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In diesem Dokument wird der Steuerungsebenenfluss bei der Anwendung von Kapselungssegment-Routing über IPv6 (SRv6) auf die BGP-IPv6-Unicast-Sitzung beschrieben.
Weitere Informationen finden Sie im Konfigurationshandbuch für Segment Routing für Cisco Router der Serie ASR 9000, IOS XR Release 24.1.x, 24.2.x, 24.3.x und 24.4.xfür .
Die in diesem Dokument verwendete Topologie ist in Abbildung 1 dargestellt. Die SRv6-Domäne besteht aus drei Routern, die alle auf Cisco IOS-XR betrieben werden. Die SRv6-Underlay-Infrastruktur wird mithilfe von IS-IS mit uSID SRv6 implementiert. Zwischen den Routern R1 und R3 wird BGP-IPv6-Unicast-Peering eingerichtet, während der Router R2 nicht am BGP teilnimmt und in dieser Konfiguration als P-Router fungiert. Die Loopback-6-Schnittstelle auf R1 und R3 stellt ein IPv6-Präfix dar, das zwischen den beiden BGP-IPv6-Unicast-Peers ausgetauscht werden muss.
Abbildung 1: Topologiediagramm von BGP IPv6-Unicast über SRv6
Dieser Abschnitt zeigt die Konfiguration aller drei SRv6-Router. Router R2 enthält nur die SRv6-Konfiguration, da er nicht Teil des BGP ist.
Router R1 ist Teil der SRv6-Domäne mit dem Locator fc00:bb00:1::/48. Er fungiert auch als BGP-IPv6-Unicast-Router, der das lokale Präfix fc00:aa00:1::1/128 ausgibt. Darüber hinaus richtet er BGP IPv6-Unicast-Peering mit Router R3 über die SRv6-Infrastruktur. Die fett markierte Konfiguration dient als Ausgangspunkt für das Debuggen des in diesem Dokument beschriebenen Kontrollflusses und ist der einzige Trigger, der im gesamten Dokument verwendet wird.
interface Loopback0 ipv4 address 10.0.0.1 255.255.255.255 ipv6 address fc00:bb00:1::1/128 ! interface Loopback6 ipv6 address fc00:aa00:1::1/128 ! interface TenGigE0/0/0/8 ipv6 enable ! router isis 1 is-type level-1 net 49.0000.0000.0001.00 address-family ipv6 unicast metric-style wide segment-routing srv6 locator MAIN ! ! ! interface TenGigE0/0/0/8 point-to-point address-family ipv6 unicast ! ! ! router bgp 1 bgp router-id 10.0.0.1 segment-routing srv6 locator MAIN ! address-family ipv6 unicast segment-routing srv6 locator MAIN alloc mode per-vrf ! network fc00:aa00:1::1/128 ! neighbor fc00:bb00:3::1 remote-as 1 update-source Loopback0 address-family ipv6 unicast encapsulation-type srv6 ! ! segment-routing srv6 encapsulation source-address fc00:bb00:1::1 ! locators locator MAIN micro-segment behavior unode psp-usd prefix fc00:bb00:1::/48 !
Router R2 ist Teil der SRv6-Domäne mit dem Locator fc00:bb00:2::/48. Er ist nicht Teil des BGP und fungiert innerhalb dieser Topologie als P-Router.
interface Loopback0 ipv4 address 10.0.0.2 255.255.255.255 ipv6 address fc00:bb00:2::1/128 ! interface TenGigE0/0/0/0 description TO R1 ipv6 enable ! interface TenGigE0/0/0/1 description TO R2 ipv6 enable ! router isis 1 is-type level-1 net 49.0000.0000.0002.00 address-family ipv6 unicast metric-style wide segment-routing srv6 locator MAIN ! ! ! interface TenGigE0/0/0/0 point-to-point address-family ipv6 unicast ! ! interface TenGigE0/0/0/1 point-to-point address-family ipv6 unicast ! ! ! segment-routing srv6 encapsulation source-address fc00:bb00:2::1 ! locators locator MAIN micro-segment behavior unode psp-usd prefix fc00:bb00:2::/48 !
Router R3 ist Teil der SRv6-Domäne mit dem Locator fc00:bb00:3::/48. Er verfügt über BGP IPv6-Unicast-Peering mit Router R1 und tauschen die IPv6-Präfixe seiner Loopback 6-Schnittstellen aus.
interface Loopback0 ipv4 address 10.0.0.3 255.255.255.255 ipv6 address fc00:bb00:3::1/128 ! interface Loopback6 ipv6 address fc00:aa00:3::3/128 ! interface TenGigE0/0/0/1 description TO R2 ipv6 enable ! router isis 1 is-type level-1 net 49.0000.0000.0003.00 address-family ipv6 unicast metric-style wide segment-routing srv6 locator MAIN ! ! ! interface TenGigE0/0/0/1 point-to-point address-family ipv6 unicast ! ! ! router bgp 1 bgp router-id 10.0.0.3 segment-routing srv6 locator MAIN ! address-family ipv6 unicast segment-routing srv6 locator MAIN alloc mode per-vrf ! network fc00:aa00:3::3/128 ! neighbor fc00:bb00:1::1 remote-as 1 update-source Loopback0 address-family ipv6 unicast encapsulation-type srv6 ! ! segment-routing srv6 encapsulation source-address fc00:bb00:3::1 ! locators locator MAIN micro-segment behavior unode psp-usd prefix fc00:bb00:3::/48 ! ! ! !
In der zugrunde liegenden SRv6-Infrastruktur verfügt jeder Router über Verbindungsstatusinformationen in der gesamten Topologie, die jeder Router über das Link-State-ISIS-Protokoll seinem SRv6-Locator mitteilt. Die ISIS-Datenbank auf R1 zeigt den Locator aller Router an, die zur SRv6-Domäne gehören.
RP/0/RSP0/CPU0:R1#show isis database verbose R1 | include SRv6 Locator SRv6 Locator: MT (IPv6 Unicast) fc00:bb00:1::/48 D:0 Metric: 1 Algorithm: 0
RP/0/RSP0/CPU0:R1#show isis database verbose R2 | include SRv6 Locator SRv6 Locator: MT (IPv6 Unicast) fc00:bb00:2::/48 D:0 Metric: 0 Algorithm: 0
RP/0/RSP0/CPU0:R1#show isis database verbose R3 | include SRv6 Locator SRv6 Locator: MT (IPv6 Unicast) fc00:bb00:3::/48 D:0 Metric: 1 Algorithm: 0
Diese SRv6-Implementierung unterstützt das Global Routing Table (GRT)-Datenverkehr-Overlay. Wenn der globale BGP-IPv6-Unicast-Overlay-Service auf R1 und R3 aktiviert ist, generiert jeder Router eine neue Service-SID. Diese Service-SID ist mit der Standard-VRF-Instanz verknüpft und nutzt das Endgeräteverhalten uDT6 in diesem Szenario. Diese Service-SID muss zwischen BGP-IPv6-Unicast-Peers ausgetauscht werden, um die SRv6-Weiterleitung zwischen den beiden BGP-Peers zu ermöglichen. Im folgenden Abschnitt werden die Schritte des BGP-Signalisierungsflusses beschrieben, angefangen bei der Triggerausführung (Aktivieren des Kapselungstyps srv6) bis hin zu dem Punkt, an dem die SRv6-Weiterleitung auf dem Router R3 programmiert ist.
Bevor die SRv6-Kapselung auf dem IPv6-Unicast-SAFI für den BGP-Peer aktiviert werden kann, muss Router R1 über BGP-IPv6-Präfixe mit zugewiesenen Service-SIDs verfügen. Dies tritt auf, wenn "segment-routing srv6" unter dem globalen IPv6-Unicast-SAFI auf R1 aktiviert ist. Die Ausgabe zeigt die lokale SID fc00:bb00:1:e002:: wird allen Präfixen unter BGP IPv6 Unicast zugewiesen.
