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Introduction
Published in Weidong Wu, Packet Forwarding Technologies, 2007
A network (including several networks administered as a whole) can be defined as an autonomous system. A network owned by a corporation, an Internet Service Provider (ISP), or a university campus often defines an autonomous system. There are two principal routing protocol types: those that operate within an autonomous system, or the Interior Gateway Protocols (IGPs), and those that operate between autonomous systems, or Exterior Gateway Protocols (EGPs). Within an autonomous system, any protocol may be used for route discovery, propagating, and validating routes. Each autonomous system can be independently administered and must make routing information available to other autonomous systems. The major IGPs include RIP, OSPF, and Intermediate System to Intermediate System (IS–IS). Some EGPs include EGP and Border Gateway Protocol (BGP).
The Internet and TCP/IP
Published in Goff Hill, The Cable and Telecommunications Professionals' Reference, 2012
It is not feasible to use OSPF to route over the interconnections between ASs, because there are too many of them (up to 65,535) and because the metrics of ASs (e.g., transit ASs) are often “politically” based. The Exterior Gateway Protocol (EGP) was used in the past, but its backbone architecture has become outdated. Confusingly, EGP refers both to this particular protocol and to the generic class of protocols that set up routes between ASs.
The Era of High-Performance Networks
Published in James Aweya, Designing Switch/Routers, 2023
A service provider network is a network that typically provides access to the Internet, transit services to the Internet, interconnection between two enterprise (or private) networks, web hosting, and access to many other services available on the Internet. A service provider network typically serves as the access point or the gateway to the public Internet. The main reasons organizations build service provider networks are summarized as follows [SCHUDSMIT08]:Provide transit connectivity services for enterprise networks (customers) to other enterprise networks and the public Internet.Provide Internet access to directly attached customers (e.g., home users).Provide access to content and services hosted by the service provider (e.g., web hosting, media broadcasts, conferencing services, etc.).The main characteristics of a service provider network are summarized as follows:It has a well-defined boundary which can be the demarcation between the service provider and the customer (customer-provider boundary), or the demarcation between the service provider and another peer service provider (peering boundary).It uses a well-defined set of IP routing protocols which include various IGPs, and BGP (iBGP and eBGP) [AWEYA2BK21V1] [AWEYA2BK21V2]. A service provider network also has its own set of network management, control, and configuration protocols (e.g., SNMP, DHCP, DNS, VRRP, syslog), and client/server applications.It has a well-defined architecture typically using the three-layer hierarchical model of access, distribution, and core layers. A service provider may have multiple Point of Presences (PoPs), often located at Internet Exchange points and colocation centers. The PoPs, which serve as local access points for users to connect to the Internet, typically house network switches, routers, servers, and other network transport equipment such as Synchronous Digital Hierarchy/Synchronous Optical Networking (SDH/SONET) and Wavelength-Division Multiplexing (WDM) multiplexers.It should be noted that IGPs such as RIPv2 and EIGRP [AWEYA2BK21V1] are suitable for small- to medium-size enterprise networks such as those used in companies, universities, hospitals, airports, shopping malls, etc. On the other hand, IGPs such as OSPF and IS-IS [AWEYA2BK21V2] are mostly used in large-scale networks such as those deployed by service providers and telecom companies. BGP is the main EGP used to interconnect all the different and separate enterprise and service provider networks to create the global Internet as we have today.
A Survey on Packet Switching Networks
Published in IETE Journal of Research, 2022
Routing protocols have two different types: static and dynamic. In the static routing protocol, the routing table is not prepared automatically; instead, the network administrator prepares it, and whenever any change is required in the routing table, the network administrator updates it. The static routing protocol is divided into four types; standard static, default static, summary static, and floating static. The dynamic routing protocol automatically configures the routing table. The network administrator does not need to update or maintain the routing table. The dynamic routing protocol has further two categories of technologies/protocols; Exterior Gateway Protocol (EGP) and Interior Gateway Protocol (IGP). The IGP has further two types that are distance vector routing protocol and link-state routing protocol. These two categories of routing protocols have further different types, see figure 6. In comparison, the EGP has only one further type that is a path-vector routing protocol. Furthermore, the Border Gateway Protocol (BGP) is a path-vector routing protocol, see figure 6.
A comprehensive review of moth-flame optimisation: variants, hybrids, and applications
Published in Journal of Experimental & Theoretical Artificial Intelligence, 2020
Abdelazim G. Hussien, Mohamed Amin, Mohamed Abd El Aziz
Routing Protocols are classified into two classes: Interior Gateway Protocol (IGP) and Exterior Gateway Protocol (EGP). The former is used in single autonomous communication and the latter is used in different autonomous networks routing. The Open Shortest Path First (OSPF) algorithm is a well-known and efficient algorithm used in selecting the shortest path between the source and destination. In (Garg & Gupta, 2017b) Garg and Gupta tried to optimise OSPF problem using MFO even if the attacker node exists.