MPLS raffic Engineering æ¥æ¬ãã¬ã³ã ( æ ª ) æŸå¶è¡ <satoru@ft.solteria.net> raffic Engineering ãšã¯äœã? åºçŸ©ã«ã¯ ãããã¯ãŒã¯äžã«æµãããã©ãã£ãã¯ãå¹ççã«éäžè¶³ãªãåŠçããããã«è¡ããããã¯ãŒã¯èšèš äœæ¥å šè¬ å¿ èŠåç·å®¹éã®èŠç©ãã åç·äœ¿çšç ãã©ãã£ãã¯éã®ç£èŠ åç·å®¹éã®å¢åŒ· å¢éäœæ¥ãªã© ã€ãŸããã©ãã£ãã¯ã®æµãããèŠãŠ ãããã¯ãŒã¯æ§æãæé©åããããš ä»¥åŸ E ãšåŒã³ãŸã 1
IP ãããã¯ãŒã¯ã«ããã E ã¿ããªã©ã㪠E ããã£ãŠããã ãã? äŸãã° MRGã§ãã©ãã£ãã¯éç£èŠ ç¹å®åç·ã®ããŒã¯ãã©ãã£ãã¯ã50% ãè¶ ãããããããå¢èšèšç»ãç«ãŠãŠ äºç®ç¢ºä¿ 70%~80% ãããã§èŠæå æ¥ããã° 100% ã«ãªããš ããããã¯ã¬ãŒã ãæ¥ã åç·æ°ãå¢ãã ããŒããã©ã³ã¹ããã ãã©ãã£ãã¯ãå¥åç·ã«ç§»ã IGP(RIPãOSPF) çµè·¯ã®ã¡ããªãã¯ãå€ãã ãªã©ãªã©ã çŸåšãŸã§ã®ãœãªã¥ãŒã·ã§ã³ äŸé¡ :IP ãããã¯ãŒã¯ã«ããã E ã«ãŒã¿ R1 ãžã®ãã©ãã£ãã¯ã®æµã æãã³ã¹ãã®å°ããçµè·¯ãéžæ R1 R3 ãã R1 ãžã®ãã©ãã£ã㯠R3 ãã R1 ãžã®ãã©ãã£ã㯠2
äŸé¡ :IP ãããã¯ãŒã¯ã«ããã E ãªã³ã¯ã®ã³ã¹ãå€ãå€ããŠã¿ã çå¯ã R1 R3 ãã R1 ãžã®ãã©ãã£ã㯠R3 ãã R1 ãžã®ãã©ãã£ã㯠äŸé¡ :IP ãããã¯ãŒã¯ã«ããã E æ¬åœã¯ãããããã£ãã®ã«! R1 R3 ãã R1 ãžã®ãã©ãã£ã㯠R3 ãã R1 ãžã®ãã©ãã£ã㯠3
äŸé¡ :IP ãããã¯ãŒã¯ã«ããã E ãªãã° AM ã Frame-Relay 㧠ã§ããŸãã R1 R3 ãã R1 ãžã® PVC R3 ãã R1 ãžã® PVC AM/FR ã IP ãã©ãã£ãã¯å¶åŸ¡ã«çšããæã®åé¡ç¹ IPãããã¯ãŒã¯ãšã¯å¥ã«AM/FRãããã¯ãŒã¯ãçšæããããšã«ãªã ã«ãŒã¿ä»¥å€ã®ãããã¯ãŒã¯ããã€ã¹ ããããã«ãããŠéçš / ç£èŠãå¿ èŠ é«ã³ã¹ã IGP ãžã®è² è·ãé«ããªã ã¡ãã·ã¥ã«ãã Adjacency å¢ è€éãªè«çããããžãŒ 垯åãå§è¿«ãããªãŒããŒããã AM Cell ax. 4
IP ãããã¯ãŒã¯ã«ããããã©ãã£ãã¯å¶åŸ¡ã®åé¡ç¹ ãªã³ã¯ã®ã³ã¹ããã¡ããªãã¯ã«ããIGPã«ãŒãã£ã³ã°ã¯ãã©ãã£ãã¯ã®æµãããèŠããš æé©ã§ã¯ãªã å©çšçãéåžžã«é«ãåç·ãšäœãåç·ãååš ãããã¯ãŒã¯è³æºãæå¹æŽ»çšã§ãã ãããé«å©çšçåç·ã®å¢åŒ·ãåžžã«äœåãªãããã é«ã³ã¹ã! å©çšç ( ãã©ãã£ãã¯é ) ã®é«ãåç·ãé害ã«ãªã£ãæã®ãªã¹ã¯ã¯éåžžã«å€§ãã éåžžãã®ãããªåç·ã¯é«é / è¶ é«éåç· ãã®ãããªåç·ãåãããšãã®ããã¯ã¢ãã容éãååã§ããããšãä¿èšŒããã®ã¯å°é£ ä¿¡é Œæ§ å¯çšæ§ã«æ¬ ãããããã¯ãŒã¯ IP ãããã¯ãŒã¯ã«ããããã©ãã£ãã¯å¶åŸ¡ã®åé¡ç¹ ãã©ãã£ãã¯ã®æé©åãéåžžã«å°é£ IGPã«ãã©ãã£ãã¯ãæé©åããçµè·¯å€æŽã¯è¡ããªã ãã©ãã£ãã¯ãããŒã«å¯ŸããŠçŽæ¥ãªãã¬ãŒã¿ãä»å ¥ããæ段ã¯ã»ãŒçç¡ æ瀺çã«ãã©ãã£ãã¯ã®æµããæé©åã§ããæ°ã㪠E ææ³ãå¿ èŠ MPLS ã«ãã raffic Engineering! 5
