Question 1. What Is Ospf Routing Protocol?
Answer :
Open shortest path first is an Open Standard Link State routing protocol which works by using Dijkastra algorithm to initially construct the shortest paths and follows that by populating the routing table with resulting best paths.
Question 2. Mention Some Characteristics Of Ospf?
Answer :
Networking Interview Questions
Question 3. What Is The Need For Dividing The Autonomous System Into Various Areas?
Answer :
we would divide the autonomous system into various areas to keep route updates to a minimum to conserve resources and to keep problems from propagating throughout the network.
Question 4. What Is The Benefit Of Dividing The Entire Network Into Areas?
Answer :
The following are benefits of dividing the entire network into areas –
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Question 5. What Is Backbone Area?
Answer :
While configuring multi-area OSPF, one area must be called area 0, referred to as backbone area. All other areas must connect to backbone area as inter-area traffic is send through the backbone area.
Switching Interview Questions
Question 6. Explain Area Border Router(abr)?
Answer :
It is the router that connects other areas to the backbone area within an autonomous system. ABR can have its interfaces in more than one area.
Question 7. What Is Autonomous System Border Router (asbr)?
Answer :
It is the Router that connects different Autonomous Systems.
Veritas Volume Manager (VVM or VxVM) Interview Questions
Question 8. What Is Ospf Router Id?
Answer :
Router Id is used to identify the Router. Highest IP address of the router’s loopback interfaces is chosen as the Router ID, If no loopback is present than highest IP address of the router’s physical interfaces will be chosen as Router ID.
Question 9. What Parameters Must Match For Two Routers To Become Neighbors?
Answer :
The following parameters must be the same on both routers in order for routers to become neighbors:-
Cisco Nexus switches Interview Questions
Question 10. How Ospf Dr & Bdr Is Elected?
Answer :
Command to change the priority on an interface
router(config)# interface fa0/0
router(config-if)# ip ospf priority 100
Question 11. Why Dr And Bdr Are Elected In Ospf?
Answer :
All OSPF routers will form adjacencies with the DR and BDR. If link-state changes, the update will be sent only to the DR, which then forwards it to all other routers. This greatly reduces the flooding of LSAs therefore conserving the bandwidth.
Border Gateway Protocol (BGP) Interview Questions
Question 12. Explain The Various Ospf States?
Answer :
OSPF routers need to go through several states before establishing a neighbor relationship:-
1.Down – No Hello packets have been received on the interface.
2.Attempt – In Attempt state neighbors must be configured manually. It applies only to nonbroadcast multi-access (NBMA) networks.
3.Init state – Router has received a Hello message from the other OSFP router.
4.2way state – The neighbor has received the Hello message and replied with a Hello message of his own. Bidirectional Communication has been established. In Broadcast network DR-BDR election can occur after this point.
5.Exstart state – DR & BDR establish adjacencies with each router in the network. Master-slave election will takes place (Master will send its DBD first).
6.Exchange state – Routing information is exchanged using DBD (Database Descriptor) packets, Link-State Request (LSR). Link-State Update packets may also be sent.
7.Loading state – LSRs (Link State Requests) are send to neighbors for every network it doesn’t know about. The Neighbor replies with the LSUs (Link State Updates) which contain information about requested networks. The requested information have been received, other neighbor goes through the same process
8.Full state – All neighbor routers have the synchronized database and adjacencies has been established.
Networking Interview Questions
Question 13. Explain Ospf Lsa, Lsu And Lsr?
Answer :
The LSAs (Link-State Advertisements) are used by OSPF routers to exchange routing and topology information. When two neighbors decide to exchange routes, they send each other a list of all LSA in their respective topology database. Each router then checks its topology database and sends Link State Request (LSR) message requesting all LSAs that was not found in its topology table. Other router responds with the Link State Update (LSU) that contains all LSAs requested by the neighbor.
Question 14. What Are The Steps Required To Change Neighborship Into Adjacency?
Answer :
Question 15. Explain Ospf Timers?
Answer :
Hello interval – This defines how often OSPF router will send the hello packet to other OSPF router.
Dead interval – This defines how long a router will wait for hello packets before it declares the neighbor dead.
Enhanced Interior Gateway Routing Protocol (EIGRP) Interview Questions
Question 16. What Is The Default Hello Interval?
Answer :
The default Hello Interval for OSPF is 10 seconds.
Question 17. What Is The Default Dead Interval?
Answer :
The Dead Interval is four times the Hello Interval. By default it is 40 seconds.
Virtual Private Network (VPN) Interview Questions
Question 18. What Multicast Address Does Ospf Use?
Answer :
OSPF use the multicast address of 224.0.0.5 & 224.0.0.6.
Switching Interview Questions
Question 19. Tables Maintained By Ospf?
