Types Routing Protocols Flashcards
What is RIP?
Routing Information Protocol (RIP)
Routing Information Protocol or RIP is one of the first routing protocols to be created. RIP is used in both Local Area Networks (LANs) and Wide Area Networks (WANs), and also runs on the Application layer of the OSI model. There are multiple versions of RIP including RIPv1 and RIPv2. The original version or RIPv1 determines network paths based on the IP destination and the hop count of the journey.
RIPv1 interacts with the network by broadcasting its IP table to all routers connected to the network. RIPv2 is a little more sophisticated than this and sends its routing table on to a multicast address. RIPv2 also uses authentication to keep data more secure and chooses a subnet mask and gateway for future traffic. The main limitation of RIP is that it has a maximum hop count of 15 which makes it unsuitable for larger networks.
What is IGRP?
Interior Gateway Protocol (IGRP)
Interior Gateway Protocol or IGRP is a distance vector routing protocol produced by Cisco. IGRP was designed to build on the foundations laid down on RIP to function more effectively within larger connected networks and removed the 15 hop cap that was placed on RIP. IGRP uses metrics such as bandwidth, delay, reliability, and load to compare the viability of routes within the network. However, only bandwidth and delay are used under IGRP’s default settings.
IGRP is ideal for larger networks because it broadcasts updates every 90 seconds and has a maximum hop count of 255. This allows it to sustain larger networks than a protocol like RIP. IGRP is also widely used because it is resistant to routing loops because it updates itself automatically when route changes occur within the network.
What is OSPF?
Open Shortest Path First (OSPF)
Open Shortest Path First or OSPF protocol is a link-state IGP that was tailor-made for IP networks using the Shortest Path First (SPF) algorithm. The SPF routing algorithm is used to calculate the shortest path spanning-tree to ensure efficient data transmission of packets. OSPF routers maintain databases detailing information about the surrounding topology of the network. This database is filled with data taken from Link State Advertisements (LSAs) sent by other routers. LSAs are packets that detail information about how many resources a given path would take.
OSPF also uses the Dijkstra algorithm to recalculate network paths when the topology changes. This protocol is also relatively secure as it can authenticate protocol changes to keep data secure. It is used by many organizations because it’s scalable to large environments. Topology changes are tracked and OSPF can recalculate compromised packet routes if a previously-used route has been blocked.
What is EGP?
Exterior Gateway Protocol (EGP)
Exterior Gateway Protocol or EGP is a protocol that is used to exchange data between gateway hosts that neighbor each other within autonomous systems. In other words, EGP provides a forum for routers to share information across different domains. The most high profile example of an EGP is the internet itself. The routing table of the EGP protocol includes known routers, route costs, and network addresses of neighboring devices. EGP was widely-used by larger organizations but has since been replaced by BGP.
The reason why this protocol has fallen out of favor is that it doesn’t support multipath networking environments. The EGP protocol works by keeping a database of nearby networks and the routing paths it could take to reach them. This route information is sent on to connected routers. Once it arrives, the devices can update their routing tables and undertake more informed path selection throughout the network.
What is EIGRP?
Enhanced Interior Gateway Routing Protocol (EIGRP)
Enhanced Interior Gateway Routing Protocol or EIGRP is a distance vector routing protocol that is used for IP, AppleTalk, and NetWare networks. EIGRP is a Cisco proprietary protocol that was designed to follow on from the original IGRP protocol. When using EIGRP, a router takes information from its neighbors’ routing tables and records them. Neighbors are queried for a route and when a change occurs the router notifies its neighbors about the change. This has the end result of making neighboring routers aware of what is going on in nearby devices.
EIGRP is equipped with a number of features to maximize efficiency, including Reliable Transport Protocol (RTP) and a Diffusing Update Algorithm (DUAL). Packet transmissions are made more effective because routes are recalculated to speed up the convergence process.
What is BGP?
Border Gateway Protocol (BGP)
Border Gateway Protocol or BGP is the routing protocol of the internet that is classified as a distance path vector protocol. BGP was designed to replace EGP with a decentralized approach to routing. The BGP Best Path Selection Algorithm is used to select the best routes for data packet transfers. If you don’t have any custom settings then BGP will select routes with the shortest path to the destination.
However many administrators choose to change routing decisions to criteria in line with their needs. The best routing path selection algorithm can be customized by changing the BGP cost community attribute. BGP can make routing decisions based Factors such as weight, local preference, locally generated, AS_Path length, origin type, multi-exit discriminator, eBGP over iBGP, IGP metric, router ID, cluster list and neighbor IP address.
BGP only sends updated router table data when something changes. As a result, there is no auto-discovery of topology changes which means that the user has to configure BGP manually. In terms of security, BGP protocol can be authenticated so that only approved routers can exchange data with each other.
