配置SRTE上的EVPN服務

簡介

本檔案介紹如何透過區段路由流量工程(SRTE)設定乙太網路虛擬私人網路(EVPN)服務。

必要條件

需求

思科建議您瞭解以下基本知識：

• 中間系統到中間系統(ISIS)
• SRTE
• EVPN

採用元件

本檔案中的資訊是根據Device:聚合服務路由器9000(ASR9K)。

本文中的資訊是根據特定實驗室環境內的裝置所建立。文中使用到的所有裝置皆從已清除（預設）的組態來啟動。如果您的網路運作中，請確保您瞭解任何指令可能造成的影響。

網路拓撲

圖1.網路拓撲圖

附註：要建立域間SRTE策略，您需要使用PCE來檢視多個域中的所有節點。

分段路由流量工程概述

SRTE策略

SR策略通過以下引數標識：

• 例項化/實施策略的前端
• 終結點（即策略的目標）
• 顏色（任意數值）

SR-TE資料庫

SRTE資料庫是分段路由(SR)體系結構中的關鍵元件，用於儲存：

• 節點和網段的SID值。
• 有關網路拓撲的詳細資訊，包括可用鏈路、指標和限制（如頻寬或延遲）。
• 路由器使用它來根據SR策略中指定的預定義限制或最佳化目標確定轉發資料包的最佳路徑。

從PE1到PE3但不配置SRTE策略的IGP路徑：

RP/0/RSP1/CPU0:ASR9906-1-PE1#traceroute mpls ipv4 10.10.33.33/32 source 10.10.11.11
Type escape sequence to abort.
  0 10.10.111.11 MRU 1500 [Labels: 16033 Exp: 0]
L 1 10.10.111.1 MRU 1500 [Labels: explicit-null Exp: 0] 7 ms >>>>>>>>>>>>>>>>> P1
! 2 10.10.133.33 4 ms>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> PE3

圖2從PE1到PE3的IGP路徑 

用於填充SRTE資料庫的配置

router isis core1
 is-type level-2-only
 net 49.0005.0000.1010.0505.00
distribute link-state
 address-family ipv4 unicast

附註：

• 填充SRTE資料庫需要分發鏈路狀態。
• 未配置此命令時，SRTE資料庫將為空。

驗證

RP/0/RSP0/CPU0:ASR9906-2-ABR #show segment-routing traffic-eng ipv4 topology
SR-TE topology database
-----------------------
Node 2
  TE router ID: 10.10.1.1
  Host name: ASR9910-4-P1
  ISIS system ID: 0000.1010.0101 level-2
  Prefix SID:
    Prefix 10.10.1.1, label 16001 (regular), flags: X:0, R:0, N:1, P:1, E:1, V:0, L:0, M:0 >>>>> node details
  Link[0]: local address 10.10.15.1, remote address 10.10.15.5
    Local node:
      ISIS system ID: 0000.1010.0101 level-2
    Remote node:
      TE router ID: 10.10.5.5
      Host name: ASR9906-2-ABR
      ISIS system ID: 0000.1010.0505 level-2
    Metric: IGP 10, TE 10, Latency 10 microseconds >>>>>>>>> metric and latency of this link between P1 and ABR 
    Bandwidth: Total link 12499999744, Reservable 0 >>>>>>> BW of this link 
    Admin-groups: 0x00000000
    Admin-groups-detail:
    Adj SID: 24005 (protected) 24006 (unprotected) >>>>>>>> adj sid of link on P1

靜態SRTE策略 

組態 

在頭端路由器PE1上配置SRTE靜態策略：

segment-routing
 traffic-eng
  segment-list STATIC-SID-LIST
   index 1 mpls label 16055 >>>>>>> node SID of ABR
   index 2 mpls label 16022 >>>>>>> node SID of PE2
   index 3 mpls label 16033 >>>>>>> node SID of PE3
  !
  policy Static-policy-evpnvpws
   binding-sid mpls 3000
   color 10 end-point ipv4 10.10.33.33
   candidate-paths
    preference 5
     explicit segment-list STATIC-SID-LIST