MPLS ã«ãã raffic Engineering MPLS-E ã®ã¡ã«ããºã Explicit ( æ瀺ç ) Routing Constraint-based ( 匷å¶ç㪠) ãã¹éžæ IGPã³ã¹ãã«ããã 空ããŠãã / èŠæ±æ¡ä»¶ã«ããããã¹ãæ€çŽ¢ã éžæãã CSPF(Constrained SPF) or Operatorã«ããèšå® IGP(IS-ISãOSPF) ãæ¡åŒµã㊠ãããã¯ãŒã¯è³æº ( ãªã³ã¯ã®åž¯åäºçŽæ å ± ) ãããªã·ãŒãé㶠空ããŠãã / èŠæ±æ¡ä»¶ã«ããããããã¹ãéžæããããã«äœ¿ããã MPLS ã«ãããã±ãããã©ã¯ãŒãã£ã³ã° IP ã¢ãã¬ã¹ã«ãããªããã©ã¯ãŒãã£ã³ã°ã«ãã Explicit Routing ãå®çŸ 6
Explicit Routing RSVP(RFC3209) RSVP-E:Extensions to RSVP for LSP unnels ã«ããLabel Switched Path(LSP) ãç¢ºç« ãããã¯ãŒã¯è³æºæ å ±ãªã©ã«ãã æ瀺çãªãã¹ãèšå®ãã ãã®ä»ã«ã LSP tunnelã®é害æ€ç¥ LSP tunnelã®re-routing 管ç IGP(IS-IS or OSPF) ã®æ¡åŒµ MPLS-Eã«å¯Ÿå¿ããã«ãŒã¿ã¯ä»¥äžã®æ å ±ãæ¡åŒµãããIS-IS/OSPFã«ããäŒéãã 垯åæ å ± (bandwidth) ã©ãã ãã®åž¯åãäºçŽå¯èœã ãªã³ã¯å±æ§ (Link Attribute) ã©ã®ãããªããªã·ãŒã®ãã¹ã§äœ¿çšãããã®ã E ã¡ããªã㯠(E-specific link metric) ãªã³ã¯ã®åŒ·ã ãã€äŒéãããã®ã? åšæç ãŸãã¯äºçŽå¯èœåž¯åãå€åãããšããªã© 7
IGP(IS-IS or OSPF) ã®æ¡åŒµ OSPF ãžã®æ¡åŒµæ¹æ³ Opaque LSA (ype10:intra-area) (draft-katz-yeung-ospf-traffic-09.txt) IS-IS ãžã®æ¡åŒµæ¹æ³ New wide LV (draft-ietf-isis-traffic-04.txt) ãªã IS-IS ã OSPF ã ããªã®ã? RIP ã®ç«å Žã¯? ããã¯ãªã³ã¯ã¹ããŒãåã ãã ã§ãªããš ãªã³ã¯ã«é¢ããæ å ±ãéã¹ãªã IS-IS/OSPF ã§ãåäžãšãªã¢å ã®ã¿æå¹ ãšãªã¢å ã«ããå šãŠã®ãªã³ã¯æ å ±ã¯ãªã MPLS ã«ãããã©ã¯ãŒãã£ã³ã° ãªã MPLS ã§ãªããã°ãªããªãã®ã? Eã¯æ瀺çã«ãã©ãã£ãã¯ã®æµãããã¹ãæå®ã§ããªããã°ãªããªã IP ã¢ãã¬ã¹ã«ããåŸæ¥ã®ãã©ã¯ãŒãã£ã³ã°ã§ã¯ããããã€ããããã©ã¯ãŒãã£ã³ã°ã«ãªã£ãŠããŸã éäžã®ã«ãŒã¿ãæå³ãããã¹ã«ãã£ãŠãã±ããã転éãããã©ããåãããªã MPLSãªãã° IPã¢ãã¬ã¹ã«ãããªããã©ã¯ãŒãã£ã³ã°ãå®çŸããããšãã§ãã 32bit åºå®é·ã®ã©ãã«ã«åºã¥ããã©ã¯ãŒãã£ã³ã° ã©ãã«ã«ãã¹ã瀺ãå€ãã€ããããšã§ Explicit Routingã«åŸã£ããã©ã¯ãŒãã£ã³ã°ãå®çŸã§ãã 8
