Configurare BGP Global IPv6 su SRv6
Sommario
Introduzione
In questo documento viene descritto il flusso del control plane quando si applica il routing del segmento di incapsulamento su IPv6 (SRv6) a una sessione unicast IPv6 BGP.
Premesse
Per ulteriori informazioni, vedere la guida alla configurazione del routing dei segmenti per i router Cisco ASR serie 9000, IOS XR release 24.1.x, 24.2.x, 24.3.x, 24.4.xx.
Topologia
La topologia utilizzata in questo documento è illustrata nella Figura 1. Il dominio SRv6 è costituito da tre router, tutti operanti su Cisco IOS-XR. L'infrastruttura di underlay SRv6 viene implementata utilizzando IS-IS con uSID SRv6. Il peering unicast BGP IPv6 viene stabilito tra i router R1 e R3, mentre il router R2 non partecipa al BGP e funziona come router P in questa configurazione. L'interfaccia di loopback 6 su R1 e R3 rappresenta un prefisso IPv6 che deve essere scambiato tra i due peer unicast IPv6 BGP.
Figura 1. Diagramma topologico di BGP ipv6 unicast su SRv6
Configurazione SRv6
In questa sezione viene illustrata la configurazione dei tre router SRv6. Il router R2 include solo la configurazione SRv6, in quanto non partecipa a BGP.
Configurazione router R1
Il router R1 fa parte del dominio SRv6 con un localizzatore fc00:bb00:1::/48. Funziona anche come router unicast BGP IPv6, originando il prefisso locale fc00:aa00:1::1/128. Inoltre, stabilisce il peer unicast BGP IPv6 con il router R3 sull'infrastruttura SRv6. La configurazione evidenziata in grassetto costituisce il punto di partenza per il debug del flusso di controllo descritto in questo documento ed è l'unico trigger utilizzato in.
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
!Configurazione router R2
Il router R2 fa parte del dominio SRv6 con un localizzatore fc00:bb00:2::/48. Non partecipa al BGP e funziona come router P all'interno di questa topologia.
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
!Configurazione router R3
Il router R3 fa parte del dominio SRv6 con un localizzatore fc00:bb00:3::/48. È dotato di peer unicast IPv6 BGP con il router R1 ed entrambi scambiano i prefissi IPv6 delle relative interfacce Loopback 6.
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
!
!
!
!Flusso di segnalazione del SID SRv6
Nell'infrastruttura SRv6 sottostante, ogni router dispone di informazioni sullo stato del collegamento in tutta la topologia, che pubblicizzano il proprio localizzatore SRv6 tramite il protocollo ISIS dello stato del collegamento. Il database ISIS su R1 mostra il localizzatore di tutti i router che fanno parte del dominio SRv6.
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
Questa implementazione di SRv6 supporta la sovrimpressione del traffico della tabella di routing globale (GRT, Global Routing Table). Quando il servizio di overlay unicast BGP IPv6 globale è abilitato sia su R1 che su R3, ogni router genera un nuovo SID del servizio. Questo SID del servizio è associato al VRF predefinito e utilizza il comportamento dell'endpoint uDT6 in questo scenario. Questo SID del servizio deve essere scambiato tra peer unicast IPv6 BGP per abilitare l'inoltro SRv6 tra i due peer BGP. La prossima sezione descrive i passaggi del flusso di segnalazione BGP, a partire dall'esecuzione del trigger (attivazione del tipo di incapsulamento srv6) fino al punto in cui l'inoltro SRv6 viene programmato sul router R3.
1. Stato prima di abilitare l'incapsulamento di SRv6
Prima di abilitare l'incapsulamento SRv6 nell'interfaccia SAFI unicast IPv6 per il peer BGP, il router R1 deve disporre di prefissi IPv6 BGP con SID del servizio assegnati. Questo si verifica quando 'segment-routing srv6' è abilitato in IPv6 unicast global SAFI su R1. L'output mostra il SID locale fc00:bb00:1:e002:: è assegnato a tutti i prefissi in BGP ipv6 unicast.
