Connecting Enterprise hub to other enterprise spokes over NBMA (frame-relay)

The original design intention is not to advertise routes using ospf over NBMA network, it is not necessary for this case. However for Buona Vista HQ to be able to reach the two sites, I need entries in the routing table to let other routers know the road map to reach. A way is to … Continue reading Connecting Enterprise hub to other enterprise spokes over NBMA (frame-relay)

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OSPF: non-broadcast multiaccess (point-to-multipoint type)

RFC2328 compliant (point-to-multipoint type) 1. RFC2328 compliant mode. 2. No DR and BDR is/are needed. 3. Multicast OSPF hello packet is sent to discover neighbours. 4. Typically for partial mesh or star topology.   Debug output of 2651-4 2651-4# *MarĀ  3 11:26:39.841: OSPF: Interface Serial0/0.301 going Up *MarĀ  3 11:26:39.841: OSPF: Send hello to 224.0.0.5 … Continue reading OSPF: non-broadcast multiaccess (point-to-multipoint type)

OSPF: non-broadcast multaccess network (broadcast type)

OSPF using broadcast network type over NBMA 1. Uses multicast (224.0.0.5, AllSPFRouter multicast) to automatically discover neighbours, no need to use neighbor command for OSPF router to send hello via unicast. 2. Cisco mode. (non RFC2328-compliant) 3. DR and BDR will be elected. 4. Typically full mesh or partial mesh topology. 5. Hello is sent … Continue reading OSPF: non-broadcast multaccess network (broadcast type)

OSPF: non-broadcast multiaccess network (non-broadcast type)

OSPF network types 1. Point-to-point: Network between a pair of routers. 2. Broadcast multiaccess: If you connect the routers to a switch, the switch is broadcast capable. OSPF over EoMPLS behaves the same as broadcast multiaccess, OSPF routers do not know the existence of EoMPLS at all. DR is required, BDR can be elected if … Continue reading OSPF: non-broadcast multiaccess network (non-broadcast type)

Non-broadcast multi-access network

Hub and spoke connectivity over frame relay (NBMA)   1. Multipoint NBMA allows one subnet to be used by hub and spoke routers. 2. In contrast to multipoint, point to point link is a subnet hence consumes more IP subnets. 3. Communication between spoke routers can be established via hub router. Both the spoke routers … Continue reading Non-broadcast multi-access network