MPLS-E ã®ã»ããã¢ãã MPLS-E ã®ã»ããã¢ãã RSVP æ¡åŒµãçšãã LSP ã»ããã¢ãã LSP ãã»ããã¢ããããã«ãŒã¿ (head-end ) ããèµ·å LSP ã«ãŒã¿ (tail-end) ããã©ãã«ãå²åœãŠã Downstream On Demand Label Distribution (DoD) LSP ã«å¯ŸããŠåž¯åãäºçŽãã ã·ã°ããªã³ã°äžã§ã®ã¿ å®éã«éã°ãããã©ãã£ãã¯ã®åž¯åãä¿èšŒããŠããããã§ã¯ãªã 9
MPLS-E ã®ããã®æ°ãã RSVP ãªããžã§ã¯ã Explicit Route Object (ERO) E ãã¹ãèšå®ãããªã³ã¯ãæ瀺çã«é£ãã (PAH) Record Route Object (RRO) RSVP ã¡ãã»ãŒãžãééãããªã³ã¯ãèšé² (PAH,RESV) Label Request Object ã©ãã«å²ãåœãŠèŠæ± (PAH) Label Object ã©ãã«å²ãåœãŠéç¥ (RESV) Session Attribute Object( ä»æ§å€æŽ ) ãã¹ã® Setup,Hold ãã©ã€ãªãªãã£, Local repair ãäºçŽã¹ã¿ã€ã« (SE) ãªã©ã®èŠæ± (PAH) æŠèŠ :MPLS-E-LSP ã»ããã¢ãã R3 R6 R7 R9 R1(Head-End) R4 R5 R8(ail-End) R1 R8 ãžã® PAH ã¡ãã»ãŒãž (ERO=R1,R3,R4,R5,R7,R8) R8 R1 ãžã® RESV ã¡ãã»ãŒãž ( ããããã®ãªã³ã¯ã§ RRO è¿œå Label éç¥ ) 10
詳现 :MPLS-E-LSP ã»ããã¢ãã - R1(Head-End)??? 2 1 2 1 R3(ail-End) PAH ã¡ãã»ãŒãž - Session(, 0, R1-lo0) -PHOP(R1-2) - Label_Request(IP) -ERO(-1, R3-1) - Session_Attribute (S(7), H(7),0x04) -Sender_emplate(R1-lo0, 00) - Sender_spec(2Mbps) - Record_Route(R1-2) 詳现 :MPLS-E-LSP ã»ããã¢ãã -?????? R1(Head-End) R3(ail-End) 2 1 2 1??? Path State: Session(, 0, R1-lo0) PHOP(R1-2) Label_Request(IP) ERO (-1, R3-1) Session_Attribute (S(7), H(7), 0x04) Sender_emplate(R1-lo0, 00) Sender_spec(2Mbps) Record_Route (R1-2) 11
詳现 :MPLS-E-LSP ã»ããã¢ãã -?????? R1(Head-End) R3(ail-End) 2 1 2 1??? PAH ã¡ãã»ãŒãž - Session(, 0, R1-lo0) -PHOP(-2) - Label_Request(IP) -ERO(R3-1) - Session_Attribute (S(7), H(7),0x04) -Sender_emplate(R1-lo0, 00) - Sender_spec(2Mbps) - Record_Route(R1-2,-2) 詳现 :MPLS-E-LSP ã»ããã¢ãã -????????? POP - R1(Head-End) R3(ail-End) 2 1 2 1 Path State: Session(, 0, R1-lo0) PHOP(-2) Label_Request(IP) ERO () Session_Attribute (S(7), H(7), 0x04) Sender_emplate(R1-lo0, 00) Sender_spec(2Mbps) Record_Route (R1-2, -2, R3-1) 12
