Interview Questions.

Q1. What Are The Six Ospf Route Types?

Intra-region, inter place, El, E2, Nl, and N2.

Q2. What Is The Purpose Of A Default Route ?

A default path is used if there isn't always a specific access in the routing desk for the vacation spot.

Q3. What Is The Order Of Preference For The Bgp Attributes As_path, Local_pref, Med, And Weight?

WEIGHT, LOACL_PREF, AS_PATH, MED

Q4. Describe The Difference Between Routing And Switching?

Routing actions a letter or telephone name to the get right of entry to layer.

Switching makes the final delivery. A switching decision is made at the part of the address that is not utilized in routing.

Q5. Compare Is-is Metrics With Ospf Metrics?

An OSPF interface metric is decided from the interface bandwidth. By default, all IS¬-IS interface metrics are equal to @Therefore, the EIGRP route is preferred.

Q6. What Are Hold-down Timers?

Hold-down timers prevent ordinary update messages from reinstating a path that would have long past horrific. Hold-down timers additionally inform routers to preserve for a period of time any changes that could affect routes.

Q7. Why Are Intra-vicinity Summary Routes Not Allowed?

OSPF databases on routers in the same place need to be same. If course summarization become allowed within a place, some routers might have precise routes and a few routers could have summary routes for routers in the place. If this were allowed, the databases for the place might never agree.

Q8. What Is The Purpose Of An Ospf Virtual Link?

To connect a nonzero vicinity to the spine if the nonzero vicinity turns into disconnected from the backbone. A virtual link also can be used if the backbone, or location 0, will become discontiguous.

Q9. What Does The Eigrp Stuck In Active Message Mean?

When EIGRP returns a caught in active (SIA) message, it me that it has no longer acquired a respond to a query. An EIGRP neighbour (or neighbours) have no longer replied to the query for that path.

When the SIA happens, the router clears the neighbour that did no longer respond to the question.

Q10. What Is Route Leaking?

Redistribution of Level 2 routes into a place as Level l routes.

Q11. How Many Two-host Subnets Can Be Made From A /24 Network?

Sixty four because 2 bits are needed for the hosts at the network, leaving 6 bits for the subnet.

Q12. What Four Timers Does Ip Rip Use To Regulate Its Performance?

Here are the 4 timers that IP RIP uses to modify its overall performance:

Route replace timer Time among router updates. The default is 30 seconds.

Route invalid timer Time that must expire before a direction turns into invalid. The default is a hundred and eighty seconds.

Route maintain-down timer If IP RIP receives an update with a hop matter better than the metric recorded in the routing desk, the router is going into holddown for a hundred and eighty seconds.

Route flush timer Time from while a course will become invalid to whilst it's far removed from the routing desk. The default is 240 seconds.

Q13. Name All The Ways For Installing A Prefix In The Bgp Routing Table?

Using the community command to trfer a router from the IP routing desk to the BGP routing table.

Redistributing routes from the IP routing table to the BGP routing table .

Learned from a BGP neighbor.

Q14. Why Do You Not See Ospf Neighbours As Full/dr Or Full/bdr On Serial Link?

This is regular. On point-to-factor and factor-to-multipoint networks, there aren't any precise routers (DRs) or backup particular routers (BDRs).

Q15. What Types Of Routes Are Allowed Into A Nssa?

OSPF intra-location and inter location routes, and probably a default direction. External routes from ABRs are blocked, and external routes from ASBRs are converted to Nl or N2 routes.

Q16. Describe Four Differences Between The Operation Of Ibgp And Ebgp?

IBGP is the protocol used among routers inside the equal self reliant system. EBGP is the protocol used among routers in distinct self sufficient systems.

IBGP routes must be synchronized before they can be trferred to the IP routing desk (until synchronization is disabled).

