Lag and LACP 20g link possible?

[redgasgiant]

Hi, 

So I have a stack of sg550x's, and sg350x's as the edge devices. I'm connecting them via lag groups with lacp enabled, and I was hoping to see a 20g link when connecting the 550x to a 350x (ports xg3&4) with 2 fiber connections 

Is that a thing with these switches? or is 10g the max?

[Jitendra Kumar]

yes, you can have 20gbps speed as both switches support the 10G Speed SFP fiber port.

High-performance 10 Gigabit Ethernet

Cisco 350X Series switches break the barrier of 10 Gigabit Ethernet adoption by providing affordable and powerful features for growing small and medium-sized business networks. With the 10G ports in both copper and fiber, you can easily and cost-effectively enable 10G connections to servers and network storage devices with standard RJ-45 Ethernet cables. You can also aggregate 10G Enhanced Small Form-Factor Pluggable (SFP+) fiber connections to build a high-performance backbone to dramatically increase the overall speed of your network.

Cisco 550X Series switches break the barrier of 10 Gigabit Ethernet adoption by providing affordable and flexible configurations customized for the demanding network requirements of small and medium businesses.

With 10G copper ports on the SX550X switches, you can easily and cost-effectively enable 10G connections to servers and network storage devices with standard RJ-45 Ethernet cable. You can also connect your SG550X access switches to the SX550X aggregation with 10G SFP+ fiber, building a high-performance backbone to speed up the overall operation of your network.

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

cisco.com/c/en/us/products/collateral/switches/350x-series-stackable-managed-switches/datasheet-c78-735986.html

[redgasgiant]

Cool. How do I know that I am getting 20gbps ? Is it going to say anywhere? 

[emilio_]

You don't get 20Gbps, you get a LAG (Link Aggregation Group) of 2x10Gbps. A packet will be sent via one of those two 10Gbps links at 10Gbps speed. With a LAG you get redundancy and some sort of load balancing.

[Jitendra Kumar · Accepted solution]

2x10 means both ports will send a max of 20G means the individual port sent traffic 10G. Yes LAG will create a redundancy means if one port or cable got faulty another port will take charge and traffic will still flow on the single port.

[emilio_]

Yes, in theory you can reach 20Gbps using the LAG but in real world that never happens because the traffic can rarely be splitted perfectly balanced. A single TCP session will only use one of the LAG interfaces at 10Gbps.

[redgasgiant]

ok, that makes sense. Thanks Guys. 

[Jitendra Kumar]

Please mark this as resolved if it's clear your query.