CCNP Interview Questions and Answers

It is crucial to use CCNP interview questions to gauge a candidate’s mastery of complex networking principles. Interviewers frequently delve into issues like routing protocols, such as OSPF and EIGRP, and their administrative distance to evaluate a possible CCNP’s competence. You may obtain all the answers to the most frequently asked questions in forthcoming CCNP interviews by using the following list of CCNP interview questions and answers. Explore the benefits of CCNA certification to get started in your networking career.

What is the dynamic desirable mode in switching, and what is an error-disabled port?

Disabled error When a port is error disabled, it is closed off and cannot be used for sending or receiving data. For example, with BPDUGourd, you stated that this port must not send or receive BPDUD messages. As a result, when this port receives a BPDDU message, it will convert to an error and disable. To restore it, simply provide the (No Shut) command.

Dynamic Desirable: sometimes known as DTP (dynamic trunk protocol), this type of protocol negotiates a front port to be used as the trunk.

Do these IP multicast addresses fall under this range?

239.255.255.255-224.0.0.0

Why is the interface command ip multicast spares-dense-mode-used used?

Used with PIMSM Auto-RP and version 2. The router switches to dense mode if the RPs are unsuccessful.

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What is the purpose of a rendezvous point?

The center of multicast traffic is an RP. Multicast sources forward traffic to the RP. Traffic is subsequently forwarded to multicast receivers by the RP.

Which protocols are used by switches to stop multicast traffic from being broadcast?

IGMP and CGMP Surveillance

Describe how Anycast RP works.

The same IP address is used to configure two or more RPs. A unicast IP routing protocol is used to advertise the IP addresses of the routers. Every multicast router selects the closest RP. When the unicast IP routing protocol converges, the routers move to the next closest RP if one RP fails. To exchange information about active multicast sources, RPs use the MSDP.

Why is protocol independence used to describe the Cisco multicast routing protocols?

The unicast IP routing table’s entries serve as the basis for multicast forwarding choices. The construction of the unicast IP routing table has no bearing on multicast; any dynamic interior routing protocol, static routes, or a mix of the two can be used. Take a glance at our CCNA course syllabus.

Identify at least four IP multicast groups that share the multicast Ethernet address of 01 00 5E 00 40 0C.

The multicast Ethernet address is determined by the low order 32 bits of the IP address. The next five bits can be anything, while the first four are always 1 1 1 0. The IP multicast addresses that correspond to the multicast ethernet address of 01 00 5E 00 40 0C are

1110 0000 0000 0000 0100 0000 1100 = 224.0.64.12

1110 0000 1000 0000 0100 0000 1100 = 224.128.64.12

1110 0001 0000 0000 0100 0000 1100 = 225.0.64.12

Describe the differences between multicast in dense and sparse modes.

Unless the neighbors have expressly pruned the traffic, dense mode multicast believes that all multicast neighbors want to receive all multicast communication. Sparse mode multicast assumes that multicast neighbors do not wish to receive multicast communication unless explicitly asked. While shared delivery trees are used in sparse mode, where traffic is first routed to an RP, they are used in dense mode.

What is the IP address 227.128.64.12’s multicast Ethernet address?

01 00 5E 00 00 00 is the base Ethernet multicast address. The IP multicast address’s first byte is not utilized. Subtract 128 if the second byte is larger than 127 to get a value of 0. After being converted to hex, the third and fourth bytes of the IP address are utilized exactly as they are. Hexadecimal values for them are 40 and 0C. 

Which four broad categories of BGP properties are there?

Well-known nontransitive, well-known transitive, well-known discretionary, and optional.

Describe the distinctions between forwarding a multicast IP transmission and a unicast IP packet.

Unicast IP packets are routed according to their destination’s IP address. Multicast packets are routed according to the IP address of their origin. A multicast packet is forwarded to multicast neighbors if it is received on the interface that was used to transmit a unicast packet back to the source. The multicast packet is rejected if it is received on an interface that isn’t intended to be used to return a unicast IP packet to the source.

