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组网需求

如图1所示：

• 路由器PE1、P1、P2和PE2属于同一自治系统，要求它们之间通过IS-IS协议达到IPv6网络互连的目的。

• PE1、P1、P2和PE2属于IS-IS进程1，都是Level-2设备。

要求在PE1和PE2之间建立双向SRv6 BE路径，承载L3VPNv4业务。同时为了充分利用网络资源，要求PE1和PE2之间SRv6 BE承载的L3VPNv4业务可以进行等值负载分担（ECMP）。

图1 配置L3VPNv4 over SRv6 BE ECMP组网图

配置思路

1. 使能PE1、P1、P2和PE2各接口的IPv6转发能力，配置各接口的IPv6地址。

2. 在PE1、P1、P2和PE2上使能IS-IS，配置Level级别，指定网络实体。同时配置动态BFD for IPv6 IS-IS。

3. 在PE1和PE2上配置VPN实例。

4. 在PE和CE之间建立EBGP对等体关系。

5. 在PE之间建立MP-IBGP对等体关系。

6. 在PE1和PE2上配置SRv6。配置IS-IS的SRv6能力。

操作步骤

1. 使能各接口的IPv6转发能力，配置IPv6地址，以PE1为例，其他路由器的配置过程相同，不再赘述

<HUAWEI> system-view
[~HUAWEI] sysname PE1
[*HUAWEI] commit
[~PE1] interface gigabitethernet 1/0/0
[~PE1-GigabitEthernet1/0/0] ipv6 enable
[*PE1-GigabitEthernet1/0/0] ipv6 address 2001:db8:1::1 96
[*PE1-GigabitEthernet1/0/0] quit
[*PE1] interface gigabitethernet 2/0/0
[*PE1-GigabitEthernet2/0/0] ipv6 enable
[*PE1-GigabitEthernet2/0/0] ipv6 address 2001:db8:3::1 96
[*PE1-GigabitEthernet2/0/0] quit
[*PE1] interface LoopBack 1
[*PE1-LoopBack1] ipv6 enable
[*PE1-LoopBack1] ipv6 address 1::1 128
[*PE1-LoopBack1] quit
[*PE1] commit

2. 配置IS-IS

配置IS-IS时，同时使能动态BFD功能，提高链路状态变化时IS-IS的收敛速度。

# 配置PE1。

[~PE1] bfd
[*PE1-bfd] quit
[*PE1] isis 1
[*PE1-isis-1] is-level level-2
[*PE1-isis-1] cost-style wide
[*PE1-isis-1] network-entity 10.0000.0000.0001.00
[*PE1-isis-1] ipv6 enable topology ipv6
[*PE1-isis-1] ipv6 bfd all-interfaces enable
[*PE1-isis-1] quit
[*PE1] interface gigabitethernet 1/0/0
[*PE1-GigabitEthernet1/0/0] isis ipv6 enable 1
[*PE1-GigabitEthernet1/0/0] quit
[*PE1] interface gigabitethernet 2/0/0
[*PE1-GigabitEthernet2/0/0] isis ipv6 enable 1
[*PE1-GigabitEthernet2/0/0] quit
[*PE1] interface loopback1
[*PE1-LoopBack1] isis ipv6 enable 1
[*PE1-LoopBack1] commit
[~PE1-LoopBack1] quit

# 配置P1。

[~P1] bfd
[*P1-bfd] quit
[*P1] isis 1 
[*P1-isis-1] is-level level-2
[*P1-isis-1] cost-style wide
[*P1-isis-1] network-entity 10.0000.0000.0002.00
[*P1-isis-1] ipv6 enable topology ipv6
[*P1-isis-1] ipv6 bfd all-interfaces enable
[*P1-isis-1] quit
[*P1] interface gigabitethernet 1/0/0
[*P1-GigabitEthernet1/0/0] isis ipv6 enable 1
[*P1-GigabitEthernet1/0/0] quit
[*P1] interface gigabitethernet 2/0/0
[*P1-GigabitEthernet2/0/0] isis ipv6 enable 1
[*P1-GigabitEthernet2/0/0] quit
[*P1] interface loopback1
[*P1-LoopBack1] isis ipv6 enable 1
[*P1-LoopBack1] commit
[~P1-LoopBack1] quit

