How to Configure a Gateway MAC Address in Dell Networking Enterprise SONiC MF-CLI

Summary: This article explains how to set gateway MAC address in Dell Networking Enterprise SONiC.

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Instructions

Dell Enterprise SONiC Gateway MAC Address

By default, an MC-LAG switch and its peer use the active peer's system MAC address as the gateway MAC address in L3 interfaces. To use a common configurable gateway MAC address for the L3 VLAN interfaces in which the peer link is a VLAN member, configure an MC-LAG gateway MAC address.
 
NOTE: On the VLAN interfaces configured with mclag-separate-ip, the VLANs take MAC address different from configured mclag gateway-mac (the mclag-separate-ip configuration takes precedence over the mclag gateway-mac).
 

Index


Configuration Syntax
Explanation
Effect of mclag-separate-ip on Configured Gateway Mac Address
 

Configuration Syntax

 

Configuration
 		 Explanation

Admin@SONIC:~$ sonic-cli
 		 Enter SONiC CLI

SONiC# configure terminal
 		 Enter configuration terminal.

SONIC(config)# mclag gateway-mac <Mac address>     
 		 Configure gateway MAC address.
  
NOTE: The gateway MAC address cannot be a zero, multicast, or broadcast MAC address.
 
NOTE: Ensure that the address is not confused with the Anycast MAC address.
 

Explanation

Below we explain with the topology.
Sample MC-LAG Topology
Figure 1: Sample MC-LAG Topology

Sample Configuration
Let us configure 66:22:33:44:55:66 as mclag gateway-mac in both MC-LAG peers.
Configure MC-LAG MAC
Figure 2: Configure MC-LAG MAC

We can see from a downstream switch, that the MAC address of VLAN 25 and VLAN 50 is 66:22:33:44:55:66.
Screenshot of show ip arp command
Figure 3: Screenshot of show ip arp command
 

Effect of mclag-separate-ip on Configured Gateway Mac Address

On the VLAN interfaces configured with mclag-separate-ip, the VLANs take MAC address different from the configured mclag gateway-mac.

Consider that we are configuring mclag-separate-ip on VLAN 25.
Screenshot of show interface vlan 25 in MCLAGSW1
Figure 4: Screenshot of show interface VLAN 25 in MCLAGSW1
 
Screenshot of show interface vlan 25 in MCLAGSW2
Figure 5: Screenshot of show interface VLAN 25 in MCLAGSW2

VLAN 50 on both switches does not have mclag-separate-ip configured.
Screenshot of show interface vlan 50 in MCLAGSW1 not having switch configured
Figure 6: Screenshot of show interface of VLAN 50 in MCLAGSW1 not having switch configured
 
Screenshot of show interface vlan 50 in MCLAGSW2 not having switch configured
Figure 7: Screenshot of show interface of VLAN 50 in MCLAGSW2 not having switch configured

We can see that the MAC address of VLAN 25 on both mclag peers changed and is not the configured gateway MAC anymore. However, MAC address VLAN 50 is still the configured gateway MAC address.
Screenshot of show ip arp with results
Figure 8: Screenshot of show ip arp with results
 

Affected Products

Enterprise SONiC Distribution, PowerSwitch S6000 ON, PowerSwitch E3200-ON Series, Dell EMC Networking N3200-ON, PowerSwitch S5232F-ON, PowerSwitch S5248F-ON, PowerSwitch S5296F-ON, PowerSwitch S6100-ON, PowerSwitch Z9100-ON, PowerSwitch Z9264F-ON , PowerSwitch Z9332F-ON ...
Article Properties
Article Number: 000191547
Article Type: How To
Last Modified: 06 Jul 2023
Version:  7
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