Effect Of Spanning Tree (Stp) On Cdp Packet Transmission - HP Switch 2800 Series Management And Configuration Manual

Configuring for Network Management Applications
CDP
13-36
Changing the Transmission Interval for Outbound CDP Packets.
Syntax: cdp timer < 5 . . 254 >
Changes the interval the switch uses to transmit CDP packets
describing itself to neighbor devices. (Default: 60 seconds)
For example, if the switch's transmit interval for CDP packets was set to a
non-default value, you would use this command to reset it to one minute:
HPswitch(config) cdp timer 60
Changing the Hold Time (CDP Packet Time-To-Live) for a Switch's
CDP Packet Information. This parameter is controlled in the transmitting
switch, and applies to all outbound CDP packets the switch transmits.
Syntax: cdp holdtime < 5 . . 254 >
Changes the hold time for the switch's CDP packet informa­
tion in the CDP Neighbors table of another CDP-aware
device. (Default: 180 seconds; Range: 10 - 255 seconds.)
For example, to configure a switch's outbound CDP packets to live for one
minute in the CDP Neighbors table of neighboring CDP devices:
HPswitch(config) cdp holdtime 60
Effect of Spanning Tree (STP) On CDP Packet
Transmission
If STP has blocked a port on the switch, that port does not transmit CDP
packets. However, the port still receives CDP packets if the device on the other
end of the link has CDP enabled. Thus, for example, if switch "A" has two ports
linked to switch "B" (which is a CDP neighbor and also the STP root device)
and STP blocks traffic on one port and forwards traffic on the other: