Link-Aggregation Modes

Backup mode

Backup mode is one of the link-aggregation methods, where one link is designated as the primary (active) link, and the others act as backups (standby). Normally, all network traffic flows through the primary link. If the primary link fails, a backup link automatically takes over, ensuring continuous network connectivity.

Broadcast mode

Balance mode is one of the link-aggregation methods, that distributes network traffic evenly across all available member links in an aggregation group. This helps optimize bandwidth usage and improves overall network performance by preventing any single link from becoming a bottleneck. Hashing on the on the header of the packet decides which part to assign.

Balance mode

Balance mode is one of the link-aggregation methods, that distributes network traffic evenly across all available member links in an aggregation group. This helps optimize bandwidth usage and improves overall network performance by preventing any single link from becoming a bottleneck. Hashing on the on the header of the packet decides which part to assign.

LACP mode

LACP mode is a link-aggregation method that enables multiple physical Ethernet links to combine into a single logical link and provides redundancy. These protocols increase network bandwidth and provide redundancy.

Benefits

This reference provides the key benefits of link aggregation technology for network infrastructure.

  • Increased Reliability: Multiple network links are combined, so network connectivity is maintained even if one or more links fail.

  • Redundancy: Backup paths for data transmission are automatically provided, significantly reducing the risk of network downtime.

  • Simplified Management: Aggregated links are managed as a single logical connection, streamlining configuration and ongoing management tasks.

  • Scalability: Network capacity can be easily expanded by adding more links to the aggregation group, supporting growing traffic demands.

  • Flexibility: Link aggregation can be configured to meet different networking needs such as load balancing, high availability, or ensuring reliable data delivery, depending on the selected mode.

Requirements for link aggregation deployment

Ensure that all prerequisites are met before deploying link aggregation to guarantee stable and consistent network performance.

  • Compatible Network Devices: Both ends of the aggregated links (such as switches, routers, or servers) must support link aggregation and the specific aggregation mode you plan to deploy.

  • Uniform Link Speed and Duplex Settings: All physical links within the aggregation group must operate at the same speed (for example, 1 Gbps or 10 Gbps) and have matching duplex settings to ensure stable and consistent performance.

  • Port Availability: Ensure that enough free ports are available on both devices to create the desired aggregation group.

  • LACP Support and Configuration: Both devices should support IEEE 802.3ad (Link Aggregation Control Protocol, or LACP). LACP must be enabled on both devices when using this dynamic aggregation mode.

Configure backup mode using CLI

This task enables a backup mechanism for link aggregation, ensuring network resilience and continued operation in case of primary link failure.

This procedure outlines the steps to configure and apply backup mode settings using the CLI, that is crucial for maintaining network availability and stability.

Procedure

SUMMARY STEPS

  1. Use the ethernet link-aggregation backup command to configure backup mode on the device.
  2. Use the write command to apply the current configuration settings to the device.
  3. Use the reboot command to restart the device.

DETAILED STEPS

Step 1

Use the ethernet link-aggregation backup command to configure backup mode on the device. 

Device# ethernet link-aggregation backup

Step 2

Use the write command to apply the current configuration settings to the device. 

Device# write

Step 3

Use the reboot command to restart the device. 

Device# reboot

Configure broadcast mode using CLI

Configure the broadcast mode to define how broadcast traffic is handled across the aggregated Ethernet link.

Use this procedure to configure broadcast mode settings on your device using the command-line interface.

Procedure

SUMMARY STEPS

  1. Use the ethernet link-aggregation broadcast command to configure broadcast mode on the device.
  2. Use the write command to apply the current configuration settings to the device.
  3. Use the reboot command to restart the device.

DETAILED STEPS

Step 1

Use the ethernet link-aggregation broadcast command to configure broadcast mode on the device. 

Device# ethernet link-aggregation broadcast

Step 2

Use the write command to apply the current configuration settings to the device. 

Device# write

Step 3

Use the reboot command to restart the device. 

Device# reboot

Configure balance mode using CLI

Perform this task to effectively configure the balance mode on your device. This process allows you to optimize network traffic distribution across aggregated links, enhancing bandwidth utilization and providing redundancy.

Configure the balance mode to distribute network traffic across aggregated links, optimizing bandwidth utilization and providing redundancy.

Procedure

SUMMARY STEPS

  1. Use the ethernet link-aggregation balance command to configure balance mode on the device.
  2. Use the ethernet link-aggregation balance policy command to configure any specific policy on the balance mode of the device.
  3. Use the write command to apply the current configuration settings to the device.
  4. Use the reboot command to restart the device.

DETAILED STEPS

Step 1

Use the ethernet link-aggregation balance command to configure balance mode on the device.

Example:

Device# ethernet link-aggregation balance

Step 2

Use the ethernet link-aggregation balance policy command to configure any specific policy on the balance mode of the device.

Example:

Device# ethernet link-aggregation balance policy
l2   l2 policy: src_mac XOR dst_mac
l23  l23 policy: src_mac XOR dst_mac XOR src_ip XOR dst_ip
l34  l34 policy: src_ip XOR dst_ip XOR src_port XOR dst_port

Note

 

  • The l2 policy operates at Layer 2, using source and destination MAC addresses.

  • The l23 policy operates at Layer 2 and Layer 3, using source and destination MAC and IP addresses.

  • The l34 policy operates only on IP traffic, supporting data transfer through TCP or UDP ports. It does not accept Ethernet traffic.

Policy options are same for both balance and LACP modes.

Step 3

Use the write command to apply the current configuration settings to the device. 

Device# write

Step 4

Use the reboot command to restart the device. 

Device# reboot

Configure LACP mode using CLI

Use this procedure to enable and customize LACP on your device, which improves network performance and redundancy.

This procedure guides you through configuring LACP mode and its associated load-balancing policies using the CLI.

Procedure

Step 1

Use the ethernet link-aggregation lacp command to configure LACP mode on the device.

Example:

Device# ethernet link-aggregation lacp

Step 2

Use the ethernet link-aggregation lacp policy command to configure any specific policy on the lacp mode of the device.

Example:

Device# ethernet link-aggregation lacp policy
l2   l2 policy: src_mac XOR dst_mac
l23  l23 policy: src_mac XOR dst_mac XOR src_ip XOR dst_ip
l34  l34 policy: src_ip XOR dst_ip XOR src_port XOR dst_port

Note

 

  • The l2 policy operates at Layer 2, using source and destination MAC addresses.

  • The l23 policy operates at Layer 2 and Layer 3, using source and destination MAC and IP addresses.

  • The l34 policy operates only on IP traffic, supporting data transfer through TCP or UDP ports. It does not accept Ethernet traffic.

Policy options are same for both balance and LACP modes.

Step 3

Use the write command to apply the current configuration settings to the device. 

Device# write

Step 4

Use the reboot command to restart the device. 

Device# reboot