附註：

• 手動配置的繫結SID 3000
• 顏色為10，終點為PE3
• 此SR TE策略使用顯式SID清單控制預定義路徑中的流量

RP/0/RSP1/CPU0:ASR9906-1-PE1#traceroute sr-mpls policy binding-sid 3000 lsp-end-point 10.10.33.33 source 10.10.11.11 verbose
Type escape sequence to abort.
  0 10.10.115.11 10.10.115.5 MRU 1500 [Labels: 16022/16033 Exp: 0/0]
L 1 10.10.115.5 10.10.225.22 MRU 1500 [Labels: explicit-null/16033 Exp: 0/0] 6 ms, ret code 8
L 2 10.10.225.22 10.10.123.33 MRU 1500 [Labels: explicit-null Exp: 0] 5 ms, ret code 8
! 3 10.10.123.33 5 ms, ret code 3

附註：第一跳為ABR，節點SID為16055;因此，在傳送封包時不會附加該封包。

圖3從PE1到PE3採用的靜態SRTE策略路徑 

驗證

RP/0/RSP1/CPU0:ASR9906-1-PE1#show segment-routing traffic-eng policy color 10
SR-TE policy database
---------------------
Color: 10, End-point: 10.10.33.33
  Name: srte_c_10_ep_10.10.33.33
  Status:
    Admin: up  Operational: up for 3d02h (since Jan 14 08:39:30.042)
  Candidate-paths:
    Preference: 5 (configuration) (active)
      Name: Static-policy-evpnvpws
      Requested BSID: 3000
        Protection Type: protected-preferred
        Maximum SID Depth: 10
      Explicit: segment-list STATIC-SID-LIST (valid)
        Weight: 1, Metric Type: TE
          16055 [Prefix-SID, 10.10.25.25]
          16022
          16033
  Attributes:
    Binding SID: 3000
    Forward Class: Not Configured
    Steering labeled-services disabled: no
    Steering BGP disabled: no
    IPv6 caps enable: yes
    Invalidation drop enabled: no

RP/0/RSP1/CPU0:ASR9906-1-PE1#show segment-routing traffic-eng forwarding policy color 10
SR-TE Policy Forwarding database
--------------------------------
Color: 10, End-point: 10.10.33.33
  Name: srte_c_10_ep_10.10.33.33
  Binding SID: 3000
  Active LSP:
    Candidate path:
      Preference: 5 (configuration)
      Name: Static-policy-evpnvpws
    Local label: 24012
    Segment lists:
      SL[0]:
        Name: STATIC-SID-LIST
        Switched Packets/Bytes: 30/2740
          [MPLS -> MPLS]: 30/2740
        Paths:
          Path[0]:
            Outgoing Label: 16022
            Outgoing Interfaces: HundredGigE0/1/0/0
            Next Hop: 10.10.115.5
            Switched Packets/Bytes: 30/2740>>>>>>>>>>> this is the number packet steered using this path 
              [MPLS -> MPLS]: 30/2740
            FRR Pure Backup: No
            ECMP/LFA Backup: No
            Internal Recursive Label: Unlabelled (recursive)
            Label Stack (Top -> Bottom): { 16022, 16033 }
  Policy Packets/Bytes Switched: 30/2620>>>>>>>>> this counter shows the packets were transmitted using this policy 

RP/0/RSP1/CPU0:ASR9906-1-PE1#show mpls forwarding labels 3000 detail
Local  Outgoing    Prefix             Outgoing     Next Hop        Bytes      
Label  Label       or ID              Interface                    Switched   
------ ----------- ------------------ ------------ --------------- ------------
3000   Pop         No ID              srte_c_10_ep point2point     2620       
     Version: 69, Priority: 2
     Label Stack (Top -> Bottom): { Unlabelled Imp-Null }
     NHID: 0x0, Encap-ID: N/A, Path idx: 0, Backup path idx: 0, Weight: 0
     MAC/Encaps: 0/0, MTU: 0
     Outgoing Interface: srte_c_10_ep_10.10.33.33 (ifhandle 0x020001e0)
     Packets Switched: 30

附註：3000 -Binding sid用於引導資料包進入SRTE。

RP/0/RSP1/CPU0:ASR9906-1-PE1#show mpls forwarding labels  24012 detail
Local  Outgoing    Prefix             Outgoing     Next Hop        Bytes      
Label  Label       or ID              Interface                    Switched   

