H3C Technologies H3C S12500-X Series Switches - Manual (Page 176)

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With CDP compatibility enabled on the switch, the switch can use LLDP to receive and recognize the CDP
packets received from the directly-connected device and send CDP packets to the directly-connected
device. The packets that the switch sends to the neighboring CDP device carry the device ID, the ID of the
port connecting to the neighboring device, the port IP address, the PVID, and the TTL. The port IP address
is the main IP address of the VLAN interface that is in up state and whose corresponding VLAN ID is the
lowest among the VLANs permitted on the port. If none of the VLAN interfaces of the permitted VLANs
is assigned an IP address or all VLAN interfaces are down, no port IP address will be advertised. The
CDP neighbor-information-related fields in the output of the display lldp neighbor-information command
show the CDP neighboring device information that can be recognized by the switch. For more
information about the display lldp neighbor-information command, see Layer 2—LAN Switching
Command Reference.
Configuration prerequisites
Before you configure CDP compatibility, complete the following tasks:
• Globally enable LLDP.
• Enable LLDP on the port connecting to a device supporting CDP, and configure the port to operate
in TxRx mode.
Configuration procedure
CDP-compatible LLDP operates in one of the following modes:
• TxRx—CDP packets can be transmitted and received.
• Disable—CDP packets cannot be transmitted or received.
LLDP traps are sent periodically, and the interval is configurable. To make CDP-compatible LLDP take
effect on specific ports, first enable CDP-compatible LLDP globally, and then configure CDP-compatible
LLDP to operate in TxRx mode.
The maximum TTL value that CDP allows is 255 seconds. To make CDP-compatible LLDP work correctly
with Cisco IP phones, configure the LLDPDU transmit interval to be no more than 1/3 of the TTL value.
To enable LLDP to be compatible with CDP:
Step Command Remarks
1. Enter system view. system-view N/A
2. Enable CDP compatibility
globally.
lldp compliance cdp
By default, CDP compatibility is
disabled globally.
3. Enter Layer 2 or Layer 3
Ethernet interface view.
interface interface-type
interface-number
N/A
4. Configure CDP-compatible
LLDP to operate in TxRx mode.
lldp compliance admin-status cdp
txrx By default, CDP-compatible LLDP
operates in Disable mode.
Configuring DCBX
Data Center Ethernet (DCE), also known as Converged Enhanced Ethernet (CEE), is enhancement and
expansion of traditional Ethernet local area networks for use in data centers. DCE uses the Data Center