D-Link DES-3326 manual Hello Packet

DES-3326 Layer 3 Fast Ethernet Switch User’s Guide

The format of the Hello packet is shown below:

Hello Packet

Version No. 1

Packet Length

Router ID

Area ID

	Checksum		Authentication Type
			Authentication
			Authentication
			Network Mask
	Hello Interval		Options	Router Priority
			Router Dead Interval
			Designated Router
			Backup Designated Router
			Neighbor
		Figure 5-26. Hello Packet
Field			Description
Network Mask		The network mask associated with this interface.
Options		The optional capabilities supported by the router.
Hello Interval		The number of seconds between this router’s Hello
		packets.
Router Priority		This router’s Router Priority. The Router Priority is
		used in the election of the DR and BDR. If this field
		is set to 0, the router is ineligible to become the DR
		or the BDR.
Router Dead Interval		The number of seconds that must pass before
		declaring a silent router as down.
Designated Router		The identity of the DR for this network, in the view of
		the advertising router. The DR is identified here by
		its IP interface address on the network.
Backup Designated Router		The identity of the Backup Designated Router (BDR)
		for this network. The BDR is identified here by its IP
		interface address on the network. This field is set to
		0.0.0.0 if there is no BDR.
Neighbor		The Router Ids of each router from whom valid Hello
		packets have been seen within the Router Dead
		Interval on the network.

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