Exam CISSP topic 1 question 257 discussion

These are two different IP subnets, hence should require a router for interconnectivity. However, 192.168.1.3/30 is a broadcast IP in that subnet and doesn't seem valid.

How is B showed as the correct answer is beyond me. These are 2 separate subnets with one being a broadcast IP address which means that even the question is wrong.

I know just enough about networks to be dangerous so before analyzing all the subnetting and host portions I read the answers carefully and deduced D as correct this way: A and C mix L2 (bridges) and L3 (routers) without much context. IMHO B is wrong as it states: B. Since each computer is on the same layer 3 network, traffic between the computers may be processed by a network router in order to communicate. If they are on the same network as stated directly in that answer, you don't (may not...:rolleyes:) need a router to communicate. With a typo on your gateway address, you'll only see the other addresses within that network without a router required.

As a CCNP. I can confirm for a fact that the answer is D without a shadow of a doubt. Inter VLAN routing is needing. performing by a layer 3 switch or a router.

(Previous comment didn't have the vote tallied) - They ARE on the same L3 network but different L2 networks. Given that L2 is implied in the subnetting, they DO need a router to communicate. Its all in the wording (these questions are all tricky). B is the correct answer as a result (very misleading). The broadcast network thing is a little weird. Had the answers stated L2 instead of L3, D would be correct.

They ARE on the same L3 network but different L2 networks. Given that L2 is implied in the subnetting, they DO need a router to communicate. Its all in the wording (these questions are all tricky). B is the correct answer as a result (very misleading). The broadcast network thing is a little weird. Had the answers stated L2 instead of L3, D would be correct.

Answer D) Devices are on different subnets....(and the first is calculated wrong) so they need a device to communicate with. Both Bridges and Routers can help connect the devices on separate networks, but the question clearly states LAYER 3, so it must use a ROUTER. Bridges are LAYER 2

Given the IP addresses 192.168.1.3/30 and 192.168.1.6/30, which have different network portions, the correct answer is: D. Since each computer is on a different layer 3 network, traffic between the computers must be processed by a network router in order to communicate.

Different subnet

the only answer is D, no other choice

/30 -only 4 ip address. 192.168.1.0 to 192.168.1.4 - First network 192.168.1.5 to 192.168.1.8-Second network . Answer :D

Without going deep into network theory, here's the executive summary. The answer is D. Now, here's the explanation in networking terms. Host IP 192.168.1.3 belongs to subnet 192.168.1.0/30. Host IP 192.168.1.6 belongs to subnet 192.168.1.4/30. Therefore the hosts are in different subnets. In order for hosts to communicate across subnet boundaries, you must have a router. And all of this leaves out the issue of giving a host the IP of 192.168.1.3, which is the broadcast address of the first subnet. Can you do it? Yes, technically it's possible. It also creates a broadcast storm because that host endlessly replies to every broadcast packet on the subnet.

B. Since each computer is on the same layer 3 network, traffic between the computers may be processed by a network router in order to communicate. The IP/CIDR address of 192.168.1.3/30 and the IP/CIDR address of 192.168.1.6/30 are on the same network (192.168.1.0/30), because the network portion of the IP address (192.168.1) is the same and the subnet mask (30) indicates that only 2 addresses are available in the subnet. So the two computers are on the same layer 3 network and can communicate directly with each other without the need for a network bridge or router.

D is the right answer. And 192.168.1.3/30 is a broadcast address, not valid IP address for a host. ! stupid ISC2 question as usual.

Devices on different subnets require a L3 device to route traffic between the subnets.

They are on the same network the traffic does not get to the router

The answer is - D -