# 配置P2。

[~P2] bfd
[*P2-bfd] quit
[*P2] isis 1 
[*P2-isis-1] is-level level-2
[*P2-isis-1] cost-style wide
[*P2-isis-1] network-entity 10.0000.0000.0004.00
[*P2-isis-1] ipv6 enable topology ipv6
[*P2-isis-1] ipv6 bfd all-interfaces enable
[*P2-isis-1] quit
[*P2] interface gigabitethernet 1/0/0
[*P2-GigabitEthernet1/0/0] isis ipv6 enable 1
[*P2-GigabitEthernet1/0/0] quit
[*P2] interface gigabitethernet 2/0/0
[*P2-GigabitEthernet2/0/0] isis ipv6 enable 1
[*P2-GigabitEthernet2/0/0] quit
[*P2] interface loopback1
[*P2-LoopBack1] isis ipv6 enable 1
[*P2-LoopBack1] commit
[~P2-LoopBack1] quit

# 配置PE2。

[~PE2] bfd
[*PE2-bfd] quit
[*PE2] isis 1
[*PE2-isis-1] is-level level-2
[*PE2-isis-1] cost-style wide
[*PE2-isis-1] network-entity 10.0000.0000.0003.00
[*PE2-isis-1] ipv6 enable topology ipv6
[*PE2-isis-1] ipv6 bfd all-interfaces enable
[*PE2-isis-1] quit
[*PE2] interface gigabitethernet 1/0/0
[*PE2-GigabitEthernet1/0/0] isis ipv6 enable 1
[*PE2-GigabitEthernet1/0/0] quit
[*PE2] interface gigabitethernet 2/0/0
[*PE2-GigabitEthernet2/0/0] isis ipv6 enable 1
[*PE2-GigabitEthernet2/0/0] quit
[*PE2] interface loopback1
[*PE2-LoopBack1] isis ipv6 enable 1
[*PE2-LoopBack1] commit
[~PE2-LoopBack1] quit

配置完成后，可按如下指导检查IS-IS是否配置成功。

# 显示IS-IS邻居信息。以PE1为例。

[~PE1] display isis peer

                          Peer information for ISIS(1)

  System Id     Interface          Circuit Id        State HoldTime Type     PRI
--------------------------------------------------------------------------------
0000.0000.0004* GE2/0/0            0000.0000.0004.02  Up   7s       L2       64 
0000.0000.0002* GE1/0/0            0000.0000.0002.02  Up   9s       L2       64 

Total Peer(s): 2

# 显示IS-IS路由表信息。以PE1为例。

[~PE1] display isis route
                         Route information for ISIS(1)
                         -----------------------------

                        ISIS(1) Level-2 Forwarding Table
                        --------------------------------

 IPV6 Dest.     ExitInterface      NextHop                    Cost     Flags    
--------------------------------------------------------------------------------
1::/128         Loop1              Direct                     0        D/-/L/-  
2::/128         GE1/0/0            FE80::3A92:6CFF:FE31:307   10       A/-/-/-  
3::/128         GE1/0/0            FE80::3A92:6CFF:FE31:307   20       A/-/-/-  
                GE2/0/0            FE80::3A92:6CFF:FE41:305                     
4::/128         GE2/0/0            FE80::3A92:6CFF:FE41:305   10       A/-/-/-  
2001:DB8:1::/96 GE1/0/0            Direct                     10       D/-/L/-  
2001:DB8:2::/96 GE1/0/0            FE80::3A92:6CFF:FE31:307   20       A/-/-/-  
2001:DB8:3::/96 GE2/0/0            Direct                     10       D/-/L/-  
2001:DB8:4::/96 GE2/0/0            FE80::3A92:6CFF:FE41:305   20       A/-/-/-  
     Flags: D-Direct, A-Added to URT, L-Advertised in LSPs, S-IGP Shortcut, 
            U-Up/Down Bit Set, LP-Local Prefix-Sid
     Protect Type: L-Link Protect, N-Node Protect

3. 在PE设备上配置使能IPv4地址族的VPN实例，将CE接入PE

# 配置PE1。

[~PE1] ip vpn-instance vpna
[*PE1-vpn-instance-vpna] ipv4-family
[*PE1-vpn-instance-vpna-af-ipv4] route-distinguisher 100:1
[*PE1-vpn-instance-vpna-af-ipv4] vpn-target 111:1 both
[*PE1-vpn-instance-vpna-af-ipv4] quit
[*PE1-vpn-instance-vpna] quit
[*PE1] interface gigabitethernet 3/0/0 
[*PE1-GigabitEthernet3/0/0] ip binding vpn-instance vpna
[*PE1-GigabitEthernet3/0/0] ip address 10.1.1.1 24
[*PE1-GigabitEthernet3/0/0] quit
[*PE1] commit