詳现 :MPLS-E-LSP ã»ããã¢ãã -????????? POP - R1(Head-End) 2 2 1 1 R3(ail-End) RESV ã¡ãã»ãŒãž - Session(, 0, R1-lo0) -PHOP(R3-1) -Style=SE - Label=POP - FlowSpec(2Mbps) - Filter_Spec(R1-lo0, 00) - Record_Route(R3-1) 13
詳现 :MPLS-E-LSP ã»ããã¢ãã - R1(Head-End)??? 20 POP 2 1 2 1 POP - R3(ail-End) RESV ã¡ãã»ãŒãž - Session(, 0, R1-lo0) -PHOP(-1) -Style=SE - Label=20 - Filter_Spec(R1-lo0, 00) - FlowSpec(2Mbps) - Record_Route(-1, R3-1) 詳现 :MPLS-E-LSP ã»ããã¢ãã -??? 20 R1(Head-End) R3(ail-End) 2 1 2 1 Resv state: Session(, 0, R1-lo0) PHOP(-1) Style=SE FlowSpec (2Mbps) Filter_Spec(R1-lo0, 00) Label=20 Record_Route(R1-2, -1, R3-1) POP POP - 14
詳现 :MPLS-E-LSP ã»ããã¢ãã - 20 20 R1(Head-End) R3(ail-End) 2 1 2 1 POP POP - LSP ã»ããã¢ããå®äº! MPLS-E ã®ã¡ãªãã 15
MPLS-E ã®ã¡ãªãããšã¯? IPãããã¯ãŒã¯äžã§ãã©ãã£ãã¯ãæé©åããããšã¯ä»ãŸã§è¿°ã¹ããšãã ãã以å€ã«ã¯? ãªã³ã¯é害æã®è² è·åæ£é«éãªé害å埩ã¡ã«ããºã (Fast Reroute) ã®é©çšãå¯èœç¹å® POP éã®ãã©ãã£ãã¯ç®¡çè² è·åæ£ã®èª¿æŽ ãªã©ãªã© ãªã³ã¯é害æã®è² è·åæ£ å¹³åžžæã¯äœè£ã§éã¹ããã©ãã£ãã¯ã R1 R3 16
ãªã³ã¯é害æã®è² è·åæ£ ã³ã¹ãã®éœåäž çŽ°ããªã³ã¯ã«çå¯ããããšèŠãã ã§ã R1 R3 ãªã³ã¯é害æã®è² è·åæ£ MPLS-E ã§å®å¿ æé©åçµè·¯å€æŽ R1 Re-Optimize 㧠IGP ã ããããé«é (< æ° Sec) R3 17
Fast Reroute Local Repair ãšåŒã°ããé«éé害å埩ææ³ã® 1 〠é害ãšãªã£ããªã³ã¯ãŸãã¯ããŒãã«é£æ¥ã ãã©ãã£ãã¯ã®äžæµãšãªã£ãŠããããŒãã«ãã£ãŠLSPãé«éè¿åããã ( æ° msec~ æ° 10msec) ãã©ã€ããªLSPã®ããã®ããã¯ã¢ããLSPãäºåã«èšå®ããã ä»ã«ã¯Global Repair,Alternative Egress Repair,etc Head-end PLR (Point of Local Repair) MP (Merge Point) ail-end ãã©ã€ã㪠LSP ããã¯ã¢ãã LSP Fast Reroute é害æ€åºæ¹æ³ãšããŠã¯ Layer2 以äžã®ã¢ã©ãŒã (e,g, å å ¥åæãSONE/SDHã¢ã©ãŒã ) IGPãRSVPã®adjacency/hello æ ããã¯ã¢ãããã¹ç¢ºç«ããã©ãã£ãã¯è¿åã«ããã€ãçš®é¡ããã One-to-one backup ãã©ã€ããªLSP1 æ¬æ¯ã«ããã¯ã¢ããLSPãèšå®ããã Facility backup å ±éã®ãªã³ã¯orããŒããééããè€æ°ã®ãã©ã€ããªLSP æ¯ã« 1ã€ã®ããã¯ã¢ããLSPãèšå®ããã Link protection ( 泚 : ä»æ§ã®äžã®erminologyã§ã¯ãªã ) é害ãšãªã£ããªã³ã¯ãééããLSPãããã¯ã¢ããLSPãžè¿åãã Node Protection é害ãšãªã£ãããŒããééããLSPãããã¯ã¢ããLSPãžè¿åãã 18