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For Internet routing, why is BGP preferable to IGPs?

Both IGRP and RIP version 1 are elegant protocols that don’t reveal subnet mask details. RIP version 2 allows for a maximum network diameter of 15 hops. EIGRP, OSPF, and IS-IS all use computationally intensive methods to determine the shortest path. BGP can handle the number of network prefixes needed for Internet routing and depends on straightforward methods for loop identification and optimal path selection.

What differentiates BGP route summarization from IGP route summarization?

The exact routes of the summary are not announced when an IGP (EIGRP, OSPF, and IS-IS) is used to construct a summary address. Unless they are silenced explicitly, BGP advertises both the summary and every individual route within the summary.

Identify two techniques to lower the total number of IBGP connections.

Route reflector and confederation.

List every method for adding a prefix to the BGP routing table.

• Moving a router from the IP routing table to the BGP routing table with the network command
• Distribution of routes between the BGP and IP routing tables
• Discovered via a BGP neighbor

Why is a full mesh necessary for IBGP?

BGP detects loops using the AS_PATH property. A router drops a BGP advertisement if it detects its own AS number in the advertisement. Since all IBGP routers have the same AS number, loop detection cannot be done using the AS number. It is necessary to have a full mesh since IBGP neighbors will not broadcast prefixes that they have learned from one neighbor to another.

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Synchronization: What is it?

One characteristic of the IBGP is synchronization. If a prefix is not included in the IP routing table, an IBGP router will not accept it from an IBGP neighbor.

Which BGP attributes—AS_PATH, LOCAL_PREF, MED, and WEIGHT—are preferred in what order?

LOACL_PREF, AS_PATH, MED, WEIGHT

When determining if a prefix is available, what is the first item that BGP looks for?

To find out if the NEXT_HOP is present in the IP routing table or is accessible, BGP examines the NEXT_HOP attribute.

What does the ‘WEIGHT’ property encompass?

‘WEIGHT’ is not advertised to BGP peers and has just local importance.

What does the MULTI_EXIT_DISC property or the metric serve as?

To choose a route into an autonomous system, MED is employed. A lower MED value is favored.

What does the LOCAL_PREF attribute serve to accomplish?

The route with the highest LOCAL_PREF, given that the routes’ ‘WEIGHT’ attributes are equal, is the optimal path when a router has multiple routes that go to the same IP prefix.

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What does the LOCAL_PREF property cover?

The autonomous system as a whole promotes the LOCAL_PREF property.

What does the WEIGHT property serve as?

The route with the highest ‘WEIGHT’ value is the preferred path if a router has many routes to the same IP prefix.

What does the AS_PATH attribute serve to accomplish?

The optimal path is the one with the shortest AS_PATH if a router has multiple routes to the same IP prefix (provided other BGP properties are equal).

What distinguishes an IS-IS-wide metric from a narrow one?

The interface metric in a narrow metric takes up 6 bits, whereas the path metric takes up 10 bits. The interface metric in a broad metric employs 24 bits, while the path metric requires 32 bits.

Compare the metrics from OSPF with IS-IS.

The interface bandwidth is used to calculate an OSPF interface measure. Every IS-IS interface metric is set at 10 by default.

Route leaking: what is it?

Redistributing Level 2 routes as Level 1 routes within a certain area.

List the four ways that IBGP and EBGP operate differently.

• IBGP is the protocol that routers in the same autonomous system use. EBGP is the name of the protocol that routers in a variety of autonomous systems employ.
• Unless synchronization is deactivated, IBGP routes cannot be moved to the IP routing database until they have been synchronized.
• The IP address of the interface used to connect with the EBGP peer is the value that EBGP assigns to the next hop property. When an IBGP router learns a prefix from an EBGP neighbor and broadcasts it to an IBGP peer, the next hop attribute remains unchanged.
• EBGP broadcasts to all other EBGP neighbors every prefix that a neighbor teaches its neighbors. IBGP routers do not share prefixes that are obtained by one IBGP neighbor from another.

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What is the purpose of a Level 1-2 router in IS-IS?

