an Aggregated Links, the ports revert to the original port settings. To open the Link
Aggregation page, click Switch→ Link Aggregation in the tree view.
Configuring Switch Module Information
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