1. 111 © 2002, Cisco Systems, Inc. All rights reserved. MPLS Bandwidth Protection - Technical

2. 2 © 2002, Cisco Systems, Inc. All rights reserved. MPLS Bandwidth Protection - Technical Cisco MPLS Bandwidth Protection Technical Presentation Santiago Alvarez Hari Rakotoranto ITD Technical Marketing

3. 333 © 2002, Cisco Systems, Inc. All rights reserved. MPLS Bandwidth Protection - Technical Agenda Introduction Using Tunnel Builder Pro FRR Configuration and Operation Summary

4. 444 © 2002, Cisco Systems, Inc. All rights reserved. MPLS Bandwidth Protection - Technical What is Bandwidth Protection? Bandwidth Protection is NOT a new problem – but using MPLS we have a new paradigm to provide a solution Subscribers want bandwidth and services from point A to B for Voice & Video traffic. They do not care what happens in the network – HOW it is offered by a Service Provider is secondary. Video Voice 100Mbps of Primary Bandwidth 100Mbps of Backup Bandwidth

5. 555 © 2002, Cisco Systems, Inc. All rights reserved. MPLS Bandwidth Protection - Technical Tunnel Builder ProCisco IOS MPLS TE Fast Reroute + New Solution consists of a Centralized Server - Tunnel Builder Pro - that computes backup tunnels used by MPLS Traffic Engineering Fast Reroute in Cisco IOS Software, such that a bandwidth guarantee can be met during a failure condition Introducing Tunnel Builder Pro and Cisco IOS ® Software Enhancements Cisco MPLS Bandwidth Protection

6. 666 © 2002, Cisco Systems, Inc. All rights reserved. MPLS Bandwidth Protection - Technical Bandwidth Protection Challenge R3 R6 R4 R8 R7 R1 R10 R5 Create all required backup tunnels to protect bandwidth under any single element failure with efficient bandwidth sharing with optimal tunnel placement with no dependency on primary tunnels

7. 777 © 2002, Cisco Systems, Inc. All rights reserved. MPLS Bandwidth Protection - Technical Backup Bandwidth Sharing at Work Objective: Protect Router, R1 – Orange and Blue Tunnels Naive approach – each tunnel needs capacity 15 Mbps Shared approach – allocate 20Mbps on Links, R2 -> R3 -> R4; 15 Mbps on R5 -> R2 15 20 R2 R5 R3 R4 R1

8. 888 © 2002, Cisco Systems, Inc. All rights reserved. MPLS Bandwidth Protection - Technical Benefits of the Algorithm within Tunnel Builder Pro Significantly outperforms Constraint-based Shortest Path First (CSPF) for protection Consistently protects more elements than CSPF algorithms Tunnel Builder Pro is the only offline tool that is independent of primary LSPs (it protects reserved bandwidth pools, not paths) Backup paths only need to be changed when there is a topology change Tools protecting LSPs should be dynamically linked to the network in order to handle the frequent changes (not practical) In the general case, allows more traffic to be protected

9. 999 © 2002, Cisco Systems, Inc. All rights reserved. MPLS Bandwidth Protection - Technical Tunnel Builder Pro versus CSPF – Node Protection, Comparative Results Real network backbone with a total of 152 router protection scenarios * Generic CSPF implementation

10. 10 © 2002, Cisco Systems, Inc. All rights reserved. MPLS Bandwidth Protection - Technical Agenda Introduction Using Tunnel Builder Pro FRR Configuration and Operation Summary

11. 11 © 2002, Cisco Systems, Inc. All rights reserved. MPLS Bandwidth Protection - Technical Tunnel Builder Pro Architecture Browser TB Applet Solaris WorkStation TB Server Web Server Telnet http Application Commands SNMP Backup Route Generator (BRG) DataControl

12. 12 © 2002, Cisco Systems, Inc. All rights reserved. MPLS Bandwidth Protection - Technical Tunnel Builder Pro GUI 1 2 3 1 2 3 Control Panel Display Panel Status Panel

13. 13 © 2002, Cisco Systems, Inc. All rights reserved. MPLS Bandwidth Protection - Technical Setting up the System for Bandwidth Protection 1.Install Tunnel Builder Pro 2.Fetch network topology data 3.Identify Shared Risk Link Groups (SRLGs)* 4.Set global parameters (e.g. timeout, backup bandwidth) * Shared Risk Link Groups: set of links that share a resource that would cause them to fail simultaneously

14. 14 © 2002, Cisco Systems, Inc. All rights reserved. MPLS Bandwidth Protection - Technical Fetching Network Topology Selected Seed Router Fetch Options Fetched Topology

15. 15 © 2002, Cisco Systems, Inc. All rights reserved. MPLS Bandwidth Protection - Technical Identifying SRLGs Invoke SRLG Mgmt. Window SRLG Mgmt. Window

16. 16 © 2002, Cisco Systems, Inc. All rights reserved. MPLS Bandwidth Protection - Technical Setting Global Parameters BRG Options Invoke BRG Options Window BRG Options Window

17. 17 © 2002, Cisco Systems, Inc. All rights reserved. MPLS Bandwidth Protection - Technical Setting Global Parameters Bandwidth to Protect (Primary Bandwidth) BackupBW = (LinkSpeedBW x LinkSpeedFactor) – PrimaryBW PrimaryBW can be total subpool or global pool Underbooking if (0 < LinkSpeedFactor < 1) Overbooking if (LinkSpeedFactor > 1 ) Max. Protectable Capacity Used for primary LSP admission Available Capacity For Backup Max Utilization During Failure

18. 18 © 2002, Cisco Systems, Inc. All rights reserved. MPLS Bandwidth Protection - Technical Setting Global Parameters Bandwidth to Be Protected (cont’d.) Bandwidth to Be Protected Link Speed Factor to control Over- Booking and Under- Booking

19. 19 © 2002, Cisco Systems, Inc. All rights reserved. MPLS Bandwidth Protection - Technical Checking Current Level of Protection 1.View existing backup tunnels 2.Select facilities (e.g. links, nodes) to check 3.Start protection check 4.Analyze results

20. 20 © 2002, Cisco Systems, Inc. All rights reserved. MPLS Bandwidth Protection - Technical Existing Backup Tunnels Start Protection Check Facilities to Check Results of Protection Check Checking Current Level of Protection (cont’d.)

21. 21 © 2002, Cisco Systems, Inc. All rights reserved. MPLS Bandwidth Protection - Technical Computing Bandwidth Protection 1.Select facilities (e.g. links, nodes) to protect 2.Start protection computation 3.Analyze results 4.Install desired backup tunnels

22. 22 © 2002, Cisco Systems, Inc. All rights reserved. MPLS Bandwidth Protection - Technical Existing Backup Tunnels Start Protection Computation Facilities to Protect Results (Warning and Suggested Tunnels) Install Selected Tunnels Computing Bandwidth Protection (cont’d.)

23. 23 © 2002, Cisco Systems, Inc. All rights reserved. MPLS Bandwidth Protection - Technical What Happens When a Topology is Not Fully Protected? Not always possible to create backup tunnels for all failures (e.g. topology, non- conformant nodes, allocated bandwidth) Existing mechanisms can be used to ensure primary tunnels are not routed through unprotected facilities (e.g. affinity bits or explicit routes)

24. 24 © 2002, Cisco Systems, Inc. All rights reserved. MPLS Bandwidth Protection - Technical Agenda Introduction Using Tunnel Builder Pro Fast Reroute Configuration and Operation Summary

25. 25 © 2002, Cisco Systems, Inc. All rights reserved. MPLS Bandwidth Protection - Technical Consider the following example Lab set-up: 172.16.255.5 R1 172.16.192.0/30.1.2 172.16.224.0/30.1.2.1.2.1.2 172.16.208.0/30 172.16.0.0/30 172.16.64.0/30 172.16.255.1172.16.255.4 172.16.255.3172.16.255.2 R3 R4 R5 R2 Pos3/1 Pos0/0/0 Pos0/1/0 Pos3/0 Pos3/2 Pos2/1/0Fas2/0/0 Fas1/0/0 Ser0/1/0 Ser1/0 MPLS Bandwidth Protection Step-by-step example

