Cisco SF200-24 Administration Manual page 62

Configuring Discovery
LLDP and CDP
NOTE
NOTE
Cisco Small Business 200 1. 1 Series Smart Switch Administration Guide
• If CDP/LLDP is globally disabled, the switch can be configured to discard,
VLAN-aware flooding, or VLAN-unaware flooding of all incoming CDP/LLDP
packets. VLAN-aware flooding floods an incoming CDP/LLDP packet to the
VLAN where the packet is received excluding the ingress port. VLAN-
unaware flooding floods an incoming CDP/LLDP packet to all the ports
excluding the ingress port. The default is to discard CDP/LLDP packets
when CDP/LLDP is globally disabled. You can configure the discard/
flooding of incoming CDP and LLDP packets from the CDP Properties page
and the LLDP Properties page respectively.
• Auto Smartport requires CDP and/or LLDP to be enabled. Auto Smartport
automatically configures an interface based on the CDP/LLDP
advertisement received from the interface.
• CDP and LLDP end devices, such as IP phones, learn the voice VLAN
configuration from CDP and LLDP advertisements. By default, the switch is
enabled to send out CDP and LLDP advertisement based on the voice
VLAN configured at the switch. Refer to the Voice VLAN and Auto Voice
VLAN sections for details.
CDP/LLDP does not distinguish if a port is in a LAG. If there are multiple ports in a
LAG, CDP/LLDP transmit packets on each port without taking into account the fact
that the ports are in a LAG.
The operation of CDP/LLDP is independent of the STP status of an interface.
If 802. 1 x port access control is enabled at an interface, the switch will transmit and
receive CDP/LLDP packets to and from the interface only if the interface is
authenticated and authorized.
If a port is the target of mirroring, then for CDP/LLDP it is considered down.
CDP and LLDP are link layer protocols for directly connected CDP/LLDP capable
devices to advertise themselves and their capabilities. In deployments where the
CDP/LLDP capable devices are not directly connected and are separated with
CDP/LLDP incapable devices, the CDP/LLDP capable devices may be able to
receive the advertisement from other device(s) only if the CDP/LLDP incapable
devices flood the CDP/LLDP packets they receives. If the CDP/LLDP incapable
devices perform VLAN-aware flooding, then CDP/LLDP capable devices can hear
each other only if they are in the same VLAN. It should be noted that a CDP/LLDP
capable device may receive advertisement from more than one device if the CDP/
LLDP incapable devices flood the CDP/LLDP packets.
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