What is a SPAN port?

A SPAN port (sometimes called a mirror port) is a software feature built into a switch or router that creates a copy of selected packets passing through the device and sends them to a designated SPAN port. Using software, the administrator can easily configure or change what data is to be monitored.

What is SPAN port or tap?

A tap is a purpose-built device that passively makes a copy of network data but does not alter the data. SPAN ports, also called mirror ports, are part of Layer 2 and 3 network switches. They are active devices and will require you to program them to copy the data desired.

What is SPAN destination port?

SPAN Terminology Source (SPAN) port —A port that is monitored with use of the SPAN feature. Source (SPAN) VLAN —A VLAN whose traffic is monitored with use of the SPAN feature. Destination (SPAN) port —A port that monitors source ports, usually where a network analyzer is connected.

What is a monitoring or SPAN Switched Port Analyzer ]) port What is it used for?

Setting up SPAN ports The Switched Port Analyzer (SPAN) feature, sometimes called port mirroring or port monitoring, allows you to take a copy of network traffic as it passes through a network switch. You use it to send a copy of network packets seen on one switch port (or an entire VLAN) to another switch port.

What happens when there are no SPAN ports?

Most switches will give you the option of creating two SPAN ports. While this may be enough for most networks, you may end up with a situation where no SPAN ports are available. In these cases, you could consider a network TAP (test access point). A passive network TAP operates by duplicating data from one port to one or more others.

Where do you find a SPAN port on a switch?

SPAN ports are typically found on network switch gear and the feature is used to send a copy of network packets seen on one switch port (or an entire VLAN) to another switch port.

What’s the difference between a tap and a SPAN port?

Unlike a network TAP, SPAN ports filter out physical layer errors, making some types of analyses more difficult, and as we have seen, incorrect delta times and altered frames can cause additional problems. TAPs, on the other hand, can run full duplex 1G links.

Where does the packet from a SPAN port go?

Because of this, the impact SPAN has on switch operation can vary. On the Cisco Catalyst 5500/5000 and 6500/6000 series switches, a packet received on a port is transmitted on the internal switching bus. Every line card in the switch starts storing this packet in its internal buffers.