[SOLVED] CISCO SG550XG - use lag as stacking port

[thomashohm2]

Dear fellow cisco users,

we have 2 cisco SG550XG and we would like to stack them over an LAG of 4 physical ports on each side.

According to the product data sheet this is possible and supported:

http://www.cisco.com/c/en/us/products/collateral/switches/550x-series-stackable-managed-switches/datasheet-c78-735874.html

High-speed stack interconnects	Cost-effective high-speed 10G fiber and copper interfaces. Support LAG as stacking interconnects for even higher bandwidth.

Unfortunately I am not able to configure it properly.

When I setup the stack vie the web frontend, I can only select physical ports. I did this, but it seems as if there is only 1x 10G used.

The CLI command show stack links gives:

Topology is Chain

Unit Id Active Links Neighbor Links Operational Down/Standby
Link Speed Links
------- -------------------- -------------------- ----------- --------------------
1 te1/0/19-22 te2/0/19-22 10G
2 te2/0/19-22 te1/0/19-22 10G

CLI command show stack configuration gives:

Unit Id After Reboot Configuration

Unit Id Stack Links
-------- ------- ---------------
1 Auto te19-22
2 Auto te19-22

Also when creating the stack via CLI config stack configuration links te 19-22

it does not give different results.

I've also created lags on both switches before stacking, but that does not make a difference.

I can not use the lag as stack port via CLI "stack configuration links lag 2"

I am stuck now. 

I would really appreciate any help!

Thanks in advance,

Thomas

[thomashohm2]

Thanks to chat support: the answer is too easy:

when you create a stack and add multiple connections / links / cables, the stack will automatically use them in parallel (if they are active).

You can check the link status via cli:

show stack links detail

Result:

Topology is Chain

UNIT ID Link Status Speed Neighbor Neighbor Neighbor
 Unit ID Link MAC Address
------- -------- ---------- ----- -------- -------- -------------------
 1 te19 Active 10G 2 te19 00:8e:73:c3:b2:94
 1 te20 Active 10G 2 te20 00:8e:73:c3:b2:94
 1 te21 Active 10G 2 te21 00:8e:73:c3:b2:94
 1 te22 Active 10G 2 te22 00:8e:73:c3:b2:94
 2 te19 Active 10G 1 te19 00:8e:73:c1:b3:2c
 2 te20 Active 10G 1 te20 00:8e:73:c1:b3:2c
 2 te21 Active 10G 1 te21 00:8e:73:c1:b3:2c
 2 te22 Active 10G 1 te22 00:8e:73:c1:b3:2c