Alternatively the SR LDP, arranged ospf sham-link

DISCLAIMER:

1. As used herein, the software from the Internet, the authors use the software only for the purpose of learning, without any software distribution behavior.

2. The configuration shown herein apply only to the experimental environment is not recommended to use exactly the same configuration in a production environment; any resulting problems, the author assumes no responsibility.

Lab topology

IP address planning

device	Loopback 0	Loopback 1	G1	G2
CSR1	11.1.1.1/32	11.1.1.2/32	172.16.0.1/30	14.1.1.1/30
CSS2	22.1.1.1/32	--	172.16.0.2/30	172.16.0.6/30
xrv	33.1.1.1/32	33.1.1.2/32	G0/0/0/2 172.16.0.5/30	G0/0/0/0 35.1.1.1/30
vIOS4	44.1.1.1/32	--	G0/0 14.1.1.2/30	G0/1 45.1.1.1/30
vIOS5	55.1.1.1/32	--	G0/0 35.1.1.2/30	G0/1 45.1.1.2/30

Device model and software version

device	platform	Software version
vIOS4, vIOS5	VIOS-ADVENTERPRISEK9-M	15.6(2)T
CSR1, CSR2	X86_64_LINUX_IOSD-UNIVERSALK9-M	16.6.2
XRv	ASR9000 IOS-XR	6.0.1

aims

1. CSR1, CSR2 and xrv arranged as a primer IS-IS protocol IGP, arranged segment-routing on this basis.

2. CSR1 and xrv as PE device configured ××× v4 BGP neighbor, the AS number 64512.

3. CSR1 and arranged vIOS4 OSPFv2 single region, the process ID 2019; xrv single region arranged with vIOS5 OSPFv2, the process ID 2019; PE device configuration and MP-BGP OSPFv2 bidirectional redistribution.

4. CSR1 and xrv arranged loopback 1 interfaces, the interfaces partitioned into the VRF customers, and declare the host MP-BGP routing process, the customer VRF.

5. CSR1 and xrv sham-link configuration of OSPFv2

---

Configuration Steps

MPLS ××× basic configuration steps:

1. Configure IGP,

2.配置MPLS（segment-routing），

3.配置MP-BGP，

4.配置VRF，

5.配置PE-CE路由协议，

6.PE 配置MP-BGP和VRF路由重分布。

---

IOS-XE和IOS-XR配置IGP(IS-IS)

设备接口IP地址配置（略）

• XEv3

router isis igp
is-type level-2-only !---配置ISIS为骨干区域
net 49.2019.0519.0001.00
log-adjacency-changes !---记录邻接log信息
metric-style wide !---使能isis宽度量
exit
interface Loopback0
ip router isis igp
interface GigabitEthernet1
ip router isis igp
isis circuit-type level-2-only !---修改链路为level-2
isis network point-to-point !---修改ISIS网络类型

• XRv4

router isis igp
is-type level-2-only
net 49.2019.0519.0003.00
log adjacency changes
address-family ipv4 unicast
metric-style wide
interface Loopback0
address-family ipv4 unicast
interface GigabitEthernet0/0/0/0
address-family ipv4 unicast
circuit-type level-2-only
point-to-point
commit

2 验证IS-IS

CSR2#show ip route isis | b bn
11.0.0.0/32 is subnetted, 1 subnets
i L2 11.1.1.1 [115/20] via 172.16.0.1, 1d00h, GigabitEthernet1
33.0.0.0/32 is subnetted, 1 subnets
i L2 33.1.1.1 [115/20] via 172.16.0.5,19:06:28, GigabitEthernet2
RP/0/0/CPU0:xrv#show route ipv4 isis
i L2 11.1.1.1/32 [115/30] via 172.16.0.6, 19:11:15, GigabitEthernet0/0/0/2
i L2 22.1.1.1/32 [115/20] via 172.16.0.6, 19:11:15, GigabitEthernet0/0/0/2
i L2 172.16.0.0/30 [115/20] via 172.16.0.6, 19:11:15, GigabitEthernet0/0/0/2

3 配置MPLS(segment-routing)

• XEv3

  segment-routing mpls
  connected-prefix-sid-map
  address-family ipv4
  11.1.1.1/32 index 1 range 1
  exit-address-family
  router isis igp
  segment-routing mpls

