© 2009 Cisco Systems, Inc. All rights reserved. ROUTE v1.0—6-1 Connecting an Enterprise Network to an ISP Network Lab 6-2 Debrief

© 2009 Cisco Systems, Inc. All rights reserved. ROUTE v1.0—6-2 Lab Topology

© 2009 Cisco Systems, Inc. All rights reserved. ROUTE v1.0—6-3 Lab Review: What did you accomplish?  Task 1: Configure fully meshed IBGP –What steps did you take to configure fully meshed IBGP? –How did you deal with loopback interfaces?  Task 2: Use the MED and local preference (LP) with route maps for BGP path manipulation –What is the difference between a MED and an LP implementation? –In what order did you execute your plan and why? –How did you apply a new policy to the BGP neighbor?

© 2009 Cisco Systems, Inc. All rights reserved. ROUTE v1.0—6-4 Verification  Is your solution working?  What method did you follow to verify that BGP path manipulation is working correctly?  Which commands did you use to verify the proper operation of different BGP policies?

© 2009 Cisco Systems, Inc. All rights reserved. ROUTE v1.0—6-5 Check Points  Full-mesh BGP  Check IP routing table  Loopbacks and next hop  Path used to reach the remote networks  Why a different path is used  Soft reconfiguration

© 2009 Cisco Systems, Inc. All rights reserved. ROUTE v1.0—6-6 Sample Solution  Configure full-mesh IBGP.  Use loopbacks for BGP sessions.  Advertise loopbacks and next hop.  Disable synchronization.  Manipulate the path using MED and LP.  Perform a soft reconfiguration.

© 2009 Cisco Systems, Inc. All rights reserved. ROUTE v1.0—6-7 Alternative Solutions  IBGP process—full mesh or partial mesh  Use loopbacks or other interfaces for BGP session  Install routes into the IP routing table or advertise next hop  BGP synchronization ON or OFF  Using other BGP attributes (beside MED or LP) for path manipulation  How to trigger an update of BGP table after policy change

© 2009 Cisco Systems, Inc. All rights reserved. ROUTE v1.0—6-8 Q and A What is the advantage of full-mesh IBGP? Why is the next hop IP address important? When is synchronization needed? What are different reconfiguration options? What is the difference between MED and LP?

© 2009 Cisco Systems, Inc. All rights reserved. ROUTE v1.0—6-9 Summary  Create a good implementation plan and define the BGP requirements before configuring a BGP path manipulation.  Several solutions exist and alternative solutions give similar or very different results.

© 2009 Cisco Systems, Inc. All rights reserved. ROUTE v1.0—6-10