How to Set Up Link Aggregation on a Synology NAS

Link aggregation, also known as port trunking or bonding, allows you to combine multiple network interfaces into a single logical interface. This can provide increased bandwidth, redundancy, and load balancing across your network.

In this comprehensive guide, I‘ll walk you through the entire process of setting up link aggregation on a Synology NAS, including:

1. Understanding the Benefits Link Aggregation
2. Network Hardware and Cabling Requirements
3. Link Aggregation Concepts and Modes
4. Configuring Switch Ports
5. Creating Load Balancing Aggregated Links
6. Setting up Active/Backup Bonds for Redundancy
7. Troubleshooting Tips for Link Aggregation
8. Monitoring and Maintaining Bonded Links

The Benefits of Link Aggregation

There are several key benefits to using link aggregation:

Increased Bandwidth – By combining two or more 1GbE interfaces with a aggregated logical port, total throughput can be multiplied, providing significantly faster file transfers.

Redundancy – In active/backup mode, automated failover prevents loss of connectivity if a component interface fails.

Load Balancing – Outbound network traffic is algorithmically divided across component links to optimize usage.

Cost Savings – LACP aggregated links make more efficient use of existing interfaces versus upgrading to faster Post-Gigabit Ethernet speeds.

So in summary, properly configured link aggregation provides superior bandwidth utilization, redundancy safeguards, and increased value from existing network infrastructure.

Network Hardware and Cabling Requirements

Creating aggregated links between your Synology NAS and Ethernet switch requires:

• Compatible Ethernet switch – Managed switches support port trunking protocols like LACP or static link aggregation.
• Synology NAS model – Most modern Synology devices have 2+ Ethernet ports capable of bonding.
• Appropriate cables – Use CAT 5e patch cables or above for 1GbE connectivity.
• Network card compatibility – For endpoint connectivity, verify Windows, Linux, or Mac Aggregation support.

With supported hardware on both ends, you can begin trunking individual links between the switch and NAS device.

Understanding Link Aggregation Concepts

Before diving into the configuration, let‘s briefly discuss some concepts that underpin aggregated links:

• Link aggregation standards – The IEEE 802.1ax standard provides the LACP framework for automating bundled Ethernet ports. Link Aggregation Control Protocol dynamically manages aggregated interfaces by negotiating parameters, detecting errors, and handling membership adjustments. Static trunking configures multi-port links without this automation.

• Link aggregation modes – Two main implementations of LACP bonds exist. Balance XOR load balances traffic by source/destination IP address or MAC address across all links. Active/backup mode utilizes one interface for all traffic while others serve as automatic failover backups if the primary goes down.

Understanding these key concepts will be helpful when configuring switch aggregation and selecting modes on your Synology NAS.

Configuring Ethernet Switch Ports

The first step in creating an aggregated link is to configure trunking on your Ethernet switch‘s ports. The exact steps depend on the make and model:

Cisco Switch Aggregation Configuration

1. Use interface range command to specify switch ports – e.g. int range gi1/0/5-8
2. Assign ports to new LAG group – e.g. channel-group 2 mode active
3. Set LACP rate fast if supported for better redundancy

interface range gi1/0/5-8
channel-group 2 mode active 
lacp rate fast

Netgear Smart Switch LAG Configuration

1. Select Group tab and click Create LAG
2. Choose LACP trunk type and ports to group – e.g gi1-gi4
3. Save settings

Determine which physical switch ports connect to your Synology device via Ethernet cables. Group these into a new LAG supporting LACP. This readies the switch side to begin supporting aggregated links.

Creating a Load Balancing Bond on Synology

Once LACP is enabled on the switch ports, you can create a matching aggregated interface on your DiskStation using Synology DSM:

1. Login to DSM, navigate to Control Panel > Network
2. Select the Network Interface tab
3. Click on Create > Create Bond
4. Choose the Balance-SLB mode
5. Select appropriate physical ports – e.g. LAN 1 – LAN 4
6. Configure IP address and interface settings
7. Save the new bonding interface (e.g. Bond0)

This equally load balances traffic across all included Ethernet ports to enhance bandwidth utilization between your NAS and network switch. Balance-XOR, Balance-TLB, IEEE 802.3ad, and Adaptive Load Balancing offer additional distribution options if needed.

By leveraging multiple ports concurrently between devices in this active-active configuration, you can achieve links beyond 1GbE speeds.

Setting Up an Active/Backup Bond

To prioritize fault tolerance rather than overall throughput, you can create Synology bonds using:

Active/Backup Mode

This designates one interface as primary and active, while remaining ports act as backups from the bonding group:

• If primary link fails, backups instantly take over
• No risk of switching issues bringing down connectivity
• Fully passive ports don‘t transmit data unless activated

To set this up on your NAS:

1. Go to Control Panel > Network in DSM
2. Navigate to Network Interface
3. Select Create > Create Bond
4. Choose Active Backup (ALB) mode
5. Add Ethernet ports and finish configuration

Now your DiskStation can sustain link failures by leveraging pooled redundancy capacity!

Active/Active Mode

In this mode, all interfaces simultaneously handle outbound communications. If any link goes down, redistribution across remaining ports occurs automatically:

• Maximizes throughput by concurrently utilizing bundled links
• Loss of any interface prompts immediate failover adjustment

This is most comparable to balance-SLB bonding, just with explicit handling of component failure.

Choose the right approach based on if your priorities are redundancy or pushing maximum performance.

LACP Aggregation Troubleshooting

Despite correct settings on both ends, aggregated links occasionally encounter issues:

• Verify consistent LACP configurations between devices
• Check if port-channels are wrongly bundled between switches
• Force LACP renegotiations or toggle interfaces
• Rule out bad transceivers or SFPs
• Test failover behavior by unplugging Ethernet cables
• Monitor port counters for increments on inactive links

Also here are answers to common FAQs:

Why are my bonded NAS speeds equal to just one link?

Check load balancing algorithm matches the switch trunking mode. Mispairing can lead to uneven distribution or premature failover.

I‘m getting LACP errors about mismatched system priorities. How is this resolved?

The system priority value controls which peer dictates final port configurations. Set this explicitly on switches and NAS devices to coordinate correctly.

With consistent troubleshooting methodology, you can identify and resolve most linked aggregation problems that arise in complex network environments.

Monitoring and Maintaining Bonds

Once your aggregated links are properly passing traffic, continue monitoring their status:

• Perform periodic failover testing – Intentionally trigger port failures to validate redundancy.
• Check link utilization – Interface counters should show relatively even loads.
• Watch for negotiated hasth parameter changes – This can indicate bonding instability.
• Upgrade firmware – Keep NAS and switch firmware up to date to benefit from aggregation bug fixes or feature improvements.

Proactively maintaining the components and configuration integrity of your LACP links is key to sustaining maximum uptime.

Conclusion

Setting up link aggregation with your Synology NAS provides measurable bandwidth improvements while adding port redundancy protections. Just be sure to carefully configure your Ethernet switches first before matching LACP settings on the NAS itself.

The ability to bond multiple physical links to operate as one always-available logical interface delivers usefulness across many applications – especially on busy home and office networks.

Let me know in the comments if you have any other questions!