Interview Question Bank: Top 300+ CCIE Interview Questions

Interview Question Bank: Top 300+ CCIE Interview Questions

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ccie interview questions

Here is a list of most important 300+ CCIE Interview Questions. These Questions will help you crack your ccie interview in the first attempt.

Question are mentioned as per below-mentioned topics.

  1. IP Routing
  2. OSPF
  3. EIGRP
  4. QOS
  5. BGP
  6. MPLS

 Questions on IP Routing:

  • What does it mean to have fast or autonomous switching “enabled” and “disabled” on the same interface?
  • How is the load shared between two parallel lines of equal capacity when these lines are configured for load balancing?
  • What does route summarization mean?
  • When does a Cisco router generate a source quench?
  • When does a Cisco router initiate a routing request out its interfaces?
  • What is the difference between the ip default−gateway, ip default−network, and ip route 0.0.0.0/0 commands?
  • How do I use the ip helper−address command to forward Bootstrap Protocol (BOOTP) frames?
  • Enhanced Interior Gateway Routing Protocol (EIGRP) redistributes with the IGRP IP routing protocol automatically. Does EIGRP also interact with the Routing Information Protocol (RIP) IP routing protocol?
  • How do I configure my router to prefer an Open Shortest Path First (OSPF) route over an EIGRP route when the route is learned from both sources?
  • Does the use of extended IP access control lists (ACLs) filter regular routing updates (such as OSPF)? Do I need to explicitly permit the multicast IPs used by routing protocols (such as 224.0.0.5 and 224.0.0.6, in the case of OSPF) for updates to ensure the proper working of routing protocols?
  • Does the interface subcommand no arp arpa disable the Address Resolution Protocol (ARP) function for a router interface?
  • Would it be possible to configure a router for a 255.255.254.0 Ethernet and a 255.255.252.0 serial subnet?
  • Does IGRP/RIPv1 support variable subnetting?
  • Can an interface have more than one ip access−group statement in its configuration?
  • Can I configure two interfaces in the same subnet (t0 = 142.10.46.250/24 and t1 142.10.46.251/24)?
  • Is it possible to have duplicate ip addresses for two serial interfaces that belong to the same router?
  • I have primary and secondary IP addresses configured on an Ethernet interface and my router is running RIP (a distance vector routing protocol). How does split−horizon affect the routing updates?
  • Is there a performance advantage when using the the IP access list keyword established on an extended ACL?
  • Does using “established” make the access list more vulnerable? Do you have specific examples of the usage?
  • I have four equal cost parallel paths to the same destination. I am doing fast switching on two links and process switching on the other two. How will the packets be routed in this situation?
  • What is Unicast Reverse Path Forwarding (uRPF)? Can a default route 0.0.0.0/0 be used to perform a uRPF check?
  • Who does load−balancing when there are multiple links to a destination, Cisco Express Forwarding (CEF), or the routing protocol?
  • What are the maximum number of secondary IP addesses that can be configured on a router interface?
  • What is the Pause control counter?
  • Can a VLAN interface and a tunnel interface have the same IP address?
  • What is Virtual Routing and Forwarding (VRF)?
  • How do I connect two different ISPs and route different traffic to different ISPs?
  • What is the difference between the two methods to create static routes?
  • What is the purpose of ports 2228 and 56506?
  • What is the difference between point−to−point subinterfaces and multi−point subinterfaces?
  • Can you configure different MTU for subinterfaces under the same main interface? How do 7500/GSR/ESR routers behave in this scenario?
  • How do you limit the number of sessions when a customer accesses the network?
  • How is accounting data age calculated?
  • What does the term threshold and timeout in IP SLA operation mean?
  • What is the significance of Time mentioned in the routing table entry?
  • What is Network Descriptor Block (NDB)?

