Full solution of layer-3 Switch Port initialization process

It is very helpful to know about layer-3 switch ports. Here we mainly introduce the process of layer-3 Switch Port initialization. It may take 30 seconds or more to connect a computer to a vswitch before the computer can communicate over the network. If you are waiting for a long time, 30 seconds of waiting will make you feel very long. Let's take a look at how to accelerate the layer-3 Switch Port initialization process.

Measure the test taker's knowledge about the port initialization process of a layer-3 switch.

When a device is connected to a layer-3 Switch Port, the layer-3 Switch Port usually goes through four steps. Let's take a closer look.

Spanning Tree Protocol (STP) initialization

STP is an IEEE 802.1d protocol that prevents loops in a LAN. It is necessary to test the vswitch port. When STP is enabled, a loop is formed within the LAN. If a hub, vswitch, or vro is connected, STP is very important. On the other hand, if a computer, printer, server, or laptop is connected, the STP initialization process is not needed. During the STP initialization phase, the port goes through five stages of STP: blocking, listening, learning, forwarding, and failure. The entire process takes 15 seconds. Therefore, if you are sure what you want to connect to, you can terminate this process.

Test the Ethernet Channel Configuration

The next step is to test the Ethernet channel, which is bound with the layer-3 Switch Port to provide more Ethernet connections. If one channel fails, the Ethernet channel usually provides redundancy. This process uses the port aggregation protocol PAgP), which takes about 15 seconds.

Trunk configuration test wired and wireless networks

Next, the switch starts to test whether the port is a port that is interconnected between the Trunk ports ). TRUNKING exchanges data between multiple VLANs through a single layer-3 Switch Port. The test on the Trunk port takes very little time. Of course, you can disable it and save 1 or 2 seconds.

Layer-3 switch port speed and full-duplex adaptive

Finally, the switch port entry speed and full-duplex automatic handshake. For example, a vswitch port can support full duplex speed of 1000 Mb (1 Gb), but the client only supports full duplex of Mb, the maximum rate that the switch and customer can automatically negotiate with each other.

You can hard-code the process during vswitch initialization to save time. However, this is not always a good choice, because it may not know how fast the client supports. This adaptive time is not long, so consider whether it is worthwhile to perform hard encoding on each vswitch port. Now we have reviewed the different phases of layer-3 Switch Port initialization. Let's see how much time can be saved. Perform the following steps to save a port initialization time of more than 30 seconds for a Cisco IOS-based switch:

Set the layer-3 Switch Port to Access mode. This can cancel the Trunk negotiation and prevent the port from entering the Ethernet channel negotiation. This can save the initialization process 15 seconds. Configure PortFast. This can prevent the port from entering STP negotiation and save 15 seconds.