------ ----------- ------------------ ------------ --------------- ------------
24012  16022       SR TE: 1 [TE-INT]  Hu0/1/0/0    10.10.115.5     2740     

     Version: 68, Priority: 2
     Label Stack (Top -> Bottom): { 16022 16033 }
     NHID: 0x0, Encap-ID: N/A, Path idx: 0, Backup path idx: 0, Weight: 0
     MAC/Encaps: 4/12, MTU: 1500
     Outgoing Interface: HundredGigE0/1/0/0 (ifhandle 0x06000480)
     Packets Switched: 30

附註：24012是分配給此策略的本地標籤，該標籤與策略的傳出標籤交換。

將靜態SRTE策略static-policy-evpnvpws與EVPN VPWS關聯

組態

l2vpn
 pw-class evpn-srte
  encapsulation mpls
   preferred-path sr-te policy srte_c_10_ep_10.10.33.33

xconnect group EVPN-vpws
  p2p EVPN-vpws-400
   interface HundredGigE0/1/0/2.400
   neighbor evpn evi 400 target 333 source 111
    pw-class evpn-srte

附註：EVPN路由沒有著色，因為SRTE策略與l2vpn手動關聯，並且所有通過此xconnect的流量都採用SRTE策略路徑。

驗證

RP/0/RSP1/CPU0:ASR9906-1-PE1#show bgp l2vpn evpn
Route Distinguisher: 10.10.11.11:400 (default for vrf VPWS:400)
*> [1][0000.0000.0000.0000.0000][111]/120
                      0.0.0.0                                0 i
*>i[1][0000.0000.0000.0000.0000][333]/120
                      10.10.33.33                   100      0 i

RP/0/RSP1/CPU0:ASR9906-1-PE1#show l2vpn xconnect    
XConnect                   Segment 1                       Segment 2               
Group      Name       ST   Description            ST       Description            ST   
------------------------   -----------------------------   -----------------------------
EVPN-vpws  EVPN-vpws-400
                      UP   Hu0/1/0/2.400          UP       EVPN 400,333,10.10.33.33
                                                                                  UP 

RP/0/RSP1/CPU0:ASR9906-1-PE1#show l2vpn xconnect group EVPN-vpws xc-name EVPN-vpws-400 detail
Group EVPN-vpws, XC EVPN-vpws-400, state is up; Interworking none
  AC: HundredGigE0/1/0/2.400, state is up
    Type VLAN; Num Ranges: 1
    Rewrite Tags: []
    VLAN ranges: [400, 400]
    MTU 1500; XC ID 0x1800008; interworking none
    Statistics:
      packets: received 90, sent 89
      bytes: received 7140, sent 7296
      drops: illegal VLAN 0, illegal length 0
  EVPN: neighbor 10.10.33.33, PW ID: evi 400, ac-id 333, state is up ( established )
    XC ID 0xa000000b
    Encapsulation MPLS
    Encap type Ethernet, control word enabled
    Sequencing not set
    Preferred path Active : SR TE srte_c_10_ep_10.10.33.33 (BSID:3000, IFH:0x20001e0), Statically configured, fallback enabled
    Ignore MTU mismatch: Enabled
    Transmit MTU zero: Enabled
    Tunnel : Up
      EVPN         Local                          Remote                       
      ------------ ------------------------------ -----------------------------
      Label        24014                          24016                        
      MTU          1514                           unknown                      
      Control word enabled                        enabled                      
      AC ID        111                            333                          
      EVPN type    Ethernet                       Ethernet                     
      ------------ ------------------------------ -----------------------------
    Create time: 14/01/2025 08:49:57 (1w1d ago)
    Last time status changed: 14/01/2025 11:14:31 (1w0d ago)
    Statistics:
      packets: received 89, sent 90
      bytes: received 7296, sent 7140