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 pathsQuesto SID del servizio è programmato localmente dal processo sid_mgr in R1, il cui comportamento dell'endpoint è uDT6, associato al file vrf predefinito e di proprietà di bgp. Questo significa semplicemente che ogni volta che il pacchetto di ricezione R1 con indirizzo di destinazione corrisponde al SID del servizio fc00:bb00:1:e002:: E rappresenta l'ultimo segmento, R1 deve decapsulare l'intestazione e inviare il pacchetto decapsulato alla ricerca FIB della tabella vrf predefinita IPv6. In base alla RFC 8986, in cui sono elencati tutti i comportamenti degli endpoint SRv6. Si noti l'output in cui viene mostrato il sid_mgr per creare il servizio SID fc00:bb00:1:e002:: e passate queste informazioni a RIB ed eventualmente FIB.
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
Poiché R1 non ha abilitato l'incapsulamento SRv6 nel peer unicast BGP ipv6, R1 annuncia questi prefissi a R3 senza TLV SRv6 nell'aggiornamento BGP, anche se R1 ha assegnato SID locali.
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: Il router R3 riceve l'aggiornamento dal router R1 senza SID. R3 installa i prefissi ricevuti da R1 nella relativa tabella RIB e FIB senza un'intestazione SRv6.
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 remote2. Abilitare l'incapsulamento SRv6
L'abilitazione dell'incapsulamento SRv6 comporta l'invio da parte di R1 di un messaggio di aggiornamento BGP al peer con attributo di tipo 40, utilizzato nel routing dei segmenti per annunciare un prefisso BGP con un SID (Segment Routing Identifier) specifico. Il router R1 invia l'aggiornamento a R3 per il prefisso IPv6 fc00:bb00:3:1 (passaggio 1) con il SID associato fc00:bb00:1:e002::. Dopo aver ricevuto l'istruzione UPDATE, il router R3 aggiorna la tabella unicast BGP IPv6 (passaggio 2) e successivamente le tabelle RIB e FIB (passaggio 3). La figura 2 illustra il flusso del segnale BGP e le fasi corrispondenti.
Figura 2. Flusso di segnalazione BGP dopo l'abilitazione dell'incapsulamento srv6
L'output visualizza il log di debug BGP subito dopo l'abilitazione dell'incapsulamento SRv6 sul peer R3, mostrando che R1 invia un messaggio di aggiornamento BGP a R3:
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
L'output visualizza la voce di traccia BGP su 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
Il messaggio BGP UPDATE decodificato mostra il tipo di attributo 40 e il tipo TLV 5, che contengono il SID del servizio fc00:bb00:1:e002::.
.
Il messaggio BGP UPDATE decodificato completo è il seguente:
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
3. R3 riceve l'aggiornamento BGP e lo installa nella tabella Unicast BGP IPv6
Il router R3 riceve un aggiornamento BGP da R1, che può essere osservato abilitando il debug BGP su R3. Il pacchetto di aggiornamento BGP ricevuto deve corrispondere a quello inviato da R1, come mostrato nell'output di debug.
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
Il router R3 genera una traccia BGP corrispondente all'elaborazione dell'aggiornamento da R1, che determina l'aggiornamento della tabella unicast BGP IPv6 in R3. Questo aggiornamento, che contiene l'attributo BGP di tipo 40, prevede l'installazione dei SID ricevuti insieme ai prefissi unicast IPv6 BGP associati da R1.
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 paths4. R3 installare RIB e FIB
Alla fine R3 installa RIB e FIB per completare il processo di segnalazione. R3 quindi funge da headend SRv6 con elenco SID fc00:bb00:1:e002::. Questo ingresso R1 funge da headend SRv6 con incapsulamento in una policy SR, abbreviato come H.Encaps (RFC 8986, sezione 5.1). Questo comportamento incapsula il pacchetto in un'intestazione IPv6, imponendo un elenco di segmenti e aggiungendo SRH se necessario. In questo caso, non è necessario aggiungere il protocollo SRH in quanto esiste un solo segmento. Il pacchetto verrà inviato con l'indirizzo di destinazione fc00:bb00:1:e002::, che è il SID del servizio in R1 con comportamento SRv6 Endpoint UDT6.
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 Nella figura 4 viene mostrato il formato del pacchetto quando il router R3 (fc00:aa00:3:3) esegue il ping di R1 (fc00:aa00:1:1).
Figura 4. Elaborazione dei pacchetti lungo il percorso di BGP IPv6 Unicast su SRv6
Cronologia delle revisioni
| Revisione | Data di pubblicazione | Commenti |
|---|---|---|
1.0 |
03-Oct-2025
|
Versione iniziale |
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