Pim Traffic Delay And Smlt Peer Reboot; Pim-Sm To Dvmrp Connection: Mbr - Avaya 8800 Planning And Engineering, Network Design

PIM traffic delay and SMLT peer reboot

PIM uses a Designated Router (DR) to forward data to receivers on the DR VLAN. The DR is the
router with the highest IP address on a LAN. If this router is down, the router with the next highest IP
address becomes the DR.
The reboot of the DR in a Split MultiLink Trunking (SMLT) VLAN may result in data loss because of
the following actions:
• When the DR is down, the nonDR switch assumes the role and starts forwarding data.
• When the DR comes back up, it has priority (higher IP address) to forward data so the nonDR
switch stops forwarding data.
• The DR is not ready to forward traffic due to protocol convergence and because it takes time to
learn the RP set and create the forwarding path. This can result in a traffic delay of 2 to 3
minutes (because the DR learns the RP set after OSPF converges).
To avoid this traffic delay, a workaroundis to configure static RP on the peer SMLT switches. This
avoids theprocess of selecting an active RP router from the list of candidateRPs, and also of
dynamically learning about RPs through the BSR mechanism.Then, when the Designated Router
comes back, traffic resumes as soonas OSPF converges. This workaround reduces the traffic delay.

PIM-SM to DVMRP connection: MBR

Use the Multicast Border Router (MBR) functionality to connect a PIM-SM domain to a DVMRP
domain. A switch configured as an MBR has both PIM-SM and DVMRP interfaces.
The easiest way to configure an MBR is to use one switch to connect a PIM-SM domain to a
DVMRP domain, although you can use redundant switches for this purpose. You can use more than
one interface on the switch to link the domains together. The following figure illustrates this basic
scenario.
June 2016
Protocol Independent Multicast-Sparse Mode guidelines
Planning and Engineering — Network Design
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