Speed determination issues can result in no connectivity. However, issues with autonegotiation of duplex generally do not result in link establishment issues. Instead, autonegotiation issues mainly result in performance-related issues. 

Below is the table —Autonegotiation Valid Configuration

Configuration NIC (Speed/Duplex)Configuration Switch (Speed/Duplex)Resulting NIC Speed/DuplexResulting Catalyst Speed/DuplexComments
AUTOAUTO1000 Mbps, Full-duplex1000 Mbps, Full-duplexAssuming maximum capability of Catalyst switch, and NIC is 1000 Mbps, full-duplex.
1000 Mbps, Full-duplexAUTO1000 Mbps, Full-duplex1000 Mbps, Full-duplexLink is established, but the switch does not see any autonegotiation information from NIC. Since Catalyst switches support only full-duplex operation with 1000 Mbps, they default to full-duplex, and this happens only when operating at 1000 Mbps.
AUTO1000 Mbps, Full-duplex1000 Mbps, Full-duplex1000 Mbps, Full-duplexAssuming maximum capability of NIC is 1000 Mbps, full-duplex.
1000 Mbps, Full-duplex1000 Mbps, Full-duplex1000 Mbps, Full-duplex1000 Mbps, Full-duplexCorrect Manual Configuration
100 Mbps, Full-duplex1000 Mbps, Full-duplexNo LinkNo LinkNeither side establishes link, due to speed mismatch
100 Mbps, Full-duplexAUTO100 Mbps, Full-duplex100 Mbps, Half-duplexDuplex Mismatch 
AUTO100 Mbps, Full-duplex100 Mbps, Half-duplex100 Mbps, Full-duplexDuplex Mismatch 
100 Mbps, Full-duplex100 Mbps, Full-duplex100 Mbps, Full-duplex100 Mbps, Full-duplexCorrect Manual Configuration
100 Mbps, Half-duplexAUTO100 Mbps, Half-duplex100 Mbps, Half-duplexLink is established, but switch does not see any autonegotiation information from NIC and defaults to half-duplex when operating at 10/100 Mbps.
10 Mbps, Half-duplexAUTO10 Mbps, Half-duplex10 Mbps, Half-duplexLink is established, but switch does not see Fast Link Pulse (FLP) and defaults to 10 Mbps half-duplex.
10 Mbps, Half-duplex100 Mbps, Half-duplexNo LinkNo LinkNeither side establishes link, due to speed mismatch.
AUTO100 Mbps, Half-duplex100 Mbps, Half-duplex100 Mbps, Half-duplexLink is established, but NIC does not see any autonegotiation information and defaults to 100 Mbps, half-duplex.
AUTO10 Mbps, Half-duplex10 Mbps, Half-duplex10 Mbps, Half-duplexLink is established, but NIC does not see FLP and defaults to 10 Mbps, half-duplex.