sham-link---是在ospf中创建的,所以建立双方的路由必须可达,因为其传递的是v4路由,所以双方建立的地址必须通告进ospf的v4路由中(opsf vrf a中)所以上面把环回接口先关联到vrf空间中,再宣告到bgp的v4中,因为有双向重发布,所以其路由会发布到ospf的v4中-----一定不能这样:关联到vrf空间后,直接宣告到ospf的v4中,***这样会出现问题,只能通过BGP的v4宣告
注:----环回地址配置为 24位,sham-link是down------自己测试
32 sham-link是up
http://blog.sina.com.cn/s/blog_3e15c5360101bovf.html
实验拓扑图
实验描述:如上图所示,现R2/R3/R4为MPLS 网络,两CE客户需要通过MPLS 骨干网络进行通信,并且CE-R1与CE-R5之间有一条链路作为备份链路,正常情况要,R4至R6的流量通过MPLS 网络走,当MPLS 网络存在故障时,通过R1与R5之间的互联链路走,下面配置OSPF Sham-Link实现上述要求。
1、首先配置MP-BGP,MPLS,VRF,PE与CE的OSPF路由协议
R2的配置:
R2#show run
Building configuration...
Current configuration : 2446 bytes
!
upgrade fpd auto
version 12.4
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname R2
!
boot-start-marker
boot-end-marker
!
logging message-counter syslog
!
no aaa new-model
ip source-route
no ip icmp rate-limit unreachable
ip cef
!
no ip domain lookup
ip vrf ccie
rd 1:1
route-target export 1:1
route-target import 1:1
!
no ipv6 cef
!
multilink bundle-name authenticated
mpls label range 100 199
!
memory-size iomem 0
archive
log config
hidekeys
!
ip tcp synwait-time 5
!
interface Loopback0
ip address 2.2.2.2 255.255.255.0
!
interface Loopback1
ip vrf forwarding ccie
ip address 100.1.1.1 255.255.255.255
ip ospf network point-to-point
!
interface FastEthernet0/0
ip vrf forwarding ccie
ip address 12.1.1.2 255.255.255.0
ip ospf 1 area 0
duplex auto
speed auto
!
interface FastEthernet0/1
ip address 23.1.1.1 255.255.255.0
duplex auto
speed auto
mpls ip
!
interface Serial1/0
no ip address
shutdown
serial restart-delay 0
!
interface Serial1/1
no ip address
shutdown
serial restart-delay 0
!
interface Serial1/2
no ip address
shutdown
serial restart-delay 0
!
interface Serial1/3
no ip address
shutdown
serial restart-delay 0
!
router eigrp 90
network 2.2.2.2 0.0.0.0
network 23.1.1.1 0.0.0.0
no auto-summary
!
router ospf 1 vrf ccie
router-id 92.2.2.2
log-adjacency-changes
area 0 sham-link 100.1.1.1 100.1.1.2
redistribute bgp 24 subnets
network 12.1.1.2 0.0.0.0 area 0
!
router bgp 24
bgp router-id 24.2.2.2
no bgp default ipv4-unicast
bgp log-neighbor-changes
neighbor 4.4.4.4 remote-as 24
neighbor 4.4.4.4 update-source Loopback0
!
address-family ipv4
neighbor 4.4.4.4 activate
no auto-summary
no synchronization
exit-address-family
!
address-family v4
neighbor 4.4.4.4 activate
neighbor 4.4.4.4 send-community both
exit-address-family
!
address-family ipv4 vrf ccie
redistribute ospf 1 vrf ccie
no synchronization
network 100.1.1.1 mask 255.255.255.255
exit-address-family
R3配置:
R3#show run
Building configuration...
