Switch User Manual

Configuring DVMRP
SecureStack C3 Configuration Guide 20-33
Configuring DVMRP
Purpose
ToenableandconfiguretheDistanceVectorM ulticastRoutingProtocol(DVMRP)onaninterface.
DVMRProutesmulticasttrafficusingatechniqueknownasReversePathForwarding.Whena
routerreceivesapacket,itfloodsthepacketoutofallpathsexcepttheonethatleadsbacktothe
packet’ssource.Doing
soallowsadatastreamtoreachallVLANs(possiblymultipletimes).Ifa 
routerisattachedtoasetofVLANsthatdonotwanttoreceivefromaparticularmulticastgroup,
theroutercansenda“prune”messagebackupthedistributiontreetostopsubsequentpackets
from
travelingwheretherearenomembers.DVMRPwillperiodicallyrefloodinordertoreach
anynewhoststhatwanttoreceivefromaparticulargroup.
Commands
Seealsoshowipmrouteonpage20‐59,whichcanbeusedtodisplaytheIPmulticastrouting
table.
Enabling DVMRP on an Interface
DVMRPisdisabledbydefault,bothgloballyandoneachinterface.EnablingDVMRPonarouted
interfacerequirescompletingthestepslistedinTable 20‐1.
* Advanced License Required *
DVMRP is an advanced routing feature that must be enabled with a license key. If you have purchased an
advanced license key, and have enabled routing on the device, you must activate your license as described in
the chapter entitled “Activating Licensed Features” in order to enable the DVMRP command set. If you wish
to purchase an advanced routing license, contact Enterasys Networks Sales.
Note: An Enterasys Networks Feature Guide document containing an in-depth discussion of
multicast configuration is located on the Enterasys Networks web site:
http://www.enterasys.com/support/manuals/
Note: IGMP must be enabled on all VLANs running DVMRP, and must also be globally enabled
on the SecureStack C3. For details on enabling IGMP, refer to Chapter 13.
For information about... Refer to page...
ip dvmrp 20-34
ip dvmrp enable 20-34
ip dvmrp metric 20-35
show ip dvmrp 20-35