In this article we will understand IPv4 class C subnetting. Let’s begin by understanding basic definitions. Definition of IP Address: An IP address is a 32 bit number that logically defines a host. IP address assigned to a LAN card or a device interface can change based on network admin’s requirement. Definition of Subnet Mask: […]
HomeRIPRIP INTERVIEW QUESTIONS Explain Split Horizon and Route Poisoning in RIP. Can we use RIP in the topology having more than 15 hops? What is Multicast address and UDP port used by RIP v2 packets? What is destination address of RIP v1 packets? What is default seed metric used by […]
Consider the below diagram: BGP NEXT-HOP ATTRIBUTE – Rule 1 Next-Hop for locally originated routes is 0.0.0.0 in an AS. For example, Next-Hop for R2’s local prefix 9.9.0.2/32 is 0.0.0.0R2#show ip bgp | i 9.9.0.2BGP table version is 8, local router ID is 9.9.0.2*> 9.9.0.2/32 0.0.0.0 0 32768 i BGP NEXT-HOP ATTRIBUTE – Rule 2 […]
To understand SDN let’s recollect how the traditional or existing networks operate and what are constraints related to such networks.Let’s take example of a well established service provider that has thousands of networking equipment (routers, switches, firewalls etc)connected in the network. The equipment have both the control and data plane hosted in same chassis. An […]
In this article, we will discuss OSPF Forward Address selection criteria in NSSA along with the OSPF FORWARD ADDRESS CONCEPT IN NSSA with the help of some useful lab scenarios. Let us begin with discussing the Forward Address selection criteria. By default, preference should be given first to the router’s internal addresses(Loopback addresses). If internal […]
IP protocol is one of the main protocols in the TCP/IP stack. It is in the form of IP Packets that all the transport layer protocols, for example, TCP, UDP, ICMP and IGMP data travels over the network. IP is connection less and unreliable protocol. It is connection less in the sense that no state […]
Virtual Network Functions (VNFs) are virtualized network services running on open source computing platforms independent of hardware technology. Common VNFs include virtualized routers, firewalls, WAN optimization, and network address translation (NAT) services. Most VNFs are run in virtual machines (VMs) on common virtualization infrastructure software such as Openstack, VMWare or KVM. VNFs can be linked […]
Route-Distinguisher(RD) is 64bit value appended to an IPv4 route/prefix to make it unique while it is advertised from a PE to PE or PE to RR. The total 96bit prefix is called a VPNv4 route/prefix. A VPNv4 (or VPN-IPv4) route comprises of 8-byte Route-Distinguisher (RD) and 4-byte IPv4 address. When a PE router receives an […]
Are you not seeing any output or neighbors under “Show ip ospf neighbors” command? This blog guides you in Troubleshooting OSPF Adjacency Issues – Part 2. If OSPF neighborship is stuck in ATTEMPT State. Attempt state is seen when the OSPF neighborship is configured b/w two routers connected via a Frame-Relay (NBMA) type of […]
In this article we are going to understand What is Openflow? To turn the concept of Software-Defined Networking (SDN) into practical implementation, we need to put into place some protocols, among which OpenFlow is the most desirable one. OpenFlow is the first standard communications interface defined between the control and forwarding layers of an SDN […]
IS-IS routing protocol is extensively used as Interior Gateway Protocol (IGP) in Service Provider (SP) environment. This document helps you gain information regarding IS-IS level types, configuration and troubleshooting. In Cisco world, Integrated IS-IS is deployed, meaning ISIS is used to route IP. We will discuss all the concepts in this article with respect to […]
HomeISISISIS Overload Bit Understanding the general technical meaning of word “Overload” tells shortage of resources (Memory/CPU etc), getting overloaded with currently handled processes. From here comes meaning of the ISIS Overload bit in the ISIS protocol. When overload-bit is set on a particular router, it signals other routers in the network topology not to […]
You might have missed or ignored noticing OSPF Forward Address in OSPF command outputs. Forward address is a IP field seen in LSA 5 and LSA7. It is the IP address to which the traffic should be forwarded for an advertised external prefix (LSA5). The output is shown below. R1#show ip ospf database external 9.9.0.4 […]