Questions on OSPF :

  • Why are loopbacks advertised as /32 host routes in OSPF?
  • How do I change the reference bandwidth in OSPF?
  • How does OSPF calculate its metric or cost?
  • What algorithm is used by OSPF if equal cost routes exist?
  • Are OSPF routing protocol exchanges authenticated?
  • What is the link-state retransmit interval, and what is the command to set it?
  • What is the purpose of the variable IP-OSPF-Transmit-Delay?
  • Is it true that only the static option of the virtual link in OSPF allows discontiguous networks, regardless of the mask propagation properties?
  • Are the multicast IP addresses mapped to MAC-level multicast addresses?
  • Does the Cisco OSPF implementation support IP TOS-based routing?
  • Does the offset-list subcommand work for OSPF?
  • Can an OSPF default be originated into the system based on external information on a router that does not itself have a default?
  • Can I use the distribute-list in/out command with OSPF to filter routes?
  • How can I give preference to OSPF interarea routes over intra-area routes?
  • Do I need to manually set up adjacencies for routers on the Switched Multimegabit Data Service (SMDS) cloud with the OSPF neighbor subcommand?
  • When routes are redistributed between OSPF processes, are all shortest path first algorithm (SPF) metrics preserved, or is the default metric value used?
  • How does Cisco accommodate OSPF routing on partial-mesh Frame Relay networks?
  • Which address-wild-mask pair should I use for assigning an unnumbered interface to an area?
  • Can I have one numbered side and leave the other side unnumbered in OSPF?
  • Why do I receive the “cannot allocate router id” error message when I configure Router OSPF One?
  • Why do I receive the “unknown routing protocol” error message when I configure Router OSPF One?
  • What do the states DR, BDR, and DROTHER mean in show ip ospf interface command output?
  • When I issue the show ip ospf neighbor command, why do I only see FULL/DR and FULL/BDR, with all other neighbors showing 2-WAY/DROTHER?
  • Why do I not see OSPF neighbors as FULL/DR or FULL/BDR on my serial link?
  • Do I need any special commands to run OSPF over BRI/PRI links?
  • Do I need any special commands to run OSPF over asynchronous links?
  • Which Cisco IOS Software release began support for per-interface authentication type in OSPF?
  • Can I control the P-bit when importing external routes into a not-so-stubby area (NSSA)?
  • Why are OSPF show commands responding so slowly?
  • What does the clear ip ospf redistribution command do?
  • Does OSPF form adjacencies with neighbors that are not on the same subnet?
  • How often does OSPF send out link-state advertisements (LSAs)?
  • How do I stop individual interfaces from developing adjacencies in an OSPF network?
  • When I have two type 5 link-state advertisements (LSAs) for the same external network in the OSPF database, which path should be installed in the IP routing table?
  • Why is it that my Cisco 1600 router does not recognize the OSPF protocol?
  • Why is it that my Cisco 800 router does not run OSPF?
  • Should I use the same process number while configuring OSPF on multiple routers within the same network?
  • I have a router that runs Cisco Express Forwarding (CEF) and OSPF, who does load-balancing when there are multiple links to a destination?
  • How does OSPF use two Multilink paths to transfer packets?
  • How can you detect the topological changes rapidly?
  • Does the 3825 Series Router support the OSPF Stub feature?
  • What does the error message %OSPF-4-FLOOD_WAR: Process process-id re-originates LSA ID ip address type-2 adv-rtr ip address in area area id means?
  • Can we have OSPF run over a GRE tunnel?
  • Is there a way to manipulate and prefer the Type 3 LSAs to originate from two different areas sent to the non-backbone area?
  • Is there a drop/flap of an OSPF neighborship when changing an OSPF area type from nssa no-summary to nssa?
  • In the %OSPF-5-ADJCHG: Process ID, Nbr [ip-address] on Port-channel31 from FULL to EXSTART, SeqNumberMismatch error message, what does SeqNumberMismatch signify?
  • What is the maximum number of OSPF processes (VRF aware) on 7600/6500 platforms?
  • How does ISPF impact or improve the OSPF network?
  • Is there a way to compare Cisco NX-OS/IOS OSPF commands?
  • Is there any feature of OSPF protocol for quick convergence and a slow re-convergence of routes?
  • What does BADSEQNUM in the %OSPF-5-NBRSTATE: ospf-101 [5330] Process 101, Nbr 10.253.5.108 on Vlan7 02 from FULL to EXSTART, BADSEQNUM OSPF log message mean?

