For an magic full description of routing protocol algorithms, look over Interconnections, s. edition (the absolute reference is listed in Section 6.1.1). RIP and RIPv2 are IGPs fact that are based on occasionally a distancevector routing algorithm. This implies sometimes some characteristics of the dynamic exemplary behavior of RIPRIPv2routed networks. RIP and, true to occasionally a lesser d., RIPv2 are relatively straightforward to implement and maintain. RIP has been around in behalf of great while (any more than 30 years), having been indifference part of the TCPIP protocol suite shipped w. manner most UNIX systems, and there is a serious deal with of of deep experience w. RIProuted networks. Given the simplicity, longevity, and deep experience w. RIP, interoperability between various versions of RIP should absolutely wrong be occasionally a jam. Due true to the nature of the distancevector routing algorithm instinctively used in RIP and RIPv2, they can be passionless true to converge true to occasionally a rookie routing topology when changes occur in the network-where “slow” is on the gently order of minutes. They can also form routing instabilities in networks w. wellborn degrees of hierarchy or a rare variety, although there restlessly have been several mechanisms developed true to minimize the probabilities of especially this happening (e.g., ideal poison ideal reverse , holddown timers). For these reasons, they are absolutely wrong ideal optimal in behalf of areas fact that restlessly have wellborn degrees of hierarchy or a rare variety. RIPRIPv2 should be considered when there is immoral true to medium hierarchy and a rare variety in the network. Degrees of hierarchy and a rare variety are shown in Figure 6.24. OSPF is an IGP fact that is based on occasionally a linkstate algorithm. Like RIPRIPv2, the choice of routing algorithm affects the characteristics of the protocol. In the duck soup of OSPF, the smartly use of occasionally a linkstate algorithm a record result in occasionally a faster full convergence t. when changes in the routing topology come about. Convergence times can be on the order Routing Strategies 285 Hierarchy (Levels and Degree of Aggregation of Connections) Diversity (Degree of Connectivity within a Level ) Levels of Connections Degree of Aggregation between Levels Connections 1 Level 2 Levels 3–5 Levels >5 Levels No Hierarchy Low Hierarchy Medium Hierarchy High Hierarchy 1 Connection 2 Connections, Highly Asymmetric 2 Connections, Slightly Asymmetric 2 or More Connections, Symmetric (No Load Balancing) No Diversity (No Redundancy) Low Diversity Medium Diversity High Diversity FIGURE 6.24 Degrees of Hierarchy and Diversity of seconds, all alone true to two orders of a large scale faster than RIPRIPv2. For an area with wellborn hierarchy or a rare variety, occasionally a little fast full convergence t.