Current configuration : 1543 bytes
!
upgrade fpd auto
version 12.4
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname R3
!
boot-start-marker
boot-end-marker
!
logging message-counter syslog
!
no aaa new-model
ip source-route
no ip icmp rate-limit unreachable
ip cef
!
no ip domain lookup
no ipv6 cef
!
multilink bundle-name authenticated
mpls label range 200 299
!
memory-size iomem 0
archive
log config
hidekeys
!
ip tcp synwait-time 5
!
interface Loopback0
ip address 3.3.3.3 255.255.255.0
!
interface FastEthernet0/0
ip address 23.1.1.2 255.255.255.0
duplex auto
speed auto
mpls ip
!
interface FastEthernet0/1
ip address 34.1.1.1 255.255.255.0
duplex auto
speed auto
mpls ip
!
interface Serial1/0
no ip address
shutdown
serial restart-delay 0
!
interface Serial1/1
no ip address
shutdown
serial restart-delay 0
!
interface Serial1/2
no ip address
shutdown
serial restart-delay 0
!
interface Serial1/3
no ip address
shutdown
serial restart-delay 0
!
router eigrp 90
network 3.3.3.3 0.0.0.0
network 23.1.1.2 0.0.0.0
network 34.1.1.1 0.0.0.0
no auto-summary
R4的配置:
R4#show run
Building configuration...
Current configuration : 2446 bytes
!
upgrade fpd auto
version 12.4
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname R4
!
boot-start-marker
boot-end-marker
!
logging message-counter syslog
!
no aaa new-model
ip source-route
no ip icmp rate-limit unreachable
ip cef
!
no ip domain lookup
ip vrf ccie
rd 1:1
route-target export 1:1
route-target import 1:1
!
no ipv6 cef
!
multilink bundle-name authenticated
mpls label range 300 399
!
memory-size iomem 0
archive
log config
hidekeys
!
ip tcp synwait-time 5
interface Loopback0
ip address 4.4.4.4 255.255.255.0
!
interface Loopback1
ip vrf forwarding ccie
ip address 100.1.1.2 255.255.255.255
ip ospf network point-to-point
!
interface FastEthernet0/0
ip address 34.1.1.2 255.255.255.0
duplex auto
speed auto
mpls ip
!
interface FastEthernet0/1
ip vrf forwarding ccie
ip address 45.1.1.1 255.255.255.0
ip ospf 1 area 0
duplex auto
speed auto
!
interface Serial1/0
no ip address
shutdown
serial restart-delay 0
!
interface Serial1/1
no ip address
shutdown
serial restart-delay 0
!
interface Serial1/2
no ip address
shutdown
serial restart-delay 0
!
interface Serial1/3
no ip address
shutdown
serial restart-delay 0
!
router eigrp 90
network 4.4.4.4 0.0.0.0
network 34.1.1.2 0.0.0.0
no auto-summary
!
router ospf 1 vrf ccie
router-id 94.4.4.4
log-adjacency-changes
area 0 sham-link 100.1.1.2 100.1.1.1
redistribute bgp 24 subnets
network 45.1.1.1 0.0.0.0 area 0
!
router bgp 24
bgp router-id 24.4.4.4
no bgp default ipv4-unicast
bgp log-neighbor-changes
neighbor 2.2.2.2 remote-as 24
neighbor 2.2.2.2 update-source Loopback0
!
address-family ipv4
neighbor 2.2.2.2 activate
no auto-summary
no synchronization
exit-address-family
!
address-family v4
neighbor 2.2.2.2 activate
neighbor 2.2.2.2 send-community both
exit-address-family
!
address-family ipv4 vrf ccie
redistribute ospf 1 vrf ccie
no synchronization
network 100.1.1.2 mask 255.255.255.255
exit-address-family
!
2、CE端路由情况分析
(1)CE配置
R1配置
R1#show run
Building configuration...
Current configuration : 1562 bytes
!
upgrade fpd auto
version 12.4
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname R1
!
boot-start-marker
boot-end-marker
!
logging message-counter syslog
!
no aaa new-model
ip source-route
no ip icmp rate-limit unreachable
ip cef
!
no ip domain lookup
no ipv6 cef
!
multilink bundle-name authenticated
!
memory-size iomem 0
archive
log config
hidekeys
!
ip tcp synwait-time 5
!
interface Loopback0
ip address 1.1.1.1 255.255.255.0
!
interface FastEthernet0/0
ip address 15.1.1.2 255.255.255.0
ip ospf cost 10
duplex auto
speed auto
!
interface FastEthernet0/1
ip address 12.1.1.1 255.255.255.0
duplex auto
speed auto
!
interface Serial1/0
no ip address
shutdown
serial restart-delay 0
!
interface Serial1/1
no ip address
shutdown
serial restart-delay 0
!
interface Serial1/2
no ip address
shutdown
serial restart-delay 0
!
interface Serial1/3
no ip address
shutdown
serial restart-delay 0
!
router ospf 1
router-id 91.1.1.1
log-adjacency-changes
network 1.1.1.1 0.0.0.0 area 0
network 12.1.1.1 0.0.0.0 area 0
network 15.1.1.2 0.0.0.0 area 0
!