• XRv4

  segment-routing
  router isis igp
  address-family ipv4 unicast
  metric-style wide
  segment-routing mpls
  interface Loopback0
  address-family ipv4 unicast
  prefix-sid index 33
  commit

4 验证MPLS

CSR1#show mpls forwarding-table
Local Outgoing Prefix Bytes Label Outgoing Next Hop
Label Label or Tunnel Id Switched interface
16 Pop Label 172.16.0.2-A 0 Gi1 172.16.0.2
21 Pop Label 11.1.1.2/32[V] 0 aggregate/ospf
16022 Pop Label 22.1.1.1/32 0 Gi1 172.16.0.2
16033 16033 33.1.1.1/32 0 Gi1 172.16.0.2

RP/0/0/CPU0:xrv#show mpls forwarding
Local Outgoing Prefix Outgoing Next Hop Bytes
Label Label or ID Interface Switched

---

16011 16011 SR Pfx (idx 11) Gi0/0/0/2 172.16.0.6 208166
16022 Pop SR Pfx (idx 22) Gi0/0/0/2 172.16.0.6 0
24006 Pop SR Adj (idx 1) Gi0/0/0/2 172.16.0.6 0
24007 Pop SR Adj (idx 3) Gi0/0/0/2 172.16.0.6 0

5 配置MP-BGP

• CSR1

  router bgp 64512
  bgp router-id 11.1.1.1
  no bgp default ipv4-unicast
  neighbor 33.1.1.1 remote-as 64512
  neighbor 33.1.1.1 update-source Loopback0
  address-family ***v4
  　neighbor 33.1.1.1 activate

• xrv

  router bgp 64512
  bgp router-id 33.1.1.1
  address-family v4 unicast
  neighbor 11.1.1.1
  　remote-as 64512
  　update-source Loopback0
  　address-family v4 unicast
  commit

• 验证如下：

  CSR1#show bgp ***v4 unicast all sum | b gh
  Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
  33.1.1.1 4 64512 1254 1429 315 0 0 20:17:43 4

  RP/0/0/CPU0:xrv#show bgp ***v4 unicast summary | b gh
  Neighbor Spk AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down St/PfxRcd
  11.1.1.1 0 64512 1890 1674 249 0 0 20:18:04 4

6 配置VRF and PE-CE routing protocol

6.1定义VRF

• CSR1

  vrf definition AAA
  rd 64512:4
  address-family ipv4
  route-target export 64512:45
  route-target import 64512:45
  exit-address-family

• xrv

  vrf AAA
  address-family ipv4 unicast
  import route-target
  64512:45
  export route-target
  64512:45

6.2 PE to CE Interface config

• CSR1

  interface GigabitEthernet2
  vrf forwarding AAA
  ip address 14.1.1.1 255.255.255.252
  no shutdown

• xrv

  interface GigabitEthernet0/0/0/0
  vrf AAA
  ipv4 address 35.1.1.1 255.255.255.252
  no shutdown

6.3 PE OSPFv2 config

• CSR1

  router ospf 2019 vrf AAA
  router-id 14.1.1.1
  interface GigabitEthernet2
  ip ospf network point-to-point
  ip ospf 14 area 0

• xrv

  router ospf 35
  address-family ipv4 unicast
  vrf AAA
  router-id 35.1.1.1
  address-family ipv4 unicast
  area 0
  interface GigabitEthernet0/0/0/0
  network point-to-point

6.4 CE OSPFv2 config

• vIOS4

  interface GigabitEthernet0/0
  ip address 14.1.1.2 255.255.255.252
  no shutdown
  ip ospf 2019 area 0
  ip ospf network point-to-point
  router ospf 2019
  router-id 44.1.1.1

• vIOS5

  interface GigabitEthernet0/0
  ipv4 address 35.1.1.2 255.255.255.252
  no shutdown
  ip ospf 2019 area 0
  ip ospf network point-to-point
  router ospf 2019
  router-id 55.1.1.1

6.5 PE OSPFv2 and MP-BGP redistribute

• CSR1

  router ospf 14 vrf AAA
  redistribute bgp 64512 metric-type 1 subnets
  interface GigabitEthernet2
  router bgp 64512
  address-family ipv4 vrf AAA
  redistribute ospf 14 match internal external 1 external 2

• xrv

  router ospf 35
  vrf AAA
  redistribute bgp 64512 metric-type 1
  router bgp 64512
  vrf AAA
  rd 64512:5
  address-family ipv4 unicast
  redistribute ospf 35 match internal external

