When connecting two Ethernet switches, a single cable creates a bottleneck. While enterprise environments use Link Aggregation (LACP) for bandwidth pooling, most desktop switches lack this capability. Let's examine the technical realities.

Cheap unmanaged switches (like Netgear GS305 or TP-Link TL-SG105) exhibit critical behaviors:

// Conceptual representation of unmanaged switch forwarding
void handlePacket(Switch s, Packet p) {
    // No STP blocking = broadcast storms possible
    if (p.destMac == BROADCAST) {
        floodAllPortsExcept(s, p.inPort); 
    }
    // No LACP support = potential loops
    forwardToMAC(p.destMac, p.inPort); 
}

Multiple connections between such switches create:

• Broadcast storms due to no Spanning Tree Protocol (STP)
• MAC address flapping as switches relearn paths
• Potential packet duplication

With managed switches (Cisco SG350, Ubiquiti USW), we can implement IEEE 802.3ad:

# Cisco IOS LACP configuration example
interface Port-channel1
 switchport mode trunk
!
interface GigabitEthernet0/1
 channel-group 1 mode active
!
interface GigabitEthernet0/2
 channel-group 1 mode active

For unmanaged switches, consider:

1. Upgrade Path: MikroTik CSS326 ($130) supports LACP
2. Alternative Topology: Daisy-chain switches with single links
3. Traffic Segmentation: Separate VLANs per uplink (requires managed switches)

Using iPerf3 between switches:

# Single link baseline
$ iperf3 -c 192.168.1.100 -t 60
[ ID] Interval       Transfer     Bitrate
[  5] 0.00-60.00 sec  6.78 GBytes   971 Mbits/sec

# Theoretical LACP improvement
$ iperf3 -c 192.168.1.100 -P 4 -t 60
[ ID] Interval       Transfer     Bitrate
[  5] 0.00-60.00 sec  13.1 GBytes  1.88 Gbits/sec

For production environments, investing in at least basic managed switches pays dividends in reliability and performance.

When connecting two desktop switches, the question often arises whether using multiple Ethernet cables can aggregate bandwidth. The short answer: yes, but with significant caveats depending on your switch type.

Standard unmanaged switches (like most consumer-grade models) will not properly handle multiple connections between them. This can cause:

• Network loops causing broadcast storms
• Spanning Tree Protocol (STP) blocking redundant paths
• No actual bandwidth aggregation

For true bandwidth multiplication, you need:

1. Managed switches supporting 802.3ad (LACP)
2. Proper configuration on both switches
3. Matching port configurations (speed/duplex)

Here's sample Cisco IOS configuration for LACP:

interface Port-channel1
 switchport mode trunk
!
interface GigabitEthernet0/1
 channel-group 1 mode active
!
interface GigabitEthernet0/2
 channel-group 1 mode active

If using unmanaged switches, your best options are:

1. Upgrade to a higher-speed single connection (e.g., 10Gbps)
2. Segment traffic across different switches
3. Replace with a single larger switch

Use iperf3 to verify actual throughput:

# Server side
iperf3 -s

# Client side
iperf3 -c server_ip -P 4