Chapter 5 Introducing SDN Control in MPLS Networks - High ...

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203packet-flow routing. The other two modules are plugins into the default routing modules.The traffic-type aware routing module ensures that only those flows of a certain traffictype(voice, video, web) are allowed into tunnels meant for the traffic-type (DS-TE).Essentially we use traffic-type to emulate traffic-classes (without actually setting or usingthe DSCP bits). And the load-balancing module ensures that traffic-flows can be loadsharedbetween regular IP-links and links representing tunnels, to the tunnel-tail.Experimental Setup: Our network of software switches is created in theMininet environment [124]. Mininet is an open-source tool that creates a network ofinterconnected software switches on a single PC for emulating networks. It uses Linuxprocess–based virtualization to run many hosts and switches on a single Linux kernel[125]. We use Mininet to emulate a wide-area IP/MPLS network. Our prototype systemruns 15 instances of OVS (modified) to form the IP/MPLS network (Fig. 5.13).(a)(b)Fig. 5.13 MPLS-TE (a) Prototype (b) GUI view showing Emulated IP/MPLS WANFig. 5.13b shows the GUI view for our emulated-WAN. The GUI shows networkstatere-created in real-time via communications with the Controller. The emulatednetworkhas nodes in 15 cities spanning the continental US. In the San Francisco (SFO)and New York (NYC) clouds, San Jose and New Jersey connect to the wide-area via therouters in SFO and NYC respectively. In Fig. 5.13b the GUI shows wide-area IP linksbetween the cities. Unidirectional TE-tunnels are routed on these bi-directional IP links
204 CHAPTER 5. INTRODUCING SDN CONTROL IN MPLS NETWORKSby reserving bandwidth on the links in the direction of the tunnel (from head-end to tailend).The GUI displays reserved-bandwidth information for each link in both directions.Each link is assumed to be a GE link, with a maximum reservable bandwidth of 90% ofthe link-bandwidth (i.e 900 Mbps). Finally, Fig. 5.13 also shows traffic-flows for threedifferent traffic types (voice, video and web traffic) originating from traffic-generators(not shown) in San Jose and New Jersey.Experiments: In the previous section we discussed several features related toMPLS-TE. The primary goal of this experiment is to achieve the basic functionality oftraffic-engineering itself. Secondary goals include the ability to show TE related featuressuch as Auto-Bandwidth and DS-TE.Tunnel-Routing and Packet-Flow Routing: Traffic Engineering in MPLS is a two-stepprocess: a) admission-control of bandwidth-reserved TE-LSPs (or tunnels) performedduring a CSPF routing process for the TE-LSP; and b) (Re-) Routing packet-flowsthrough a newly created TE-LSP. In Fig. 5.13b, we see the operation of a networkwithout traffic-engineering. Traffic flows from the SFO and NY areas, destined toKansas, Phoenix, Houston and NY, all follow the shortest path in the network; potentiallycongesting the SFO DEN KANNY links.Fig. 5.14 Tunnel Routes, Bandwidth-Reservations & Auto-Route
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Page 10 and 11: 181routers make decisions on LSP pa
Page 12 and 13: 183benefits of the map-abstraction
Page 14 and 15: 185all upgraded at the same time. M
Page 16 and 17: 187However the tunnel’s reserved
Page 18 and 19: 189Admission-Control: The MPLS cont
Page 20 and 21: 191This latter point can best be ex
Page 22 and 23: 193different customer’s traffic d
Page 24 and 25: 195the start of the tunnel, to the
Page 26 and 27: 197forwarding traffic-type (or clas
Page 28 and 29: 199controller, as well as link-stat
Page 30 and 31: 201netdev-linux module that abstrac
Page 34 and 35: 205In Fig. 5.14 we show two tunnels
Page 36 and 37: 207forced to route along a less-uti
Page 38 and 39: 209tunnel carries both video and Vo
Page 40 and 41: 211former include (i) our implement
Page 42 and 43: 213these backup tunnels usually do
Page 44 and 45: 215annotated fiber topology, on whi
Page 46: 217of magnitude fewer than implemen

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