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How to Connect Cisco SG-300-10 L3 mode Switch to SG-300-20 L2 Mode Switch

spati1976
Level 1
Level 1

Dear colleagues, Please forgive me if you find my question too basic. But, I would truly appreciate your help. I have two Cisco switches (SG-300-10 and SG-300-20) and I am struggling to connect them together. 

Requirements: Cisco SG-300-10 switch, which is in L3 mode needs to send VLAN tagged traffic to Cisco SG-300-20 switch which is L2 mode

What I have Done so far

1. Connected Cisco SG-300-10 (L3 Mode) to the router directly and configured the IP addresses, 192.168.0.21. Configured GVRP for Port 5. Created VLAN 1000 with IP interface (192.168.100.1) and configured Port 5 trunk mode (1U, 1000T)

2. Connected Cisco SG-300-20 ( L2 Mode) to the router and configured the management IP address, 192.168.0.22. Configured GVRP for Port 5. Created VLAN 1000 and configured Port 5 trunk mode (1U, 1000T)

What is not working

I am unable to access the management address of the L2 switch (192.168.0.22). Note that the L2 switch has only on uplink, which is to the L3 switch. Since the Port 5 also receives untagged traffic from VLAN1 (192.168.1.1), I am assuming that it would receive the management network from VLAN1. 

Other Observations

When I connect cable between Port5 of both switches, I am expecting them to exchange VLAN information, per documentation. But, the lights don't blink at all. 

Other things I have tried

I have tried to connect Port 2 (1U) of L3 switch to Port 2 of L3 (1U) switch. Still, I am unable to access the management port of the L2 switch. However, when I connect Port 2 of L3 switch to my laptop, I get an IP address. This tells me that I have to fix the management network issue before pairing the switches. 

 

 

1 Accepted Solution

Accepted Solutions

Tom Watts
VIP Alumni
VIP Alumni

Hi Spati,

 

I think the confusion is the IP addressing you're using and how you're managing your computer.

VLAN 1 = 192.168.1.1

VLAN 1000 = 192.168.0.21

 

From how I read you, you're connecting layer 2 switch VLAN 1 on 192.168.0.21 to a layer 3 interface of the same VLAN 1 at 192.168.1.1. This is confusing.

 

So first thing to do is this - Change layer 2 switch IP to 192.168.1.x network and confirm management works on VLAN 1.

 

If you want layer 2 switch to work on VLAN 1000 then you will need to change the default VLAN to 1000 then you may configure your uplink as either the way you have it 1u, 1000t or you can use 1000u.

 

Your management VLAN on the layer 2 switch is VLAN 1 still unless you changed it (which you did not say???)

 

Next important thing for the layer 2 switch is going to be the default gateway. On the layer 3 switch you will need to specify the VLAN 1000 IP address, which I believe you did at 192.168.0.21 /24. This 192.168.0.21 will need to be the default gateway for your layer 2 switch.

 

Lastly, the computer you connect to Layer 3 switch, whatever VLAN you choose to connect it to (1 untagged), you will need to set the IP and default gateway appropriately. So if you're going to VLAN 1 then your computer is 192.168.1.x with gateway 192.168.1.1

 

And for additional commentary, GVRP is a horrible and very pitiful protocol, I do not recommend to use it.

-Tom Please mark answered for helpful posts http://blogs.cisco.com/smallbusiness/

View solution in original post

3 Replies 3

Tom Watts
VIP Alumni
VIP Alumni

Hi Spati,

 

I think the confusion is the IP addressing you're using and how you're managing your computer.

VLAN 1 = 192.168.1.1

VLAN 1000 = 192.168.0.21

 

From how I read you, you're connecting layer 2 switch VLAN 1 on 192.168.0.21 to a layer 3 interface of the same VLAN 1 at 192.168.1.1. This is confusing.

 

So first thing to do is this - Change layer 2 switch IP to 192.168.1.x network and confirm management works on VLAN 1.

 

If you want layer 2 switch to work on VLAN 1000 then you will need to change the default VLAN to 1000 then you may configure your uplink as either the way you have it 1u, 1000t or you can use 1000u.

 

Your management VLAN on the layer 2 switch is VLAN 1 still unless you changed it (which you did not say???)

 

Next important thing for the layer 2 switch is going to be the default gateway. On the layer 3 switch you will need to specify the VLAN 1000 IP address, which I believe you did at 192.168.0.21 /24. This 192.168.0.21 will need to be the default gateway for your layer 2 switch.