EBGP sets the subsequent hop attribute to the IP deal with of the interface used to talk with the EBGP peer. The next hop characteristic isn't modified whilst an IBGProuter advertises a prefix to an IBGP peer if the prefix was found out from an EBGP neighbor.

EBGP advertises all prefixes found out from an EBGP neighbor to all other EBGP buddies. IBGP routers do not advertise prefixes learned from one IBGP neighbor to every other IBGP neighbor

Q17. Why Are The Cisco Multicast Routing Protocols Referred To As Protocol Independent ?

Multicast forwarding selections are based at the entries inside the unicast IP routing table. Multicast isn't always dependent on how the unicast IP routing desk was built; you c use any dynamic interior routing protocol, static routes, or a aggregate of the 2.

Q18. What Is The Full Ipv6 Address Represented By Ff02::130f:5?

FF02:0000:0000:0000:0000:0000: 130F:0005 

Q19. Describe The Operation Of Anycast Rp?

Two or extra RPs are configured with the equal IP address. The IP addresses of the RPs are advertised the use of a unicast IP routing protocol. Each multicast router chooses the closet RP. If an RP fails, the routers transfer to the next nearest RP after the unicast ip routing protocol converges. The MSDP is used among RPs to alternate active multicast supply statistics.

Q20. What Is The Scope Of The Weight Attribute?

WEIGHT has best nearby significance and isn't advertised to BGP peers.

Q21. What Is The Administrative Distance Of Ospf Routes?

110

Q22. What Are Broadcast Domains?

A broadcast area defines a collection of devices that acquire every others’ broadcast messages. As with collisions, the extra declares that occur on the community, the slower your community will be. This is due to the fact every tool that receives a published need to procedure it to look if the broadcast is supposed for it.

Q23. How Do You Enable Igrp On A Cisco Router?

The manner you permit IGRP on a Cisco router is just like the manner you enable RIP, besides you specify IGRP because the protocol and upload an autonomous device range.

For example: RouterA(config)#router igrp 10 (10 is the AS quantity)

RouterA(config-router)#network 192.168.Zero.Zero

RouterA(config-router)#community 192.168.1.0

RouterA(config-router)#network 192.168.2.0

Q24. What Is The Scope Of The Local_pref Attribute?

The LOCAL _PREF attribute is advertised during the self sustaining device.

Q25. How Do You Display The Contents Of A Cisco Ip Routing Table?

The show ip direction command shows the Cisco routing desk’s contents.

Q26. What Is A Default Route?

Also known as the gateway of last hotel, a default path is a special kind of static course with an all-zeros network and network mask. The default direction is used to route any packets to a community that a router does no longer immediately recognise about to a next-hop router. By default, if a router receives a packet to a destination community that is not in its routing table, it drops the packet. When a default direction is particular, the router does not drop the packet. Instead, it forwards the packet to the IP deal with special in the default direction.

Q27. What Is The First Thing That Bgp Checks To Determine If A Prefix Is Accessible?

BGP exams the NEXT HOP characteristic to decide if the NEXT HOP is accessible or in the IP routing table.

Q28. What Types Of Routes Are Allowed Into A Totally Stubby Area?

OSPF intra-vicinity routes and a default course. OSPF inter vicinity and external routes are not marketed into a completely stubby region.

Q29. What Is The Major Difference Between Bgp And Igp Route Summarization?

When a summary cope with is created with an IGP (EIGRP, OSPF, and IS-IS), the specific routes of the precis are not advertised. BGP advertises the summary, and all of the unique routes of the precis until they're specifically suppressed.

Q30. What Are The Three Classes Of Routing Protocols?

Distance vector

Link-state

Balanced hybrid

Q31. What Is A Routing Protocol?

A Routing protocol defines the set of guidelines utilized by a router whilst it communicates with neighboring routers. Routing protocols listens for packets from different members with a purpose to learn and keep a routing table.

Q32. What Are Triggered Updates?