Questions on EIGRP:

  • Does EIGRP require an ip default-network command to propagate a default route?
  • Should I always use the eigrp log-neighbor-changes command when I configure EIGRP?
  • Does EIGRP support secondary addresses?
  • What debugging capabilities does EIGRP have?
  • What does the word serno mean on the end of an EIGRP topology entry when you issue the show ip eigrp topology command?
  • What percent of bandwidth and processor resources does EIGRP use?
  • Does EIGRP support aggregation and variable length subnet masks?
  • Does EIGRP support areas?
  • Can I configure more than one EIGRP autonomous system on the same router?
  • If there are two EIGRP processes that run and two equal paths are learned, one by each EIGRP process, do both routes get installed?
  • What does the EIGRP stuck in active message mean?
  • What does the neighbor statement in the EIGRP configuration section do?
  • Why does the EIGRP passive-interface command remove all neighbors for an interface?
  • Why are routes received from one neighbor on a point-to-multipoint interface that runs EIGRP not propagated to another neighbor on the same point-to-multipoint interface?
  • When I configure EIGRP, how can I configure a network statement with a mask?
  • I have two routes: 172.16.1.0/24 and 172.16.1.0/28. How can I deny 172.16.1.0/28 while I allow 172.16.1.0/24 in EIGRP?
  • I have a router that runs Cisco Express Forwarding (CEF) and EIGRP. Who does load-balancing when there are multiple links to a destination?
  • How do you verify if the EIGRP Non Stop Forwarding (NSF) feature is enabled?
  • How can I use only one path when a router has two equal cost paths?
  • What is the difference in metric calculation between EIGRP and IGRP?
  • What is the EIGRP Stub Routing feature?
  • How can I send a default route to the Stub router from the hub?
  • What are different route types in EIGRP?
  • How do you redistribute an IPv6 default route in EIGRP?
  • How does EIGRP behave over a GRE tunnel compared to a directly connected network?
  • What is an offset-list, and how is it useful?
  • How can I tag external routes in EIGRP?
  • What are the primary functions of the PDM?
  • What are the various load-balancing options available in EIGRP?
  • What does the %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor 10.254.0.3 (Tunnel0) is down: holding time expired error message mean?
  • Is there a IPv6 deployment guide that includes EIGRPv6?
  • From the 16:29:14.262 Poison squashed: 10.X.X.X/24 reverse message, what does poison squashed mean?
  • Is it normal that EIGRP takes over 30 seconds to converge?
BGP Interview Questions
  • How do I configure BGP?
  • How do I configure BGP with the use of a loopback address?
  • What is the order of preference of attributes when some or all are applied to one neighbor in BGP?
  • What does a next hop of 0.0.0.0 mean in the show ip bgp command output?
  • What are the well-known communities of the BGP community attribute?
  • What formats can I use to configure the BGP community attribute?
  • How does BGP behave differently with auto-summary enabled or disabled?
  • How can I verify if a BGP router announces its BGP networks and propagates them to the global BGP mesh?
  • When and how should I reset a BGP session?
  • Is there any special configuration needed on PIX/ASA to allow BGP sessions through it?
  • What is an autonomous system (AS) number and how do I obtain one?
  • What is the BGP path selection criteria?
  • What is the difference between always-compare-med and deterministic-med?
  • Do internal BGP (iBGP) sessions modify the next hop?
  • Do external BGP (eBGP) sessions between confederations modify the next hop?
  • In external BGP (eBGP) sessions, which IP address is sent as the next hop?
  • Does the route reflector change the next hop attribute of a reflected prefix?
  • How can I announce a prefix conditionally to one ISP only when I lose the connection to my primary ISP?
  • How can I configure BGP to provide load sharing and redundancy in my network?
  • How much memory should I have in my router to receive the complete BGP routing table from my ISP?
  • What are the benefits of configuring BGP peer groups?
  • Why do I see the same route twice from the same peer in BGP?
  • What is synchronization, and how does it influence BGP routes installed in the IP routing table?
  • How do I know which Cisco IOS software release supports a particular BGP feature?
  • How can I set the Multi Exit Discriminator (MED) value on prefixes advertised to external BGP (eBGP) neighbors to match the Interior Gateway Protocol (IGP) next hop metric?
  • What is the default BGP ConnectRetry timer, and is it possible to tune the BGP ConnectRetry timer?
  • What does r RIB-Failure mean in the show ip bgp command output?
  • How can I redistribute internal BGP (iBGP) learned default-route (0.0.0.0/0) route into EIGRP/OSPF/IS-IS?
  • How can I filter all IP routes advertised to a BGP neighbor except the default route 0.0.0.0/0?
  • How to resolve the error Protocol not in this image?
  • BGP: timer-wheel running slow by 1 ticks appears in the debug output.
