What is Cisco SPAN port?
Switch port Analyzer (SPAN) is an efficient, high performance traffic monitoring system. It duplicated network traffic to one or more monitor interfaces as it transverse the switch. SPAN is used for troubleshooting connectivity issues and calculating network utilization and performance, among many others.
What is SPAN port in networking?
What is a SPAN port? SPAN (Switched Port Analyzer) is a dedicated port on a switch that takes a mirrored copy of network traffic from within the switch to be sent to a destination. The destination is typically a monitoring device, or other tools used for troubleshooting or traffic analysis.
How do I configure a port SPAN on a Cisco switch?
Each SPAN session must have a destination port that receives a copy of the traffic from the source ports and VLANs. A destination port has these characteristics: A destination port must reside on the same switch as the source port (for a local SPAN session). A destination port can be any Ethernet physical port.
What is SPAN VLAN?
A VLAN SPAN (VSPAN) configuration is a monitor session whose source is a VLAN rather than specific interfaces. When a VLAN is the source of a monitor session, all physical interfaces that are members of the VLAN are also sources. In a VSPAN configuration, the monitor session is still sourced from physical interfaces.
How does span port work?
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.
Can you span a port channel?
You can configure the source channels for a SPAN session. These ports can be port channels, SAN port channels, VLANs, and VSANs. The monitored direction can only be ingress and applies to all physical ports in the group.
Can you span a trunk port?
When you monitor a trunk port as a source port, by default, all VLANs active on the trunk are monitored. You can limit SPAN traffic monitoring on trunk source ports to specific VLANs by using VLAN filtering.
What is the purpose of port mirroring?
Port mirroring is used on a network switch to send a copy of network packets seen on one switch port (or an entire VLAN) to a network monitoring connection on another switch port.
Does port mirroring cause downtime?
Just wondering if it will affect the network performance in a time-critical environment. In short, no. This sort of thing happens all the time with frames that have unknown destinations or are broadcasts. Typically, duplication and forwarding are done in hardware at wire speed.
What is remote span?
A remote SPAN (RSPAN) is sourced in the same manner as a traditional SPAN, either from individual ports or all ports in a VLAN. An RSPAN consumes one SPAN session in the same way that a local SPAN does, however, the RSPAN uses a VLAN for a destination instead of an interface.
What are the features of span in Cisco?
Table 1. Default SPAN Configuration Feature Default Setting SPAN state Disabled. Source port traffic to monitor Both received and sent traffic ( both ) Encapsulation type (destination port) Native form (untagged packets). Ingress forwarding (destination port) Disabled.
How does span analyze traffic between source ports?
SPAN analyzes all traffic between source ports by directing the SPAN session traffic to a destination port with an external analyzer attached to it. You can define the sources and destinations to monitor in a SPAN session on the local device. The interfaces from which traffic can be monitored are called SPAN sources.
Which is Cisco encapsulated remote span ( erspan )?
Encapsulated remote SPAN (ERSPAN): encapsulated Remote SPAN (ERSPAN), as the name says, brings generic routing encapsulation (GRE) for all captured traffic and allows it to be extended across Layer 3 domains. ERSPAN is a Cisco proprietary feature and is available only to Catalyst 6500, 7600, Nexus, and ASR 1000 platforms to date.
How does RSPAN work on a Cisco switch?
RSPAN works by mirroring the traffic from the source ports of an RSPAN session onto a VLAN that is dedicated for the RSPAN session. This VLAN is then trunked to other switches, allowing the RSPAN session traffic to be transported across multiple switches.