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22 Cards in this Set
- Front
- Back
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What is a routing protocol?
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A protocol whose purpose is to learn the available routes, place the best routes into the routing table, and remove the routes when they are no longer valid.
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What is an exterior routing protocol?
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A routing protocol designed for use between different organizations such as ISP's. BGP is an example.
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What is an interior routing protocol?
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A routing protocol designed for use inside a single organization. RIP, IGRP, and OSPF are examples.
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What are the differences between RIP-1 and RIP-2?
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RIP-2 supports VLSM (Variable Length Subnet Masking). RIP-2 supports MD5 encryption to authenticate the source of an update. A router can advertise a route but point listeners to a different next-hop router on the same subnet. RIP-2 can import and redistribute routes from external sources. RIP-2 uses multicast packets instead of broadcast packets, reducing network traffic.
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What is VLSM?
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Variable Length Subnet Masking allows you to break networks up into multiple subnets by using a subnet mask.
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How does RIP calculate a metric for each route?
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Hop count
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How does IGRP calculate a metric for each route?
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Based on bandwidth for each link and cumulative delay.
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What are the goals of a routing protocol?
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1. To dynamically learn and fill the routing table with a route to all subnets in the network. 2. If more than one route is available, to put the best in the routing table. 3. To notice when routes become invalid and remove them. 4. To add new routes, or replace lost routes, as quickly as possible. 5. To prevent routing loops.
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What is the difference between a classless and a classful routing protocol?
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Classless routing protocols transmit a netmask along with each route, so they support VLSM. Classful routing protcols do not, and so cannot support VLSM.
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What term does BGP use to group routes belonging to an organization?
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Autonomous System (AS).
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What does OSPF stand for?
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Open Shortest Path First.
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What does IS-IS stand for?
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Intermediate System to Intermediate System
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Why do distance vector protocols converge slowly, compared to link state protocols?
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Most of the delays come from loop avoidance features, which are not necessary with link state protocols.
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Why are link state updates larger than distance vector updates?
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Link state updates include detailed topographical information about a network, whereas distance vector updates are just lists of subnets, netmasks, and next hops.
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What algorithm does OSPF rely on?
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Dijkstra Shortest Path First
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What algorithm does EIGRP rely on?
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Diffusing Update Algorithm (DUAL)
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What are the key features of EIGRP?
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EIGRP is a hybrid protocol. It transmits more topology information than a distance vector protocol, but not as much as a link state protocol. DUAL calculations require less processing than Dijkstra SPF so it is more efficient. It also calculates a feasible successor route for every route that can be used if the primary route fails. This allows for very fast convergence.
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Describe the key features of RIP-1
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Uses hop count for metric, slow convergence, no VLSM support, Full Routing Updates every 30 seconds.
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Describe the key features of RIP-2
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Uses hop count for metric, slow convergence, full VLSM support, Full Routing Updates every 30 seconds.
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Describe the key features of IGRP
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Metric based on up to 5 parameters, including bandwidth and delay. Slow convergence, no VLSM support, Full Routing Updates every 90 seconds.
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Describe the key features of EIGRP
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Metric based on up to 5 parameters, including bandwidth and delay (uses DUAL algorithm). Very fast convergence, full VLSM support, includes a feasible successor route.
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Describe the key features of OSPF
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Metric based on bandwidth (uses Dijkstra SPF algorithm), fast convergence, full VLSM support.
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