RP/0/RSP0/CPU0:R1#show bgp ipv6 unicast local-sids BGP router identifier 10.0.0.1, local AS number 1 BGP generic scan interval 60 secs Non-stop routing is enabled BGP table state: Active Table ID: 0xe0800000 RD version: 7 BGP table nexthop route policy: BGP main routing table version 7 BGP NSR Initial initsync version 7 (Reached) BGP NSR/ISSU Sync-Group versions 0/0 BGP scan interval 60 secs Status codes: s suppressed, d damped, h history, * valid, > best i - internal, r RIB-failure, S stale, N Nexthop-discard Origin codes: i - IGP, e - EGP, ? - incomplete Network Local Sid Alloc mode Locator *> fc00:aa00:1::1/128 fc00:bb00:1:e002:: per-vrf MAIN *>ifc00:aa00:3::3/128 NO SRv6 Sid - - Processed 2 prefixes, 2 paths
Diese Service-SID wird lokal durch den Prozess "sid_mgr" auf R1 programmiert, der das Endpunktverhalten als uDT6 aufweist, das mit Standard-VRF verknüpft ist und dem BGP gehört. Dies bedeutet, dass immer dann, wenn das R1-Empfangspaket mit der Zieladresse mit der Service-SID fc00:bb00:1:e002:: Dabei handelt es sich um das letzte Segment. R1 muss den Header entkapseln und das entkapselte Paket an die FIB-Suche der IPv6-Standard-VRF-Tabelle senden. Dies entspricht RFC 8986, in dem das Verhalten aller SRv6-Endpunkte aufgeführt ist. Beachten Sie die Ausgabe, in der der Befehl sid_mgr die Service-SID fc00:bb00:1:e002:: und diese Informationen an RIB und schließlich an FIB weiterzuleiten.
RP/0/RSP0/CPU0:R1#show segment-routing srv6 sid all *** Locator: 'MAIN' *** SID Behavior Context Owner State RW -------------------------- ---------------- -------------------------------- ------------------ ----- -- fc00:bb00:1:: uN (PSP/USD) 'default':1 sidmgr InUse Y fc00:bb00:1:e001:: uA (PSP/USD) [Te0/0/0/8, Link-Local]:0 isis-1 InUse Y fc00:bb00:1:e002:: uDT6 'default' bgp-1 InUse Y
RP/0/RSP0/CPU0:R1#show segment-routing srv6 sid fc00:bb00:1:e002:: internal *** Locator: 'MAIN' *** SID Behavior Context Owner State RW -------------------------- ---------------- -------------------------------- ------------------ ----- --
fc00:bb00:1:e002:: uDT6 'default' bgp-1 InUse Y SID Function: 0xe002 SID context: { table-id=0xe0800000 ('default':IPv6/Unicast) } App data: [0000000000000000] Locator: 'MAIN' Allocation type: Dynamic Owner List: 1) Name: bgp-1, Client-ID: 32, Proto-ID: 8, Node-ID: 0, Locator-ID: 5 () Refcount: 1 Flags: 0x0 () Chkpt Obj ID: 0x2f60 TI Object: Type: Entry Ptr: 0x140160285526000, Producer ID: 0 Flags: Generic: 0x0 () Specific: 0x0 () Modified: Fri Jun 27 16:27:05 EST 2025 (2d01h ago) Created: Jun 27 16:17:40.796 (2d01h ago) Event history: SIDMGR-OPCODE-EVENT-CLASS Total entries : 4 +---------------------------------+----------------------+------+ | Event | Time Stamp | S, M | +---------------------------------+----------------------+------+ | object create | Jun 27 16:17:40.864 | 1, 0 | | object delete | Jun 27 16:27:04.320 | 1, 1 | | object modify | Jun 27 16:27:04.320 | 0, 1 | | object refcount decrement | Jun 27 16:27:04.320 | 0, 1 | +---------------------------------+----------------------+------+ RP/0/RSP0/CPU0:R1#show route ipv6 fc00:bb00:1:e002:: detail Routing entry for fc00:bb00:1:e002::/64 Known via "local-srv6 bgp-1", distance 0, metric 0, SRv6 Endpoint uDT6, SRv6 Format f3216 Installed Jun 27 16:27:06.040 for 2d01h Routing Descriptor Blocks directly connected Route metric is 0 Label: None Tunnel ID: None Binding Label: None Extended communities count: 0 NHID: 0x0 (Ref: 0) Route version is 0x15 (21) No local label IP Precedence: Not Set QoS Group ID: Not Set Flow-tag: Not Set Fwd-class: Not Set Route Priority: RIB_PRIORITY_LOCAL (3) SVD Type RIB_SVD_TYPE_LOCAL Download Priority 0, Download Version 3140327 No advertising protos.
RP/0/RSP0/CPU0:R1#show cef ipv6 fc00:bb00:1:e002:: fc00:bb00:1:e002::/64, version 3140327, SRv6 Endpoint uDT6, internal 0x1000001 0x0 (ptr 0x7bb98f54) [1], 0x400 (0x7ba7cfa0), 0x0 (0x7a90d290) Updated Jun 27 16:27:06.043 Prefix Len 64, traffic index 0, precedence n/a, priority 0 gateway array (0x78e92608) reference count 3, flags 0x0, source rib (7), 0 backups [4 type 3 flags 0x8401 (0x78f35598) ext 0x0 (0x0)] LW-LDI[type=3, refc=1, ptr=0x7ba7cfa0, sh-ldi=0x78f35598] gateway array update type-time 1 Jun 26 15:54:48.345 LDI Update time Jun 26 15:54:48.349 LW-LDI-TS Jun 27 16:17:42.533 Accounting: Disabled via ::/128, 0 dependencies, weight 0, class 0 [flags 0x0] path-idx 0 NHID 0x0 [0x781b61e8 0x0] next hop ::/128 Load distribution: 0 (refcount 4) Hash OK Interface Address 0 Y recursive Lookup in table
Da R1 die SRv6-Kapselung unter seinem BGP IPv6-Unicast-Peer nicht aktiviert hat, kündigt R1 diese Präfixe in Richtung R3 ohne SRv6 TLV im BGP-Update an, obwohl R1 lokal lokale SIDs zugewiesen hat.
RP/0/RSP0/CPU0:R1#show bgp ipv6 unicast BGP router identifier 10.0.0.1, local AS number 1 BGP generic scan interval 60 secs Non-stop routing is enabled BGP table state: Active Table ID: 0xe0800000 RD version: 7 BGP table nexthop route policy: BGP main routing table version 7 BGP NSR Initial initsync version 7 (Reached) BGP NSR/ISSU Sync-Group versions 0/0 BGP scan interval 60 secs Status codes: s suppressed, d damped, h history, * valid, > best i - internal, r RIB-failure, S stale, N Nexthop-discard Origin codes: i - IGP, e - EGP, ? - incomplete Network Next Hop Metric LocPrf Weight Path *> fc00:aa00:1::1/128 :: 0 32768 i *>ifc00:aa00:3::3/128 fc00:bb00:3::1 0 100 0 i Processed 2 prefixes, 2 paths RP/0/RSP0/CPU0:R1#show bgp ipv6 unicast advertised neighbor fc00:bb00:3::1 fc00:aa00:1::1/128 is advertised to fc00:bb00:3::1 Path info: neighbor: Local neighbor router id: 10.0.0.1 valid local best Received Path ID 0, Local Path ID 1, version 4 Attributes after inbound policy was applied: next hop: :: MET ORG AS origin: IGP metric: 0 aspath: Attributes after outbound policy was applied: next hop: fc00:bb00:1::1 MET ORG AS origin: IGP metric: 0 aspath:
Router R3 erhalten die Aktualisierung von Router R1 ohne SID. R3 installieren die Präfixe, die von R1 an seine RIB- und FIB-Tabelle ohne SRv6-Header empfangen werden.
