2.2 Compare and contrast routing technologies and bandwidth management concepts. Flashcards
Dynamic routing Protocols
Dynamic routing protocols are network protocols that automatically adjust and determine the best routing paths based on network topology changes. These protocols help routers exchange routing information and make decisions about where to forward traffic in real-time, without requiring manual configuration.
For the exam, you should know that dynamic routing protocols are divided into two main types: distance-vector and link-state. Distance-vector protocols, like RIP, use hop count as a metric to determine the best route, while link-state protocols, such as OSPF, have a broader view of the network by understanding the state of each link to build more efficient paths. Dynamic routing protocols can adapt to network changes, such as link failures or new devices, making them highly useful for scalable and resilient network management. Common protocols include RIP, OSPF, EIGRP, and BGP. Understanding how these protocols work and their differences is essential for configuring and managing efficient networks.
Routing Internet Protocol (RIP)
Routing Information Protocol (RIP) is a distance-vector routing protocol used in local and wide area networks to determine the best path for data to travel between routers. It operates using hop count as a metric, with a maximum allowable hop count of 15, meaning it is generally suited for smaller networks.
For the exam, you should know that RIP regularly updates routing tables by sharing information with neighboring routers every 30 seconds, which can result in slower convergence compared to other protocols. RIP exists in two versions: RIP version 1 (RIPv1) and RIP version 2 (RIPv2). RIPv1 is a classful protocol, meaning it doesn’t support subnet information, while RIPv2 is classless, supporting CIDR (Classless Inter-Domain Routing) and more efficient routing. Understanding RIP’s limitations, such as scalability issues due to the hop count limit, and its distinction from more advanced routing protocols like OSPF or EIGRP, is crucial for grasping basic network routing concepts.
Open Shortest Path First (OSPF)
Open Shortest Path First (OSPF) is a link-state routing protocol used in IP networks to determine the most efficient path for data. OSPF dynamically updates routing information by building a complete map of the network, known as a link-state database, which it uses to calculate the shortest path using Dijkstra’s algorithm.
For the exam, you should know that OSPF is classless, meaning it supports variable-length subnet masks (VLSM) and CIDR, allowing for efficient use of IP addresses. It is also hierarchical, with areas to minimize routing table size and reduce update traffic. Unlike distance-vector protocols like RIP, OSPF only sends updates when there are network changes, making it more efficient. OSPF is commonly used in large enterprise networks due to its scalability and fast convergence times. Understanding OSPF’s operation, such as its use of areas, cost metric, and the concept of designated routers, is essential for managing complex networks.
Enhanced Interior Gateway Routing Protocol (EIGRP)
Enhanced Interior Gateway Routing Protocol (EIGRP) is an advanced distance-vector routing protocol developed by Cisco that is used to efficiently route data within an autonomous system. EIGRP combines the features of both distance-vector and link-state protocols, making it a hybrid protocol with fast convergence and scalability.
For the exam, you should know that EIGRP uses a metric based on bandwidth, delay, reliability, and load to determine the best route, rather than just hop count like RIP. It also supports classless routing, making it compatible with variable-length subnet masks (VLSM) and CIDR. EIGRP uses the Diffusing Update Algorithm (DUAL) to ensure loop-free and efficient routing, providing backup routes in case of failure. Although EIGRP is a Cisco proprietary protocol, it is known for its speed and efficiency in large networks. Understanding how EIGRP operates and its benefits, such as fast convergence and flexible metrics, is important for configuring and optimizing Cisco-based networks.
Border Gateway Protocol (BGP)
Border Gateway Protocol (BGP) is an external routing protocol primarily used to route data between different autonomous systems (AS) on the internet. BGP is a path-vector protocol that relies on a list of autonomous system numbers (ASNs) to determine the best path for data to travel across networks.
For the exam, you should know that BGP is essential for managing large-scale networks, such as those of internet service providers (ISPs), and is used to control routing between different organizations or large segments of the internet. Unlike interior routing protocols like OSPF or EIGRP, BGP does not rely on metrics like bandwidth or delay; instead, it uses path attributes such as AS-path, next-hop, and community tags to influence routing decisions. BGP is highly customizable and can manage complex routing policies, but it is slower to converge due to its focus on stability over speed. Understanding BGP’s role in internet routing, its path selection process, and its importance in global network connectivity is key for working with large-scale, multi-network environments.
Link state vs. distance vector vs. hybrid
Link-state, distance-vector, and hybrid are three types of dynamic routing protocols that determine the best path for data in a network, but they differ in how they share information and make routing decisions.
Link-state protocols, like OSPF, work by building a complete map of the network. Each router knows the full topology and calculates the best path independently using algorithms like Dijkstra’s. Link-state protocols are more efficient in large networks because they only send updates when changes occur, and they have faster convergence times compared to distance-vector protocols.
