This article explains how to create and manage Link Aggregation (LAG) on a Dell Networking X Series Switch
Objectives
- Overview
- LAG Membership
- VLAN LAG Settings
Overview
Link Aggregation optimizes port usage by linking a group of ports together to form a single Link Aggregation Group (LAG). Aggregating ports multiplies the bandwidth between two devices, increases port flexibility, and provides link redundancy.
Ports added to a LAG lose their individual port configuration. When ports are removed from the LAG, the original port configuration is applied to the ports.
The device uses a hash function to assign packets to a LAG member. The hash function statistically load-balances the aggregated link members. The device considers a LAG to be a single logical port.
Aggregate ports can be linked into link-aggregation port-groups. Each group comprises ports with the same speed, set to full-duplex operations.
The device supports the following types of LAGs:
- Static LAGs - Manually configured LAGs.
- Link Aggregation Control Protocol (LACP) LAGs - LACP LAGs negotiate aggregating a port's links with other LACP ports located on a different device. If the other device ports are also LACP ports, the devices establishes a LAG between them.
LAG Membership
Each device supports up to 12 LAGs per system, and eight ports per LAG.
When you add a port to a LAG, the port acquires the LAG's properties. If the port cannot be configured with the LAG's properties, it is not added to the LAG and an error message is generated.
If the first port joining the LAG cannot be configured with the LAG settings,the port is added to the LAG, using the port default settings, and an error message is generated. Since this is the only port in the LAG, the entire LAG
operates with the port's settings, instead of the LAG's defined settings.
To manually select ports that comprise a LAG:
- Click Network Administration > Spanning Tree and LAG > Link Aggregation (LAG)
- Click Edit to the right of LAG Membership.
- In the drop down menu next to LAG, Select a LAG (LAG1-12).
- Select whether it is a Standard (user-defined LAG) or an LACP-defined LAG. The port will turn yellow if LACP is set correctly.
- Click on the ports that will comprise the LAG.
- Click OK
VLAN LAG Settings
VLANs can either be composed of individual ports or of LAGs. Untagged packets entering the device are tagged with the LAGs ID specified by the PVID.
To assign LAGs to a VLAN:
1 Click Network Administration > Spanning Tree and LAG > Link Aggregation (LAG) > VLAN LAG Settings.
All LAGs and their settings are displayed.
2 Click Edit, select a LAG, click its Edit icon and enter the fields:
- LAG - Displays the LAG to be modified.
- Switchport Mode - Enter the LAG system mode. The possible options are:
- Layer 2 - Set the LAG to layer 2 mode.
- Layer 3 - Set the LAG to layer 3 mode. in which static routing is supported.
- Port VLAN Mode - Enter the port VLAN mode. The possible options are:
- General - The port belongs to VLANs, and each VLAN is user-defined as tagged or untagged (full 802.1Q mode).
- Access - The port belongs to a single untagged VLAN. When a port is in Access mode, the frame types that are accepted on the port cannot be designated. Ingress filtering cannot be enabled/disabled on an access port.
- Trunk - The port belongs to VLANs on which all ports are tagged (except for one port that can be untagged).
- Customer - When a port is in Customer mode, an added tag provides a VLAN ID to each customer, ensuring private and segregated network traffic for that customer.
- Private VLAN Promiscuous - The port is a promiscuous port.
- Private VLAN Host - The port is an isolated port
- Current Reserved VLAN - Displays the VLAN currently designated as the reserved VLAN.
- Reserve VLAN for Internal Use (1-4094) - Enter the VLAN that will be used when assigning IP Address on a port, or select None.
- PVID - Assigns a VLAN ID to untagged packets. The possible VLAN IDs are 1-4095. VLAN 4095 is defined as per standard and industry practice, as the discard VLAN. Packets classified to this VLAN are dropped.
- VLAN List - Enter the VLAN(s) to which this LAG belongs. Click Add/Remove to move the LAG to the VLAN list together with its type.
- Membership - Packet tagging on VLAN. The possible options are:
- Tagged - The LAG is a member of a VLAN. All packets
forwarded to the LAG are tagged. The packets contain VLAN
information.
- Untagged - The LAG is a member of a VLAN. Packets forwarded
to the LAG are untagged.
- Forbidden - The LAG is denied membership to a VLAN.
- Frame Type - Packet type accepted by the LAG. The possible options are:
- Admit All - Tagged and untagged packets are both accepted by the LAG.
- Admit Tagged Only - Only tagged packets are accepted by the LAG.
- Admit Untagged Only - Only untagged packets are accepted on the LAG.
- Ingress Filtering - Enable/disable Ingress filtering by the LAG. Ingress filtering discards packets that are destined to VLANs of which the specific LAG is not a member.
- Native VLAN ID - Enter VLAN used for untagged traffic to trunk ports, or select None.
- Multicast VLAN ID - Enter VLAN used for Multicast TV VLAN traffic on access ports, or select None.
- Customer VLAN ID - Enter VLAN used for customer ports, or select None.