Digisol DG-GS4826S, Management Manual

Page: 614 / 1344

C
HAPTER
22 | Multicast Routing
Configuring PIM for IPv4
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The election process for each group is based on the following criteria:
n
Find all RPs with the most specific group range.
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Select those with the highest priority (lowest priority value).
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Compute hash value based on the group address, RP address,
priority, and hash mask included in the bootstrap messages.
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If there is a tie, use the candidate RP with the highest IP address.
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This distributed election process provides faster convergence and
minimal disruption when an RP fails. It also serves to provide load
balancing by distributing groups across multiple RPs. Moreover, when
an RP fails, the responsible RPs are re-elected on each router, and the
groups automatically distributed to the remaining RPs.
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To improve failover recovery, it is advisable to select at least two core
routers in diverse locations, each to serve as both a candidate BSR and
candidate RP. It is also preferable to set up one of these routers as both
the primary BSR and RP.
P
ARAMETERS
These parameters are displayed in the web interface:
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VLAN – Identifier of configured VLAN interface. (Range: 1-4093)
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Interval – The interval at which this device advertises itself as an RP
candidate. (Range: 60-16383 seconds; Default: 60 seconds)
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Priority – Priority used by the candidate RP in the election process.
The RP candidate with the largest priority is preferred. If the priority
values are the same, the candidate with the larger IP address is elected
to be the RP. Setting the priority to zero means that this router is not
eligible to server as the RP. (Range: 0-255; Default: 0)
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Group Address – An IP multicast group address.
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Group Mask – Subnet mask that is used for the group address.
W
EB
I
NTERFACE
To advertise the switch as an RP candidate:
1. Click Multicast, Multicast Routing, SM.
2.
Select RP Candidate from the Step list.
3. Specify a VLAN interface, the interval at which to advertise the router
as an RP candidate, the priority to use in the election process, and the
multicast group address and mask indicating the groups for which this
router is bidding to become the RP.
4. Click Apply.