26. 26 © 2002, Cisco Systems, Inc. All rights reserved. MPLS Bandwidth Protection - Technical ! interface Tunnel 100 description FROM_R1_TO_R4 ip unnumbered Loopback0 no ip directed-broadcast tunnel destination 172.16.255.4 tunnel mode mpls traffic-eng tunnel mpls traffic-eng autoroute announce tunnel mpls traffic-eng priority 3 3 tunnel mpls traffic-eng bandwidth sub-pool 1000 tunnel mpls traffic-eng path-option 1 explicit name FROM_R1_TO_R4 tunnel mpls traffic-eng record-route tunnel mpls traffic-eng fast-reroute ! Tunnel 100 Tunnel100 configured as fast re-routable SESSION_ATTRIBUTE Flag = 0x01 in PATH message MPLS TE - Local Protection R3R4 R5 R2R1

27. 27 © 2002, Cisco Systems, Inc. All rights reserved. MPLS Bandwidth Protection - Technical interface Tunnel99 description BACKUP_WHEN_Link-R2-R3_DOWN ip unnumbered Loopback0 no ip directed-broadcast tunnel destination 172.16.255.3 tunnel mode mpls traffic-eng tunnel mpls traffic-eng priority 7 7 tunnel mpls traffic-eng backup-bw sub-pool 1000 tunnel mpls traffic-eng path-option 1 explicit name BACKUP_R2_TO_R3 tunnel mpls traffic-eng record-route ! ip explicit-path name BACKUP_R2_TO_R3 enable next-address 172.16.224.2 next-address 172.16.208.2 ! Backup Tunnel99 (explicitly routed) is configured on R2 No autoroute (MUST be used just when failure occurs) MPLS TE - Link Protection R3R4 R5 R2R1 Tu99

28. 28 © 2002, Cisco Systems, Inc. All rights reserved. MPLS Bandwidth Protection - Technical interface POS3/1 description Link R2-R3 bandwidth 155000 ip address 172.16.192.1 255.255.255.252 no ip directed-broadcast ip router isis encapsulation ppp mpls traffic-eng tunnels mpls traffic-eng backup-path Tunnel99 tag-switching ip crc 32 pos ais-shut pos report lrdi ip rsvp bandwidth 155000 155000 sub-pool 15500 ! Tunnel99 will protect failures detected on POS3/1 MPLS TE - Link Protection (POS Interface) R3R4R2R1 R5 Tu99

29. 29 © 2002, Cisco Systems, Inc. All rights reserved. MPLS Bandwidth Protection - Technical Local Protection Desired Will look for NHOP (Link) and NNHOP (node) Protection MPLS TE - Link Protection R5 R3R4R2R1 Path

30. 30 © 2002, Cisco Systems, Inc. All rights reserved. MPLS Bandwidth Protection - Technical Local Protection available at R2, it is NHOP Protection: Link Protection MPLS TE - Link Protection R5 R3R4R2 R1 RESV

31. 31 © 2002, Cisco Systems, Inc. All rights reserved. MPLS Bandwidth Protection - Technical Once, Local Protection is desired for an LSP, Each node along the LSP path will try to find a backupto NHOP or NNHOP MPLS TE - Link Protection, Fast Reroute message at R1 R5 R3 R4R2 R1

32. 32 © 2002, Cisco Systems, Inc. All rights reserved. MPLS Bandwidth Protection - Technical On R2 Same here, but we also have Tunnel99 as NHOP backup MPLS TE - Link Protection, Fast Reroute messages at R2 R5 R3 R4R2 R1

33. 33 © 2002, Cisco Systems, Inc. All rights reserved. MPLS Bandwidth Protection - Technical ! interface Tunnel 100 description FROM_R4_TO_R1_VIA_FAST-ETHERNET_R3_R5 ip unnumbered Loopback0 no ip directed-broadcast tunnel destination 172.16.255.1 tunnel mode mpls traffic-eng tunnel mpls traffic-eng autoroute announce tunnel mpls traffic-eng priority 1 1 tunnel mpls traffic-eng bandwidth sub-pool 1000 tunnel mpls traffic-eng path-option 1 explicit name FROM_R4_TO_R1_FS tunnel mpls traffic-eng record-route tunnel mpls traffic-eng fast-reroute ! ip explicit-path name FROM_R4_TO_R1_FS enable next-address 172.16.64.1 next-address 172.16.208.1 next-address 172.16.224.1 next-address 172.16.0.1 ! Tunnel 100 Tunnel 100 configured as fast re-routable going thru Fast Ethernet interface between R3 and R5 SESSION_ATTRIBUTE Flag = 0x01 in PATH message MPLS TE - Local Protection (with RSVP Hello) R3 R4 R2 R1 R5

