KTHNOC, MPLS/RSVP lab, rev: 1.7 KTHNOC. MPLS/RSVP lab. Juniper version. Group Nr. Name1. Name2. Name3. Name4. Date. Grade. Instructor s Signature

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1 KTHNOC MPLS/RSVP lab Juniper version Group Nr Name1 Name2 Name3 Name4 Date Grade Instructor s Signature

2 Table of Contents 1 Goals Preparations RSVP concepts Initial configuration RSVP-signalled LSPs Using LSPs for transit Traffic engineering: paths Loose source routing Strict source routing Traffic engineering: failover Cleanup References...7 2

3 1 Goals This lab gives an overview of signalled MPLS tunnels (LSPs) using RSVP(Resource Reservation Protocol) and traffic-engineering. When you have finished the lab, you will understand how signalled LSPs work and how it interacts with the IGP. You will also understand how to set-up simple traffic engineering scenarios, where you can steer traffic in other directions than the shortest path computation offered by the IGP. 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 handouts about MPLS. You should also be familiar with ISIS[4] and static MPLS[5]. Extra material from vendors published on the web are also useful. 2.1 RSVP concepts Before you begin the lab, answer the following questions. 1. What does RSVP-TE stand for? 2. What is loose and strict source routing? 3. What does ERO stand for and what is its purpose in RSVP? 3

4 3 Initial configuration Connect the routers according to netmap topology 1 [3] (see also figure above). Configure the interfaces according to the netmap. Configure loopback interfaces, and set the router-id to that address. Configure IGP using IS-IS 1, so that the directly connected subnets and the router-id are announced in this manner. Note however, that the user networks of fe-0/0/0 should not be announced by IS- IS! Disable level-1. Check with ping and traceroute and then check the routing table. Even though the opposite workstation-networks is visible on the border routers, you should not be able to ping them. 4 RSVP-signalled LSPs Enable RSVP and MPLS on all internal interfaces (that is, not user networks). Set-up LSPs between all other routers in both directions using RSVP. The egress of the LSPs should be the loopback address of the router. Disable constrained path LSPs since you want to control the paths RSVP takes. Allocate bandwidth to the LSPs, for example 2Mbps. Examine the established MPLS label operations at the ingress, transit and egress. Which labels /label operations are used at each hop? (examine the mpls.0 routing table using the detailed option) 1 It is possible to use OSPF as an alternative to IS-IS 4

5 Set explicit-null on all routers. What happens to the MPLS label operations on the pen-ultimate router? Examine the RSVP and MPLS state of the machine using the showcommands. Specifically, examine interface, and lsp state, with the detailed option set. You can set traceoptions so that you are able to trace the RSVP operation. Try now to ping between the workstations. Does it work? Examine the routing tables. Where does the LSP routes appear (the routes created when the LSP was created)? The inet.3 table is used by BGP when selecting paths for transit traffic. We do not use the LSPs in this way in this lab, so we have to move the routes to inet.0. This is done by the traffic-engineering bgp_igp command. Ensure that it is possible to reach the other workstations now. Milestone 1: RSVP signalled LSPs Signature: 5 Traffic engineering: paths 5.1 Loose source routing The LSPs set-up in the previous section used the IGP to set-up a shortest-path. Regard the LSP to one of your neighbours. Use loose source routing in both directions to alter its automatic choice and make it go the longer way via the other two routers. Create an mpls path, and then use that in the LSP as a primary path. It is generally advised to use loopback addresses when specifying loose source routing. Why? Check with show mpls lsp detail. 5

6 5.2 Strict source routing Steer your LSP to your neighbour by using strict source routing in both directions instead. Let the LSP visit all internal routers. Here it is advised to use interface addresses instead. Why? Milestone 2: Traffic-engineering: source routing Signature: 6 Traffic engineering: failover 1 Make two paths for each LSP. The primary uses strict source routing along one of the internal routers. The secondary uses the alternative path and uses loose source routing. Are both paths active? Measure how long it takes for the fail-over to take place: Set-up a continuous ping and traceroute between R5 and R6. You may also need to enable RSVP tracing. Disconnect or shut-down an interface on the primary path and observe what happens: When can you observe the LSP fail-over (how long is traffic lost)? When you re-enable the interface, how long does it take for the LSP to resume the primary path (use traceroute or the show lsp command)? Milestone 3: Traffic engineering: paths and failover Signature: 7 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/baseconf configuration. 2. Halt the routers using request system halt. After the system has stopped, you can power-down the routers. 1 Optional 6

7 3. Disconnect the cables and ensure the equipment is in the same state (or better) as when you started. Also do not forget to log out from your workstations. 8 References [1] KTHNOC Router lab Introduction - Juniper version [2] KTHNOC Router lab Reference - Juniper version [3] KTHNOC Router lab Netmap - Topology 1 [4] KTHNOC Router lab ISIS - Juniper version [5] KTHNOC Router lab MPLS static Juniper version 7