RP/0/RSP1/CPU0:ASR9906-1-PE1#show im database ifhandle 0x20001e0
Node 0/RSP1/CPU0 (0x120)
Interface srte_c_10_ep_10.10.33.33, ifh 0x020001e0 (up, 1500)
  Interface flags:          0x000000000042c457 (PHYS_ON_RP|REPLICATED        
                            |DYN_REP|TUNNEL|IFINDEX|VIRTUAL|CONFIG|VIS|DATA  
                            |CONTROL)                                        
  Encapsulation:            mpls_te                                          
  Interface type:           IFT_TUNNEL_TE                                    
  Control parent:           None                                             
  Data parent:              None                                             
  Views:                    UL|GDP|LDP|G3P|L3P|OWN                           
  Protocol        Caps (state, mtu)
  --------        -----------------
  None            mpls_te (up, 1500)
  ipv4            ipv4 (up, 1500)
  mpls            mpls (up, 1500)
  ipv6            ipv6_preswitch (up, 1500)
  ipv6            ipv6 (up, 1500)

隨選下一躍點(ODN)SRTE

ODN SRTE策略根據即時網路需求和指定的限制自動建立分段路由流量工程路徑，從而確保動態且高效的流量引導。

這些策略由與ODN策略共用相同顏色的已接收路由觸發。LSP（標籤交換路徑）端點動態地與這些路由的協定下一跳相關聯。

組態

segment-routing
 traffic-eng
  on-demand color 500
   dynamic
    metric
     type te

附註：此策略僅具有有效的LSP端點，該端點為具有匹配顏色擴展社群的已接收路由的下一跳。

為EVPN ELAN服務使用ODN SRTE策略

由於ODN SRTE是動態策略，因此接收的路由需要對500進行著色，因此對發往該路由的流量進行著色。如果路由沒有著色，則下一跳採用ODN SRTE策略路徑，則採用IGP路徑。

組態

extcommunity-set opaque color_500
  500
end-set   

顏色在擴展團體中定義：

route-policy RPL_color_500
  if evpn-route-type is 1 or evpn-route-type is 3 then
    set extcommunity color color_500
  endif
end-policy

附註：

• 當BUM流量必須從PE1傳送到遠端PE3以便通過SRTE策略顏色500傳送時，evpn-route-type 3需要著色，因為它提供用於傳輸BUM流量的標籤。
• 對於單播流量，RT-2會通告MAC的單播標籤，但是當RT-2使用RPL著色時，會觀察到錯誤消息：

RP/0/RP0/CPU0:PE2#RP/0/RP0/CPU0: UTC: l2vpn_mgr[1291]: %L2-EVPN-4-ODN_ON_UNSUPPORTED_ROUTE : EVPN: ODN/AS Nexthop received on unsupported Route-Type 2 (MAC/IP Advertisement), SR-TE BSID tunnel, bridge domain EVPN_ELAN, ESI 0000.0000.0000.0000.0000.

• 將訪問介面（即使對於SH）與ESI相關聯，並根據EAD/EVI路由進行著色，以便通過SRTE策略引導流量：

evi 500
  bgp
   route-policy export RPL_color_500
  !
  advertise-mac

l2vpn
bridge group EVPN-ELAN-500
  bridge-domain EVPN-ELAN-500
   interface HundredGigE0/1/0/2.500
   !
   evi 500

驗證

RP/0/RSP0/CPU0:ASR9910-3-PE3#show bgp l2vpn evpn rd 10.10.33.33:500
Route Distinguisher: 10.10.33.33:500 (default for vrf EVPN-ELAN-500)
*>i[1][0000.1111.1111.1111.1111][0]/120
                      10.10.11.11 C:500
                                                    100      0 i
*>i[1][0000.1111.1111.1111.1111][4294967295]/120
                      10.10.11.11                   100      0 i
*> [1][0000.2222.2222.2222.2222][0]/120
                      0.0.0.0                                0 i
*>i[3][0][32][10.10.11.11]/80
                      10.10.11.11 C:500
                                                    100      0 i
*> [3][0][32][10.10.33.33]/80
                      0.0.0.0                                0 

附註：當PE3收到具有擴展社群顏色500的路由型別1或3時，PE3啟動目的地為PE1的ODN SRTE策略500

每個EVI路由都連線到顏色擴展團體並連線到SRTE策略：

RP/0/RSP0/CPU0:ASR9910-3-PE3#show bgp l2vpn evpn rd 10.10.33.33:500 [1][0000.1111.1111.1111.1111][0]/120
Not advertised to any peer
  Local
    10.10.11.11 C:500 (bsid:24020) (metric 20) from 10.10.11.11 (10.10.11.11)
      Received Label 24015 
      Origin IGP, localpref 100, valid, internal, best, group-best, import-candidate, imported, rib-install
      Received Path ID 0, Local Path ID 1, version 534
      Extended community: Color:500 RT:100:500
      SR policy color 500, up, registered, bsid 24020, if-handle 0x00000360
      Source AFI: L2VPN EVPN, Source VRF: default, Source Route Distinguisher: 10.10.11.11:500

