Sample Configuration - Network Load Balancing (NLB) Multicast mode over routed subnet - Cisco Switch Static ARP Configuration

Products

• VMware vSphere ESX 6.x
• VMware vSphere ESX 7.x
• VMware vSphere ESX 8.x

Issue/Introduction

NLB Multicast Mode – Static ARP Resolution

• Since NLB packets are unconventional, meaning the IP address is Unicast while the MAC address of it is Multicast, switches and routers drop NLB packets.
• NLB Multicast Packets get dropped by routers and switches, causing the ARP tables of switches to not get populated with cluster IP and MAC address.
• Manual ARP Resolution of NLB cluster address is required on physical switch and router interfaces
• Cluster IP and MAC static resolution is set on each switch port that connects to ESX/ESXi host
• Virtual Switch NIC Team Policy > Notify Switches is set to Yes.
• If CDP (Cisco Discovery Protocol) is Enabled on ESX/ESXi and the Cisco Switch - you can determine proper switch ports connecting to ESX/ESXi via the vSphere/Virtual Infrastructure Client.

Environment

VMware vSphere ESXi 6.x
VMware vSphere ESXi 7.x
VMware vSphere ESXi 8.x

Resolution

To configure the switch:

1. Telnet in to Cisco Switch Console and log in.
2. Run this command to enter Configuration mode:
   
   config t
   
   
3. STATIC ARP RESOLUTION Cisco Global command mode
   
   For example:
   
   arp [ip] [cluster multicast mac] ARPA
   arp 192.168.1.100 03bf.c0a8.0164 ARPA
   
   
4. STATIC MAC RESOLUTION Cisco Global command mode
   
   For example:
   
   mac-address-table static [cluster multicast mac] [vlan id] [interface]
   mac-address-table static 03bf.c0a8.0164 vlan 1 interface GigabitEthernet1/1 GigabitEthernet1/2
   GigabitEthernet1/15 GigabitEthernet1/16

Additional Information

For more information, see Sample Configuration - Network Load Balancing (NLB) Multicast Mode Configuration (1006558).Sample Configuration - Network Load Balancing (NLB) Multicast Mode Configuration
Ejemplo de configuración - Modo de multidifusión de equilibrio de carga de red (NLB) en una subred enrutada - Configuración de ARP estática de conmutador Cisco
Configuração de amostra - Modo multicast de balanceamento de carga de rede (NLB) sobre sub-rede roteada - Configuração Cisco Switch Static ARP
配置示例 - 基于路由子网的网络负载平衡 (NLB) 多播模式 - Cisco 交换机静态 ARP 配置
サンプル構成 - 経路指定サブネットを介したネットワーク ロード ラバンシング (NLB) のマルチキャスト モード - Cisco スイッチの静的 ARP 構成

More information on vendor articles , https://learn.microsoft.com/en-us/troubleshoot/windows-server/networking/configure-network-to-support-nlb-operation-mode
https://www.cisco.com/c/en/us/support/docs/ip/multicast/116150-configure-Nexus7000-00.html