Distance-vector protocols, such as RIP, rely on each router sharing its routing table with neighboring routers at regular intervals. Routing decisions are made based on the distance (typically hop count) to the destination. These protocols are simpler but can be slower to converge and may suffer from issues like routing loops.
Hybrid protocols, like EIGRP, combine the best of both worlds. They use distance-vector techniques to share information but include features like more advanced metrics and the ability to detect topology changes quickly, as seen in link-state protocols. Hybrid protocols offer scalability, fast convergence, and flexibility in metric calculations.
For the exam, understanding these differences helps in determining which protocol is best suited for different network sizes and needs.
Static routing
Static routing is a method where routes are manually configured and added to a router’s routing table by a network administrator. Unlike dynamic routing protocols, static routes do not change unless the administrator updates them.
For the exam, you should know that static routing is simple, reliable, and secure, as it doesn’t require routing protocols to broadcast or learn routes dynamically. However, it lacks scalability and flexibility because any network topology change requires manual updates. Static routing is typically used in smaller, stable networks, or as backup routes in larger networks. It’s important to understand how to configure static routes, and when they are preferable over dynamic routing solutions.
Default route
A default route is a special type of static route that directs any traffic for which there is no specific route in the routing table to a designated next-hop address, typically the gateway or router that connects to external networks, such as the internet.
For the exam, you should know that the default route is commonly represented as 0.0.0.0/0 in IPv4 or ::/0 in IPv6. It acts as a catch-all for any destination that isn’t explicitly defined in the routing table. Default routes are essential in simplifying routing tables, particularly in smaller networks or when connecting to the internet. Understanding how to configure a default route is key for managing traffic efficiently in both static and dynamic routing environments.
Administrative distance
Administrative Distance (AD) is a value used by routers to determine the trustworthiness of a route received from different routing sources. It helps the router choose the best route when multiple routes to the same destination exist from different protocols or sources.
For the exam, you should know that each routing protocol has a predefined AD value; for example, directly connected routes have an AD of 0 (most trustworthy), static routes typically have an AD of 1, OSPF has an AD of 110, and RIP has an AD of 120. The lower the AD, the more preferred the route. Understanding AD is important for configuring routing decisions in networks where multiple routing protocols are in use.
Exterior vs. interior
Exterior and interior routing protocols are used to manage routing within and between networks, respectively, but they serve different purposes.
Interior routing protocols (IGPs), such as OSPF, EIGRP, and RIP, are used within a single autonomous system (AS), typically within an organization’s internal network. They are designed for managing routing inside the network to ensure efficient data delivery between devices in the same network.
Exterior routing protocols (EGPs), like Border Gateway Protocol (BGP), are used to route data between different autonomous systems, such as between different organizations or ISPs. These protocols focus on exchanging routing information on a global scale, ensuring connectivity across the internet.
For the exam, you should know that IGPs manage routing within a network, while EGPs handle routing between networks. Understanding the roles of IGPs and EGPs is essential for distinguishing between internal network routing and internet-wide routing.
Time to live
Time to Live (TTL) is a field in the Internet Protocol (IP) header that specifies the maximum time a packet can exist in a network before being discarded. It serves to prevent packets from circulating indefinitely due to routing loops or network errors.
For the exam, you should know that TTL is expressed in seconds or as a hop count. Each time a packet passes through a router, the TTL value is decremented by one. When the TTL reaches zero, the packet is discarded, and an ICMP error message may be sent back to the sender. This mechanism helps to ensure efficient network operation by eliminating stale packets and managing network congestion. Understanding how TTL works is crucial for troubleshooting network issues and optimizing data flow.
Traffic shaping
Traffic shaping is a network management technique that controls the flow of data packets to ensure a smooth and consistent transmission rate. It involves regulating the amount and timing of traffic sent into the network, allowing for better bandwidth utilization and improved performance.
For the exam, you should know that traffic shaping is often used to prioritize certain types of traffic, such as voice or video, over less critical data. This is done by setting limits on bandwidth usage and smoothing out bursts of traffic, which helps prevent network congestion. Traffic shaping can enhance the quality of service (QoS) for applications that require stable bandwidth and low latency. Understanding the principles of traffic shaping is essential for managing network resources effectively and ensuring optimal performance for various applications.
Quality of service (QoS)
Quality of Service (QoS) refers to a set of technologies and techniques used to manage network resources and ensure a certain level of performance for specific types of data traffic. QoS is essential in networks where bandwidth is limited or where certain applications, like voice over IP (VoIP) or video streaming, require priority treatment to function effectively.
For the exam, you should know that QoS mechanisms include traffic prioritization, bandwidth allocation, and traffic shaping. By categorizing data into different classes and applying policies, QoS can reduce latency, minimize packet loss, and ensure more reliable delivery for critical applications. Understanding QoS principles is crucial for designing and maintaining networks that can support diverse traffic types and deliver a consistent user experience.