R5配置
R5#show run
Building configuration...
Current configuration : 1562 bytes
!
upgrade fpd auto
version 12.4
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname R5
!
boot-start-marker
boot-end-marker
!
logging message-counter syslog
!
no aaa new-model
ip source-route
no ip icmp rate-limit unreachable
ip cef
!
no ip domain lookup
no ipv6 cef
!
multilink bundle-name authenticated
!
memory-size iomem 0
archive
log config
hidekeys
!
ip tcp synwait-time 5
!
interface Loopback0
ip address 5.5.5.5 255.255.255.0
!
interface FastEthernet0/0
ip address 45.1.1.2 255.255.255.0
duplex auto
speed auto
!
interface FastEthernet0/1
ip address 15.1.1.1 255.255.255.0
ip ospf cost 10
duplex auto
speed auto
!
interface Serial1/0
no ip address
shutdown
serial restart-delay 0
!
interface Serial1/1
no ip address
shutdown
serial restart-delay 0
!
interface Serial1/2
no ip address
shutdown
serial restart-delay 0
!
interface Serial1/3
no ip address
shutdown
serial restart-delay 0
!
router ospf 1
router-id 95.5.5.5
log-adjacency-changes
network 5.5.5.5 0.0.0.0 area 0
network 15.1.1.1 0.0.0.0 area 0
network 45.1.1.2 0.0.0.0 area 0
!
(3)查看CE端路由情况
R1#show ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route
Gateway of last resort is not set
1.0.0.0/24 is subnetted, 1 subnets
C 1.1.1.0 is directly connected, Loopback0
100.0.0.0/32 is subnetted, 2 subnets
O E2 100.1.1.1 [110/1] via 12.1.1.2, 00:09:52, FastEthernet0/1
O E2 100.1.1.2 [110/1] via 12.1.1.2, 00:08:22, FastEthernet0/1
5.0.0.0/32 is subnetted, 1 subnets
O 5.5.5.5 [110/4] via 12.1.1.2, 00:08:16, FastEthernet0/1
12.0.0.0/24 is subnetted, 1 subnets
C 12.1.1.0 is directly connected, FastEthernet0/1
45.0.0.0/24 is subnetted, 1 subnets
O 45.1.1.0 [110/3] via 12.1.1.2, 00:08:16, FastEthernet0/1
15.0.0.0/24 is subnetted, 1 subnets
C 15.1.1.0 is directly connected, FastEthernet0/0
从CE-R1看到5.5.5.5路由为区域内路由,是由于CE-R4与CE-R6之间互联的线路运行OSPF,并且在区域1中,而从MPLS 骨干网络中传过来的5.5.5.5路由为区域间路由;而OSPF的选路原则是区域内路由优于区域间路由;
在PE-R2上查看VPNV4路由,也可以看到5.5.5.5的路由,下一跳指向的是PE-R4,如下:
R2#show ip bgp v4 all
BGP table version is 21, local router ID is 24.2.2.2
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
Route Distinguisher: 1:1 (default for vrf ccie)
*> 1.1.1.1/32 12.1.1.1 2 32768 ?
r>i5.5.5.5/32 4.4.4.4 2 100 0 ?
*> 12.1.1.0/24 0.0.0.0 0 32768 ?
* i15.1.1.0/24 4.4.4.4 11 100 0 ?
*> 12.1.1.1 11 32768 ?
r>i45.1.1.0/24 4.4.4.4 0 100 0 ?