When a router notices that a directly connected subnet has changed kingdom, it right now sends every other routing update out its other interfaces in place of watching for the routing replace timer to expire. Triggered updates also are known as Flash updates.

Q33. What Is Type-1 And Type-2 Lsas In Ospf?

Type-1 LSAs are router LSAs and are generated through every router for the area to which the router belongs.

Type-2 LSAs are network LSAs and are generated through the DR and BDR.

Q34. Explain The Function Of A Rendezvous Point ?

A RP is the focal point for multicast traffic. Traffic is forward to the RP from multicast resources. The RP then forwards traffic to multicast receivers.

Q35. What Is The Ad For Each Of The Following?

Directly linked interface 0

Static route 1

EIGRP 90

IGRP one hundred

OSPF a hundred and ten

RIP a hundred and twenty

External EIGRP 170

Unknown 255

Q36. What Is The Purpose Of The Weight Attribute?

If a router has more than one course to the identical IP prefix, the high-quality course is the one with the highest WEIGHT price.

Q37. What Types Of Routes Are Allowed Into A Totally Nssa?

OSPF intra-region routes and a default direction. External routes from ABRs are blocked, and outside routes from ASBRs are converted to Nl or N2 routes.

Q38. What Devices Are Used To Break Up Collision And Broadcast Domains?

Switches and bridges are used to interrupt up collision domains. They create extra collision domains and less collisions. Routers are used to interrupt up broadcast domain names. They create more broadcast domain names and smaller broadcast regions.

Q39. What Is The Purpose Of The Interface Command Ip Multicast Spares-dense-mode ?

Used with PIMSM Auto-RP and version @if the RPs fail, the router reverts to dense mode.

Q40. What Is Convergence?

Convergence is when all routers have consistent understanding and accurate routing tables.

Q41. What Is The Ospf Counterpart To A Level 1-2 Is-is Router?

An Area Border Router (ABR).

Q42. What Is The Difference Between The Types Of Routes Allowed By Default Into Is-is And Ospf Areas?

By default, all routes are advertised into all OSPF regions. This includes inter location OSPF routes and outside routes which have been injected into OSPF. By default, IS-IS does no longer put it up for sale inter vicinity or outside routes into a place, however injects a default direction.

Q43. How Do You Stop Rip Updates From Propagating Out An Interface On A Router?

Sometimes you do not want RIP updates to propagate throughout the WAN, losing valuable bandwidth or giving out valuable statistics about your internetwork. The easiest manner to stop RIP updates from propagating out an interface is to apply the passive-interface worldwide configuration command.

Q44. What Is Split Horizon?

The rule of cut up horizon is that it's far by no means beneficial to send records approximately a path again inside the route from which the original update got here.

Q45. If A Router Learns About The Same Network Prefix Through Rip, Igrp, Eigrp, And Ospf, Which Route Will Be Preferred?

EIGRP has an administrative distance of 90

IGRP has an administrative distance of @

OSPF has an administrative distance of 1@

RIP has an administrative distance of 12@

Therefore, the EIGRP route is favored.

Q46. What Are The Three Types Of Routes You Can Use In A Cisco Router?

The 3 varieties of routes are static routes, dynamic routes, and default routes.

Q47. What Is The Difference Between Static And Dynamic Routes?

Static routes are routes that an administrator manually enters right into a router. Dynamic routes are routes that a router learns robotically via a routing protocol.

Q48. What Is The Ospf Counterpart To Level L Routing?

Intra-place routing.

Q49. How Does Ospf Determine The Dr On A Multi-get right of entry to Network?

The router with the best interface precedence will be the router ID. If all the interface priorities at the multi-get right of entry to network are the identical, the router with the highest router ID could be the DR.

Q50. Describe The Structure And Format Of An Nsap Address?

An NSAP address has a length of8 to twenty bytes and consists of three additives:

One to thirteen byte place identity

Six byte machine identity

One byte NSAP selector this is usually identical to zero for a router