Lab 5 Introduction
The purpose of this lab is to build on lab #4 and gain more experience
with routers and routing protocols. The particular focus of this lab
is to expand the scope to include communication between
administrative domains. In contrast to lab #4, in which all of the
decisions on configuration, management and troubleshooting are
confined to a single administrative entity (i.e., intra-domain
routing and forwarding), this lab will consider the thorny issues
related to enabling entire networks to interconnect,
i.e., inter-domain routing and packet forwarding.
Unlike intra-domain routing, there is only one protocol that is used
to establish forwarding tables between networks. That protocol is the
Boarder Gateway Protocols (BGP). It can be argued that BGP is the
protocol that is at the very heart of the Internet since the Internet
is all about connecting networks. However, the fact that BGP is used
to communicate routing information (in particular, information about
which networks -- as indicated by IP address ranges -- are available)
between administrative domains with potentially very different
objectives means its requirements differ from standard intra-domain
routing protocols. The primary requirements for BGP are that it
established loop-free routes and that it be flexible (especially in
terms of expressing policies). While the former is accomplished
through the use of path vectors (similar in some respects to distance
vector routing), the latter can lead to problems such as loss of
connectivity, slow convergence and inefficient routes.
Students will be introduced to the basic concepts of inter-domain
forwarding and routing in this lab by configuring and running tests a
small network composed of IP routers. In this lab, each of the
routers will act as a BGP speaker for an administrative domain (even
though it will not be connected to a separate network). Expertise
with inter-domain routing configuration is important if you are
interested in eventually getting a job as a network administrator -
especially with large Internet Service Providers whose networks connect
to many other networks. The routers used in this lab are not emulated
systems - they are Cisco routers running real instances of BGP such as
would be observed in the Internet today. Students will gain further
experience with the command line interface of Cisco's Internetwork
Operating System (IOS).
This lab will be conducted entirely via Schooner. This lab will be
about the same level of complexity as Lab #2 so please start early.
Lab #5 will be the only lab in which inter-domain routing is covered,
so if you would like to experiment with inter-domain routing in other
ways, please see Prof. Barford for ideas.
Objectives
- Become familiar with inter-domain routing concepts.
- Become familiar with BGP basics.
- Gain further experience with Cisco's IOS.
- Gain experience with inter-domain routing configurations.
- Gain experience with troublshooting BGP configurations.