RP/0/RSP0/CPU0:R3#show bgp ipv6 unicast received-sids BGP router identifier 10.0.0.3, local AS number 1 BGP generic scan interval 60 secs Non-stop routing is enabled BGP table state: Active Table ID: 0xe0800000 RD version: 44 BGP table nexthop route policy: BGP main routing table version 44 BGP NSR Initial initsync version 6 (Reached) BGP NSR/ISSU Sync-Group versions 0/0 BGP scan interval 60 secs Status codes: s suppressed, d damped, h history, * valid, > best i - internal, r RIB-failure, S stale, N Nexthop-discard Origin codes: i - IGP, e - EGP, ? - incomplete Network Next Hop Received Sid *>ifc00:aa00:1::1/128 fc00:bb00:1::1 NO SRv6 Sid *> fc00:aa00:3::3/128 :: NO SRv6 Sid Processed 2 prefixes, 2 paths
RP/0/RSP0/CPU0:R3#show route ipv6 unicast fc00:aa00:1::1/128 detail Routing entry for fc00:aa00:1::1/128 Known via "bgp 1", distance 200, metric 0, type internal Installed Jun 8 17:34:24.126 for 00:12:38 Routing Descriptor Blocks fc00:bb00:1::1, from fc00:bb00:1::1 Route metric is 0 Label: None Tunnel ID: None Binding Label: None Extended communities count: 0 NHID: 0x0 (Ref: 0) Path Grouping ID: 1 Route version is 0x1d (29) No local label IP Precedence: Not Set QoS Group ID: Not Set Flow-tag: Not Set Fwd-class: Not Set Route Priority: RIB_PRIORITY_RECURSIVE (12) SVD Type RIB_SVD_TYPE_LOCAL Download Priority 4, Download Version 162 No advertising protos. RP/0/RSP0/CPU0:R3#show cef ipv6 fc00:aa00:1::1/128 fc00:aa00:1::1/128, version 162, internal 0x5000001 0x40 (ptr 0x7941f0f4) [1], 0x0 (0x0), 0x0 (0x0) Updated Jun 8 17:34:24.128 Prefix Len 128, traffic index 0, precedence n/a, priority 4 gateway array (0x78eac518) reference count 1, flags 0x2010, source rib (7), 0 backups [1 type 3 flags 0x48441 (0x78f4f538) ext 0x0 (0x0)] LW-LDI[type=0, refc=0, ptr=0x0, sh-ldi=0x0] gateway array update type-time 1 Jun 8 17:34:24.129 LDI Update time Jun 8 17:34:24.129 Level 1 - Load distribution: 0 [0] via fc00:bb00:1::1/128, recursive Accounting: Disabled via fc00:bb00:1::1/128, 5 dependencies, recursive [flags 0x6000] path-idx 0 NHID 0x0 [0x7941edb4 0x0] next hop fc00:bb00:1::1/128 via fc00:bb00:1::/48 Load distribution: 0 (refcount 1) Hash OK Interface Address 0 Y TenGigE0/0/0/1 remote
Durch Aktivieren der SRv6-Kapselung sendet R1 eine BGP-Update-Nachricht an seinen Peer mit dem Attributtyp 40, der in Segment Routing verwendet wird, um ein BGP-Präfix mit einer bestimmten Segment Routing Identifier (SID) anzukündigen. Router R1 sendet UPDATE an R3 für das IPv6-Präfix fc00:bb00:3::1 (Schritt 1) mit der zugehörigen SID fc00:bb00:1:e002::. Nach Erhalt des UPDATE aktualisiert Router R3 seine BGP IPv6-Unicast-Tabelle (Schritt 2) und anschließend seine RIB- und FIB-Tabellen (Schritt 3). Abbildung 2 zeigt den BGP-Signalisierungsfluss und die entsprechenden Schritte.
Abbildung 2: BGP-Signalisierungsfluss nach der Aktivierung von Kapselungssrv6
Die Ausgabe zeigt das BGP-Debug-Protokoll unmittelbar nach der Aktivierung der SRv6-Kapselung auf dem R3-Peer an und zeigt an, dass R1 eine BGP-Update-Nachricht an R3 sendet:
router bgp 1 neighbor fc00:bb00:3::1 address-family ipv6 unicast encapsulation-type srv6 ! ! ! end RP/0/RSP0/CPU0:R1(config)#commit
bgp[1100]: [default-upd] (ip6u): Added reference to table TBL:default (2/1) refcount 9 bgp[1100]: [default-upd] (ip6u): Created update group for table TBL:default (2/1), index 0.3 neighbor fc00:bb00:3::1 bgp[1100]: [default-upd] (ip6u): Removed neighbor fc00:bb00:3::1 from update group 0.2 for IPv6 Unicast bgp[1100]: [default-upd] (ip6u): Removing neighbor fc00:bb00:3::1 from update filter-group 0.2 in IPv6 Unicast sub-group 0.2 in updgrp 0.2 bgp[1100]: [default-upd]: Enqueue Wdw: Nbr:fc00:bb00:3::1(5) Wdw:0 Del:0 Pending:0 RefreshPending:0 bgp[1100]: [default-upd]: Deleting filter-group 0.2 in TBL:default (2/1) refcount 2 bgp[1100]: [default-upd] (ip6u): Deleted update group 0.2 bgp[1100]: [default-upd] (ip6u): Added reference to table TBL:default (2/1) refcount 10 bgp[1100]: [default-upd]: Compute RT set for vrf default neighbor fc00:bb00:3::1 from old filter-group 0.2 rtset 0in subgrp 0.2 bgp[1100]: [default-upd]: Allocating filter-group 0.3in TBL:default (2/1) bgp[1100]: [default-upd] (ip6u): Added reference to table TBL:default (2/1) refcount 11 bgp[1100]: [default-upd] (ip6u): Adding vrf default neighbor fc00:bb00:3::1 to new filter-group 0.3 in IPv6 Unicast sub-group 0.1 rtset size 0 in updgrp 0.3 bgp[1100]: [default-upd] (ip6u): Added vrf default neighbor fc00:bb00:3::1 to update filter-group 0.3 in IPv6 Unicast sub-group 0.1 bgp[1100]: [default-upd] (ip6u): Added neighbor fc00:bb00:3::1 to update sub-group 0.1 in IPv6 Unicast update-group 0.3 bgp[1100]: [default-upd] (ip6u): Added vrf default neighbor fc00:bb00:3::1 to update group 0.3 for IPv6 Unicast bgp[1100]: [default-upd] (ip6u): Removed reference to Table TBL:default (2/1) refcount 10 bgp[1100]: [default-upd] (ip6u): Started updgrp timer for updgrp 0.3:: delay=0.010, delaytype=0 bgp[1100]: [default-upd] (ip6u): Removed reference to Table TBL:default (2/1) refcount 9 bgp[1100]: [default-upd] (ip6u): Starting updgen walk for updgrp 0.3:: targetver=27: tblver=27, labelver=27, minfwdver=27, ackdfwdver=27, standbyver=0 bgp[1100]: [default-upd] (ip6u): Computing updates for update sub-group 0.1 (Regular) bgp[1100]: [default-upd] (ip6u): bgp_srv6_execute_sid_alloc_mode_policy: Use default SRv6 alloc mode per-vrf as policy NOT in use/configured for net and table TBL:default (2/1) bgp[1100]: [default-upd]: table-attr walk for table TBL:default (2/1), resume version 0, subgrp version 0, target version 27 bgp[1100]: [default-upd] (ip6u): process UPDATE for: tbl=TBL:default (2/1), afi=5: ug=0.3, (Regular), pelem (Regular), sg=0.1, ugfl=0x00104183: bgpctxfl=0x00, tblctxfl=0x10000021, ltblctxfl=0x10000021, sendlab=0: net=fc00:aa00:1::1/128, nver=24: PELEM=0x7f4566d78f60 (lpathid=1, ver=24, fl=0x00000001): PATH=0x7f4566ee3eb8 (::/128,::,0, 0x20000000010401a3)::: allowbe=0, isbe=0, allowspurwdr=0, pelem-send=1, pelem-wdr=0, netExtflag=21000000 bgp[1100]: [default-upd] (ip6u): Ran 'internal' policy '(null)', result 'TRUE', ptr 0x7f4584005f30, use (nil) bgp[1100]: [default-upd] (ip6u): : tbl=TBL:default (2/1), afi=5: ug=0.3, sg=0.1, ugfl=0x00104183: net=fc00:aa00:1::1/128, PELEM=0x7f4566d78f60(lpathid=1, fl=0x00000001), PATH=0x7f4566ee3eb8(::/128,::,0, 0x20000000010401a3), reflected=0, bmsgfl=0x00000000, wdr=0::: netlab=0/0, pathlab=1048577, updlab= bgp[1100]: [default-upd] (ip6u): <NH&LABEL-SEL>: tbl=TBL:default (2/1), afi=5: ug=0.3, sg=0.1, ugfl=0x00104183+0x00001022: net=fc00:aa00:1::1/128, netlab=0/0, PELEM=0x7f4566d78f60(lpathid=1, fl=0x00000001), PATH=0x7f4566ee3eb8(::/128,::,0, 0x20000000010401a3), pathlab=1048577, reflected=0, bmsgfl=0x00000000::: pelemwdr=0, isnhself=1, enforcenhself=0, nhselectdone=0, nhcfgeval=1, updnh=0x00000000, nhlen=16, nhif=0x00000000, nh3rdp=0 bgp[1100]: [default-upd] (ip6u): <nh&label-sel>::: labselectdo=1, labselectdone=0, updlab=1048577(0x00100001) bgp[1100]: [default-upd]: Comm-lib: Assigned ID (0x1d000008) for elem-type PREFIX_SID SRV6_L3SVC bgp[1100]: [default-upd]: Comm-lib: Assigned ID (0x900000c) for elem-type Attribute bgp[1100]: [default-upd] (ip6u): Permit UPDATE to filter-group 0.3 (Regular, pelem Regular) for fc00:aa00:1::1/128 (changedfl=0x0/0x0), path bgp[1100]: [default-upd] (ip6u): Sending UPDATE message(0x0x7f4589fd4ba4) to sub-group 0.1 (Regular, pelem Regular) for fc00:aa00:1::1/128 (changedfl=0x0/0x0) - creating new message with bmsgflags=0x00000000, attributes: nexthop ::, originator 0.0.0.0 bgp[1100]: [default-upd] (ip6u): origin i, path , metric 0, localpref 100, Prefix-SID attribute 0x05002200 0x01001e00 0xfc00bb00 0x0001e002 0x00000000 0x00000000 0x00003e00 0x01000620 0x10100000 0x0000 bgp[1100]: [default-upd] (ip6u): Created msg elem 0x0x7f4589e3afc8 (pointing to message 0x0x7f4589fd4ba4), for filtergroup 0.3 bgp[1100]: [default-upd] (ip6u): process UPDATE for: tbl=TBL:default (2/1), afi=5: ug=0.3, (Regular), pelem (Regular), sg=0.1, ugfl=0x00104183: bgpctxfl=0x00, tblctxfl=0x10000021, ltblctxfl=0x10000021, sendlab=0: net=fc00:aa00:3::3/128, nver=27: PELEM=0x7f4566d78d30 (lpathid=1, ver=27, fl=0x00000001): PATH=0x7f4566ee3d98 (fc00:bb00:3::1/128,fc00:bb00:3::1,0, 0x2000000001060005)::: allowbe=0, isbe=0, allowspurwdr=0, pelem-send=1, pelem-wdr=0, netExtflag=20000000 bgp[1100]: [default-upd] (ip6u): No unreachable (not advertising to sender: fc00:bb00:3::1) sent to sub-group 0.1 (Regular) with fc00:aa00:3::3/128 - already withdrawn bgp[1100]: [default-upd] (ip6u): Generated 1 updates for update sub-group 0.1 (average size = 126 bytes, maximum size = 126 bytes) bgp[1100]: [default-upd] (ip6u): Updates replicated to neighbor fc00:bb00:3::1 bgp[1100]: [default-iowt]: fc00:bb00:3::1 send UPDATE length (incl. header) 126 bgp[1100]: [default-iowt]: Send message dump for fc00:bb00:3::1: bgp[1100]: [default-iowt]: ffff ffff ffff ffff ffff ffff ffff ffff bgp[1100]: [default-iowt]: 007e 0200 0000 6790 0e00 2600 0201 10fc bgp[1100]: [default-iowt]: 00bb 0000 0100 0000 0000 0000 0000 0100 bgp[1100]: [default-iowt]: 80fc 00aa 0000 0100 0000 0000 0000 0000 bgp[1100]: [default-iowt]: 0140 0101 0040 0200 8004 0400 0000 0040 bgp[1100]: [default-iowt]: 0504 0000 0064 c028 2505 0022 0001 001e bgp[1100]: [default-iowt]: 00fc 00bb 0000 01e0 0200 0000 0000 0000 bgp[1100]: [default-iowt]: 0000 003e 0001 0006 2010 1000 0000 bgp[1100]: [default-iowt]: bgp_io_nbr_add_version: New ver: nbr=fc00:bb00:3::1, io_wr_txsn=58992, acksn=58866: ver=27 <58992>, osver=2 bgp[1100]: [default-iowt]: bgp_io_nbr_derive_acked_version: nbr=fc00:bb00:3::1, io_wr_txsn=58992, acksn=58866, osver=2 bgp[1100]: [default-iowt]: fc00:bb00:3::1 (afi:4) advancedpeer_acked_version to 10refresh peer acked version to 0 bgp[1100]: [default-iowt]: fc00:bb00:3::1 (afi:5) received ack for version 27 bgp[1100]: [default-iowt]: bgp_write_list_tonet: IO_SENDMSG: nbr=fc00:bb00:3::1, fd=530: total=1, send-attempt=1 (size 126), sent-successful=1: res=0 allmsg_adv_count = 1 msg 0x7f4589fd4ba4 bmsg_nbr_count 0 bgp[1100]: [default-iowt] (ip6u): Deleting msg elem 0x0x7f4589e3afc8 (message 0x0x7f4589fd4ba4), for filtergroup 0.3 bgp[1100]: [default-iowt] (ip6u): Deleting message 0x0x7f4589fd4ba4, from subgroup 0.1 bgp[1100]: [default-iowt]: Keepalive timer started for fc00:bb00:3::1(loc 10): last 529293 this 529308 bgp[1100]: [default-iowt]: bgp write for afi 4 for neighbor fc00:bb00:3::1 (fd 530) bgp[1100]: [default-iowt]: bgp write for afi 5 for neighbor fc00:bb00:3::1 (fd 530) bgp[1100]: [default-iowt]: bgp_io_nbr_derive_acked_version: nbr=fc00:bb00:3::1, io_wr_txsn=58992, acksn=58866, osver=1 bgp[1100]: [default-iowt]: fc00:bb00:3::1 (afi:4) advancedpeer_acked_version to 10refresh peer acked version to 0 bgp[1100]: [default-iowt]: fc00:bb00:3::1 (afi:5) advancedpeer_acked_version to 27refresh peer acked version to 0 bgp[1100]: [default-iowt]: bgp_io_write_nbr_ver_timer_process: nbr_ver_timer handler: Walk complete: nbrcount=1, synctrigger=1
In der Ausgabe wird der BGP-Ablaufverfolgungseintrag auf R1:
