Hon'ble Prime Minister's Interaction with IT Professionals

DHCP Server and unnecessary traffic for your DHCP server.

Have you ever implemented central DHCP server for all of your network (VLANS), and you used a command "IP Helper-Address? The ip helper-address will actually forward many other UDP-based broadcasts to the address specified as tft, dns, time, netbios-ns, netbios-dgm, tacacs, bootpc, bootps etc. 

Many times it is generating unnecessary traffic for your DHCP server. Have you applied "ip forward-protocol udp ...." command to prevent this?

Voice VLAN and Port Fast Combination on Cisco Switch

The Port Fast feature is automatically enabled when voice VLAN is configured. When you disable voice VLAN, the Port Fast feature is not automatically disabled.

Why?
I will be share shortly. 

Design Tips: Guide for choose VLAN Number

Design Tip— To ensure optimal convergence for voice traffic Cisco recommends that VLAN number assignments be mapped such that the most loss-sensitive applications such as voice are assigned the lowest VLAN numbers on each physical interface, as shown in table:

Table Recommendations for VLAN Assignments 

VLAN Function	VLAN Interface
Wired_Voice_VLAN	7
Wireless_Voice_VLAN	57
Wired_Data_VLAN	107
Wireless_Multicast_VLAN	157

Not all VLANs trunked on a specific interface converge at the same time. Cisco IOS throttles the notifications for VLAN loss to the routing process (EIGRP/OSPF) at a rate of one every 100 msec. As an example, if you configure six VLANs per access switch, upon failure of an uplink, fiber traffic on the sixth VLAN converges 500 msec after the first.