Tips For The Configuration - Hirschmann MACH 4000 User Manual

Multicast Routing

9.5.3 Tips for the configuration

Selection of the PIM-DM Multicast routing protocol
You select PIM-DM if your application requires fast switching times and is
able to tolerate any packet duplications during the switching time. You set
fast switching times by reducing the "Hello Time".
Packet duplications occur when multiple routers are connected to a
subnetwork. In this case, the Assert Process clarifies which router is
permitted to send into the subnetwork. Until this is clarified, all routers
send into this subnetwork.
Selection of the DVMRP Multicast routing protocol
You select DVMRP if your application does not tolerate packet
duplications and is content with higher switching times.
DVMRP provides a big advantage when you are using subdivided
subnetworks/VLANs in a HIPER-Ring. Using its own Multicast routing
tables, DVMRP already knows the topology and thus prevents packet
duplications.
Reducing the switching times
With both DVMRP and PIM-DM you can reduce the switching times by
reducing the IGMP Querier Interval on the router interface. This reduction
becomes effective when an inactive router to which Multicast recipients
are connected becomes active again.
enable
configure
interface 2/1
ip igmp query-max-response-
time 10
ip igmp query-interval 5
Routing L3P
Release 4.0 11/07
9.5 Multicast Configuration
Switch to the Priviledged EXEC mode.
Switch to the Configuration mode.
Switch to the Interface Configuration mode of
interface 2.1.
Set the Query Max Response Time smaller than
the Query Interval
In this example: 1 second,
Default setting: 10 seconds
Set the Query Interval
In this example: 5 seconds
Default setting: 125 seconds.
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