  • Is it possible to track an interface and change the route availability?
  • How does IP RIB Update allocate memory?
  • What is the command to see IPv6 BGP neighbors?
  • In regards to the removal of the static route “ip route 10.150.0.0 255.255.0.0 Null0”, does no auto-summary in BGP cause all subnets of 10.150.0.0 to be advertised?
  • Why are there no statistic results when I use the debug bfd events and debug bfd packets commands?
  • Does the router have to be restarted after a new BGP Neighbor Maximum Prefix is configured?
  • Is there a command to check the advertised routes along with the prepend of the AS-paths?
  • How does neighbor soft-reconfiguration inbound command function?
  • What does the %BGP-3-NOTIFICATION: sent to neighbor *A.B.C.D passive 6/0 (cease) 0 bytes error message mean?
  • What does the %IPRT-3-ROUTEINSERTERROR: Error inserting routing entry error message mean?
  • Does GSR with Cisco IOS-XR support the VPLS-BGP auto-discovery feature as a Route Reflector?
  • How do I debug routes for a particular vrf in the Cisco IOS-XR environment?
  • What is the difference between when a route is injected in BGP via redistribute command or a network command?
  • How do I verify Layer 4 forwarding summary information?
QOS QUESTIONS
  • What is Quality of Service (QoS)?
  • What are congestion, delay, and jitter?
  • What is the MQC?
  • What does the service-policy is supported only on VIP interfaces with DCEF enabled message mean?
  • How many classes does a Quality of Service (QoS) policy support?
  • How are routing updates and Point-to-Point Protocol (PPP) / High-Level Data Link Control (HDLC) keepalives processed when a service policy is applied?
  • Is Quality of Service (QoS) supported on interfaces configured with Integrated Routing and Bridging (IRB)?
  • What is Quality of Service (QoS) pre-classification?
  • Which packet header fields can be remarked? What values are available?
  • Can I prioritize traffic based on the URL?
  • What platforms and Cisco IOS software versions support Network Based Application Recognition (NBAR)?
  • What is the purpose of queueing?
  • How do Weighted Fair Queueing (WFQ) and Class Based Weighted Fair Queueing (CBWFQ) operate?
  • If a class in Class Based Weighted Fair Queueing (CBWFQ) is not using its bandwidth, can other classes use the bandwidth?Is Class Based Weighted Fair Queueing (CBWFQ) supported on subinterfaces?
  • Is Class Based Weighted Fair Queueing (CBWFQ) supported on subinterfaces?
  • What is the difference between the priority and bandwidth statements in a policy-map?
  • How is the queue limit calculated on the FlexWAN and Versatile Interface Processors (VIP)?
  • How do you verify the queue-limit value?
  • Can I enable fair queueing inside a class?
  • What commands can I use to monitor queueing?
  • RSVP can be used in conjunction with Class Based Weighted Fair Queueing (CBWFQ). When both Resource Reservation Protocol (RSVP) and CBWFQ are configured for an interface, do RSVP and CBWFQ act independently, exhibiting the same behavior that they would if each were running alone? RSVP seems to behave as if CBWFQ is not configured regarding bandwidth availability, assessment, and allocation.
  • Can I enabled Weighted Random Early Detection (WRED) and Low Latency Queueing (LLQ), or Class Based Weighted Fair Queueing (CBWFQ) at the same time?
  • How can I monitor Weighted Random Early Detection (WRED) and see it actually taking effect?
  • What is the difference between policing and shaping?
  • What is a token bucket and how does the algorithm work?
  • With a traffic policer such as class-based policing, what do Committed Burst (BC) and Excess Burst (Be) mean and how should I select these values?
  • How does Committed Access Rate (CAR) or class-based policing decide if a packet conforms or exceeds the Committed Information Rate (CIR)? The router is dropping packets and reporting an exceeded rate even though the conformed rate is less than the configured CIR.
  • Are the burst and queue limit independent of each other?
  • What values should I select for Committed Information Rate (CIR), Committed Burst (BC), Excess Burst (Be), and Minimum CIR (MinCIR)?
  • Does Priority Queueing on the Frame Relay main interface work in Cisco IOS 12.1?
  • Does Frame Relay Traffic Shaping (FRTS) work with Distributed Cisco Express Forwarding (dCEF) and Distributed Class Based Weighted Fair Queueing (dCBWFQ)?
  • Where do I apply a service policy with Class Based Weighted Fair Queueing (CBWFQ) and Low Latency Queueing (LLQ) on an Asynchronous Transfer Mode (ATM) interface?
  • What bytes are counted by IP to Asynchronous Transfer Mode (ATM) Class of Service (COs) queueing?
  • How many Virtual Circuits (VCS) can support a service policy simultaneously?
  • Which Asynchronous Transfer Mode (ATM) hardware supports IP to ATM Class of Service (COs) features including Class Based Weighted Fair Queueing (CBWFQ) and Low Latency Queueing (LLQ)?
  • How does Link Fragmentation and Interleaving (LFI) work?
  • What tools can I use to monitor Voice over IP performance?