每個ESI路由沒有顏色：

RP/0/RSP0/CPU0:ASR9910-3-PE3# show bgp l2vpn evpn rd 10.10.33.33:500 [1][0000.1111.1111.1111.1111][4294967295]/120
Local
    10.10.11.11 (metric 20) from 10.10.11.11 (10.10.11.11)
      Received Label 0
      Origin IGP, localpref 100, valid, internal, best, group-best, import-candidate, imported, rib-install
      Received Path ID 0, Local Path ID 1, version 539
      Extended community: EVPN ESI Label:0x01:24017 RT:100:100 RT:100:400 RT:100:500 RT:300:300
      Source AFI: L2VPN EVPN, Source VRF: default, Source Route Distinguisher: 10.10.11.11:1

附註：每個ESI路由沒有著色，因為它與多個EVI關聯，並且所有EVI都不採用SRTE路徑。

路由型別–3已著色：

RP/0/RSP0/CPU0:ASR9910-3-PE3#show bgp l2vpn evpn rd 10.10.33.33:500 [3][0][32][10.10.11.11]/80
Local
    10.10.11.11 C:500 (bsid:24020) (metric 20) from 10.10.11.11 (10.10.11.11)
      Origin IGP, localpref 100, valid, internal, best, group-best, import-candidate, imported
      Received Path ID 0, Local Path ID 1, version 524
      Extended community: Color:500 RT:100:500
      PMSI: flags 0x00, type 6, label 24016, ID 0x0a0a0b0b
      SR policy color 500, up, registered, bsid 24020, if-handle 0x00000360
      Source AFI: L2VPN EVPN, Source VRF: default, Source Route Distinguisher: 10.10.11.11:500

路由型別2未著色：

RP/0/RSP1/CPU0:ASR9906-1-PE1#  show bgp l2vpn evpn rd 10.10.11.11:500 [2][0][48][bce7.12a3.b716][0]/104
  Local  
    10.10.33.33 (metric 10) from 10.10.33.33 (10.10.33.33)
      Received Label 24010
      Origin IGP, localpref 100, valid, internal, best, group-best, import-candidate, imported, rib-install
      Received Path ID 0, Local Path ID 1, version 302
      Extended community: SoO:10.10.33.33:500 0x060e:0000.0000.01f4 RT:100:500
      EVPN ESI: 0000.2222.2222.2222.2222
      Source AFI: L2VPN EVPN, Source VRF: default, Source Route Distinguisher: 10.10.33.33:500

RP/0/RSP0/CPU0:ASR9910-3-PE3#show segment-routing traffic-eng policy color 500
SR-TE policy database
---------------------
Color: 500, End-point: 10.10.11.11
  Name: srte_c_500_ep_10.10.11.11
  Status:
    Admin: up  Operational: up for 6d22h 
  Candidate-paths:
    Preference: 200 (BGP ODN) (active)
      Requested BSID: dynamic
      Constraints:
        Protection Type: protected-preferred
        Maximum SID Depth: 10
      Dynamic (valid)
        Metric Type: TE,   Path Accumulated Metric: 20 
          16001 [Prefix-SID, 10.10.1.1]
          16005 [Prefix-SID, 10.10.5.5]
          16011 [Prefix-SID, 10.10.11.11]
    Preference: 100 (BGP ODN) (inactive)
      Requested BSID: dynamic
      PCC info:
        Symbolic name: bgp_c_500_ep_10.10.11.11_discr_100
        PLSP-ID: 1
      Constraints:
        Protection Type: protected-preferred
        Maximum SID Depth: 10
      Dynamic (pce) (inactive)
        Metric Type: NONE,   Path Accumulated Metric: 0
  Attributes:
    Binding SID: 24020
    Forward Class: Not Configured
    Steering labeled-services disabled: no
    Steering BGP disabled: no
    IPv6 caps enable: yes
    Invalidation drop enabled: no
    Max Install Standby Candidate Paths: 0

