Describe the rationale for using multiple network interface cards.
Multiple Network Interface Cards
There are several reasons why you might use multiple network interface cards (NICs) in Red Hat Enterprise Linux (RHEL) 9.5. Here are some of the most common:
Redundancy and High Availability: Multiple NICs can be bonded together to provide redundancy. If one NIC fails, the other takes over, ensuring continuous network connectivity. This is crucial for servers providing critical services.
Increased Bandwidth: By combining multiple NICs, you can increase the overall network bandwidth available to your system. This is particularly useful for applications that require high throughput, such as file servers or streaming media servers.
Traffic Separation: Different NICs can be used for different types of network traffic. For example, one NIC could be dedicated to public network traffic, while another handles traffic on a private internal network. This can improve security and performance.
VLAN Segmentation: Each NIC can be assigned to a different VLAN (Virtual LAN), allowing you to logically segment your network and isolate traffic between different departments or applications.
Supporting Different Network Types: You might need different NICs for different network technologies, such as one for a standard Ethernet connection and another for a fiber channel network.
Separate Networks: One NIC might connect to your production network, while another connects to a management network used for system administration.
Important Considerations:
Network Configuration: Properly configuring multiple NICs in RHEL 9.5 requires an understanding of networking concepts like bonding, bridging, and routing.
Hardware Requirements: Ensure your server has enough PCIe slots to accommodate the additional NICs.
Driver Support: Make sure you have the correct drivers installed for your NICs.
In RHEL 9.5, NIC teaming (using the `teamd` daemon) is deprecated in favor of bonding, which is managed by NetworkManager. If you're upgrading from an earlier RHEL version with NIC teaming, you can use the `team2bond` utility to migrate your configuration.
Multiple network interface cards (NIC) allow communication across different networks. Linux supports multiple network interface cards (NICs) in the same machine, enabling a single Linux computer to act as a router, bridge[1], or firewall.
Routing:
Routing lets a computer move traffic from one logical network to another. Linux supports advanced routing features, such as Quality of Service, that allow an administrator to optimize traffic flow between networks.
Bridging Bridging isolates physical segments of the same network to cut down on overall network traffic. For example, a group of Macintosh computers and a group of Linux computers on the same network might talk among their respective groups almost exclusively,
but traffic from one group will be seen by and possibly collide with hosts and traffic from the other. A bridge between the two groups will reduce the number of collisions.
Mixed network
Collision
Linux
Data
Mac OS
Bridged network
Bridge
Features of the Diagram
Mixed Network (Top Section):
The diagram illustrates a network topology with various devices, including computers running different operating systems (Linux and Mac OS).
These devices are connected in a shared medium that experiences collisions, indicating a lack of controlled traffic management.
The term "Data" suggests data flow between devices, but the collision icon (a bright starburst symbol) highlights issues due to network congestion or shared bandwidth.
Bridged Network (Bottom Section):
This part of the diagram shows a topology where the same devices are separated into two segments connected by a bridge.
The bridge prevents collisions by segmenting traffic and managing data flow, improving network efficiency.
The bridge symbol (an arc) represents the connection between the two sub-networks, ensuring organized communication and reduced contention.
The comparison emphasizes the advantage of bridging in minimizing collisions and managing traffic effectively in a network.
Diagram displaying a Mixed Network and a Bridged Network
Firewalling
Firewalling protects hosts on one network from hosts on another. A computer acting as a firewall filters, logs, and audits traffic flowing from one network to the other. Information about how to set up routers, bridges, and firewalls is included in the LDP Linux Bridge+Firewall Mini-HOWTO, Bridge HOWTO, and Firewall HOWTO, available from the Resources page.
[1]bridge: Between two networks: a bridge is an intelligent wire, a router directs traffic between logical subnets, and a firewall is an insulating router.
