Giới thiệu mô hình TCP / IP Giới thiệu các mạng LAN và các thành phần của họ Tự thêm các tuyến đường bằng cách sử dụng tiện ích đường đến các mạng con từ xa. sys11 # route add thêm net net : sys11 # tuyến đường thêm net thêm net | Introducing Routing Protocol Types Interior Routing Protocols IGP is a route table protocol within an autonomous system. IGPs are used within an organization or an organization s site. Exterior Gateway Protocols EGPs as shown in Figure 7-5 are used between organizations or sites for example a large wide area network WAN such as the Internet or a large corporation s intranet. Figure 7-5 shows the role of EGP in Internet routing. AS AS EGP EGP EGP AS Figure 7-5 Role of EGP in Internet Routing Many routing protocols pass route table information within an autonomous system. Two popular protocols are the RIP and the Open Shortest Path First OSPF Protocol. RIP is a distance-vector protocol that exchanges route information between IP routers. Distance-vector algorithms obtain their name from the fact that they compute the least-cost path by using information that is exchanged with other routers that describes reachable networks with their distances in the form of hop counts. Configuring Routing Copyright 2002 Sun Microsystems Inc. All Rights Reserved. Enterprise Services Revision A 7-7 Introducing Routing Protocol Types OSPF is a link-state protocol. OSPF maintains a map of the network topology instead of computing route paths that are based on distance vectors in the way that RIP computes the route paths. OSPF provides a global view of the network and provides the shortest path choices on routes. The map on each OSPF router is updated regularly. Exterior Routing Protocols An exterior routing protocol is a routing protocol that communicates routes between autonomous systems. EGP and the Border Gateway Protocol BGP are the two principal protocols that exchange route table information among autonomous systems. EGP was developed in the early 1980s. The concept of an autonomous system developed out of the research and development of EGP. BGP was developed in the mid 1990s to replace EGP. BGP replaces the distance-vector algorithm of EGP with a path-vector algorithm. The path