default-bgp/spkr-tr2-upd 0/RSP0/CPU0 t32561 [UPD]:7799: trying to find update group for nbr fc00:bb00:3::1, afi IPv6 Unicast default-bgp/spkr-tr2-upd 0/RSP0/CPU0 t32561 [UPD]:6752: created update group for table TBL:default (2/1), index 0.3, nbr fc00:bb00:3::1, flags 0x104183 default-bgp/spkr-tr2-upd 0/RSP0/CPU0 t32561 [UPD]:2039: Filter-group op (Filter-group Rm Nbr) Tbl/Nbr(Afi:IPv6 Unicast:Nbr:fc00:bb00:3::1) fgrp idx 0.2 subgrp idx 0.2 updgrp 0.2 rtset 0 default-bgp/spkr-tr2-upd 0/RSP0/CPU0 t32561 [UPD]:1501: Filter-group op (Delete) Tbl/Nbr(TBL:default (2/1)) fgrp idx 0.2 subgrp idx 0.2 updgrp 0.0 rtset 2 default-bgp/spkr-tr2-upd 0/RSP0/CPU0 t32561 [UPD]:6798: Delete update group for table TBL:default (2/1), index 0.2 default-bgp/spkr-tr2-upd 0/RSP0/CPU0 t32561 [UPD]:2181: Filter-group op (Filter-group Compute Nbr RT) Tbl/Nbr(fc00:bb00:3::1) fgrp idx 0.2 subgrp idx 0.2 updgrp 0.3 rtset 0 default-bgp/spkr-tr2-upd 0/RSP0/CPU0 t32561 [UPD]:1411: Filter-group op (Alloc) Tbl/Nbr(TBL:default (2/1)) fgrp idx 0.3 subgrp idx 0.1 updgrp 0.0 rtset 3 default-bgp/spkr-tr2-upd 0/RSP0/CPU0 t32561 [UPD]:2725: Filter-group op (Filter-group Add Nbr new) Tbl/Nbr(Afi:IPv6 Unicast:Vrf:default:Nbr:fc00:bb00:3::1) fgrp idx 0.3 subgrp idx 0.1 updgrp 0.3 rtset 0 default-bgp/spkr-tr2-upd 0/RSP0/CPU0 t32561 [UPD]:2751: created filtergrp 3 for vrf default nbr fc00:bb00:3::1, afi 5, subgrp version 0, refresh 0 default-bgp/spkr-tr2-upd 0/RSP0/CPU0 t32561 [UPD]:4473: Created subgrp:1(0x840070a0) refr:0 for nbr fc00:bb00:3::1 (vrf default), afi 5 version 0 default-bgp/spkr-tr2-upd 0/RSP0/CPU0 t32561 [UPD]:6935: added vrf default nbr fc00:bb00:3::1 to update group 0.3, afi IPv6 Unicast, flags 0x104183 default-bgp/spkr-tr2-upd 0/RSP0/CPU0 t32561 [UPD]:3088: TBL:default (2/1) free subgrp SG:2 subgrp:0x84007440 default-bgp/spkr-tr2-upd 0/RSP0/CPU0 t32561 [UPD]:1316: Update gen Start bit operation Filtergrp delete-timer fgrp idx/size 2 default-bgp/spkr-tr2-upd 0/RSP0/CPU0 t32561 [UPD]:11342: Updgen - TBL:default (2/1) UG: 0.3 SG: 0.1 msg: 1 default-bgp/spkr-tr2-upd 0/RSP0/CPU0 t32561 [UPD]:11344: Updgen - pfx: [tot] adv/wdn/sup/skp/be[2] 1/0/0/1/0 default-bgp/spkr-tr2-upd 0/RSP0/CPU0 t32561 [UPD]:11351: Updgen - fpx: wdn/skp[0/0] ver: 0 -> 27 res ver: 0 -> 27 default-bgp/spkr-tr2-upd 0/RSP0/CPU0 t32561 [UPD]:4009: Updgen - UG: 3 FG: 3 afi:5 msg: 1 ver -> 27 default-bgp/spkr-tr2-upd 0/RSP0/CPU0 t32561 [UPD]:4011: pfx: adv/wdn/sup/skp 1/0/0/1 default-bgp/spkr-tr2-common 0/RSP0/CPU0 t32558 [COMMON]:638: vrf default nbr fc00:bb00:3::1, set peer ack version to 27, afi 5, loc 2 default-bgp/spkr-tr2-gen 0/RSP0/CPU0 t32501 [GEN]:617: vrf default nbr 2000:0:0:1::1, old state 1, new state 3, fd type 2, fd 0
Die decodierte BGP UPDATE-Nachricht zeigt den Attributtyp 40 und den TLV-Typ 5 an, die die Service-SID fc00:bb00:1:e002:: enthalten.
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Die vollständige decodierte BGP UPDATE-Nachricht lautet wie folgt:
Message #1 - 126 bytes FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF 00 7E 02 00 00 00 67 90 0E 00 26 00 02 01 10 FC 00 BB 00 00 01 00 00 00 00 00 00 00 00 00 01 00 80 FC 00 AA 00 00 01 00 00 00 00 00 00 00 00 00 01 40 01 01 00 40 02 00 80 04 04 00 00 00 00 40 05 04 00 00 00 64 C0 28 25 05 00 22 00 01 00 1E 00 FC 00 BB 00 00 01 E0 02 00 00 00 00 00 00 00 00 00 00 3E 00 01 00 06 20 10 10 00 00 00 BGP Marker: 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF BGP Length: 0x007E - 126 bytes BGP Type: 0x02 - UPDATE UPDATE UNFEASIBLE ROUTES LENGTH: 0x0000 - 0 bytes TOTAL PATH ATTRIBUTES LENGTH: 0x0067 - 103 bytes Attribute ATTRIBUTE FLAG: 0x90 ATTRIBUTE FLAG binary: 10010000 Bit 0, the Optional bit, is 1 so this is an optional attribute Bit 1, the Transitive bit, is 0 so this is a non-transitive attribute Bit 2, the Partial bit, is not set Bit 3, the Extended Length Bit, is 1 so the length field is 2 bytes The lower-order four bits of the Attribute Flag are unused and are set to 0000 ATTRIBUTE TYPE: 0x0E - 14 ATTRIBUTE LENGTH: 0x0026 - 38 bytes ATTRIBUTE CONTENT: 0x00020110FC00BB000001000000000000000000010080FC00AA00000100000000000000000001 AFI: 2 (0x0002) Sub AFI: 1 (0x01) NEXTHOP Length: 16 (0x10) bytes NEXTHOP: FC00:BB00:0001:0000:0000:0000:0000:0001 Numb of SNPAs: 0 (0x00) NLRI Length: 128 bits (0x80) MP_REACH_NLRI: FC00:AA00:0001:0000:0000:0000:0000:0001/128 (0xFC00AA00000100000000000000000001) Attribute ATTRIBUTE FLAG: 0x40 ATTRIBUTE FLAG binary: 01000000 Bit 0, the Optional bit, is 0 so this is a well-known attribute Bit 1, the Transitive bit, is 1 so this is a transitive attribute Bit 2, the Partial bit, is not set Bit 3, the Extended Length Bit, is 0 so the length field is 1 byte The lower-order four bits of the Attribute Flag are unused and are set to 0000 ATTRIBUTE TYPE: 0x01 - 1 ATTRIBUTE LENGTH: 0x01 - 1 bytes ATTRIBUTE CONTENT: 0x00 - IGP Attribute ATTRIBUTE FLAG: 0x40 ATTRIBUTE FLAG binary: 01000000 Bit 0, the Optional bit, is 0 so this is a well-known attribute Bit 1, the Transitive bit, is 1 so this is a transitive attribute Bit 2, the Partial bit, is not set Bit 3, the Extended Length Bit, is 0 so the length field is 1 byte The lower-order four bits of the Attribute Flag are unused and are set to 0000 ATTRIBUTE TYPE: 0x02 - 2 ATTRIBUTE LENGTH: 0x00 - 0 bytes Attribute ATTRIBUTE FLAG: 0x80 ATTRIBUTE FLAG binary: 10000000 Bit 0, the Optional bit, is 1 so this is an optional attribute Bit 1, the Transitive bit, is 0 so this is a non-transitive attribute Bit 2, the Partial bit, is not set Bit 3, the Extended Length Bit, is 0 so the length field is 1 byte The lower-order four bits of the Attribute Flag are unused and are set to 0000 ATTRIBUTE TYPE: 0x04 - 4 ATTRIBUTE LENGTH: 0x04 - 4 bytes ATTRIBUTE CONTENT: 0x00000000 - 0 Attribute ATTRIBUTE FLAG: 0x40 ATTRIBUTE FLAG binary: 01000000 Bit 0, the Optional bit, is 0 so this is a well-known attribute Bit 1, the Transitive bit, is 1 so this is a transitive attribute Bit 2, the Partial bit, is not set Bit 3, the Extended Length Bit, is 0 so the length field is 1 byte The lower-order four bits of the Attribute Flag are unused and are set to 0000 ATTRIBUTE