Understanding and Configuring Network Bonding

What is Network Bonding?

Network bonding (also called NIC teaming) combines multiple network interfaces into a single logical interface for increased bandwidth or redundancy.

Bonding Modes

• Mode 0 (balance-rr) — round-robin, packets distributed across all interfaces
• Mode 1 (active-backup) — one active interface, others standby for failover
• Mode 4 (802.3ad / LACP) — IEEE standard link aggregation, requires switch support

Setup with Netplan

network:
  version: 2
  ethernets:
    eth0:
      dhcp4: no
    eth1:
      dhcp4: no
  bonds:
    bond0:
      interfaces:
        - eth0
        - eth1
      addresses:
        - 198.51.100.10/24
      routes:
        - to: default
          via: 198.51.100.1
      parameters:
        mode: active-backup
        primary: eth0
        mii-monitor-interval: 100

sudo netplan apply

Verify

cat /proc/net/bonding/bond0
ip addr show bond0