Link Aggregation: what to consider?

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Link Aggregation: what to consider?

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I would like to bond LAN 1 and LAN 2 on my Syno DS920+ to speed up the connection and more. At the moment the NAS is connected to a switch through LAN 1.

As far I understood (please correct me if I'm wrong) I need to connected another LAN cable to the Syno e Switch and then follow this:


There is something I have to consider? Do I have to define another static IP address than the one I am using now? At the moment I have something like 192.168.1:3031

- I have defined a static IP address for LAN 1 in DSM
- I mapped the shared folder on my Mac like this: afp://192.168.1:3031
- The router defined a static IP address for the NAS
- Sometimes I need to connect via VPN when I'm not in the office

Many thanks in advance
 
In general, each LAN adapter will have its own IP. After the bond has been made you will configure it to any IP address you want and automatically it will take over your initial LAN1 IP address.

The idea behind LAG is to help you with concurrent access from multiple clients. It will not upgrade your speed from single client access to your nas even if that client is also on an aggregated link. It will still use a single lane inside the LAG, in this case, 1G.

There is something I have to consider?
You will need to have a switch that support LAG configuration.
 
There are two groups of LAG and which group you have access to depends on if you've enabled vSwitch (needed for Virtual Machine Manager).

  1. Without vSwitch emabled:​

    • Adaptive Load Balancing: This mode optimizes the network traffic received and sent by your Synology NAS whether or not the switch supports Link Aggregation. To avoid unexpected errors, please do not enable Link Aggregation on the switch even when it is supported.
    • IEEE 802.3ad Dynamic Link Aggregation: This mode optimizes the network traffic received and sent by your Synology NAS, and requires IEEE 802.3ad (Dynamic) Link Aggregation (LACP, 802.1AX) to be enabled on the switches. If multiple switches are used, these switches have to be stackable and properly configured.
    • Balance XOR: This mode balances the network traffic received and sent by your Synology NAS, and requires Static Link Aggregation to be enabled on the switches. If multiple switches are used, these switches have to be stackable and properly configured. If Link Aggregation is not supported by the switch, the traffic sent by your Synology NAS can still be balanced. With this mode, the lost links can be detected but not the cause (e.g., when the Ethernet cables are unplugged or the switch is wrongly configured).
    • Active/Standby: This mode provides your Synology NAS with network fault tolerance. That is, when the active network interface goes down, one of the other LAN ports will take over to maintain the network connection. You can choose this mode without configuring the switch or with a switch that supports IEEE 802.3ad Link Aggregation.

    With vSwitch enabled:​

    • Balance-SLB: This mode balances the network traffic without requiring the support for specific network switches and enables the connection between two switches.
    • Balance-TCP: This mode enables the connection with the switches configured as Dynamic Link Aggregation (IEEE 802.3ad LACP). If multiple switches are used, they must be stackable and properly configured.
    • Active/Backup Mode: This mode provides your Synology NAS with network fault tolerance using two network interfaces. When the active network interface malfunctions, the other one will take over to maintain the network connectivity. You can choose this mode without configuring the switch.

If you have an unmanaged switch then your options are limited to either Adaptive Load Balancing or Balance-SLB. It works well and there's zero switch configuration (even if you do use a managed switch). I used to do this with with a TP-Link Easy Smart 8-port switch and my DS1520+.

If you have a managed switch that supports IEEE 802.3ad / 802.1AX then you have more options: IEEE 802.3ad Dynamic Link Aggregation and Balance-TCP. But this does require you to setup the dynamic LAG on the switch. I now use this with a TP-Link managed switch and the DS1520+.

As I've vSwitch enabled I haven't tried Balance XOR, which sounds like static LAG and may be supported by my Easy Smart switch, and I've not considered using active/backup LAG.



So what's the difference between Adaptive Load Balancing and dynamic LAG? Well that's a hard one to google but I'm leaning towards this:
  • ALB will share the links to between the connected clients but a client can't span links. So two links and three clients could have one client with a 1G connections and the other two would have up to 500M each.
  • Dynamic LAG is similar but the three clients could get a better share of the connections, up to 1G.

Probably wrong but it's where I stopped caring. My main reason to use LAG was to allow better uploads for various devices doing concurrent Time Machine and AB4B.

I've done a static LAG of two ports between the two switches and this forms the link between the RT2600ac LAN and MR2200ac backhaul.
 
There are two groups of LAG and which group you have access to depends on if you've enabled vSwitch (needed for Virtual Machine Manager).