6.6 验证PE-CE OSPFv2配置

CSR1#show ip route vrf AAA ospf | b bn
35.0.0.0/30 is subnetted, 1 subnets
O 35.1.1.0 [110/2] via 33.1.1.1, 00:00:32
44.0.0.0/32 is subnetted, 1 subnets
O 44.1.1.1 [110/2] via 14.1.1.2, 00:00:34, GigabitEthernet2
45.0.0.0/29 is subnetted, 1 subnets
O IA 45.1.1.0 [110/20001] via 14.1.1.2, 00:00:34, GigabitEthernet2

vIOS4#sho ip route ospf | b bn
35.0.0.0/30 is subnetted, 1 subnets
O E1 35.1.1.0 [110/2] via 14.1.1.1, 00:23:54, GigabitEthernet0/0
55.0.0.0/32 is subnetted, 1 subnets
O E1 55.1.1.1 [110/3] via 14.1.1.1, 00:23:54, GigabitEthernet0/0

vIOS4#ping 55.1.1.1 sour lo 0
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 55.1.1.1, timeout is 2 seconds:
Packet sent with a source address of 44.1.1.1
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 11/15/33 ms
vIOS4#traceroute 55.1.1.1 sour lo 0
Type escape sequence to abort.
Tracing the route to 55.1.1.1
VRF info: (vrf in name/id, vrf out name/id)
1 14.1.1.1 8 msec 5 msec 3 msec
2 172.16.0.2 [MPLS: Labels 16033/24003 Exp 0] 19 msec 25 msec 10 msec
3 172.16.0.5 [MPLS: Label 24003 Exp 0] 13 msec 12 msec 8 msec
4 35.1.1.2 12 msec 19 msec *
vIOS4#

CSR1#sho bgp *v4 uni all 44.1.1.1
BGP routing table entry for 64512:4:44.1.1.1/32, version 383
Paths: (1 available, best #1, table AAA)
Advertised to update-groups:
5
Refresh Epoch 1
Local
14.1.1.2 (via vrf ospf) from 0.0.0.0 (11.1.1.1)
Origin incomplete, metric 2, localpref 100, weight 32768, valid, sourced, best
Extended Community: RT:64512:45 OSPF DOMAIN ID:0x0005:0x0000000E0200
OSPF RT:0.0.0.0:2:0 OSPF ROUTER ID:14.1.1.1:0
mpls labels in/out 23/nolabel
rx pathid: 0, tx pathid: 0x0
!--- DOMAIN ID:0x0005:0x0000000E0200 16进制E=10进制14**（CSR1 ospfv2 进程ID）

6.7 修改/添加ospfv2 DOMAIN ID

• IOS-XR默认不携带DOMAIN ID值

  RP/0/0/CPU0:xrv#show bgp ***v4 uni vrf ospf 55.1.1.1/32
  BGP routing table entry for 55.1.1.1/32, Route Distinguisher: 64512:5
  Versions:
  Process bRIB/RIB SendTblVer
  Speaker 345 345
  Local Label: 24003
  Last Modified: May 22 02:21:42.463 for 06:05:44
  Paths: (1 available, best #1)
  Advertised to peers (in unique update groups):
  11.1.1.1
  Path #1: Received by speaker 0
  Advertised to peers (in unique update groups):
  11.1.1.1
  Local
  35.1.1.2 from 0.0.0.0 (33.1.1.1)
  Origin incomplete, metric 2, localpref 100, weight 32768, valid, redistributed, best, group-best, import-candidate
  Received Path ID 0, Local Path ID 1, version 345
  Extended community: OSPF route-type:0:1:0x0 OSPF router-id:35.1.1.1 RT:64512:45

  CSR1#show bgp ***v4 uni vrf AAA 55.1.1.1/32
  BGP routing table entry for 64512:4:55.1.1.1/32, version 417
  Paths: (1 available, best #1, table ospf, RIB-failure(17))
  Not advertised to any peer
  Refresh Epoch 1
  Local, imported path from 64512:5:55.1.1.1/32 (global)
  33.1.1.1 (metric 30) (via default) from 33.1.1.1 (33.1.1.1)
  Origin incomplete, metric 2, localpref 100, valid, internal, best
  Extended Community: RT:64512:45 OSPF RT:0.0.0.0:1:0
  OSPF ROUTER ID:35.1.1.1:0
  mpls labels in/out nolabel/24003
  rx pathid: 0, tx pathid: 0x0

