Chapter Summary and Review

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Chapter Summary and Review

In this chapter, we saw that one of several protocols can be used to dynamically program switches in order to build and implement cross-connect tables. We compared and contrasted various aspects of those protocols and examined the tradeoffs in each.

Knowledge Review

Answer the following questions in the spaces provided.

What does a cross-connect table allow a router to do?
What are the two methods used to load cross-connect tables?
Within the ordered control mode of label distribution, two primary methods are used to trigger the distribution of labels. What are these two methods?
What is the component of an MPLS network that creates cross-connect tables?

Answers: 1. Process packets with incoming labels; 2. independent control and ordered control; 3. downstream unsolicited (DOU) and downstream on demand (DOD); 4. label switch router (LSR).

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Going Further

Read how the IETF is considering discontinuing work on CR-LDP drafts:

CD-LDP vs. RSVP-TE: www.dataconnection.com/download/crldprsvp.pdf

George Mason University: www.gmu.edu/news/release/mpls.html

Network Training: www.globalknowledge.com/

MPLS links page: www.rickgallaher.com/mplslinks.htm

MPLS Resource Center: http://MPLSRC.COM

RSVP: www.juniper.net/techcenter/techpapers/200006-08.html

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Chapter 3: MPLS Signaling

Introduction

In this chapter, we explore the fundamentals of MPLS signaling, the history of signaling, call setup procedures, traffic control measures, and the advantages and disadvantages of leading signaling and traffic control protocols. The chapter includes applications, examples, hands-on exercises, and resource links to augment the information presented.

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Introduction to MPLS Signaling

Your commute to work every day is a long one, and it seems to take forever with all the congestion that you encounter. New lanes have recently been added to the highway , but they are reserved as express lanes. Sure, they would cut your travel time in half, but to use them you would have to carry extra passengers. You decide to try it; you decide to carry four additional passengers so that you can use the express lanes.

The four passengers do not cost much more to transport than yourself alone, and they allow you to both increase your speed markedly due to enabling you to use the express lanes and lower the rate of interference from the unpredictable and impossible -to-correct behavior of the routine traffic.

One day, you enter the express lanes and find that they are all mired in bumper-to- bumper congestion (see Figure 3.1). You are angry , of course, because you were guaranteed use of these lanes as express lanes, yet you are confronted with the same routine traffic you faced every day in the regular lanes. As you slowly make your way down the road, you see that construction has closed the routine lanes and diverted the traffic to your express lanes. So, what good is it to operate under this arrangement if regular traffic is simply going to be diverted onto your express lanes?

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Figure 3.1: Backed-Up Express Lane