Hi Aksher,
1- Trunk port are used to carry multiple vlan traffic across the Switches.
2- Duplex Auto means switch will try to negotiate the duplex mode to be half or full depending upon neighboring device. it also depend upon type of ethernet interface also like 1gbps interface will negotiate to full duplex ist than try half duplex. but 10/100 fastethernet interface try to use 10 mbps half 1st than 10 full and than 100 half and than 100 full. in cisco switches they use FLP fast link pulse method to select the duplex.
The 802.3u committee defined Fast Link Pulse (FLP) to support the autonegotiation process.10BaseT's Link Integrity Test, sends a series of pulses on the link announcing its capabilities. The other end also transmits FLP announcements, and the two ends settle on whatever method has highest priority in common between them
Autonegotiation
Method
1 100BaseT2 full duplex
2 100BaseT2 half duplex
3 100BaseTX full duplex
4 100BaseT4 (Only half duplex)
5 100BaseTX half duplex
6 10BaseT full duplex
7 10BaseT half duplex
Non-negotiate function will turn off the this function and switch has to manually set duplex.
please rate if helps.
HTH
kamlesh
