HP 6125G HP 6125G & 6125G/XG Blade Switches Layer 2 - LAN Switching Co - Page 212

Setting an encapsulation format for LLDPDUs, Configuring CDP compatibility

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Step 5. Set the number of LLDPDUs sent each time fast LLDPDU transmission is triggered. Command lldp fast-count count Remarks Optional. 3 by default. Setting an encapsulation format for LLDPDUs LLDPDUs can be encapsulated in the following formats: Ethernet II or SNAP frames. • With Ethernet II encapsulation configured, an LLDP port sends LLDPDUs in Ethernet II frames and processes only incoming, Ethernet II encapsulated LLDPDUs. • With SNAP encapsulation configured, an LLDP port sends LLDPDUs in SNAP frames and processes only incoming, SNAP encapsulated LLDPDUs. By default, Ethernet II frames encapsulate LLDPDUs. If the neighbor devices encapsulate LLDPDUs in SNAP frames, configure the encapsulation format for LLDPDUs as SNAP to guarantee normal communication with the neighbors. To set the encapsulation format for LLDPDUs to SNAP: Step 1. Enter system view. 2. Enter Layer 2 Ethernet interface view. 3. Set the encapsulation format for LLDPDUs to SNAP. Command system-view interface interface-type interface-number lldp encapsulation snap Remarks N/A N/A Ethernet II encapsulation format applies by default. NOTE: LLDP-CDP (Cisco Discovery Protocol) packets use only SNAP encapsulation. Configuring CDP compatibility To make your device work with Cisco IP phones, you must enable CDP compatibility. If your LLDP-enabled device cannot recognize CDP packets, it does not respond to the requests of Cisco IP phones for the voice VLAN ID configured on the device. As a result, a requesting Cisco IP phone sends voice traffic without any tag to your device, and, as a result, your device cannot differentiate the voice traffic from other types of traffic. With CDP compatibility enabled, your device can receive and recognize CDP packets from a Cisco IP phone and respond with CDP packets, which carry the voice VLAN configuration TLVs. According to the voice VLAN configuration TLVs, the IP phone automatically configures the voice VLAN. As a result, the voice traffic is confined in the configured voice VLAN, and differentiated from other types of traffic. For more information about voice VLANs, see "Configuring a voice VLAN." Configuration prerequisites Before you configure CDP compatibility, complete the following tasks: 203

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203
Step
Command
Remarks
5.
Set the number of LLDPDUs
sent each time fast LLDPDU
transmission is triggered.
lldp fast-count
count
Optional.
3 by default.
Setting an encapsulation format for LLDPDUs
LLDPDUs can be encapsulated in the following formats: Ethernet II or SNAP frames.
With Ethernet II encapsulation configured, an LLDP port sends LLDPDUs in Ethernet II frames and
processes only incoming, Ethernet II encapsulated LLDPDUs.
With SNAP encapsulation configured, an LLDP port sends LLDPDUs in SNAP frames and processes
only incoming, SNAP encapsulated LLDPDUs.
By default, Ethernet II frames encapsulate LLDPDUs. If the neighbor devices encapsulate LLDPDUs in
SNAP frames, configure the encapsulation format for LLDPDUs as SNAP to guarantee normal
communication with the neighbors.
To set the encapsulation format for LLDPDUs to SNAP:
Step
Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Enter Layer 2 Ethernet
interface view.
interface
interface-type interface-number
N/A
3.
Set the encapsulation
format for LLDPDUs to
SNAP.
lldp encapsulation
snap
Ethernet II encapsulation
format applies by default.
NOTE:
LLDP-CDP (Cisco Discovery Protocol) packets use only SNAP encapsulation.
Configuring CDP compatibility
To make your device work with Cisco IP phones, you must enable CDP compatibility.
If your LLDP-enabled device cannot recognize CDP packets, it does not respond to the requests of Cisco
IP phones for the voice VLAN ID configured on the device. As a result, a requesting Cisco IP phone sends
voice traffic without any tag to your device, and, as a result, your device cannot differentiate the voice
traffic from other types of traffic.
With CDP compatibility enabled, your device can receive and recognize CDP packets from a Cisco IP
phone and respond with CDP packets, which carry the voice VLAN configuration TLVs. According to the
voice VLAN configuration TLVs, the IP phone automatically configures the voice VLAN. As a result, the
voice traffic is confined in the configured voice VLAN, and differentiated from other types of traffic.
For more information about voice VLANs, see "
Configuring a voice VLAN
."
Configuration prerequisites
Before you configure CDP compatibility, complete the following tasks: