MPLS Traffic Engineering Course Number Presentation_ID © 2001, Cisco Systems, Inc Agenda • Prerequisites • How MPLS-TE Works • Basic Configuration • Knobs! Knobs! Knobs! • Deploying and Desiginig Presentation_ID © 2001, Cisco Systems, Inc How MPLS-TE Works • How MPLS-TE Works -What good is MPLS-TE? -Information Distribution -Path Calculation -Path Setup -Forwarding Traffic Down A Tunnel Presentation_ID © 2001, Cisco Systems, Inc What Good Is MPLS-TE? • There are two kinds of networks Those that have plenty of bandwidth everywhere Those with congestion in some places, but not in others • Presentation_ID The first kind always evolve into the second kind! © 2001, Cisco Systems, Inc What Good Is MPLS-TE? • MPLS-TE introduces a 3rd kind: Those that have plenty of bandwidth everywhere Those with congestion in some places, but not in others Those that use all of their bandwidth to its maximum efficiency, regardless of shortest-path routing! Presentation_ID © 2001, Cisco Systems, Inc How MPLS-TE Works • How MPLS-TE Works -What good is MPLS-TE? -Information Distribution -Path Calculation -Path Setup -Forwarding Traffic Down A Tunnel Presentation_ID © 2001, Cisco Systems, Inc Information Distribution • You need a link-state protocol as your IGP IS-IS or OSPF • Link-state requirement is only for MPLS-TE! Not a requirement for VPNs, etc! Presentation_ID © 2001, Cisco Systems, Inc Need for a Link-State Protocol • Why I need a link-state protocol? To make sure info gets flooded To build a picture of the entire network Presentation_ID © 2001, Cisco Systems, Inc Need for a Link-State Protocol Consider the following network: - All links have a cost of 10 - RtrA’s path to RtrE is A->B->E, cost 20 - All traffic from A to {E,F,G} goes A->B->E RtrB RtrF RtrA RtrE RtrG RtrC Presentation_ID © 2001, Cisco Systems, Inc RtrD What a DV Protocol Sees Node Next-Hop Cost B B 10 C C 10 D C 20 E B 20 F B 30 G B 30 • RtrA doesn’t see all the links • RtrA only knows about the shortest path • This is by design RtrB RtrF RtrA RtrE RtrG RtrC Presentation_ID © 2001, Cisco Systems, Inc RtrD 10 TunnelVision Architecture Control Data Browser http Web Server TV Applet TV Server Application Commands Presentation_ID © 2001, Cisco Systems, Inc Solaris WorkStation Telnet SNMP 54 TunnelVision Client Screenshot Presentation_ID â 2001, Cisco Systems, Inc 55 TunnelVision Cisco is also working with an external partner to add node protection path calculation • The partner has world-class algorithm development experience • TunnelVision will feed topology to this tool, tool will calculate backup paths Presentation_ID © 2001, Cisco Systems, Inc 56 TunnelVision • TunnelVision has a 2-phase EFT • May ship in 4CQ01 If interested, have your account team talk to us Presentation_ID © 2001, Cisco Systems, Inc 57 Other Tools • There are other MPLS-TE tools WANDL, Make Systems, Orchestream, OpNet, etc • Off-net modeling and path calculation very important to help scale TE deployment Presentation_ID © 2001, Cisco Systems, Inc 58 Deploying and Designing • Deployment Methodologies • Scalability • Management • Security Presentation_ID © 2001, Cisco Systems, Inc 59 Security • MPLS-TE is not enabled on externally facing intefaces • Biggest security risk is spoofed RSVP -hacker would have to know a lot about your topo to anything -RSVP authentication exists (rfc2747), not implemented Presentation_ID © 2001, Cisco Systems, Inc 60 Security • MPLS-TE can hide your network topology from the outside world • Is this “security”? That’s debatable But it’s certainly a neat knob! RtrA(config)#no mpls ip propagate-ttl ? forwarded Propagate IP TTL for forwarded traffic local Presentation_ID Propagate IP TTL for locally originated traffic © 2001, Cisco Systems, Inc 61 Knobs! Knobs! Knobs! • Influencing the Path Selection • DiffServ-Aware Traffic Engineering Presentation_ID © 2001, Cisco Systems, Inc 62 Diffserv-Aware Traffic Engineering • MPLS can advertise and reserve bandwidth on a link • Works great, but what if you send a mix of LLQ and BE traffic down a TE tunnel? • Need some way to differentiate and reserve LLQ bandwidth on a link Presentation_ID © 2001, Cisco Systems, Inc 63 Diffserv-Aware Traffic Engineering RtrA RtrE RtrC RtrG RtrB RtrD RtrF • tunnels across CE link • 40MB each tunnel • 100MB reservable on CE, with a 30MB LLQ • What happens when both tunnels send 20MB of VoIP traffic? Presentation_ID © 2001, Cisco Systems, Inc 64 Diffserv-Aware Traffic Engineering RtrA 30MB LLQ+40MB LLQ traffic = 10MB not LLQ’d! RtrE RtrC RtrG RtrB RtrD RtrF • Problem: only one pool on an interface, no way to differentiate what types of traffic are carried! Solution: advertise more than one pool! Presentation_ID â 2001, Cisco Systems, Inc 65 Diffserv-Aware Traffic Engineering ip rsvp bandwidth sub-pool • ‘this link has available bandwidth of X, Y of which is in a sub-pool’ • Not quite two pools, really – no sense in witholding bandwidth from global availabilty if it’s not in use • …which means sub-pool tunnels need to have a better priority than non-sub-pool tunnels Presentation_ID © 2001, Cisco Systems, Inc 66 Diffserv-Aware Traffic Engineering tunnel mpls traffic-eng bandwidth sub-pool • ‘this tunnel wants to reserve X Kbps from a sub-pool’ • sub-pool BW is looked at instead of global pool BW • if sub-pool BW is not available, tunnel won’t come up Presentation_ID © 2001, Cisco Systems, Inc 67 Presentation_ID © 1999, Cisco Systems, Inc 68 ... • How MPLS- TE Works • Basic Configuration • Knobs! Knobs! Knobs! • Deploying and Desiginig Presentation_ID © 2001, Cisco Systems, Inc How MPLS- TE Works • How MPLS- TE Works -What good is MPLS- TE?... Presentation_ID © 2001, Cisco Systems, Inc How MPLS- TE Works • How MPLS- TE Works -What good is MPLS- TE? -Information Distribution -Path Calculation -Path Setup -Forwarding Traffic Down A Tunnel... RtrE OC3 © 2001, Cisco Systems, Inc DS3 OC3 RtrD 13 How MPLS- TE Works • How MPLS- TE Works -What good is MPLS- TE? -Information Distribution -Path Calculation -Path Setup -Forwarding Traffic Down A