The popular routing protocol used on the Internet is the Border Gateway Protocol (BGP) which is an exterior gateway routing protocol. Corporate networks manage internal routing with the help of Routing Information Protocol version 2 (RIPv2) and Open Shortest Path First (OSPF) which are interior gateway routing protocols. In this case study, the practical implementation of a complex network for an International Travel Agency is demonstrated using Cisco Routing devices. The protocols implemented are RIP, OSPF and BGP whereby RIP routes and redistributed into OSPF which in turn are redistributed into BGP.
This is a case study of an International Travel Agency that relies heavily on the Internet for advertising & sales operations. The organization has core interface to Internet at San Jose whereby two links are planned - Primary as a T3 connectivity and backup as T1 connectivity. The organization has planned large back-office operations at London and Capetown whereby London needs to have 30 networks with OSPF routing only (OSPF Stubby Area), Capetown needs to have another 30 networks with OSPF routing with limited external redistribution (OSPF Not-So-Stubby-Area) along with a large RIP area whereby 30 networks need to be connected using EZ IP configurations. The organization has a class B license of the network 18.104.22.168/16 with an Autonomous Number assignment of AS200 and hence BGP peering is planned with the ISP with AS Number 100. It is planned that all the routes are injected into the core (including the redistributed routes) such that the entire network can connect to a web enabled Server Farm co-located over the Internet.
The desired network is presented in the figure below:
Figure 1: The network requirement of the International Travel Agency
The Core routers are deployed in Area 0 at SanJose (SanJose 1 and SanJose 3) that runs OSPF. The BGP is planned to be deployed on the router named as "Firewall". This router needs to establish BGP peering with AS100 of the ISP and also ensure that all traffic from AS200 is able to go out to Internet but no traffic from AS100 (the ISP) or any other AS except AS 200 is allowed inside. The router at London shall connect 30 networks advertising over OSPF but not allowing advertisement from any other routing protocol (stubby). The router at SanJose 1 is an ABR. The highest load is on the router at Capetown which is required to be configured as an OSPF NSSA-ASBR. This router needs to connect 30 networks advertising over OSPF but remaining not-so-stubby such that other protocols can share "limited" information with the OSPF domain. The other part of this router shall connect 30