1. Introduction

A bond interface is a virtual network interface that combines multiple network interfaces into a single one. It ensures that if one network interface fails, others can take over, and systems remain connected.

Create a bond interface.

$ ip link add <interface-name> type bond
  

• interface-name: the name assigned to the interface.

Add interfaces to the bond interface.

  
$ ip link set <another_interface> master <bond_interface>
  

Set bond mode.

  
$ ip link set <interface-name> type bond mode <bond_mode>
  

• Bond modes:
  • balance-rr: Packets are transmitted by the Round-Robin algorithm across all slave interfaces.
  • active-backup: Only one slave is active at a time. Another slave becomes active if the currently active slave fails.
  • balance-xor: Transmits based on a hash algorithm, usually involving the source and destination MAC addresses.
  • broadcast: Transmits packets to all slave interfaces.
  • balance-tlb: Adaptive Transmit Load Balancing. Dynamically adjusts the transmission load among slave interfaces based on the current traffic.
  • balance-alb: Adaptive Load Balancing. Includes the features of balance-tlb plus receiving load balancing.
  • 802.3ad: Link Aggregation Control Protocol (LACP).

2. Labs

2.1. Create a Bond Interface

• Create dummy interfaces: dummy1, dummy2
• Create a bond interface: bond0
• Add dummy1, dummy2 to bond0.

flowchart LR
    subgraph "bond interface"
        bond0
        dummy1
        dummy2
    end

    network <---> bond0
    bond0 <-- primay --> dummy1
    bond0 <-. backup .-> dummy2

# create dummy interfaces
$ ip link add dummy1 type dummy
$ ip link add dummy2 type dummy

# create bond interface
$ ip link add bond0 type bond

# set bond mode
$ ip link set bond0 type bond mode active-backup

# add dummy1, dummy2 to bond0
$ ip link set dummy1 master bond0
$ ip link set dummy2 master bond0

# assign IP address to bond0
$ ip addr add 192.168.1.3/24 dev bond0

# turn on interfaces
$ ip link set dummy1 up
$ ip link set dummy2 up
$ ip link set bond0 up
  

• Check the bond0 interface.

   
$ ping -I bond0 192.168.1.3
$ cat /proc/net/bonding/bond0
   

• Redundancy test: turn off a interface.

  
# turn of primary interface and ping
$ ip link set dummy1 down
$ cat /proc/net/bonding/bond0
$ ping -I bond0 192.168.1.3
  

References

• https://man7.org/linux/man-pages/man8/ip-link.8.html
• https://www.kernel.org/doc/Documentation/networking/bonding.txt