3Com 2928 User Guide - Page 265

Item TTL Multiplier Trap Interval Reinit Delay Tx Delay Description Set the TTL multiplier. The TTL TLV carried in an LLDPDU determines how long the device information carried in the LLDPDU can be saved on a recipient device. You can configure the TTL of locally sent LLDPDUs to determine how long information about the local device can be saved on a neighbor device by setting the TTL multiplier. The TTL is expressed as TTL multiplier × LLDPDU transit interval. z If the product of the TTL multiplier and the LLDPDU transmit interval is greater than 65535, the TTL carried in transmitted LLDPDUs takes 65535 seconds. z As the maximum TTL allowed by CDP is 255 seconds, you must ensure that the product of the TTL multiplier and the LLDPDU transmit interval is less than 255 seconds for CDP-compatible LLDP to work properly with Cisco IP phones. Set the minimum interval for sending traps. With the LLDP trapping function enabled on a port, traps are sent out the port to advertise the topology changes detected over the interval to neighbors. By tuning this interval, you can prevent excessive traps from being sent when topology is instable. Set initialization delay for LLDP-enabled ports. Each time the LLDP operating mode of a port changes, its LLDP protocol state machine re-initializes. To prevent LLDP from being initialized too frequently at times of frequent operating mode change, initialization delay is introduced. With this delay mechanism, a port must wait for the specified interval before it can initialize LLDP after the LLDP operating mode changes. Set LLDPDU transmit delay. With LLDP enabled, a port advertises LLDPDUs to its neighbors both periodically and when the local configuration changes. To avoid excessive number of LLDPDUs caused by frequent local configuration changes, an LLDPDU transmit delay is introduced. Thus, after sending an LLDPDU, the port must wait for the specified interval before it can send another one. LLDPDU transmit delay must be less than the TTL to ensure that the LLDP neighbors can receive LLDPDUs to update information about the device you are configuring before it is aged out. Set the LLDPDU transmit interval. Tx Interval If the product of the TTL multiplier and the LLDPDU transmit interval is greater than 65535, the TTL carried in transmitted LLDPDUs takes 65535 seconds. In this case, the likelihood exists that the LLDPDU transmit interval is greater than TTL. You should avoid the situation, because the LLDP neighbors will fail to receive LLDPDUs to update information about the device you are configuring before it is aged out. Return to LLDP Configuration Task List. Displaying LLDP Information for a Port Select Network > LLDP from the navigation tree to enter the Port Setup tab, as shown in Figure 1-4. In the port list click a port name to display its LLDP information at the lower half of the page. The LLDP 1-14