tailieunhanh - Using the AS_PATH Attribute

In this lab, you use BGP commands to prevent private AS numbers from being advertised to the outside world. You also use the AS_PATH attribute to filter BGP routes based on their source AS numbers. | Using the AS_PATH Attribute Objective In this lab you use BGP commands to prevent private AS numbers from being advertised to the outside world. You also use the AS_PATH attribute to filter BGP routes based on their source AS numbers. Scenario The International Travel Agency s Internet service provider ISP2 has been assigned an AS number of 300. This provider uses BGP to exchange routing information with several customer networks. Each customer network is assigned an AS number from the private range such as AS 65000. Before leaving the provider s network these private AS numbers must be stripped from the AS_PATH information. You are asked to configure this. In addition Provider ISP2 would like to prevent its customer networks from receiving route information from International Travel Agency s AS 100. You need to use the AS_PATH attribute to implement this policy. Step 1 Build and configure the network according to the diagram but do not configure a routing protocol. Use ping to test connectivity between the directly connected routers. Note SanJose2 will not be able to reach ISP2 s customer network CustRtr. 1 - 3 Semester 5 Advanced Routing - Lab Copyright 2001 Cisco Systems Inc. Step 2 Configure BGP for normal operation. Enter the appropriate BGP commands on each router so that they advertise their Ethernet networks SanJose2 config router bgp 100 SanJose2 config-router no synchronization SanJose2 config-router neighbor remote-as 300 SanJose2 config-router network ISP2 config router bgp 300 ISP2 config-router no synchronization ISP2 config-router neighbor remote-as 100 ISP2 config-router neighbor remote-as 65000 ISP2 config-router network CustRtr config router bgp 65000 CustRtr config-router no synchronization CustRtr config-router neighbor remote-as 300 CustRtr config-router network Verify that these routers have established the appropriate neighbor relationships by .