34. 34 © 2002, Cisco Systems, Inc. All rights reserved. MPLS Bandwidth Protection - Technical interface Tunnel99 description BACKUP_WHEN_R3-R5_DOWN ip unnumbered Loopback0 no ip directed-broadcast tunnel destination 172.16.255.2 tunnel mode mpls traffic-eng tunnel mpls traffic-eng priority 1 1 tunnel mpls traffic-eng backup-bw sub-pool 1000 tunnel mpls traffic-eng path-option 1 explicit name BACKUP_R3_TO_R2_VIA_POS tunnel mpls traffic-eng record-route ! ip explicit-path name BACKUP_R3_TO_R2_VIA_POS enable next-address 172.16.192.1 Tu99 MPLS TE - Link Protection (with RSVP Hello) Backup Tunnel99 (explicitly routed) is configured on R3 No autoroute (MUST be used just when failure occurs) R3 R4 R2 R1 R5

35. 35 © 2002, Cisco Systems, Inc. All rights reserved. MPLS Bandwidth Protection - Technical MPLS TE - Node and Link Protection (with RSVP Hello) On R3, need a protocol to detect Link Failure (Non-POS interface) Configure RSVP Hello Extension Between two adjacent neighbors Allows detection of link or Node failure based on Hello Request/Hello Ack Advantages of Hellos Independent of the link type Detect that a node is not reachable even if link up

36. 36 © 2002, Cisco Systems, Inc. All rights reserved. MPLS Bandwidth Protection - Technical ip rsvp signalling hello ip rsvp signalling hello statistics ! interface FastEthernet1/0/0 description Link R3-R5 ip address 172.16.208.2 255.255.255.252 no ip directed-broadcast ip router isis mpls traffic-eng tunnels mpls traffic-eng backup-path Tunnel99 tag-switching ip ip rsvp bandwidth 100000 100000 sub-pool 10000 ip rsvp signalling hello ip rsvp signalling hello refresh interval 50 ip rsvp signalling hello refresh misses 5 ! MPLS TE - Node and Link Protection (with RSVP Hello) Enabled RSVP hellos globally on both ends (R3 and R5) Enabled RSVP hellos on both ends of the protected interface Tu99 R3 R4 R2 R1 R5

37. 37 © 2002, Cisco Systems, Inc. All rights reserved. MPLS Bandwidth Protection - Technical On R3 Hello Instance protecting one LSP, on interface Fa 1/0/0 Currently ACTIVE (sending Hello Requests) and UP Refresh Interval 50ms MPLS TE - Link Protection (with RSVP Hello) To check status of HELLO instances at R3 show ip rsvp hello instance detail Show ip rsvp hello statistics R3R4R2R1 R5

38. 38 © 2002, Cisco Systems, Inc. All rights reserved. MPLS Bandwidth Protection - Technical On R5 Hello Instance protecting one LSP, on interface Fa 2/0/0 Currently PASSIVE (responding to Hello Requests and UP Refresh Interval 50ms MPLS TE - Link Protection (with RSVP Hello) To check status of HELLO instances at R5 show ip rsvp hello instance detail Show ip rsvp hello statistics R3R4R2R1 R5

39. 39 © 2002, Cisco Systems, Inc. All rights reserved. MPLS Bandwidth Protection - Technical On R3 Adjacencies Lost due to I/F down Will target FRR to Tunnel 99 State is now PASSIVE MPLS TE - Link Protection (with RSVP Hello) Link failure (FastEthernet1/0/0) on R3 R3R4R2R1 R5