TYPE: 0x05 - 5 ATTRIBUTE LENGTH: 0x04 - 4 bytes ATTRIBUTE CONTENT: 0x00000064 - 100 Attribute ATTRIBUTE FLAG: 0xC0 ATTRIBUTE FLAG binary: 11000000 Bit 0, the Optional bit, is 1 so this is an optional attribute Bit 1, the Transitive bit, is 1 so this is a transitive attribute Bit 2, the Partial bit, is not set Bit 3, the Extended Length Bit, is 0 so the length field is 1 byte The lower-order four bits of the Attribute Flag are unused and are set to 0000 ATTRIBUTE TYPE: 0x28 - 40 ATTRIBUTE LENGTH: 0x25 - 37 bytes ATTRIBUTE CONTENT: 0x0500220001001E00FC00BB000001E002000000000000000000003E00010006201010000000 BGP Prefix-SID: Type: 5 (0x05) - SRv6 L3 Service Length: 34 - 0x0022 Value: 0x0001001E00FC00BB000001E002000000000000000000003E00010006201010000000 Reserved: 0x00 Sub Type: 1 (0x01) Sub Length: 30 (0x001E) SRv6 SID = FC00:BB00:0001:E002:0000:0000:0000:0000 SID Flags: 0 (0x00) Endpoint Behavior: 62 (0x003E) Reserved2 : 0 (0x00) SRv6 SID Optional Type: 1 (0x01) SRv6 SID Optional Len: 6 (0x0006) SRv6 SID Optional Value: 35253360001024 (0x201010000000) NLRI NLRI LENGTH: UPDATE Length - 23 - TOTAL PATH ATTRIBUTES LENGTH - UNFEASIBLE ROUTES LENGTH NLRI LENGTH: 126 - 23 - 103 - 0 NLRI LENGTH: 0 bytes
Der Router R3 empfängt ein BGP-Update von R1, das durch Aktivieren des BGP-Debugging auf R3 beobachtet werden kann. Das empfangene BGP-Update-Paket muss mit dem von R1 gesendeten Paket übereinstimmen, wie in der Debug-Ausgabe dargestellt.
bgp[1100]: [default-rtr]: UPDATE from fc00:bb00:1::1 contains nh fc00:bb00:1::1/128, gw_afi 5, flags 0x0, nlri_afi 5 bgp[1100]: [default-rtr]: NH-Validate-Create: addr=fc00:bb00:1::1/128, len=16, nlriafi=5, nbr=fc00:bb00:1::1, gwafi=5, gwlen=32, gwaddrlen=128::: nhout=0x0x7fc41b5fdcb0, validity=1, attrwdrflags=0x00000000 bgp[1100]: [default-rtr]: --bgp4_rcv_attributes--: END: nbr=fc00:bb00:1::1:: msg=0x0x7fc420108bdc/126, updlen=107, attrbl=0x0x7fc420108bf3/103, ipv4reachlen=0, msginpath=0x0x7fc3e2d54830, asloopcheck=1, attrwdrfl=0x00000000:: samecluster=0, local_as_prepended=0, attr_wdr_flags 0x00000000, myascount=0:: myconfedascount=0::rcvdata=0x0x7fc420108c5a/0, errptr=0x0x7fc420108c32/40 bgp[1100]: [default-rtr]: Comm-lib: Assigned ID (0x1d0000ac) for elem-type PREFIX_SID SRV6_L3SVC bgp[1100]: [default-rtr]: Comm-lib: Assigned ID (0x90000de) for elem-type Attribute bgp[1100]: [default-rtr] (ip6u): Received UPDATE from fc00:bb00:1::1 with attributes: bgp[1100]: [default-rtr] (ip6u): nexthop fc00:bb00:1::1/128, origin i, localpref 100, metric 0 bgp[1100]: [default-rtr] (ip6u): Received prefix fc00:aa00:1::1/128 (path ID: none) from fc00:bb00:1::1 bgp[1100]: [default-rtr] (ip6u): Handling OCRIB attrs while relacing path 0x7fc3e1be61d8. Old oc attr (nil), new oc attr (nil) bgp[1100]: [default-rtr]: bgp_bmp_table_path_update_cb: Operation: 0x1, Inbound Post-Policy Route Mon is not enabled (0) (or) not primary active - return bgp[1100]: [default-rtr] (ip6u): Done modify path (old tlv size=0 new tlv size=0) for net=fc00:aa00:1::1/128, nver=2000371, nfl=0x00003001+0x20000000: usedpath=0x0x7fc3e1be61d8(fc00:bb00:1::1/128,fc00:bb00:1::1,0,0x2000000000060005), rcvdpath=0x0x7fc3e2d52b20: needmove=0, pcount=1 IdenticalPath=0, TLVPresent=0 bgp[1100]: [default-rtr]: bgp_set_path_metric:8712 afi 5 net fc00:aa00:1::1/128 path 0x7fc3e1be61d8 nh fc00:bb00:1::1/128 (0x7fc41b5fdcb0) metric 21 bgp[1100]: [default-rtr] (ip6u): bestpath: (full bp 1) start for net=fc00:aa00:1::1/128, nver=2000371, nfl=0x00003001+0x20000200: lastpath=0x0x7fc3e1be61d8(fc00:bb00:1::1/128,fc00:bb00:1::1,0,0x2000000000060005): PELEM=0x0x7fc3e1a82930(lpathid=1, ver=2000371, fl=0x00000801, path=0x0x7fc3e1be61d8) bgp[1100]: [default-rtr] (ip6u): bestpath: (full 1) calculated for net=fc00:aa00:1::1/128, nver=2000371, nfl=0x00003001+0x20000200, pelemver=2000371, pelemfl=0x00000881: oldbest=0x0x7fc3e1be61d8(fc00:bb00:1::1/128,fc00:bb00:1::1,0,0x2000000001060005), newbest=0x0x7fc3e1be61d8(fc00:bb00:1::1/128,fc00:bb00:1::1,0,0x2000000001060005), lastpath=0x0x7fc3e1be61d8(fc00:bb00:1::1/128,fc00:bb00:1::1,0,0x2000000001060005), bumpv=1 bgp[1100]: [default-rtr] (ip6u): bestpath: change for net=fc00:aa00:1::1/128, nver=2000371, nfl=0x00003001+0x20000200: oldbest=0x0x7fc3e1be61d8: PELEM=0x0x7fc3e1a82930(lpathid=1, ver=2000371, fl=0x00000901, path=0x0x7fc3e1be61d8) bgp[1100]: [default-rtr] (ip6u): bestpath: update flags for net=fc00:aa00:1::1/128, nver=2000371, nfl=0x00003001+0x20000200: oldtblattr=0x0x7fc41b5eccc0, oldnh=0x0x7fc41b5fdcb0: PELEM=0x0x7fc3e1a82930(lpathid=1, ver=2000371, fl=0x00000901, path=0x0x7fc3e1be61d8) bgp[1100]: [default-rtr] (ip6u): bestpath: modified path: net=fc00:aa00:1::1/128, nver=2000371, nfl=0x00003001+0x20000200: PELEM=0x0x7fc3e1a82930(lpathid=1, ver=2000371, fl=0x00001901, path=0x0x7fc3e1be61d8) bgp[1100]: [default-rtr] (ip6u): bgp_srv6_get_alloc_mode_locator_from_policy: Use default SRv6 alloc mode as policy NOT in use/configured for net and table TBL:default (2/1) bgp[1100]: [default-rtr] (ip6u): bestpath: complete for net=fc00:aa00:1::1/128, nver=2000371, nfl=0x00007001+0x20000200: pselect=0x0, bumpv=1(1:1,0,0,0) bgp[1100]: [default-rtr]: Received UPDATE from fc00:bb00:1::1 (length incl. header = 126) bgp[1100]: [default-rtr]: Receive message dump for fc00:bb00:1::1: bgp[1100]: [default-rtr]: ffff ffff ffff ffff ffff ffff ffff ffff bgp[1100]: [default-rtr]: 007e 0200 0000 6790 0e00 2600 0201 10fc bgp[1100]: [default-rtr]: 00bb 0000 0100 0000 0000 0000 0000 0100 bgp[1100]: [default-rtr]: 80fc 00aa 0000 0100 0000 0000 0000 0000 bgp[1100]: [default-rtr]: 0140 0101 0040 0200 8004 0400 0000 0040 bgp[1100]: [default-rtr]: 0504 0000 0064 c028 2505 0022 0001 001e bgp[1100]: [default-rtr]: 00fc 00bb 0000 01e0 0200 0000 0000 0000 bgp[1100]: [default-rtr]: 0000 003e 0001 0006 2010 1000 0000 bgp[1100]: [default-rtr]: Enabling read from: fc00:bb00:1::1 readset: 1 msgcount: 0 bgp[1100]: [default-iowt]: bgp write for afi 4 for neighbor fc00:bb00:1::1 (fd 516) bgp[1100]: [default-iowt]: bgp write for afi 5 for neighbor fc00:bb00:1::1 (fd 516) bgp[1100]: [default-impt] (ip6u): START import walk from 2000371 to 2000372 skip_walk 1 bgp[1100]: [default-rib2] (ip6u): RIB thread triggered for versioned walk: current version 2000371, acked version 2000371, target version 2000371 bgp[1100]: [default-rib2] (ip6u): RNH rib opaque update for (IPv6 Unicast) bgp[1100]: [default-rib2] (ip6u): RIB thread triggered for RNH walk for nh table(IPv6 Unicast): current version 2000371, target version 2000372 bgp[1100]: [default-lbl] (ip6u): Label update triggered: current version 2000371, target version 2000372, mpls component is up bgp[1100]: [default-lbl]: Table: TBL:default (2/1) bgp_label_srv6_sid_config_release: label_sid_need_eval:0 loc trigger:0 srv6 enabled:1 label disabled:1 dual mode:0 label alloc mode:2 sid alloc mode:0 sid release:0 bgp[1100]: [default-lbl]: uSID WLIB allocation is (LIB Default) bgp[1100]: [default-lbl]: Table: TBL:default (2/1) bgp_label_thread_walk_type: rd:0x7fc3e1efbf30(ALLzero:0:0) rd_flags:0x1 SRv6 eval/en/cnt:1/1/1 locator:MAIN Label up/dis/cnt: 1/1/0 dual mode:0 ibgp_nhself_count:0 policy_set_nhself:0 bgp[1100]: [default-lbl] (ip6u): rd:0x7fc3e1efbf30 sid_walk:1 label_walk:0 bgp[1100]: [default-lbl]: uSID WLIB allocation is (LIB Default) bgp[1100]: [default-upd] (vpn4u): Started updgrp timer for updgrp 0.1:: delay=0.010, delaytype=0 bgp[1100]: [default-lbl] (ip6u): SRv6 SID process for net: TBL:default (2/1)fc00:aa00:1::1/128(SID N) extflags 20000000 Default locator Y UP/exh/oor/rclm MAIN/N/N/N mode 0 clear handle 0 bgp[1100]: [default-lbl] (ip6u): SRv6 SID process for net: TBL:default (2/1)fc00:aa00:1::1/128 point 1 sid_mode 0 clear_handle 0 bgp[1100]: [default-lbl]: uSID WLIB allocation is (LIB Default) bgp[1100]: [default-lbl] (ip6u): Label update run from 2000371 target label version 2000372, rib version 2000371, bgp table version 2000372,best-external allocs 0 bgp[1100]: [default-lbl] (ip6u): Wake up rib thread, label version 2000372, rib version 2000371, bgp table version 2000372, bgp[1100]: [default-rib2] (ip6u): RIB thread triggered for versioned walk: current version 2000371, acked version 2000371, target version 2000372 bgp[1100]: [default-rib2] (ip6u): RNH rib opaque update for (IPv6 Unicast) bgp[1100]: [default-rib2] (ip6u): RIB thread triggered for RNH walk for nh table(IPv6 Unicast): current version 2000371, target version 2000372 bgp[1100]: [default-rib2] (ip6u): Rib Batch-buf Route ADD: table=TBL:default (2/1), tableid=0xe0800000, net=fc00:aa00:1::1/128, netfl=0x00003001: label=1048577, dist=200, attrkey=0x00000000, pathcount=1: batchres=1, succ=1, send=0 locator prefix No, 0 bgp[1100]: [default-rib2] (ip6u): Revise route batch: installing fc00:aa00:1::1/128 with next hop fc00:bb00:1::1(tbl-id=0xe0800000, ifh=0x0), pathribflags: 0x9800000008, #ext-comms=0, to IP-RIB table[0xe0800000] bgp[1100]: [default-rib2] (ip6u): [0]: Rib Batch-buf Path ADD: table=TBL:default (2/1), net=fc00:aa00:1::1/128: nh=fc00:bb00:1::1, nhifh=0x00000000, nhtableid=0xe0800000: rlabel=1048577, metric=0, bsid=0, numecomms=0: pelemfl=0x00001001, pathfl=0x2000000001060005,pathribfl=0x9800000008, nhresplenmin=0 (constraint=1):: batchres=1, succ=1, sendbatch=0 bgp[1100]: [default-rib2] (ip6u): Sending convergence info for IPv6 Unicast - not converged, version: 0, last received version 0 bgp[1100]: [default-upd] (ip6u): Started updgrp timer for updgrp 0.1:: delay=0.010, delaytype=0 bgp[1100]: [default-rib2] (ip6u): vrf default: RIB update run to 2000372: installed 0, modified 1, skipped 0, removed 0 IPv6 Unicast prefixes, installed 0 attributes, removed 0 attributes. bgp[1100]: [default-rib2] (ip6u): RIB thread finished versioned walk: table version 2000372, acked table version 2000372 bgp[1100]: [default-upd] (vpn4u): Starting updgen walk for updgrp 0.1:: targetver=463: tblver=463, labelver=463, minfwdver=463, ackdfwdver=463, standbyver=0 bgp[1100]: [default-upd] (ip6u): Starting updgen walk for updgrp 0.1:: targetver=2000372: tblver=2000372, labelver=2000372, minfwdver=2000372, ackdfwdver=2000372, standbyver=0 bgp[1100]: [default-upd] (ip6u): Computing updates for update sub-group 0.1 (Regular) bgp[1100]: [default-upd] (ip6u): bgp_srv6_execute_sid_alloc_mode_policy: Use default SRv6 alloc mode per-vrf as policy NOT in use/configured for net and table TBL:default (2/1) bgp[1100]: [default-upd]: table-attr walk for table TBL:default (2/1), resume version 0, subgrp version 2000371, target version 2000372 bgp[1100]: [default-upd] (ip6u): process UPDATE for: tbl=TBL:default (2/1), afi=5: ug=0.1, (Regular), pelem (Regular), sg=0.1, ugfl=0x00104183: bgpctxfl=0x00, tblctxfl=0x10000021, ltblctxfl=0x10000021, sendlab=0: net=fc00:aa00:1::1/128, nver=2000372: PELEM=0x7fc3e1a82930 (lpathid=1, ver=2000372, fl=0x00001001): PATH=0x7fc3e1be61d8 (fc00:bb00:1::1/128,fc00:bb00:1::1,0, 0x2000000001060005)::: allowbe=0, isbe=0, allowspurwdr=0, pelem-send=1, pelem-wdr=0, netExtflag=20000000 bgp[1100]: [default-upd] (ip6u): No unreachable (not advertising to sender: fc00:bb00:1::1) sent to sub-group 0.1 (Regular) with fc00:aa00:1::1/128 - already withdrawn
Router R3 generiert eine BGP-Ablaufverfolgung, die der Aktualisierungsverarbeitung von R1 entspricht. Daraus resultiert schließlich, dass R3 seine BGP-IPv6-Unicast-Tabelle aktualisiert. Bei diesem Update, das den BGP-Attributtyp 40 enthält, werden die empfangenen SIDs zusammen mit den zugehörigen BGP-IPv6-Unicast-Präfixen von R1 installiert.
