Cisco Systems N3KC3064TFAL3 Manual De Usuario
In these cases, the UDLD aggressive mode disables one of the ports on the link, which prevents traffic from
being discarded.
being discarded.
About Interface Speed
A Cisco Nexus 3000 Series switch has a number of fixed 10-Gigabit ports, each equipped with SFP+ interface
adapters.
adapters.
About the Cisco Discovery Protocol
The Cisco Discovery Protocol (CDP) is a device discovery protocol that runs over Layer 2 (the data link layer)
on all Cisco-manufactured devices (routers, bridges, access servers, and switches) and allows network
management applications to discover Cisco devices that are neighbors of already known devices. With CDP,
network management applications can learn the device type and the Simple Network Management Protocol
(SNMP) agent address of neighboring devices running lower-layer, transparent protocols. This feature enables
applications to send SNMP queries to neighboring devices.
on all Cisco-manufactured devices (routers, bridges, access servers, and switches) and allows network
management applications to discover Cisco devices that are neighbors of already known devices. With CDP,
network management applications can learn the device type and the Simple Network Management Protocol
(SNMP) agent address of neighboring devices running lower-layer, transparent protocols. This feature enables
applications to send SNMP queries to neighboring devices.
CDP runs on all media that support Subnetwork Access Protocol (SNAP). Because CDP runs over the data-link
layer only, two systems that support different network-layer protocols can learn about each other.
layer only, two systems that support different network-layer protocols can learn about each other.
Each CDP-configured device sends periodic messages to a multicast address, advertising at least one address
at which it can receive SNMP messages. The advertisements also contain time-to-live, or holdtime information,
which is the length of time a receiving device holds CDP information before discarding it. Each device also
listens to the messages sent by other devices to learn about neighboring devices.
at which it can receive SNMP messages. The advertisements also contain time-to-live, or holdtime information,
which is the length of time a receiving device holds CDP information before discarding it. Each device also
listens to the messages sent by other devices to learn about neighboring devices.
The switch supports both CDP Version 1 and Version 2.
Default CDP Configuration
The following table shows the default CDP configuration.
Table 3: Default CDP Configuration
Default Setting
Feature
Enabled
CDP interface state
60 seconds
CDP timer (packet update frequency)
180 seconds
CDP holdtime (before discarding)
Enabled
CDP Version-2 advertisements
About the Error-Disabled State
An interface is in the error-disabled (err-disabled) state when the inteface is enabled administratively (using
the no shutdown command) but disabled at runtime by any process. For example, if UDLD detects a
unidirectional link, the interface is shut down at runtime. However, because the interface is administratively
the no shutdown command) but disabled at runtime by any process. For example, if UDLD detects a
unidirectional link, the interface is shut down at runtime. However, because the interface is administratively
Cisco Nexus 3000 NX-OS Layer 2 Switching Configuration Guide, Release 5.0(3)U3(1)
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OL-26590-01
Configuring Ethernet Interfaces
About Interface Speed