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Linking Two SG300 52P Managed Together


I have two Cisco SG300 52P Managed switches, switch A and switch B. I ran out of ports on "switch A" and "switch B" is not currently in use. I would like to expand "switch A" onto "switch B" so that I can have more ports available. Both switches have the latest firmware. Is there an optimal way for me to accomplish this? I have read similar posts to what I'm trying to do and there doesn't seem to be a consensus on this topic.



Cisco Employee


there is no consensus on this since it is very much related to the exact models and network needs.

There are 3 terms you might take into consideration:

1. stack - connecting several switch in ring or chain topology and manage like one unit; this is each vendor proprietary protocol and you can only stack particular switches to each other

2. lag - building ports aggregation so group of ports are behaving almost like one port; this is industry standard and can be used between different vendors switches; the main purpose is increase throughput and redundancy in case of failure; 802.3ad 

3. trunk - extending layer 2 isolation (VLAN) to another switches; it is also industry standard so can be used between different vendors devices, 802.1q


I hope it sheds some light on the subject,




Thank you for replying, Aleksandra. Our office is small and we do not intend to extend past the two switches. What would you recommend in setting up using these switches? Could you also set up stacking on switches that do not have a specialized port?




Hi CC,

Unfortunately only specific series of switches can be stacked such as SG500, SF500 or SG500X. In case such a small office I would imagine that you traffic is mainly LAN to WAN.

In this case the bottle neck would be ISP and internet access speed so LAG may not be needed.

If you would like to create some isolation on your network such a Guest VLAN and Office VLAN you could think of trunk. 

Still all really depends on your network traffic pattern and users requirements. Can you provide a bit more details?




Thanks for helping us out Aleksandra, we really appreciate it.


We're currently a ~50 person office with about 200 nodes (desktops, laptops, smart phones and tablets). Most of those nodes are wireless. We have a heavy reliance on cloud based tools: source control, email, document management and storage (e.g., Google products, Dropbox, Github, etc.). We have a fair amount of wireless and VPN traffic. We do not need VLAN for guest networking because our wireless solution internally handles guest network traffic and partitioning. We have no future plans for utilizing a VLAN. Our internet bandwidth is an aggregate of 400Mb (across two pipes). We generally utilize about 50% of that but have periods where we burst to 100% for periods.


Thanks again,




So in this case there is no need for any specific configuration. I would just recommend you to connect switches as well as router using last ports 49-52 since those are DA interfaces and should be used for uplink. Configuration wise however there is no difference.

Please note that there are some default settings which are enabled on managed switches and not even present on unmanaged such as STP, Green Ethernet, DHCP autoconfiguration, auto smartport macro, QoS. 

I hope this helps.



Hello again Aleksandra,


Thanks again for the info.


We have just a few clarifying questions we hope you can help with.  I apologize in advance for asking so many.  There just seems to be a vacuum when it comes to consensus or useful guides for setting up even the most basic network setup with Cisco equipment.  Whatever info we can find seems to vary from product to product and does not map nicely to the equipment we've purchased.  At any rate here are our questions:

1. Are you saying we should connect all the last 4 ports (ports 49 thru 52) of switch A to all the last 4 ports of switch B or are you saying anyone of the last 4 ports could be used?  I'm sure you are saying the later but I just want to be extra sure.


2. You mentioned that these were DA interfaces and should be used for uplink.  What does DA stand for and what make that important?


3. When we connect the two switches using this port (or ports) should we use a crossover cable?  Does it matter?


4. After the two switches are connected to each other is there anything special we have to do, configuration wise on either switch, to make it work or will it just work transparently?


5. Not sure what you were referring to by: configuration wise there's no difference.


6. We're also confused by your last paragraph about default settings or what we should do about that for our two switches.


7. (final questions) since you mentioned that the last 4 ports should be used to connect other switches or routers.  Should we connect our firewall to one of these ports?  What are the benefits of doing so?  If the answer is yes, is there anything we should do - configuration wise for it (on the switch or the firewall)?


When we are all setup and working we will probably blog about this so other small businesses like our that want a basic network setup using this equipment could have a simple guide to follow.


Thanks again for your time.



Hi CC,

I am sorry for late response. Answering your questions:

1. the last 4 ports should be uplink ports but for various devices such a switch or firewall; different for different ports

2. DA - Directly Attached ports – interfaces connected directly to Packet Processor without use of PHY

3. it does not matter anymore since most of the devices are using MDX/MDIX auto mechanism to detect the cable

4. you should not need to make any changes but it is still recommended to verify if all works as expected 

5. no difference in default configuration between all ports; some old switches used to have small difference between specific port which made them to be designed for connection to routers, firewalls, Unified Communication devices

6. no need to change anything

7. since you mentioned that there is no need for VLAN on your network those switches should work well with no configuration; but still it is always recommended to verify this by testing basic connectivity to the internet, local resources etc.

I hope this helps,