RP/0/RSP0/CPU0:R3#show bgp trace
default-bgp/spkr-tr2-imp 0/RSP0/CPU0 t16100 [IMPORT]:6661: Skipping Import walk: import ver 2000371 -> 2000372: afi 5 forced 0 default-bgp/spkr-tr2-rib 0/RSP0/CPU0 t30391 [RIB]:17177: RIB walk for afi IPv6 Unicast: target version 2000371, min_fwdtable_version 2000371, import_version 2000372, label_version 2000371, table_version 2000372 default-bgp/spkr-tr2-label 0/RSP0/CPU0 t16061 [LABEL]:8505: label walk afi:IPv6 Unicast, lbl ver 2000371 -> 2000372, be 0, skp 0 upd 0 default-bgp/spkr-tr2-label 0/RSP0/CPU0 t16061 [LABEL]:8510: label walk afi:IPv6 Unicast, lbl ver 2000371 -> 2000372, be 0, skp 0 upd 1 default-bgp/spkr-tr2-rib 0/RSP0/CPU0 t30391 [RIB]:17177: RIB walk for afi IPv6 Unicast: target version 2000372, min_fwdtable_version 2000371, import_version 2000372, label_version 2000372, table_version 2000372 default-bgp/spkr-tr2-rib 0/RSP0/CPU0 t30391 [RIB]:14681: send converge to RIB, afi IPv6 Unicast, tableid 0xe0800000, converged 0, send_version 0, last_recv_version 0 default-bgp/spkr-tr2-rib 0/RSP0/CPU0 t30391 [RIB]:15892: RIB(default:v6u): ver 2000371 -> 2000372 :pfx inst/upd/skip/rem 0/1/0/0 default-bgp/spkr-tr2-upd 0/RSP0/CPU0 t16101 [UPD]:11342: Updgen - TBL:default (2/1) UG: 0.1 SG: 0.1 msg: 0 default-bgp/spkr-tr2-upd 0/RSP0/CPU0 t16101 [UPD]:11344: Updgen - pfx: [tot] adv/wdn/sup/skp/be[1] 0/0/0/1/0 default-bgp/spkr-tr2-upd 0/RSP0/CPU0 t16101 [UPD]:11351: Updgen - fpx: wdn/skp[0/0] ver: 2000371 -> 2000372 res ver: 0 -> 2000372 default-bgp/spkr-tr2-common 0/RSP0/CPU0 t16101 [COMMON]:3628: vrf default nbr fc00:bb00:1::1, set peer ack version to 2000372, afi 5, loc 4 default-bgp/spkr-tr2-upd 0/RSP0/CPU0 t16101 [UPD]:11663: Updgen - Skip EoR for Tbl:(TBL:default (2/1)) subgrp:(1) UG:(1) end 2000372
RP/0/RSP0/CPU0:R3#show bgp ipv6 unicast received-sids BGP router identifier 10.0.0.3, local AS number 1 BGP generic scan interval 60 secs Non-stop routing is enabled BGP table state: Active Table ID: 0xe0800000 RD version: 46 BGP table nexthop route policy: BGP main routing table version 46 BGP NSR Initial initsync version 6 (Reached) BGP NSR/ISSU Sync-Group versions 0/0 BGP scan interval 60 secs Status codes: s suppressed, d damped, h history, * valid, > best i - internal, r RIB-failure, S stale, N Nexthop-discard Origin codes: i - IGP, e - EGP, ? - incomplete Network Next Hop Received Sid *>ifc00:aa00:1::1/128 fc00:bb00:1::1 fc00:bb00:1:e002:: *> fc00:aa00:3::3/128 :: NO SRv6 Sid Processed 2 prefixes, 2 paths
R3 installieren schließlich die RIB und die FIB, um den Signalisierungsprozess abzuschließen. R3 fungieren dann als SRv6-Headend mit der SID-Liste fc00:bb00:1:e002::. Dieser Eingangs-R1 fungiert als SRv6-Headend mit Kapselung in einer SR-Richtlinie, abgekürzt als H.Encaps (RFC 8986, Abschnitt 5.1). Dieses Verhalten kapselt das Paket in einen IPv6-Header, legt eine Segmentliste fest und fügt bei Bedarf SRH hinzu. In diesem Fall muss SRH nicht hinzugefügt werden, da nur ein Segment vorhanden ist. Das Paket wird mit der Zieladresse fc00:bb00:1:e002:: gesendet, die die Service-SID auf R1 mit dem Verhalten SRv6-Endpunkt UDT6 ist.
RP/0/RSP0/CPU0:R3#show route ipv6 fc00:aa00:1::1/128 detail Routing entry for fc00:aa00:1::1/128 Known via "bgp 1", distance 200, metric 0, type internal Installed Jun 8 17:52:31.546 for 00:53:55 Routing Descriptor Blocks fc00:bb00:1::1, from fc00:bb00:1::1 Route metric is 0 Label: None Tunnel ID: None Binding Label: None Extended communities count: 0 NHID: 0x0 (Ref: 0) Path Grouping ID: 1 SRv6 Headend: H.Encaps.Red [f3216], SID-list {fc00:bb00:1:e002::} Route version is 0x1f (31) No local label IP Precedence: Not Set QoS Group ID: Not Set Flow-tag: Not Set Fwd-class: Not Set Route Priority: RIB_PRIORITY_RECURSIVE (12) SVD Type RIB_SVD_TYPE_LOCAL Download Priority 4, Download Version 166 No advertising protos.
RP/0/RSP0/CPU0:R3#show cef ipv6 fc00:aa00:1::1/128 fc00:aa00:1::1/128, version 166, SRv6 Headend, internal 0x5000001 0x40 (ptr 0x7941f0f4) [1], 0x0 (0x0), 0x0 (0x7ad58368) Updated Jun 8 17:52:31.551 Prefix Len 128, traffic index 0, precedence n/a, priority 4 gateway array (0x78eac428) reference count 1, flags 0x2010, source rib (7), 0 backups [1 type 3 flags 0x48441 (0x78f4f4d8) ext 0x0 (0x0)] LW-LDI[type=0, refc=0, ptr=0x0, sh-ldi=0x0] gateway array update type-time 1 Jun 8 17:52:31.551 LDI Update time Jun 8 17:52:31.551 Level 1 - Load distribution: 0 [0] via fc00:bb00:1::/128, recursive Accounting: Disabled via fc00:bb00:1::/128, 5 dependencies, recursive [flags 0x6000] path-idx 0 NHID 0x0 [0x7941edb4 0x0] next hop fc00:bb00:1::/128 via fc00:bb00:1::/48 SRv6 H.Encaps.Red SID-list {fc00:bb00:1:e002::} Load distribution: 0 (refcount 1) Hash OK Interface Address 0 Y TenGigE0/0/0/1 remote
Abbildung 4 zeigt das Paketformat, wenn der Router R3 (fc00:aa00:3::3) R1 (fc00:aa00:1::1) pingt.
Abbildung 4: Paketverarbeitung auf dem Pfad von BGP IPv6 Unicast over SRv6
Überarbeitung | Veröffentlichungsdatum | Kommentare |
---|---|---|
1.0 |
03-Oct-2025
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Erstveröffentlichung |