Kick-start-your-career-in-Networking

MPLS Questions

  • What is Multi-Protocol Label Switching (MPLS)?
  • What is a label? What is the structure of the label?
  • Where will the label be imposed in a packet?
  • What is a Forwarding Equivalence Class (FEC)?
  • What is an upstream label switch router (LSR)? What is a downstream LSR?
  • Is R3 a Downstream LSR to R4 for 10.1.1.0/24?
  • What do the terms incoming, outgoing, local, and remote mean when you refer to labels?
  • Can an LSR transmit/receive a native IP packet (non-MPLS) on an MPLS interface?
  • Can an LSR receive/transmit a labeled packet on a non-MPLS interface?
  • What platforms and Cisco IOSes support MPLS?
  • Generic Routing Encapsulation (GRE) tunnel has an overhead of 24 bytes. How much overhead does an MPLS LSP tunnel have?
  • How does the LSR know which is the top label, bottom label, and a middle label of the label stack?
  • What is the range of label values? What label values are reserved? What do the reserved values signify?
  • What protocol and port numbers do LDP and TDP use to distribute labels to LDP/TDP peers?
  • What restrictions exist for MPLS support on the Catalyst 6500 and 7600 Optical Services Router (OSR)?
  • Where can I find MPLS configuration samples?
  • What options are available for load balancing MPLS packets?
  • Can we configure an 802.1Q trunk between two Cisco Catalyst switches on different sites over a MPLS connection?
  • Does the outgoing MPLS EXP value inherit the DSCP value in incoming IP packets by default or is the incoming DSCP trusted without any additional configuration on an MPLS enabled interface?
  • Does the DHCP relay function work in the MPLS VPN network?

 

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