Fast Reroute One-to-one backup Head-endãã One-to-one backup desired (FAS_REROUE Object) ãšããŠProtected LSPãèŠæ± PLRã§ããã¯ã¢ããLSP(Detour LSP) ãCSPFã«ããèšç®ãèšå® PLRããDetour Object ä»ãã®Pathã«ããèšå®ããã Detour LSPã¯ããŒãžãããããšããã Head-end PLR1 PL MP ail-end ãã©ã€ã㪠LSP Detour MP DetourLSP1 DetourLSP2 DetourLSP3 (merge 1,2) Fast Reroute Labeled Packet Head-end Facility backup ã©ãã«ã¹ã¿ã㯠( ã©ãã«ã®2 段éã ) ã«ãã£ãŠ 1ããã¯ã¢ããLSP(Bypass unnel) ã§è€æ° LSPã®ããã¯ã¢ãããå¯èœ One-to-one backupã§ã®detour LSPã¯Protected LSPã«1 察 1ã§å¯Ÿå¿ããã®ã§ ããã¯ã¢ããã®ããã«ã©ãã«ã¹ã¿ãã¯ã¯å¿ èŠãªã PLRã¯MPã«ããããã©ã€ããªLSPã©ãã«ãåŠç¿ å€æŽåŸããã¯ã¢ãã Label recordingãå¿ èŠ (Resvã¡ãã»ãŒãžå RROã«MPã§ã®ã©ãã«ãå ¥ã ) MPãGlobal Label Spaceã§ãªããš åå¥ã·ã°ããªã³ã°ãå¿ èŠãšãªã PLR MP ail-end 泚 : ãã©ã€ã㪠LSP ããã¯ã¢ãã LSP (Bypass unnel) ã®ã©ãã«å€ã¯å®éã«ã¯ Hop-by-hop ã§å€ãããŸã Bypass unnel ã®PHPãè¡ã (Penultimate Hop Popping) 19
Fast Reroute Facility backup ( ããŒããããã¯ã·ã§ã³ ) R1 é£æ¥äžæµããŒãããŒãããŠã³æã«äžæµé£é£æ¥ (Next-Next-HOP) ãžé«éåæ¿ One-to-one backupã®å Žå㯠æŽã«äžæµããŒããMPãšãªãããšãå¯èœ PLRããNNHOPãžããã¯ã¢ããLSP(Bypass unnel) ãèšå® PLRã¯MPã«ããããã©ã€ããªLSPã©ãã«ãåŠç¿ ãã©ã€ããªLSPã®ããããšã³ãããæ瀺çã«èŠæ±å¯èœ PLR MP / NNHOP(Next-Next-Hop) R3 ãã©ã€ã㪠LSP ããã¯ã¢ãã LSP (Bypass unnel) Fast Reroute Facility backupã®çš®é¡ ( ãªã³ã¯ãããã¯ã·ã§ã³ ) äžæµãªã³ã¯ãªã³ã¯åææã«é£æ¥ããŒã (Next-HOP) ãžé«éåæ¿ ä»æ§äž Facility backupã®æã®ã¿å¯èœ R1 One-to-one backupã¯é£æ¥ããŒãã«detour LSPãèšå®ããªã PLRããNHOPãžããã¯ã¢ããLSP(Bypass unnel) ãèšå® ããŒããããã¯ã·ã§ã³ãšç¹å¥åºå¥ããããã®ã§ã¯ãªãã NHOPãžã®Bypass unnelãããªãã£ãå Žåãã®ãããªåäœãšãªã MPã«ããããã©ã€ããªLSPã©ãã«ã¯ãã®ãŸãŸäœ¿ãã PLR MP / NHOP(Next-HoP) R3 ãã©ã€ã㪠LSP ããã¯ã¢ãã LSP (Bypass unnel) 20
