📦 Understanding NIC Bonding in Linux

Network Interface Card (NIC) bonding is a technique used to combine multiple network interfaces into a single logical interface to achieve redundancy and/or improved performance. This guide will explore the benefits of NIC bonding, its various modes, and how to configure it in a Linux environment.

🔍 What is NIC Bonding?

NIC bonding involves combining multiple physical network interfaces (NICs) into a single logical interface. This approach provides:

Increased Bandwidth: Aggregates bandwidth from multiple NICs.
Redundancy: Offers failover capabilities if one NIC fails.
Load Balancing: Distributes network traffic across multiple NICs.

🔧 How Does NIC Bonding Work?

NIC bonding uses a bonding driver that supports various modes to achieve different objectives. Each mode offers specific features and requirements.

🧩 Bonding Modes

Mode	Description	Benefit	Requirement
Mode 0 (Balance-Round-Robin)	Distributes packets in a round-robin fashion across all NICs.	Load balancing and redundancy.	Switch must support this mode.
Mode 1 (Active-Backup)	Only one NIC is active at a time; others are standby.	Failover redundancy; no special switch configuration needed.	No special switch configuration needed.
Mode 2 (Balance-XOR)	Uses XOR operation on MAC addresses to determine packet routing.	Load balancing with redundancy.	Switch must support this mode.
Mode 3 (Broadcast)	Transmits packets to all NICs in the bond.	Ensures all NICs receive all traffic; useful for monitoring.	No special switch configuration needed.
Mode 4 (802.3ad - LACP)	Aggregates links using LACP (Link Aggregation Control Protocol).	Load balancing and redundancy; requires switch support for LACP.	Switch must support LACP.
Mode 5 (Balance-TLB)	Balances outbound traffic based on NIC load.	Load balancing with redundancy; no special switch configuration needed.	No special switch configuration needed.
Mode 6 (Balance-ALB)	Balances both inbound and outbound traffic; includes ARP monitoring.	Load balancing and redundancy; no special switch configuration needed.	No special switch configuration needed.

🔧 How to Configure NIC Bonding

Follow these steps to configure NIC bonding on a Linux system:

Step 1: Install Bonding Module

Ensure the bonding module is installed and loaded.

sudo modprobe bonding

Step 2: Create Bonding Configuration

Create a configuration file for the bonded interface. For example, on systems using ifcfg files (like RHEL/CentOS):

sudo vi /etc/sysconfig/network-scripts/ifcfg-bond0

Example Configuration:

DEVICE=bond0
BONDING_OPTS="mode=1 miimon=100"
BOOTPROTO=none
ONBOOT=yes
IPADDR=192.168.1.10
NETMASK=255.255.255.0
GATE_WAY=192.168.0.1

Step 3: Configure Slave Interfaces

Edit the configuration files for each NIC that will be part of the bond. For example:

sudo vi /etc/sysconfig/network-scripts/ifcfg-eth0

Example Configuration:

TYPE=Ethernet
DEVICE=eth0
MASTER=bond0
SLAVE=yes
BOOTPROTO=none
ONBOOT=yes
HWADDR=e8:84:a5:36:0b:af

Repeat this for other NICs (eth1, eth2, etc.).

Step 4: Restart Networking

Restart the networking service to apply changes.

sudo systemctl restart network

Step 5: Verify Bonding

Check the bonding status to ensure it's configured correctly.

cat /proc/net/bonding/bond0

📚 Summary

NIC bonding in Linux allows for combining multiple network interfaces into a single logical interface, offering benefits like increased bandwidth, redundancy, and load balancing. By configuring bonding modes and following setup steps, you can optimize network performance and reliability.

Happy configuring! 💻🚀

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