  1. Without vSwitch emabled:​

    • Adaptive Load Balancing: This mode optimizes the network traffic received and sent by your Synology NAS whether or not the switch supports Link Aggregation. To avoid unexpected errors, please do not enable Link Aggregation on the switch even when it is supported.
    • IEEE 802.3ad Dynamic Link Aggregation: This mode optimizes the network traffic received and sent by your Synology NAS, and requires IEEE 802.3ad (Dynamic) Link Aggregation (LACP, 802.1AX) to be enabled on the switches. If multiple switches are used, these switches have to be stackable and properly configured.
    • Balance XOR: This mode balances the network traffic received and sent by your Synology NAS, and requires Static Link Aggregation to be enabled on the switches. If multiple switches are used, these switches have to be stackable and properly configured. If Link Aggregation is not supported by the switch, the traffic sent by your Synology NAS can still be balanced. With this mode, the lost links can be detected but not the cause (e.g., when the Ethernet cables are unplugged or the switch is wrongly configured).
    • Active/Standby: This mode provides your Synology NAS with network fault tolerance. That is, when the active network interface goes down, one of the other LAN ports will take over to maintain the network connection. You can choose this mode without configuring the switch or with a switch that supports IEEE 802.3ad Link Aggregation.
    • With vSwitch enabled:
    • Balance-SLB: This mode balances the network traffic without requiring the support for specific network switches and enables the connection between two switches.
    • Balance-TCP: This mode enables the connection with the switches configured as Dynamic Link Aggregation (IEEE 802.3ad LACP). If multiple switches are used, they must be stackable and properly configured.
    • Active/Backup Mode: This mode provides your Synology NAS with network fault tolerance using two network interfaces. When the active network interface malfunctions, the other one will take over to maintain the network connectivity. You can choose this mode without configuring the switch.

If you have an unmanaged switch then your options are limited to either Adaptive Load Balancing or Balance-SLB. It works well and there's zero switch configuration (even if you do use a managed switch). I used to do this with with a TP-Link Easy Smart 8-port switch and my DS1520+.

If you have a managed switch that supports IEEE 802.3ad / 802.1AX then you have more options: IEEE 802.3ad Dynamic Link Aggregation and Balance-TCP. But this does require you to setup the dynamic LAG on the switch. I now use this with a TP-Link managed switch and the DS1520+.

As I've vSwitch enabled I haven't tried Balance XOR, which sounds like static LAG and may be supported by my Easy Smart switch, and I've not considered using active/backup LAG.



So what's the difference between Adaptive Load Balancing and dynamic LAG? Well that's a hard one to google but I'm leaning towards this:
  • ALB will share the links to between the connected clients but a client can't span links. So two links and three clients could have one client with a 1G connections and the other two would have up to 500M each.
  • Dynamic LAG is similar but the three clients could get a better share of the connections, up to 1G.

Probably wrong but it's where I stopped caring. My main reason to use LAG was to allow better uploads for various devices doing concurrent Time Machine and AB4B.

I've done a static LAG of two ports between the two switches and this forms the link between the RT2600ac LAN and MR2200ac backhaul.
Thanks for the detailed infos!

Do I see which option is better for my switch by simply plug in the LAN 2 into it? Or do I have to found it out on the Switch website?
 
If you have a basic switch then attach two ethernet cables between the NAS and two ports on the switch. Then create a bond and select whichever of ALB or Balance-SLB is offered.

The bond will be pre-configured using LAN 1's settings. When you delete the bond then AN 2 will revert to its previous network settings.
 
I don't have a router or switch that supports LACP so I need to use ALB. But I do have a question about the physical connections. Is it best in this case to have both ports of the Synology going to the router, the switch, or one to each?

Thanks!
 
I jus saw your same post on the Lawrence System's forum. For aggregation purposes you should have both going to a switch that supports aggregation groups. In most cases aggregation groups are bound to the domain of the switch itself. I have mine setup on a 16 port Unifi switch with aggregation group for my Synology to handle multiple users doing file based activities. You won't get double the bandwidth but you will get more capacity to support users.
 
Adaptive Load Balancing doesn't need any switch configuration and works well with unmanaged switches. As for putting one connection to a router's switch and another to an unmanaged switch... the DSM info seems to say it works but I've never done it but most likely the router and unmanaged switch will also have to be connected.
 
Since I already had both NAS ethernet ports connected to the router, I went ahead and did the Adaptive Load Balancing and kept both ports connected to the router. Without any doubt this has improved the NAS throughput. Previously when streaming to the Xbox or Shield connected via wireless and simultaneously streaming live TV (HDHomeRun -> Plex -> PC) via cat5, I would get interruptions occasionally on the Xbox/Shield streaming and video artifacts/interruptions on the live TV. After bonding the two Synology ports connected to the router, that problem is gone. Further, just to push a wee bit more, I added a live TV stream via Plex to my iPhone and everything worked without any issues. The live TV was problematic before because the NAS has to handle the incoming HDhomeRun streams (2 independent channels) and then turning that around out to client devices. The NAS network throughput was previously clearly affected and now after bonding everything is all cleaned up.

I've seen a lot of feedback from the forums and various YouTube channels saying this Adaptive Load Balancing really doesn't work on an unmanaged switch. But nobody discusses connecting to a router that doesn't support LACP (as far as I can tell). Maybe hiccups will develop down the road, but right now, I'm tickled pink. ;)
 
I've seen a lot of feedback from the forums and various YouTube channels saying this Adaptive Load Balancing really doesn't work on an unmanaged switch.
ALB does work with unmanaged switches as the configuration is managed by the NAS alone. There are other variants of LAG (LACP) that don't work because they required a managed switch (one that can be configured appropriately).

Good to hear it's working well for you.
 

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