*> 100.1.1.1/32 0.0.0.0 0 32768 i
*>i100.1.1.2/32 4.4.4.4 0 100 0 i
R2#show ip route vrf ccie
Routing Table: ccie
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route
Gateway of last resort is not set
1.0.0.0/32 is subnetted, 1 subnets
O 1.1.1.1 [110/2] via 12.1.1.1, 00:14:42, FastEthernet0/0
100.0.0.0/32 is subnetted, 2 subnets
C 100.1.1.1 is directly connected, Loopback1
B 100.1.1.2 [200/0] via 4.4.4.4, 00:13:12
5.0.0.0/32 is subnetted, 1 subnets
O 5.5.5.5 [110/3] via 4.4.4.4, 00:13:06
12.0.0.0/24 is subnetted, 1 subnets
C 12.1.1.0 is directly connected, FastEthernet0/0
45.0.0.0/24 is subnetted, 1 subnets
O 45.1.1.0 [110/2] via 4.4.4.4, 00:13:06
15.0.0.0/24 is subnetted, 1 subnets
O 15.1.1.0 [110/11] via 12.1.1.1, 00:14:34, FastEthernet0/0
当将CE-R1与CE-R5互联的线路shutdown后,查看R4的路由如下:
R1(config)#int fa0/0
R1(config-if)#shutdown
R1#show ip route
1.0.0.0/24 is subnetted, 1 subnets
C 1.1.1.0 is directly connected, Loopback0
100.0.0.0/32 is subnetted, 2 subnets
O E2 100.1.1.1 [110/1] via 12.1.1.2, 00:00:04, FastEthernet0/1
O E2 100.1.1.2 [110/1] via 12.1.1.2, 00:00:04, FastEthernet0/1
5.0.0.0/32 is subnetted, 1 subnets
O 5.5.5.5 [110/4] via 12.1.1.2, 00:00:04, FastEthernet0/1
12.0.0.0/24 is subnetted, 1 subnets
C 12.1.1.0 is directly connected, FastEthernet0/1
45.0.0.0/24 is subnetted, 1 subnets
O 45.1.1.0 [110/3] via 12.1.1.2, 00:00:04, FastEthernet0/1
15.0.0.0/24 is subnetted, 1 subnets
O 15.1.1.0 [110/13] via 12.1.1.2, 00:00:04, FastEthernet0/1
现在看到的路由是区域间路由,是PE-R2传过来的,为实现网络的可靠性,正常情况下,R1与R5之间的链路是备份线路,平时数据通过MPLS 传递,为实现上述R4路由输出情况,现在在PE路由器之间配置Sham-Link实现两CE端日常数据通过MPLS 网络传递,当MPLS 网络出现故障时,数据流量切换至R4与R6的互联线路,以便不影响两CE端的互访。
3、Sham-Link配置
部署:
1.在PE端创建接口,划入VRF中
R2#show run interface loopback 1
Building configuration...
Current configuration : 121 bytes
!
interface Loopback1
ip vrf forwarding ccie
ip address 100.1.1.1 255.255.255.255
ip ospf network point-to-point
end
2.将接口路由通告进入MP-BGP VRF中
R2#show run | s router bgp
router bgp 24
bgp router-id 24.2.2.2
no bgp default ipv4-unicast
bgp log-neighbor-changes
neighbor 4.4.4.4 remote-as 24
neighbor 4.4.4.4 update-source Loopback0
!
address-family ipv4
neighbor 4.4.4.4 activate
no auto-summary
no synchronization
exit-address-family
!
address-family v4
neighbor 4.4.4.4 activate
neighbor 4.4.4.4 send-community both
exit-address-family
!