Fast Reroute èšå®äŸ (C) interface unnel100 ip unnumbered Loopback0 tunnel destination 100.200.1.1 tunnel mode mpls traffic-eng tunnel mpls traffic-eng path-option 1 explicit name frr! interface POS6/1 ip address 10.1.0.1 255.255.255.0 mpls traffic-eng tunnels mpls traffic-eng backup-path unnel100 pos ais-shut ip rsvp bandwidth 116250 116250! router ospf 1 mpls traffic-eng router-id Loopback0 mpls traffic-eng area 0! ip explicit-path name frr enable next-address 10.1.0.2 Fast Reroute èšå®äŸ (J) interfaces { so-0/2/0 { unit 0 { family inet { address 10.0.11.1/24; } family mpls; } } } protocol { mpls { no-propagate-ttl; label-switched-path to-hoge { from 192.168.254.22; to 192.168.254.21; fast-reroute; } } 21
ç¹å® POP éã®ãã©ãã£ãã¯ç®¡ç POP éã®ãã©ãã£ãã¯ãç¥ããã! äžã®ãããªæ§æã§ç¹å® POP éã®ãã©ãã£ãã¯ç®¡çã¯å°é£ ããã POP-A POP-C ã³ã¢ãããã¯ãŒã¯ POP-B POP-D ç¹å® POP éã®ãã©ãã£ãã¯ç®¡ç MPLS-E ã§å¯èœã«ãªã! ãã POP ããä» POP ãžã®ãã©ãã£ãã¯ãã©ã³ã¯ã«å¯Ÿå¿ãã LSP ã®ãã±ãããã«ãŠã³ãã§ããããã«ãªã POP-A POP-C LSP POP-B POP-D 22
è² è·åæ£ã®èª¿æŽ RIP ã OSPF ãªã©ã® IGP ã§ã¯ ã³ã¹ããã¡ããªãã¯ã®è¶³ãç®ã®çµæã®å€§å°ã§ ãã©ãã£ãã¯ãæµãã or æµããªããšãã極端ãªå·®ãçŸãã MPLS-E ã§ã¯ ãªã³ã¯ã®äºçŽå¯èœåž¯åéã調æŽããããšã«ããã³ã¹ãã«é¢ããã ãããªãã®ãã©ãã£ãã¯ããã®ãªã³ã¯ã«ã®ããããšãã§ãã MPLS-E ã®èª²é¡ 23
MPLS-E ã®èª²é¡ã¯? raffic Engineeringã®æå¹æ§ã¯ååã«ããã æ°ã«ãªããšãã MPLS-Eã䜿ãããšã§IGPã«ãŒãã£ã³ã°ãšãã©ãã£ãã¯ã®æµãã®é¢ä¿ãçã«ãªã LSPãèšå®ããã«ãŒã¿ã§ãªããšèŠããªããªã Constraint-Pathã®å ãšãªããã¹èšç®ãæ£ãããšããããšãã©ããã£ãŠç¢ºèªããã°è¯ãã®ã? LSPã®æ£åœããè©äŸ¡ããããŒã«ã欲ãã éçšçµéš ã©ããã£ãŠèšèšããã°ããã®? ãã£ã±ããã«ã¡ãã·ã¥? éçšè£å©ããŒã« / ã·ã¹ãã ã®ç»å Ž MPLSView (http//http://www.wandl.com/html/mplsview/mplsview_new.cfm) etc ãŸãšã Eãšã¯ ãã©ãã£ãã¯ã®æµãããèŠãŠãããã¯ãŒã¯æ§æãæé©åããããš MPLS-Eã§ã¯ä»¥äžã«ããEãå®çŸ IGP(IS-IS/OSPF) æ¡åŒµãªã©ã«ãã匷å¶çãã¹éžæ RSVPã«ããæ瀺çãã¹èšå® MPLSã«ãããã±ãããã©ã¯ãŒãã£ã³ã° FastReroute ãªã©æ°ããã¡ãªãããçã¿åºãåé¢ éçšããŠããŠãªã©ã®èç©ãå¿ èŠ 24