EVI 500的單點傳播流量通過SRTE傳送，輸出可確認此情況：

RP/0/RSP0/CPU0:ASR9910-3-PE3#show evpn internal-label vpn-id 500 private
VPN-ID     Encap  Ethernet Segment Id         EtherTag     Label  
---------- ------ --------------------------- ----------   --------
500        MPLS   0000.1111.1111.1111.1111    0            None   
   Multi-paths resolved: FALSE (Remote single-active)
   Multi-paths Internal label: None
    EAD/ES      10.10.11.11                                0             
                  Path Version:2, Originating PE:::
    EAD/EVI     SR-TE BSID 24020
                10.10.11.11                                24015          
                  Path Version:4, Originating PE:::
   Num EAD objects linked: 2
   Source: MPLS
   Local CW: Unknown
   Local MTU: 0
   Local ignore MTU mismatch: Enabled
   Next path version: 5
   Object: EVPN LABEL
   Base info: version=0xdbdb000a, flags=0x4000, type=10, reserved=0
   EVPN Internal-Label event history  [Num events: 16]
   ----------------------------------------------------------------------------
     Time                Event                         Flags      Flags     
     ====                =====                         =====      =====     
     Jan 28 19:53:08.224 LSD Label Req (Add/Del)       00000de1 00005dd8 -  -
     Jan 28 21:29:09.888 Modify Redundant              00000000 00000000 -  -
     Jan 28 21:29:09.888 Int-Lbl Multi-Path Resolution 01010100 0100020e -  -
     Jan 28 21:29:09.888 LSD Label Req (Add/Del)       00000add 00100001 -  -
     Jan 28 21:29:09.888 LSD Label Got                 01f40000 01005dd8 -  -
     Jan 28 23:27:01.632 LSD Label Req (Add/Del)       00000de1 00005dd8 -  -
     Jan 29 01:06:15.808 Modify Redundant              00000000 00000000 -  -
     Jan 29 01:06:15.808 Int-Lbl Multi-Path Resolution 01010100 0100020e -  -
     Jan 29 01:06:15.808 LSD Label Req (Add/Del)       00000add 00100001 -  -
     Jan 29 01:06:15.808 LSD Label Got                 01f40000 01005dd8 -  -
     Jan 29 03:00:44.416 LSD Label Req (Add/Del)       00000de1 00005dd8 -  -
     Jan 29 04:45:32.032 Modify Redundant              00000000 00000000 -  -
     Jan 29 04:45:32.032 Int-Lbl Multi-Path Resolution 01010100 0100020e -  -
     Jan 29 04:45:32.032 LSD Label Req (Add/Del)       00000add 00100001 -  -
     Jan 29 04:45:32.032 LSD Label Got                 01f40000 01005dd8 -  -
     Jan 29 06:34:24.000 LSD Label Req (Add/Del)       00000de1 00005dd8 -  -
   ----------------------------------------------------------------------------

附註：24015 — 是PE1通告的每EVI標籤。

RP/0/RSP0/CPU0:ASR9910-3-PE3#show mpls forwarding labels 24020
Local  Outgoing    Prefix             Outgoing     Next Hop        Bytes      
Label  Label       or ID              Interface                    Switched   
------ ----------- ------------------ ------------ --------------- ------------
24020  Pop         No ID              srte_c_500_e point2point     4182  

RP/0/RSP0/CPU0:ASR9910-3-PE3#show l2vpn forwarding bridge-domain EVPN-ELAN-500:EVPN-ELAN-500 evpn inclusive-multicast detail location 0/1/CPU0
Bridge-Domain Name               BD-ID  XCID       TEP-id     Next Hop             Label/VNI  Encap    Status  E-Tree

-------------------------------- ------ ---------- ---------- -------------------- ---------- -------- ------- ------
EVPN-ELAN-500:EVPN-ELAN-500      2      0x8000000b
   Status: bound
   Flags: default multicast replication
                                                   0x02000001 SRTE BSID 24020      24016      10       bound   Root

附註：24016 - PE1在路由型別–3中通告的BUM標籤。

結論

使用SR-TE的EVPN將EVPN強大的服務交付的優勢與SR-TE的流量工程和操作簡便性結合在一起，從而形成靈活、可擴展且高效的網路架構。