Which two routing protocols operate over NBMA point-to-multipoint networks without the use of point-to-point subinterfaces? (Choose two.)

A. OSPF
B. EIGRP
C. RIPv2
D. RIPv1
E. IGRP
F. IS-IS
Correct Answer: AB
Section: Voice Video
Explanation
Explanation/Reference:
OSPF over NBMA
For OSPF to run over NBMA you are required to implement the neighbor IP Address but not subinterfaces
Configure an Interface as Point-to-Multipoint, Nonbroadcast (Non-Broadcast Multi-access NBMA)
To treat the interface as point-to-multipoint when the media does not support broadcast, perform the following task in interface configuration mode.

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EIGRP over NBMA
NBMA Interfaces (Frame Relay, X.25, ATM)
It is particularly critical to configure nonbroadcast multi-access (NBMA) interfaces correctly, because otherwise many EIGRP packets may be lost in the switched
network. There are three basic rules:
There are three different scenarios for NBMA interfaces.
Configuration Commands
no ip split-horizon eigrp
no ip next-hop-self eigrp
RIP over NBMA
Exchange of Routing Information
RIP is normally a broadcast protocol, and in order for RIP routing updates to reach nonbroadcast networks, you must configure the Cisco IOS software to permit
this exchange of routing information. To control the set of interfaces with which you want to exchange routing updates, you can disable the sending of routing
updates on specified interfaces by configuring the passive-interface router configuration command. See the discussion on filtering in the “Filter Routing
Information” section in the “Configuring IP Routing Protocol-Independent Features” module. An offset list is the mechanism for increasing incoming and outgoing
metrics to routes learned via RIP. Optionally, you can limit the offset list with either an access list or an interface. To increase the value of routing metrics, use the
following command in router configuration mode: Routing protocols use several timers that determine such variables as the frequency of routing updates, the
length of time before a route becomes invalid, and other parameters. You can adjust these timers to tune routing protocol performance to better suit your
internetwork needs.
IS-IS over NBMA
IS-IS can work over an NBMA multipoint network only if the network is configured with a full mesh. Anything less than a full mesh could cause serious connectivity
and routing issues. However, even if a full mesh is configured, this is no guarantee that a full mesh will exist at all times. A failure in the underlying switched WAN
network or a misconfiguration on one or more routers could break the full mesh either temporarily or permanently. Therefore, you should avoid NBMA multipoint
configurations for IS-IS networks. Use point-to-point subinterfaces instead.

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