IS-IS databases are present in two Level 1-2 routers. The router’s configured area is the routing destination for the Level 1 database. Routes between locations in various regions are created using the Level 2 database.

What distinguishes the routes that are automatically permitted into OSPF and IS-IS areas?

Every route is automatically promoted into every OSPF area. This covers external routes injected into OSPF as well as interarea OSPF routes. By default, IS-IS injects a default route into an area instead of advertising external or inter-area routes.

What is the equivalent of a Level 1-2 IS-IS router in OSPF?

An ABR, or area border router

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What is Level 1 routing’s equivalent in OSPF?

Routing within an area.

What distinguishes an IS-IS backbone from an OSPF backbone?

Area 0 serves as the backbone of OSPF. A router or virtual link must connect each nonzero area to the backbone. The backbone of IS-IS is composed of a continuous network of routers with Level 2 capabilities.

Let’s say a router is assigned the loopback address 135.77.9.254. Change the loopback address to a system ID for IS-IS.

135.077.009.254 is the value of the loopback address when written in dotted decimal, with three digits for each byte. It is 13.50.77.00.92.54, the system ID.

How is an interface’s OSPF cost determined?

An OSPF interface costs 100,000,000/(Interface bandwidth) by default. The auto-cost reference-bandwidth command can be used to modify the constant 100,000,000.

How is an interarea shortest path found using OSPF?

1. Determine the quickest path to an ABR first.
2. Next, determine the most direct route from area 0 to an ABR connected to the destination region.
3. Third, find the shortest route from the ABR to the destination network across the destination area.

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What is the function of an OSPF virtual link?

If a nonzero area separates from the backbone, reattach it to it. In case the backbone, or area 0, becomes non-contiguous, another option is to employ a virtual link.

In IS-IS, what does Level 1 routing mean?

Routing inside the same IS-IS area constitutes Level 1 routing.

What constitutes a North American phone number’s distribution, access, and fundamental elements?

At the access layer, a phone’s last four digits are used to identify it. At the distribution layer, the next three digits are used to identify an exchange that supports multiple phone numbers. Routing across various regions is done at the core level using the area code.

Instead of having a single protocol that defines everything, why are multiple protocols needed for things like packages, addressing, delivery, and transportation?

Modularity is achieved by using numerous protocols, which enable modifications to one without impacting the others. For instance, if the delivery protocol and the addressing protocol are interdependent, then modifications to one would necessarily require modifications to the other.

What constitutes a postal address’s essential components, distribution, and access?

The components of the access layer are the street name and number. The component of the distribution layer is the city name. The fundamental layer element is the state name.

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Is there another well-known system that employs a hierarchical delivery method for routing?

At the core routing level, there are significant hub airports such as Denver, Chicago, New York, and Atlanta. The primary airports oversee the movement of passengers and goods to the main regions of the country. Regional airports, located at the distribution layer, are connected to core airports and service a particular region. Lastly, you have a few options for getting to your final destination: bus, taxi, train, or rental car. You may think of this as the access layer.

How is a scalable delivery system made possible by the use of a hierarchical routing structure (access, distribution, and core)?

Every point in the delivery system must keep track of every potential destination address to decide which delivery to make if the system is not separated into access, distribution, and core layers. When a layered system is used, each layer just needs the data required to send data to the layer above or below.

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What does “information hiding” mean in the context of a route summary?

The state or city/state information is all that is required at the core layer of the postal system to determine a routing choice. The street names and numbers are not visible to the core layer; they are not necessary. The area code is used to determine routing at the telephone system’s core layer. The last four phone numbers or the particular exchange are not required or concealed from the core layer.

Conclusion

We have addressed often requested CCNP interview questions in this blog post. These questions will assist you in showcasing your computer network knowledge and expertise, regardless of the position for which you are applying—network engineer or otherwise. We hope that this blog has helped you gain some understanding of the types of questions and answers you might anticipate seeing in CCNP interviews. Enroll in our hardware and networking training in Chennai at SLA Jobs and enhance your networking and CCNP skills.