40. 40 © 2002, Cisco Systems, Inc. All rights reserved. MPLS Bandwidth Protection - Technical Detailed Signaling RSVP -HELLO and FRR when I/F Down IP RSVP debugging (RSVP-HELLOS) is on *17:31:51.589: RSVP-HELLO: rsvp_hello_if_down: Got notification Fa1/0/0 is down *17:31:51.589: RSVP-HELLO: rsvp_hello_if_down: Update hello instance 172.16.208.2->172.16.208.1 on Fa1/0/0 *17:31:51.589: RSVP-HELLO: Communication lost with 172.16.208.1 *17:31:51.589: RSVP-HELLO: rsvp_hello_communication_lost: interface Fa1/0/0 is down *17:31:51.589: RSVP-HELLO: rsvp_hello_inst_init: Initializing PASSIVE hello inst 172.16.208.2->172.16.208.1 I/F Down notification will target FRR IP RSVP debugging (RSVP-FRR) is on *17:31:51.589: RSVP_FRR: 172.16.255.4_39->172.16.255.1_100_172.16.255.4, Event: Protected I/F FastEthernet1/0/0 went down *17:31:51.589: RSVP_FRR rsvp_frr_event_protected_if_dn: Action: LSP is ready, switch to backup (=>ACTIVE) *17:31:51.589: RSVP_FRR: 172.16.255.4_39->172.16.255.1_100, if_output FastEthernet1/0/0 down, change to Tunnel99, set FRR *17:31:51.589: RSVP_FRR: ERO updated for backup tunnel to 172.16.255.2 *17:32:06.781: RSVP_FRR: 172.16.255.4_39->172.16.255.1_100_2886795012 sending Path msg via backup tunnel Tunnel99 *17:32:06.781: RSVP_FRR: 172.16.255.4_39->172.16.255.1_100_172.16.255.4 rec'd Resv msg (for path *17:32:06.781: RSVP_FRR: fixing up filterspec source to match ext tun id *17:32:06.781: RSVP_FRR: 172.16.255.4_39->172.16.255.1_100_172.16.255.4, Event: RRO Changed *17:32:06.781: RSVP_FRR rsvp_frr_event_rro_changed: Action: LSP is active, ignore event Link Protection (with RSVP Hello) Detailed Signalling on R3 when I/F Down

41. 41 © 2002, Cisco Systems, Inc. All rights reserved. MPLS Bandwidth Protection - Technical Multiple Backup Tunnels Multiple Backup Tunnel protecting an interface No limit to the number of backup tunnel (except memory) Can end at different destinatio n Load balancing (extension of multiple backup per interface) Limited-bandwidth backup tunnels Un-limited-bandwidth backup tunnel s Backup Tunnel selection Priorities Based on Backup Tunnel Type NHOP, NNHOP Based on LSP Type (Global/Sub pool) Based on available bandwidth (limited/unlimited)

42. 42 © 2002, Cisco Systems, Inc. All rights reserved. MPLS Bandwidth Protection - Technical ! interface FastEthernet1/0/0 description Link R3-R5 ip address 172.16.208.2 255.255.255.252 no ip directed-broadcast ip router isis mpls traffic-eng tunnels mpls traffic-eng backup-path Tunnel98 mpls traffic-eng backup-path Tunnel99 tag-switching ip ip rsvp bandwidth 100000 100000 sub-pool 10000 ip rsvp signalling hello ip rsvp signalling hello refresh interval 50 ip rsvp signalling hello refresh misses 5 ! interface Tunnel98 description BKUP_tu98 tunnel destination 172.16.255.1 tunnel mode mpls traffic-eng tunnel mpls traffic-eng backup-bw sub-pool 1200 tunnel mpls traffic-eng priority 1 1 tunnel mpls traffic-eng path-option 1 explicit name BKUP_tu98 tunnel mpls traffic-eng record-route ! interface Tunnel99 description BKUP_tu99 tunnel destination 172.16.255.2 tunnel mode mpls traffic-eng tunnel mpls traffic-eng backup-bw sub-pool 1200 tunnel mpls traffic-eng priority 1 1 tunnel mpls traffic-eng path-option 1 explicit name BKUP_tu99 tunnel mpls traffic-eng record-route ! R4 R1 R3 R5 R2 Tu100 Tu98 Tu99 R6 Multiple Backup Tunnels Multiple Backup Tunnel protecting an interface (link R3-R5) Tunnel98 going to R2 thru link R3-R2 Tunnel99 going to R2 thru link R2-R6

43. 43 © 2002, Cisco Systems, Inc. All rights reserved. MPLS Bandwidth Protection - Technical Backup Bandwidth Protection Bandwidth protection on backup tunnels (backup-bandwidth) Inform the router of the amount of bw a backup tunnel can protect Ensure LSP is mapped to the backup tunnel if bw available Router select LSP mapping to Backup -> provide maximum bandwidth protection Bandwidth pool restriction Restrict the LSP which can use a given backup tunnel Example: different backup if primary LSP use global/sub pool Tunnel mpls traffic-eng backup-bw {} (sub-pool {} | unlimited, global-pool {} | unlimited) (interface level)

