When the computer is connected to a Cisco switch, it may take 30 seconds or more time, and the computer can communicate using the network. If you are waiting to be used, wait for 30 seconds to wait enough to make you feel extremely long. Let's take a look at how to accelerate the port initialization process.
Understand the process of initialization of switches
When the device is connected to the port of the switch that has been started, the switch port generally experiences 4 steps. Let's take a closer look.
Generated Tree Protocol (STP) initialization
STP is an IEEE 802.1D protocol that prevents a loop in a local area network. Testing this switch port is necessary; a cycle is formed in the LAN when starting STP. If it comes up is a hub, switch or router, STP is important. On the other hand, if it comes up, it is a computer, printer, server, or a laptop, then the STP initialization process does not need.
In the middle of the STP initialization phase, the port will experience 5 stages of STP: blocking, listening, learning, forwarding, and failure. The whole process is 15 seconds. So if you determine what will be connected, you can terminate this process.
Ethernet configuration test
The next process is a test of the Ethernet channel, which is bound to the switch port to provide more Ethernet connections. If a channel is not, the Ethernet will usually provide redundancy. This process uses a port aggregation protocol (PAGP), which is about 15 seconds.
Trunk configuration test Wired and Wi-Fi
Next, the switch starts testing whether the port is a Trunk port (port between the interconnection between the switches). Trunking switches data between multiple VLANs through a single switch port. There is very little time for Trunk ports, of course, you can also ban it, save 1, 2 seconds.
Switch port speed and full-duplex adaptive
Finally, the switch port enters the speed and the automatic handshake of the full duplex. For example, a switch port supports 1000MB (1GB) full-duplex speed, but the client only supports 100MB full-duplex, the switch and client automatically negotiates the highest rate that can support each other.
This process can be hardcoded to save time during the switch initialization process. But this is not always a good choice, because it may not be known that the speed of the client support is much. This adaptive time is not long, so you may wish to consider whether it is worth considering if you want to make a hard coding of each switch port.
Now we have reviewed the different phases of the initialization of the switch port, let us see how much time can be saved from it.
Perform the following steps, you can save more than 30 seconds of port initialization time for a switch based on the Cisco IOS protocol:
Set the switch port to Access mode. This can cancel the Trunk negotiation and block the port from entering the Ethernet access negotiation. This can save the initialization process for 15 seconds.
Configure Portfast. This prevents the port from entering the STP negotiation and saves another 15 seconds.
Here is an example:
Switch (config) # int FA0 / 21
Switch (config-if) # switchport mode access
Switch (config-if) # spanning-tree portfast
% Warning: Only Enable Portfast On Ports Connected to a Single Host.
Connecting Hubs, Concentrators, Switches, Bridges, etc. To this
Interface when You've Portfast Cause Temporary Bridge Loops.
Use with caution.
% This Has Configured Portfast On Fastethernet0 / 21 But Will Only
Have an Effect When The Interface Is in A Non-Trunking Mode.
Switch (config-if) # no shutdownswitch (config-if) #
You can also set up on a series of ports, such as:
Switch (config) # int Ran FasteThernet 0/1 - 24
Switch (config-if-range) # switchport mode access
Switch (config-if-range) # spanning-tree portfast
If you feel that you can set the speed of the switch port, save a little time. The following is an example.
Switch (config-if) # Speed 100
Switch (config-if) # duplex full
By prohibiting STP initialization, Trunk negotiation, Ethernet negotiation can save the initialization process for 30 seconds. Alternatively, you can use the range command of the interface to set all ports of the switch.