• 在IOS-XR设备添加DOMAIN ID

  RP/0/0/CPU0:xrv#conf
  RP/0/0/CPU0:xrv(config)#router ospf 35
  RP/0/0/CPU0:xrv(config-ospf)#vrf AAA
  RP/0/0/CPU0:xrv(config-ospf-vrf)#domain-id type 0005 value 000000230200
  RP/0/0/CPU0:xrv(config-ospf-vrf)#commit
  !--- 23(hex)=35(dec)
  RP/0/0/CPU0:xrv(config-ospf-vrf)#do show bgp ***v4 uni vrf ospf 55.1.1.1/32 | in community
  Wed May 22 09:38:03.422 UTC
  Extended community: OSPF domain-id:0x5:0x000000230200 OSPF route-type:0:1:0x0 OSPF router-id:35.1.1.1 RT:64512:45

  CSR1#show bgp ***v4 uni vrf ospf 55.1.1.1/32 | i unity
  Extended Community: RT:64512:45 OSPF DOMAIN ID:0x0005:0x000000230200

6.8 配置CE之间的backdoor link

• vIOS5

  interface GigabitEthernet0/1
  ip address 45.1.1.5 255.255.255.248
  ip ospf network point-to-point
  ip ospf 2019 area 45
  ip ospf cost 20000
  !---模拟×××链路故障，在vIOS5上手工shutdown链路
  vIOS5(config-if)#int g0/0
  vIOS5(config-if)#shu
  May 20 10:17:09.190: %OSPF-5-ADJCHG: Process 2019, Nbr 35.1.1.1 on GigabitEthernet0/0 from FULL to DOWN, Neighbor Down: Interface down or detached
  May 20 10:17:11.136: %LINK-5-CHANGED: Interface GigabitEthernet0/0, changed state to administratively down
  May 20 10:17:12.137: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/0, changed state to down
  vIOS5(config-if)#
  vIOS5(config-if)#do sho ip route ospf | b bn
  14.0.0.0/30 is subnetted, 1 subnets
  O IA 14.1.1.0 [110/20001] via 45.1.1.4, 00:00:33, GigabitEthernet0/1
  35.0.0.0/30 is subnetted, 1 subnets
  O 35.1.1.0 [110/20003] via 45.1.1.4, 00:00:33, GigabitEthernet0/1
  44.0.0.0/32 is subnetted, 1 subnets
  O IA 44.1.1.1 [110/20001] via 45.1.1.4, 00:00:33, GigabitEthernet0/1
  vIOS5(config-if)#
  !---在vIOS4上查看ospf路由
  vIOS4#sho ip route ospf | b bn
  35.0.0.0/30 is subnetted, 1 subnets
  O IA 35.1.1.0 [110/3] via 14.1.1.1, 00:09:31, GigabitEthernet0/0
  55.0.0.0/32 is subnetted, 1 subnets
  O IA 55.1.1.1 [110/4] via 14.1.1.1, 00:09:31, GigabitEthernet0/0
  vIOS4#sho ip route ospf | b bn
  35.0.0.0/30 is subnetted, 1 subnets
  O IA 35.1.1.0 [110/3] via 14.1.1.1, 00:11:41, GigabitEthernet0/0
  55.0.0.0/32 is subnetted, 1 subnets
  O IA 55.1.1.1 [110/20001] via 45.1.1.5, 00:00:05, GigabitEthernet0/1
  !---恢复链路
  vIOS5(config-if)#no shu
  May 20 10:18:48.972: %LINK-3-UPDOWN: Interface GigabitEthernet0/0, changed state to up
  May 20 10:18:49.971: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/0, changed state to up
  May 20 10:19:04.220: %OSPF-5-ADJCHG: Process 2019, Nbr 35.1.1.1 on GigabitEthernet0/0 from LOADING to FULL, Loading Done

  vIOS4#sho ip route ospf | b bn
  35.0.0.0/30 is subnetted, 1 subnets
  O IA 35.1.1.0 [110/3] via 14.1.1.1, 00:14:48, GigabitEthernet0/0
  55.0.0.0/32 is subnetted, 1 subnets
  O IA 55.1.1.1 [110/4] via 14.1.1.1, 00:01:18, GigabitEthernet0/0

