Multi PoP deployments

Following aspects should be taken care in cnWave Multi PoP deployments

Layer 2 domain

All cnWave PoP nodes must be connected to the same Layer 2 broadcast domain. PoP nodes learn about other PoP nodes using IPv6 multicast packets, which do not cross broadcast domain.

This allows cnWave PoP nodes to forward traffic to other cnWave PoP nodes via a wired connection when the routing path of the other PoP node is closer to the traffic’s destination. This concept is known as tromboning, because the traffic enters a PoP node and then leaves toward another PoP node.

Open/R on the PoP interface port

PoP interface port should be configured to run Open/R protocol. This can be done by marking the port as Multi PoP/ Relay port.

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MTU of upstream switch ports

PoP ports use an 1986 MTU size. So, all the switch ports should be atleast 1986. Even if the user traffic is limited to 1500 sized packets, switch ports should allow the higher MTU size. Following packets exchanged between PoPs can be of higher size - Open/R packets, L2GRE packets (in Layer 2 mode), Software download packets.

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