Month: August 2019
Understanding the Shortest Path First (SPF) Protocol: Link-State Routing with Dijkstra’s Algorithm
In networking, efficient routing is crucial for data transmission across complex topologies. The Shortest Path First (SPF) Protocol, also known as Link-State Routing, uses Edsger Dijkstra’s SPF Algorithm to determine the optimal path for packets. Protocols like Open Shortest Path First (OSPF) and Intermediate System-to-Intermediate System (IS-IS) are prime examples of link-state routing protocols. These...
How to Advertise IPv6 Networks in RIPng
IPv6 Routing Information Protocol (RIP), also known as RIPng (RIP Next Generation), supports IPv6 addresses. It is a Distance Vector routing protocol that uses a hop count as a routing metric. After enabling IPv6 RIP, we also need to configure the advertisement of IPv6 RIP routes. We can display IPv6 RIP settings to verify the...
Propagating a Default Route in RIP: Step-by-Step Cisco Configuration Guide (Updated 2025)
Propagating a default route in RIP is a key feature of the Routing Information Protocol (RIP), a distance-vector routing protocol commonly used in small networks. It uses hop count as its metric and is suitable for CCNA-level studies, where understanding basic dynamic routing is key. A default route (0.0.0.0/0), also known as the gateway of...
How to Configure RIP Passive Interface
By default, the Routing Information Protocol (RIP) sends routing table updates every 30 seconds on all enabled interfaces. In RIP version 1 (RIPv1), these are broadcasts to 255.255.255.255, while RIP version 2 (RIPv2) uses multicasts to 224.0.0.9. However, updates should only be sent on interfaces connected to other RIP-enabled routers to avoid unnecessary traffic. This...
How to Configure Routing Information Protocol (RIP)
Routing Information Protocol (RIP) is a dynamic routing protocol that defines a way for routers to connect different networks using the Internet Protocol (IP) to share information about how to route traffic among these other networks. The Routing Information Protocol (RIP) uses hop count as a routing metric to determine the best path between the source and...
Fixed-Length Subnet Masking (FLSM) Exclusive Explanation
Fixed-Length Subnet Masking (FLSM), also known as traditional or classful subnetting, is a foundational concept in IP addressing that CCNA students must master before advancing to more efficient techniques like VLSM in CCNP. In FLSM, an equal number of addresses is allocated to each subnet using a uniform mask length, which simplifies routing in internal...
What is Classless Inter-Domain Routing (CIDR)
The IETF introduced RFC 1517 in 1993, introducing classless inter-domain routing (CIDR). The CIDR replaced the old classful network assignments. The classful address has now become obsolete due to the CIDR scheme. The CIDR network address is determined by the subnet mask instead of the value of the address’s first octet. The network and host...
IPv4 Classful Network Exclusive Explanation
A classful network is a network addressing architecture used in networks since 1981. RFCs 790 and 791, released in 1981, describe how IPv4 network addresses were primarily allocated based on a classification system. The authors of IPv4 addresses set up three classes of network addresses: class A, B, and C for different network sizes. Classful...
Configure a Directly Connected Static IPv6 Route
The directly connected static IPv6 route is the best routing solution when CEF is not working on the router. In the old Cisco IOs before 12.0 versions, this is the best solution to avoid recursive routing. It is also the best in point-to-point networks. It is also the best alternative to using the next-hop IPv6...
Static IPv6 Route Using Next-Hop IPv6 Address
Only the IP address of the next-hop IPv6 is specified in the next-hop static IPv6 route. The exit interface is derived from the next hop. For example, in Figure 1, three next-hop static routes are configured on Router 0. Before forwarding any packet, the router must resolve the route to determine the exit interface to...