6.9 配置OSPFv2 sham-link

6.9.1 Config loopback 1 and propaganda into BGP VRF address-family IPv4

• CSR1

  interface Loopback1
  vrf forwarding ospf
  ipv4 address 11.1.1.2 255.255.255.255
  router bgp 64512
  address-family ipv4 vrf AAA
  network 11.1.1.2 mask 255.255.255.255

• xrv

  interface Loopback1
  vrf AAA
  ipv4 address 33.1.1.2 255.255.255.255
  router bgp 64512
  vrf AAA
  address-family ipv4 unicast
  network 33.1.1.2/32

6.9.2 Under OSPFv2 process config sham-link

• CSR1

  router ospf 14 vrf AAA
  area 0 sham-link 11.1.1.2 33.1.1.2 cost 200

• xrv

  router ospf 35
  vrf AAA
  address-family ipv4 unicast
  area 0
  sham-link 33.1.1.2 11.1.1.2
  cost 200

6.10 验证sham-ink

CSR1(config-router)#area 0 sham-link 11.1.1.2 33.1.1.2 cost 200
CSR1(config-router)#do sho ip ospf neig
*May 22 08:45:02.593: %OSPF-5-ADJCHG: Process 14, Nbr 35.1.1.1 on OSPF_SL3 from LOADING to FULL, Loading Done
Neighbor ID Pri State Dead Time Address Interface
35.1.1.1 0 FULL/ - 00:00:37 33.1.1.2 OSPF_SL3
44.1.1.1 0 FULL/ - 00:00:34 14.1.1.2 GigabitEthernet2

CSR1#show ip route vrf AAA ospf | b bn
35.0.0.0/30 is subnetted, 1 subnets
O 35.1.1.0 [110/201] via 33.1.1.1, 01:04:13
44.0.0.0/32 is subnetted, 1 subnets
O 44.1.1.1 [110/2] via 14.1.1.2, 01:05:46, GigabitEthernet2
45.0.0.0/29 is subnetted, 1 subnets
O IA 45.1.1.0 [110/20001] via 14.1.1.2, 01:05:46, GigabitEthernet2
55.0.0.0/32 is subnetted, 1 subnets
O 55.1.1.1 [110/202] via 33.1.1.1, 01:04:13
vIOS4#sho ip route ospf | b bn
11.0.0.0/32 is subnetted, 1 subnets
O E1 11.1.1.2 [110/2] via 14.1.1.1, 01:06:20, GigabitEthernet0/0
33.0.0.0/32 is subnetted, 1 subnets
O E1 33.1.1.2 [110/2] via 14.1.1.1, 01:06:20, GigabitEthernet0/0
35.0.0.0/30 is subnetted, 1 subnets
O 35.1.1.0 [110/202] via 14.1.1.1, 01:04:42, GigabitEthernet0/0
55.0.0.0/32 is subnetted, 1 subnets
O 55.1.1.1 [110/203] via 14.1.1.1, 01:04:42, GigabitEthernet0/0

6.11 隐藏sham-link地址

• CSR1:

  ip prefix-list conn seq 5 permit 11.1.1.2/32
  ip prefix-list conn seq 10 permit 33.1.1.2/32
  route-map deny-conn deny 10
  match ip address prefix-list conn
  route-map deny-conn permit 20
  CSR1(config-router-af)#router ospf 14 vrf ospf
  CSR1(config-router)#redis bgp 64512 subnets route-map deny-conn

• xrv:

  prefix-set conn
  11.1.1.2/32,
  33.1.1.2/32
  end-set

  route-policy deny-conn
  if destination in conn then
  drop
  else
  pass
  endif
  end-policy

  RP/0/0/CPU0:xrv(config)#router ospf 35
  RP/0/0/CPU0:xrv(config-ospf)#vrf ospf
  RP/0/0/CPU0:xrv(config-ospf-vrf)#redist bgp 64512 route-policy deny-conn
  RP/0/0/CPU0:xrv(config-ospf-vrf)#commit

  SHO IP OSPF route # vIOS5 | B BN
  14.0.0.0/30 IS subnetted, the subnets. 1
  O 14.1.1.0 [110/202] Via 35.1.1.1, 00:07:05, the GigabitEthernet0 / 0
  44.0.0.0/32 IS subnetted, the subnets. 1
  O 44.1.1.1 [110/203] Via 35.1.1.1, 00:07:05, the GigabitEthernet0 / 0
  the CE device does not receive sham-link address