KTHNOC
MPLS static lab
Juniper version
Group Nr Name1 Name2 Name3 Name4 Date GradeTable of Contents
1 Goals...3 2 Preparations...3 2.1MPLS concepts...3 2.2 Assign labels...4 3 Static LSPs...5 4 More labels...6 4.1 Pen-ultimate popping...6 4.2 Label-stacking...6 5 Cleanup...6 6 References...71 Goals
The goal with this lab is to introduce you to the MPLS protocol, an in particular, how label operations work. You will manually create MPLS paths (LPSs) through an internal network with no dynamic routing enabled.
The lab is not realistic since MPLS should not be manually
configured (as you will find out). However, the lab gives you a basic understanding of how MPLS actually works. In particular, it gives you an understanding of MPLS label operation.
2 Preparations
Before you begin this lab, please consult documents [1] and [2]. Ensure that you have the network map of topology 1 [3]. You should also have read the lecture notes and RFC pages about MPLS. Extra material from vendors published on the web are also useful.
2.1 MPLS concepts
Before you begin the lab, answer the following questions. 1. What does LSP stand for?
___________________________________________
2. An LSP goes from an ingress router, via some transit router, to a pen-ultimate, and finally an egress router. Which label
operations does a router make in the following roles?: ingress: ___________________________________________ transit: ___________________________________________ pen-ultimate: _____________________________________ egress: ___________________________________________
3. How large is the MPLS shim header, and which fields does it contain?
___________________________________________ ___________________________________________ ___________________________________________
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7. Explain why you may have to set “icmp-tunnelling”? ___________________________________________
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2.2 Assign labels
You will set up static LSPs connecting the customer networks of RTX1 with RTX4 and RTX2 with RTX3 in both directions, as shown in the figure. However, the LSPs should make a detour around the other two routers. Note that LSPs are unidirectional so you will have to set up one LSP in each direction.
The customer networks of RTX1 and RTX4 should be able to
communicate with each other; as well as the customer networks of RTX2 and RTX3. But no other customer networks should be able to communicate.
This also means that every router will have one ingress LSP, one egress LSP, one pen-ultimate and one transit LSP.
Assign operations and labels for your LSPs and fill in the values below.
At this point do not use the label 3 for pen-ultimate popping. (In JunOS, static MPLS labels should be in the range 1000000-1048575.)
LSPRTX1RTX4 LSPRTX4RTX1
LSP name ingress transit pen-ultimate LSP-RTX1-RTX4 (RTX 1) (RTX2) (RTX3) LSP-RTX4-RTX1 (RTX4) (RTX3) (RTX2) LSP-RTX2-RTX3 (RTX2) (RTX1) (RTX4) LSP-RTX3-RTX2 (RTX3) (RTX4) (RTX1)
3 Static LSPs
You shall now set-up static LSP:s without using any kind of dynamic routing protocol. The LSP:s will be set-up between the customer networks.
Set-up the routers in a quad/square using the fe-1/0/X interfaces according to network topology 1[3]. Do not set-up the hub network. Enable MPLS on all interfaces, except the customer networks (both in the interface, and protocol sub-menus).
In order for debugging to work properly, you should enable icmp-tunneling.
Study the mpls interface status. Study also the MPLS label swap routing table (mpls.0). Which labels are in the table?
___________________________________________ ___________________________________________ ___________________________________________
Specify your ingress LSP:s using the static-path command, and the transit and egress LSP:s using the label-map command.
Which commands do you use?
___________________________________________ ___________________________________________ ___________________________________________
route does MPLS add to the inet.0 routing table? ___________________________________________
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Which new routes appear (and in which table) for the transit LSP:s? Write down these entries and explain them:
___________________________________________ ___________________________________________
Make a traceroute to the end-point of the static LSP. (You may have to make the traceroute from the ingress router using the source option with IP address from fe-0/0/0) Write down the entries. Do you see the labels?
___________________________________________ ___________________________________________ ___________________________________________
Milestone 1: Show a working static MPLS configuration.
Signature: _____________________
4 More labels
This lab is a continuation of the previous lab with some extra label assignments.
4.1 Pen-ultimate popping
At the pen-ultimate router, swap the label to 3 instead of 0. What effect does this have?
___________________________________________ ___________________________________________
4.2 Label-stacking
In the ingress of each LSP, make a double label-stack by pushing two labels, one after the other. This corresponds to an aggregation of labels.
In the first transit of each LSP, pop the top label, and propagate the inner label to the pen-ultimate router.
What does the mpls.0 routing table now show? ___________________________________________ ___________________________________________ What does the traceroute show?
Milestone 2: Label-stacking.
Signature: _____________________
5 Cleanup
To reset the machines to their initial state, follow the following steps for all routers.
1. Reset the configuration by loading (using override) the ~root/labconf configuration.
Also do not forget to log out from your workstations.
6 References
[1] KTHNOC Router lab Introduction - Juniper version [2] KTHNOC Router lab Reference - Juniper version [3] KTHNOC Router lab Netmap - Topology 1