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[anigwei]

Hi!!

We have bought 4 (+2 spare) DGS-1510-52 switch.

Our plan is to create two stacks of two, for adding redundancy to our network. And I have two questions regarding link aggregation.

Linux Servers are configured using 802.3ad LACP between ports of two members of the stack. This works perfect!

For example:

Server 1 connected to Channel1 (formed by ports eth0/1 and eth1/1). All correct.

The problem comes while interconnecting two stacks with a LACP.

If I create LACP like I do with servers: doesn't work. Concretely, only works with one of both ports connected. With two ports connected, link is lost.
I create LACP ACTIVE-ACTIVE in both ports (for servers).

In the documentation (http://www.dlink.com/uk/en/support/faq/switches/layer-2-gigabit/dgs-series/uk_dgs_1510_28_configure_link_aggregation_lacp) they tell you to add ports to LACP in Mode: ON. Wait: Mode ON is supposed to be "old" load-balancing without 803.2ad, isn't?

  So.. the quick question: How do you interconect two stacks with a LACP channel?

Another quick question: Imagine that I have some configuration set on ports n and m. (Vlan, etc). And then I create a LACP between these n and m ports. Then I configure VLANS for them as "Channel N", not ethN and M any more. BUT:    A LACP member port still have its own "old" settings individually?

A quick example:

Port 1 and 2 have access to VLAN 1 untagged, and 35, 36, 37 tagged.

Then I create a LACP (Port Channel 1) between Port 1 and 2. And I assign Port Channel 1 to access VLAN 2 tagged only.

What happens with "old" settings that Port 1 and 2 had? Are still working? Ports 1 and 2 are into VLAN 1 untagged? Or only makes sense for them settings from Port Channel?

Thank you!!!!

[PacketTracer]

Hi,

The problem comes while interconnecting two stacks with a LACP.

If I create LACP like I do with servers: doesn't work. Concretely, only works with one of both ports connected. With two ports connected, link is lost.
I create LACP ACTIVE-ACTIVE in both ports (for servers).

In the documentation (http://www.dlink.com/uk/en/support/faq/switches/layer-2-gigabit/dgs-series/uk_dgs_1510_28_configure_link_aggregation_lacp) they tell you to add ports to LACP in Mode: ON. Wait: Mode ON is supposed to be "old" load-balancing without 803.2ad, isn't?

  So.. the quick question: How do you interconect two stacks with a LACP channel?

"ON" means "old" or better static link aggregation (yes: without 803.2ad). This has nothing to do with "load-balancing": Any load sharing or frame distribution algorithms are independent on LAG mode (that is they work the same on static or dynamic link aggregations). The advantages of dynamic (LACP) over static LAG are described here. The referred DLINK documentation gives a hint that for switch interconnections only static LAG is supported. Don't know if this is true, please ask DLINK support.

Another quick question: Imagine that I have some configuration set on ports n and m. (Vlan, etc). And then I create a LACP between these n and m ports. Then I configure VLANS for them as "Channel N", not ethN and M any more. BUT:    A LACP member port still have its own "old" settings individually?

From my experience with switches from another well known vendor (C...o): For any member port of a LAG only the settings for the LAG are valid, that is LAG settings mask individual port settings (makes sense to you?). However, if a port loses its LAG membership (e.g. by administration), its individual settings become valid again. In practice it may be useful to configure the same settings as for the LAG for each individual member port, so traffic can continue to flow as wanted (at least via the one member that wins spanning tree) in case the LAG breaks.

PT

[anigwei]

Hi PacketTracer!!

Hi,
"ON" means "old" or better static link aggregation (yes: without 803.2ad). This has nothing to do with "load-balancing": Any load sharing or frame distribution algorithms are independent on LAG mode (that is they work the same on static or dynamic link aggregations). The advantages of dynamic (LACP) over static LAG are described here. The referred DLINK documentation gives a hint that for switch interconnections only static LAG is supported. Don't know if this is true, please ask DLINK support.

Thank you for your information! So I'll give a try with static aggregation. In fact, there is dLink Staff here, isn't? 

In fact, if you take a look to Dlink Link Aggregation FAQ: Is not clear: They indicate you Mode: ON. But in the picture (Step 6) appears a Snapshot with Mode: LACP...

From my experience with switches from another well known vendor (C...o): For any member port of a LAG only the settings for the LAG are valid, that is LAG settings mask individual port settings (makes sense to you?). However, if a port loses its LAG membership (e.g. by administration), its individual settings become valid again. In practice it may be useful to configure the same settings as for the LAG for each individual member port, so traffic can continue to flow as wanted (at least via the one member that wins spanning tree) in case the LAG breaks.

PT

Ok!! This makes sense. Thank you for the information and your recommendation!

Andreu.

[anigwei]

Hi again,

I just tested it and it fails. Only works if one of the ports are connected. If both are connected, pings to the other side are lost.

I set PortChannel32 on both sides, configured as a VLAN 2-4096 Trunk, aggregation mode: ON.



In fact, port is running in "bundl" mode but Working Mode: None 
This snapshot is taken while both ports connected, and no link to other side.

Any ideas?

Thank you!!

[PacketTracer]

Hi anigwei,

does it work, if you form the portchannel from eth1/0/1 + eth1/0/2 (instead of eth1/0/1 + eth2/0/1), hence using only one switch of the stack on both ends of the switch interlink? If yes, this may be a hint, that at least one side of the portchannel regards the opposite end as two switches and not as a single logical switch (due to physical stacking). (On the other hand this contradicts the fact that you can successfully connect your Linux hosts via a portchannel to both switches of a stack).

The following excerpt from the manual may give additional hints:

All of the ports in the group must be members of the same VLAN, and their STP status, static multicast, traffic control; traffic segmentation and 802.1p default priority configurations must be identical. Port locking and 802.1X must not be enabled on the trunk group. Further, the LACP aggregated links must all be of the same speed and should be configured as full duplex.

PT

[anigwei]

Hi PT,

Thanks. You may say me RTFM 

The port 2/0/1 didn't had any VLAN configured.

Now configuring identical VLAN settings in both 1/0/1 + 2/0/1  + PortChannel32 it works! (However, on the Channel Detail page there is not any information about the link -- like snapshot from previous post).

In fact here makes sense what we commented on first posts about individual port configurations inside aggregations... Conclusion is that all ports should from a LACP (or must..) have identical configuration individually!!

Thanks again.

Andreu

[FurryNutz]

http://forums.dlink.com/index.php?topic=65428.0

http://forums.dlink.com/index.php?topic=65409.0

[anigwei]

http://forums.dlink.com/index.php?topic=65428.0

http://forums.dlink.com/index.php?topic=65409.0

Hi FurryNutz: Maybe would be better to create a subforum for this model? DGS-1510-xx?

Thanks

[FurryNutz]

This forum will have to suffice for now. The forums don't see much activity for the DGS products.