EIGRP Successor & Feasible Successor explained with Feasible Distance and Reported Distance

I am not good in language, so I don’t know whether I have wrote in a diluted way which can help you but still I have tried. The successor route is the best route to reach a subnet, based on the advertised distance (AD) from the neighbor plus the distance to reach that neighbor. This is the route which is installed in the routing table. The feasible successor route is a route which has a higher metric than the successor route to reach a subnet but meets the feasibility condition and can be used in the event that the successor route goes down. This route does NOT get installed in the routing table but is kept in the topology table. Successor – A successor route (think successful!) is the best route to a remote network. A successor route is used by EIGRP to forward traffic to a destination and is stored in the routing table. It is backed up by a feasible successor route

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OSPF Reference Bandwidth

People will say “Hey! What is there in OSPF Reference Bandwidth………..its 100 Mbps”. Yes, you are correct but there are few more things which you should keep in mind. By default, OSPF reference bandwidth is 10^8 i.e 100 Mbps but yes you can change it to any desired value but since OSPF link cost is a 16 bit number so cost can be maximum up to 65,535, hence if you change the reference bandwidth to 4294967 which is maximum in Cisco routers still the cost of your 64K link will be 65535 not 67108859 which comes according to the Metric formula. I believe Cisco did this to keep 64K link under consideration when some network is having 100G link as well as 64K link which is merely impossible. The details of the OSPF reference bandwidth is mentioned in the RFC 4750 Page 45. Please find few details below. Where OSPF reference bandwidth is used, it is used in Link metric calculation

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VTP Simplified for beginners

VLAN Trunking Protocol(VTP) VTP- VLAN Trunking Protocol it is actually not a trunking protocol rather it is a replication protocol for VLAN over the trunk interface. VTP is Cisco proprietary protocol. It is having advantages and disadvantages, those are below: Advantages of VTP: It reduces administrative overhead like suppose you have 100 switches in your network and you want to create a new VLAN without VTP, you need to login to 100 switches and create the VLAN whereas with VTP you only need to create VLAN in your VTP server. Disadvantages of VTP: VTP can be devastating as well. Suppose your network VTP server is having a revision number of 10 and now you have a switch failure in your network which you are replacing with your LAB switch which belongs to same VTP domain of your network with a higher revision number than your VTP server and having different VLAN…………Your existing VLAN database gone. You have no clue other

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Virtual LAN for Beginners

Virtual LAN(VLAN) & It’s Concepts VLAN- Virtual LAN is being used for virtually or logically segregating or separating the local LAN according to the requirement. Reasons behind the creation of multiple VLANs or what we will achieve by creating different VLANs. We can separate the Broadcast domain according to the dept./floor or any other parameter, which will reduce the broadcast propagation to a limited number of users. This will reduce the network and processing overhead of the switching device. We can apply security policies i.e access control rules as per each VLAN requirement and have different rules or policies for different VLAN. Creating Multiple VLANs will increase the scalability of the network and make the troubleshooting easy. Even, we can use different QoS Policies in different VLANs for classification or marking of different VLANs. How many types of ports are there in a VLAN: Types of L2 Port: Access Port- This can allow only one VLAN and used to connect a

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Difference Between Redundancy Mode RPR, RPR+ and SSO

Cisco high-end switches or routers (4500, 6500, 7600, etc) allow a redundant Supervisor Engine to take over if the primary Supervisor Engine fails in order to support fault resistance. Redundant Supervisor Engines must be of the same type with the same model feature card to support redundancy. When you install two Supervisor Engines, the first one to come online becomes the active module. The second Supervisor Engine goes into standby mode. All administrative and network management functions, such as SNMP, CLI console, Telnet, STP, CDP, and VTP, etc. are processed on the active Supervisor Engine. On the standby Supervisor Engine, the console port is inactive. Redundant Supervisor Engines are hot-swappable. The system continues to operate with the same configuration after it switches over to the redundant Supervisor Engine. Redundancy is always enabled and cannot be disabled. Redundancy is enabled anytime the switch has two Supervisor Engines installed on it and the switch decides which specific redundancy mode to use in

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