Answer :
Router participating in OSPF routing protocol maintains three OSPF tables:-
1.Neighbor table – Stores information about OSPF neighbors.
command to see # sh ip ospf neighbor
2.Topology table – Stores the topology structure of a network.
command to see # sh ip ospf topology
3.Routing table – Stores the best routes to all known networks.
command to see # sh ip route ospf
Question 20. What Are Different Ospf Lsa Types ?
Answer :
Cisco Network Engineer Interview Questions
Question 21. How Do We Configure Ospf Routing Protocol?
Answer :
router(config)# router ospf 10
router(config-router)# network 12.1.1.0 0.0.0.255 area 0
router(config-router)# network 23.1.0.0 0.0.255.255 area 1
router(config-router)# exit
250 Network administrator interview questions and answers. The Network administrator Interview questions and answers ebook contains 250 questions based on networking concepts like Firewall, NAT, VPN, Wireless networking, TCP/IP, Frame relay, Routing and switching. The book also includes scenario based questions with diagrams and detailed tutorials. Routing Interview Questions And Answers Global Guideline. COM host will automatically quit, and the rc files will fall through to in.routed. Solaris routers will also automatically bring up in.rdisc at boot time, if there is no /etc/defaultrouter file. They will not ever exit. Engineering interview questions,Mcqs,Objective Questions,Class Notes,Seminor topics,Lab Viva Pdf free download. Switching Interview Questions. 1Q routing on a.
What is VLAN?
By default, all ports on a switch are in the same broadcast domain. A Virtual Local Area Network, Virtual LAN, or VLAN, can be used to divide a single broadcast domain to multiple broadcast domains in a layer 2 switched network.
Routing is the process in which items are forwarded from one location to another. Routing is a hop-by-hop paradigm. A Cisco router performs routing and switching functions. Describe what each function does. Routing is a way to learn and maintain awareness of the network topology.
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What are the VLAN membership types?
Static VLANs & Dynamic VLANs
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What is Static VLAN?
In a static VLAN, the network administrator creates a VLAN and then assigns switch ports to the VLAN. Static VLANs are also called port based VLANs. The association with the VLAN does not change until the administrator changes the port assignment. End-user devices become the members of VLAN based on the physical switch port to which they are connected.
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What is Dynamic VLAN?
In a dynamic VLAN, the switch automatically assigns the port to a VLAN using information from the user device like MAC address, IP address etc. When a device is connected to a switch port the switch queries a database to establish VLAN membership. A network administrator must configure VLAN database of a VLAN Membership Policy Server (VMPS).
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What are the types of VLAN connection links?
There are two types of VLAN connection links and they are Access link and Trunk link.
Click on the Image to see it
The solid lines in above picture are access links and dotted line connecting two switches together is a trunk link. The access links are part of only one VLAN and carry traffic to only the end devices connected to that particular VLAN. But a trunk link is used to connect switches to other switches or to routers and can carry traffic from multiple VLANs.
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What is VLAN Frame Tagging?
To identify the VLAN that a frame belongs to, Cisco switches support different identification techniques (VLAN Frame tagging).
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What are the different VLAN Frame tagging techniques?
• Inter-Switch Link (ISL): Cisco proprietary VLAN frame tagging. No much support from other vendors. Supported only in old Cisco Switch models.
• IEEE 802.1Q: IEEE industry standards VLAN frame tagging.
• LAN Emulation (LANE): LANE is used to communicate with multiple VLANs over ATM.
• 802.10 (FDDI): Protocol for sending VLAN information over FDDI.
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What is Native VLAN?
Normally a Switch port configured as a trunk port send and receive IEEE 801.q VLAN tagged Ethernet frames.
If a switch receives untagged Ethernet frames on its Trunk port, they are forwarded to the VLAN that is configured on the Switch as native VLAN. Both sides of the trunk link must be configured to be in same native VLAN.
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What is VTP?
VLAN Trunking Protocol (VTP) is used to communicate VLAN information between switches in the same VTP domain.
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What is VTP Domain?
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What are the VLAN Trunking Protocol (VTP) Modes?
A network switch, which is participating in VLAN Trunking Protocol (VTP), can have three different modes.
• Server Mode
• Client Mode
• Transparent Mode
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What is VTP Server Mode?
VLAN Trunking Protocol (VTP) Server mode is the default VTP mode for all Catalyst switches.
At least one Server is required in a VTP domain to propagate VLAN information within the VTP domain.
We can create, add, or delete VLANs of a VTP domain in a Switch which is in VTP Server mode.
The changes made in a switch in server mode are advertised to the entire VTP domain.
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What is VTP Client Mode?
VLAN Trunking Protocol (VTP) client mode switches listen to VTP advertisements from other switches and modify their VLAN configurations accordingly.
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What is VTP Transparent Mode?
VLAN Trunking Protocol (VTP) transparent mode switches do not participate in the VTP domain, but VTP transparent mode switches can receive and forward VTP advertisements through the configured trunk links.
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What is VTP Pruning?
VLAN Trunking Protocol (VTP) pruning is a feature in Cisco switches, which stops VLAN update information traffic from being sent down trunk links if the updates are not needed.
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