Edge-Core ECS4660-28F, Руководство по управлению, Страница: 837 / 2020

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HAPTER
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| Multicast Routing
Configuring PIM for IPv4
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Dense-Mode Attributes
◆
Graft Retry Interval – The time to wait for a Graft acknowledgement
before resending a Graft message. (Range: 1-10 seconds; Default: 3
seconds)
A graft message is sent by a router to cancel a prune state. When a
router receives a graft message, it must respond with an graft
acknowledgement message. If this acknowledgement message is lost,
the router that sent the graft message will resend it a number of times
(as defined by Max. Graft Retries).
◆
Max. Graft Retries – The maximum number of times to resend a Graft
message if it has not been acknowledged. (Range: 1-10; Default: 3)
◆ State Refresh Origination Interval – The interval between sending
PIM-DM state refresh control messages. (Range: 1-100 seconds;
Default: 60 seconds)
The pruned state times out approximately every three minutes and the
entire PIM-DM network is reflooded with multicast packets and prune
messages. The state refresh feature keeps the pruned state from
timing out by periodically forwarding a control message down the
distribution tree, refreshing the prune state on the outgoing interfaces
of each router in the tree. This also enables PIM routers to recognize
topology changes (sources joining or leaving a multicast group) before
the default three-minute state timeout expires.
This command is only effectively for interfaces of first hop, PIM-DM
routers that are directly connected to the sources of multicast groups.
Sparse-Mode Attributes
◆ DR Priority – Sets the priority advertised by a router when bidding to
become the Designated Router (DR). (Range: 0-4294967294;
Default: 1)
More than one PIM-SM router may be connected to an Ethernet or
other shared-media LAN. If multicast hosts are directly connected to
the LAN, then only one of these routers is elected as the DR, and acts
on behalf of these hosts, sending periodic Join/Prune messages toward
a group-specific RP for each group. A single DR is elected per interface
(LAN or otherwise) using a simple election process.
The router with the highest priority configured on an interface is elected
as the DR. If more than one router attached to this interface uses the
same priority, then the router with the highest IP address is elected to
serve as the DR.
If a router does not advertise a priority in its hello messages, it is
assumed to have the highest priority and is elected as the DR. If more
than one router is not advertising its priority, then the router with the
highest IP address is elected to serve as the DR.
◆ Join/Prune Interval – Sets the interval at which join/prune messages
are sent. (Range: 1-65535 seconds; Default: 60 seconds)