ZyXEL Communications GS-4024 - Manual (Page 246)

Chapter 30 DVMRP
GS-4012F/4024 User’s Guide
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Figure 132 How DVMRP Works
30.2.1 DVMRP Terminology
DVMRP probes are used to discover other DVMRP Neighbors on a network.
DVMRP reports are used to exchange DVMRP source routing information. These packets are
used to build the DVMRP multicast routing table that is used to build source trees and also
perform Reverse Path Forwarding (RPF) checks on incoming multicast packets. RPF checks
prevent duplicate packets being filtered when loops exist in the network topology.
DVMRP prunes trim the multicast delivery tree(s). DVMRP grafts attach a branch back onto
the multicast delivery tree.
30.3 Configuring DVMRP
Configure DVMRP on the Switch when you wish it to act as a multicast router (“mrouter”).
Click IP Application, DVMRP in the navigation panel to display the screen as shown.
Figure 133 DVMRP
The following table describes the labels in this screen.
Table 93 DVMRP
LABEL DESCRIPTION
Active Select Active to enable DVMRP on the Switch. You should do this if you want the Switch
to act as a multicast router.
Threshold Threshold is the maximum time to live (TTL) value. TTL is used to limit the scope of
multicasting. You should reduce this value if you do not wish to flood Layer 3 devices many
hops away with multicast traffic. This applies only to multicast traffic this Switch sends out.