address-family ipv4 vrf ccie
redistribute ospf 1 vrf ccie
no synchronization
network 100.1.1.1 mask 255.255.255.255
exit-address-family
3.在PE两端启用sham-link 通告进入0区域
R2#show run | s router os
router ospf 1 vrf ccie
router-id 92.2.2.2
log-adjacency-changes
area 0 sham-link 100.1.1.1 100.1.1.2
redistribute bgp 24 subnets
network 12.1.1.2 0.0.0.0 area 0
查看sham-link建立的OSPF邻
查看其邻居是否建立成功,可用show ip ospf neighbor或者show ip ospf sham-link
R2#show ip ospf neighbor
Neighbor ID Pri State Dead Time Address Interface
94.4.4.4 0 FULL/ - - 100.1.1.2 OSPF_SL0
91.1.1.1 1 FULL/BDR 00:00:35 12.1.1.1 FastEthernet0/0
R2#show ip ospf sham-links
Sham Link OSPF_SL0 to address 100.1.1.2 is up
Area 0 source address 100.1.1.1
Run as demand circuit
DoNotAge LSA allowed. Cost of using 1 State POINT_TO_POINT,
Timer intervals configured, Hello 10, Dead 40, Wait 40,
Hello due in 00:00:08
Adjacency State FULL (Hello suppressed)
Index 2/2, retransmission queue length 0, number of retransmission 0
First 0x0(0)/0x0(0) Next 0x0(0)/0x0(0)
Last retransmission scan length is 0, maximum is 0
Last retransmission scan time is 0 msec, maximum is 0 msec
4、Sham-link配置分析及结果分析
R1#show ip route 5.5.5.5
Routing entry for 5.5.5.5/32
Known via "ospf 1", distance 110, metric 4, type intra area
Last update from 12.1.1.2 on FastEthernet0/1, 00:02:12 ago
Routing Descriptor Blocks:
* 12.1.1.2, from 95.5.5.5, 00:02:12 ago, via FastEthernet0/1
Route metric is 4, traffic share count is 1
查看R2上的bgp v4 5.5.5.5的路由情况
R2#show ip bgp v4 all 5.5.5.5
BGP routing table entry for 1:1:5.5.5.5/32, version 20
Paths: (1 available, best #1, table ccie, RIB-failure(17))
Not advertised to any peer
Local
4.4.4.4 (metric 158720) from 4.4.4.4 (24.4.4.4)
Origin incomplete, metric 2, localpref 100, valid, internal, best
Extended Community: RT:1:1 OSPF DOMAIN ID:0x0005:0x000000010200
OSPF RT:0.0.0.0:2:0 OSPF ROUTER ID:94.4.4.4:0
mpls labels in/out nolabel/304
从上述路由输出分析可知,R1直接传给R5(之间互联线路)的5.5.5.5的路由,其OSPF开销值为4;而从MPLS 网络经PE-R2传至PE-R4的5.5.5.5路由的开销值为2。
要想实现两CE端互访通过MPLS 网络,可以修改COST值来实现,现修改R4与R6互联接口的ospf cost值;
R1(config)#int fa0/1
R41config-if)#ip ospf cost 10 将其cost值设置大于通过MPLS 的cost值
R5(config)#int fa0/1
R5(config-if)#ip ospf cost 10
现在R4上查看路由表情况
R1#show ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route
Gateway of last resort is not set
1.0.0.0/24 is subnetted, 1 subnets
C 1.1.1.0 is directly connected, Loopback0
100.0.0.0/32 is subnetted, 2 subnets
O E2 100.1.1.1 [110/1] via 12.1.1.2, 00:05:18, FastEthernet0/1
O E2 100.1.1.2 [110/1] via 12.1.1.2, 00:05:18, FastEthernet0/1
5.0.0.0/32 is subnetted, 1 subnets
O 5.5.5.5 [110/4] via 12.1.1.2, 00:05:18, FastEthernet0/1
12.0.0.0/24 is subnetted, 1 subnets
C 12.1.1.0 is directly connected, FastEthernet0/1
45.0.0.0/24 is subnetted, 1 subnets
O 45.1.1.0 [110/3] via 12.1.1.2, 00:05:18, FastEthernet0/1
15.0.0.0/24 is subnetted, 1 subnets
C 15.1.1.0 is directly connected, FastEthernet0/0
测试:
R5#traceroute
Protocol [ip]:
Target IP address: 1.1.1.1
Source address: 5.5.5.5
Numeric display [n]:
Timeout in seconds [3]:
Probe count [3]:
Minimum Time to Live [1]:
Maximum Time to Live [30]:
Port Number [33434]:
Loose, Strict, Record, Timestamp, Verbose[none]:
Type escape sequence to abort.
Tracing the route to 1.1.1.1
1 45.1.1.1 48 msec 20 msec 20 msec
2 34.1.1.1 [MPLS: Labels 200/107 Exp 0] 84 msec 84 msec 80 msec
3 12.1.1.2 [MPLS: Label 107 Exp 0] 56 msec 52 msec 64 msec
4 12.1.1.1 96 msec 80 msec 84 msec
//107为MP-BGP分配的内层标签
5、总结
配置sham-link时要根据CE端备份链路所在区域来配置所属区域,如果配置其它区域,该PE发布的至CE端路由将会变成区域间路由,优先级低于区域内路由,因此需要将sham-link配置与备份链路所属区域在同一区域中。如果两CE端没有备份链路,也就不需要配置sham-link链路了。
在调整CE端的选路时,需要根据sham-link配置的COST值及备份链路的接口cost值来完成。