44. 44 © 2002, Cisco Systems, Inc. All rights reserved. MPLS Bandwidth Protection - Technical Promotion Backup tunnel choice for an LSP might change New backup tunnel up (e.g. NNHOP) Current backup tunnel goes down Available bandwidth for this backup tunnel changes FRR Promotion timer configurable with ‘ mpls traffic-eng fast-reroute timers promotion’ (default 300s)

45. 45 © 2002, Cisco Systems, Inc. All rights reserved. MPLS Bandwidth Protection - Technical Tunnel100 protected by Tunnel98 (NHOP), but Tunnel99 is now on-line *16:59:44.483: RSVP_FRR: rsvp_frr_event_promote: *16:59:44.483: RSVP_FRR: 172.16.255.4_1->172.16.255.1_100 *16:59:44.483: RSVP_FRR: Attempt to promote 172.16.255.4_1->172.16.255.1_100 *16:59:44.483: RSVP_FRR rsvp_frr_remove_lsp: 172.16.255.4_1->172.16.255.1_100 clearing 1000 kbs *16:59:44.483: RSVP_FRR: rsvp_frr_remove_lsp: 172.16.255.4_1->172.16.255.1_100, reducing 1000 kbs on Tunnel99 *16:59:44.483: RSVP_FRR: rsvp_frr_parse_ero_rro: Looking in RRO for NHOP & NNHOP Addrs/Labels: *Mar 19 16:59:44.483: RSVP_FRR: rsvp_frr_parse_ero_rro: In RRO, found: NHOP Addr 172.16.224.2 N-NHOP Addr 172.16.0.2 NHOP RRR ID 172.16.255.5 N-NHOP RRR ID 172.16.255.2 *16:59:44.483: NHOP Label 0x1E N-NHOP Label 0x301B *16:59:44.483: RSVP_FRR: rsvp_frr_prepare: 172.16.255.4_1->172.16.255.1_100,Look for N-NHOP Bkup Tun to 172.16.255.2 protecting FastEthernet1/0/0with > 1000 kbs avail *16:59:44.483: RSVP_FRR: rsvp_frr_prepare: 172.16.255.4_1->172.16.255.1_100, Found Bkup Tunnel Tunnel99 *16:59:44.483: RSVP_FRR rsvp_frr_prepare: Prepare succeeded *16:59:44.487: RSVP_FRR rsvp_frr_set_backup: Got a backup => READY *16:59:44.487: RSVP_FRR: rsvp_frr_event_promote: -- Finished Promotion R4 R1 R3 R5 R2 Tu100 Tu99 Tu98 R6 R7

46. 46 © 2002, Cisco Systems, Inc. All rights reserved. MPLS Bandwidth Protection - Technical Agenda Introduction Using Tunnel Builder Pro FRR Configuration and Operation Summary

47. 47 © 2002, Cisco Systems, Inc. All rights reserved. MPLS Bandwidth Protection - Technical Summary Bandwidth protection requires careful placement of backup tunnels and proper accounting of backup Bandwidth Tunnel Builder Pro automates bandwidth protection with no dependency on primary tunnels Tunnel Builder Pro algorithm provides superior bandwidth sharing and protection compared with CSPF-based solutions Cisco IOS Software Release 12.2(22)S provides the required infrastructure to implement bandwidth protection

48. 48 © 2002, Cisco Systems, Inc. All rights reserved. MPLS Bandwidth Protection - Technical References ITD Tunnel Builder page http://wwwin/ios/mpls/tb.shtml ITD MPLS TE page http://wwwin/ios/mpls/te.shtml Tunnel Builder – CCO documentation http://www.cisco.com/univercd/cc/td/doc/product/rtrmgmt/tnlbldr/index.htm Node and Link Protection – CCO documentation http://www.cisco.com/univercd/cc/td/doc/product/software/ios120/120newft/12 0limit/120s/120s22/fs_frnod.htmhttp://www.cisco.com/univercd/cc/td/doc/product/software/ios120/120newft/12 0limit/120s/120s22/fs_frnod.htm

49. 49 © 2002, Cisco Systems, Inc. All rights reserved. MPLS Bandwidth Protection - Technical