 

Lastly, the computer you connect to Layer 3 switch, whatever VLAN you choose to connect it to (1 untagged), you will need to set the IP and default gateway appropriately. So if you're going to VLAN 1 then your computer is 192.168.1.x with gateway 192.168.1.1

 

And for additional commentary, GVRP is a horrible and very pitiful protocol, I do not recommend to use it.

-Tom Please mark answered for helpful posts http://blogs.cisco.com/smallbusiness/

HI Tom, thank you for answering.my posting had some typos, which I have corrected below.  Sorry about that. Your answer helped quite a bit. I am able to connect the L2 and L3 switches now. I have changed the administrative default gateway of the L2 switch to the management IP address of the L3 switch.  

I have a question for you. I was under assumption that GVRP is needed to share VLANs between cisco SG-300 L3 and L2 switches as they don't support VTP. If there is a better way, please let me know. 

Here is my confusion

================

I have created a VLAN (VLAN 1000) in the L3 switch with an IP interface (192.168.100.x) . The L3 Switch is connected to an L2 Switch on Port 5 on both switches. I was under the impression that I have to do the following three tasks for the devices connected to the L2 switch to receive ip addresses from VLAN 1000.

1. Create a VLAN with the same VLAN ID in L2 switch

2. Enable GVRP on both L2 and L3 switch port (port 5) to ensure that the IP interface for VLAN 1000 is also used in L2 switch (as there is no IP interface of VLAN 1000 in the L2 switch)

3. Make Port 5 of both Switches Trunk Ports, as they are used for inter-switch connectivity.

 

==========

Dear colleagues, Please forgive me if you find my question too basic. But, I would truly appreciate your help. I have two Cisco switches (SG-300-10 and SG-300-20) and I am struggling to connect them together. 

Requirements: Cisco SG-300-10 switch, which is in L3 mode needs to send VLAN tagged traffic to Cisco SG-300-20 switch which is L2 mode

What I have Done so far

1. Connected Cisco SG-300-10 (L3 Mode) to the router directly and configured the IP addresses, 192.168.1.21. Configured GVRP for Port 5. Created VLAN 1000 with IP interface (192.168.100.1) and configured Port 5 trunk mode (1U, 1000T)

2. Connected Cisco SG-300-20 ( L2 Mode) to the router and configured the management IP address, 192.168.0.22. Configured GVRP for Port 5. Created VLAN 1000 and configured Port 5 trunk mode (1U, 1000T)

What is not working

I am unable to access the management address of the L2 switch (192.168.1.22). Note that the L2 switch has only on uplink, which is to the L3 switch. Since the Port 5 also receives untagged traffic from VLAN1 (192.168.1.1), I am assuming that it would receive the management network from VLAN1. 

Other Observations

When I connect cable between Port5 of both switches, I am expecting them to exchange VLAN information, per documentation. But, the lights don't blink at all. 

Other things I have tried

I have tried to connect Port 2 (1U) of L3 switch to Port 2 of L3 (1U) switch. Still, I am unable to access the management port of the L2 switch. However, when I connect Port 2 of L3 switch to my laptop, I get an IP address. This tells me that I have to fix the management network issue before pairing the switches. 

Hi Spati,

 

There isn't a specific rule or guide line for your switch interconnection. It's basically whatever works for you. GVRP isn't a robust protocol like VTP and although it may populate VLAN information on a trunk dynamically the adminstrative overhead of the actual configuration and to have it reliably work is more difficult than just statically setting your VLANS.

 

When you say you want the layer 2 switch to receive an IP address, does it imply you want your layer 2 switch to get a DHCP address? Or is your goal for a host connection (computer) to get a DHCP address from some server or something?

 

Right now all of your indication shows to have the layer 2 switch management on VLAN 1000. The layer 2 switch has only 1 management connection so the default VLAN must be changed to VLAN 1000 if you want the layer 2 switch to be managed via VLAN 1000 subnet from your upstream connection.

 

As for the physical interconnection between the switches it is simple enough to have a matching native VLAN (don't confuse native VLAN and default VLAN) on each port then tag every additional VLAN on both sides of this trunk and that will take care of the configuration for interconnection (although leaves much more incomplete if you have other goals).

-Tom Please mark answered for helpful posts http://blogs.cisco.com/smallbusiness/
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