# 配置PE2。

[~PE2] ip vpn-instance vpna
[*PE2-vpn-instance-vpna] ipv4-family
[*PE2-vpn-instance-vpna-af-ipv4] route-distinguisher 200:1
[*PE2-vpn-instance-vpna-af-ipv4] vpn-target 111:1 both
[*PE2-vpn-instance-vpna-af-ipv4] quit
[*PE2-vpn-instance-vpna] quit
[*PE2] interface gigabitethernet 3/0/0
[*PE2-GigabitEthernet3/0/0] ip binding vpn-instance vpna
[*PE2-GigabitEthernet3/0/0] ip address 10.2.1.1 24
[*PE2-GigabitEthernet3/0/0] quit
[*PE2] commit

# 按图1配置各CE的接口IP地址，配置过程请参见后面的配置文件。

配置完成后，在PE设备上执行display ip vpn-instance verbose命令可以看到VPN实例的配置情况。各PE能ping通自己接入的CE。

4. 在PE与CE之间建立EBGP对等体关系

# 配置CE1。

[~CE1] interface loopback 1
[*CE1-LoopBack1] ip address 11.11.11.11 32
[*CE1-LoopBack1] quit
[*CE1] bgp 65410
[*CE1-bgp] peer 10.1.1.1 as-number 100
[*CE1-bgp] network 11.11.11.11 32
[*CE1-bgp] quit
[*CE1] commit

# 配置PE1。

[~PE1] bgp 100
[*PE1-bgp] router-id 1.1.1.1
[*PE1-bgp] ipv4-family vpn-instance vpna
[*PE1-bgp-vpna] peer 10.1.1.2 as-number 65410
[*PE1-bgp-vpna] import-route direct
[*PE1-bgp-vpna] commit
[~PE1-bgp-vpna] quit
[~PE1-bgp] quit

# 配置CE2。

[~CE2] interface loopback 1
[*CE2-LoopBack1] ip address 22.22.22.22 32
[*CE2-LoopBack1] quit
[*CE2] bgp 65420
[*CE2-bgp] peer 10.2.1.1 as-number 100
[*CE2-bgp] network 22.22.22.22 32
[*CE2-bgp] quit
[*CE2] commit

# 配置PE2。

[~PE2] bgp 100
[*PE2-bgp] router-id 2.2.2.2
[*PE2-bgp] ipv4-family vpn-instance vpna
[*PE2-bgp-vpna] peer 10.2.1.2 as-number 65420
[*PE2-bgp-vpna] import-route direct
[*PE2-bgp-vpna] commit
[~PE2-bgp-vpna] quit
[~PE2-bgp] quit

配置完成后，在PE设备上执行display bgp vpnv4 vpn-instance peer命令，可以看到PE与CE之间的BGP对等体关系已建立，并达到Established状态。

以PE1与CE1的对等体关系为例：

[~PE1] display bgp vpnv4 vpn-instance vpna peer
 BGP local router ID : 1.1.1.1
 Local AS number : 100

 VPN-Instance vpna, Router ID 1.1.1.1:
 Total number of peers : 1            Peers in established state : 1

  Peer            V    AS  MsgRcvd  MsgSent    OutQ  Up/Down    State        PrefRcv
  10.1.1.2        4   65410  11     9          0     00:06:37   Established  1

5. 在PE之间建立MP-IBGP对等体关系

# 配置PE1。

[~PE1] bgp 100
[~PE1-bgp] peer 3::3 as-number 100
[*PE1-bgp] peer 3::3 connect-interface loopback 1
[*PE1-bgp] ipv4-family vpnv4
[*PE1-bgp-af-vpnv4] peer 3::3 enable
[*PE1-bgp-af-vpnv4] commit
[~PE1-bgp-af-vpnv4] quit
[~PE1-bgp] quit

# 配置PE2。

[~PE2] bgp 100
[~PE2-bgp] peer 1::1 as-number 100
[*PE2-bgp] peer 1::1 connect-interface loopback 1
[*PE2-bgp] ipv4-family vpnv4
[*PE2-bgp-af-vpnv4] peer 1::1 enable
[*PE2-bgp-af-vpnv4] commit
[~PE2-bgp-af-vpnv4] quit
[~PE2-bgp] quit

配置完成后，在PE设备上执行display bgp vpnv4 all peer命令，可以看到PE之间的BGP对等体关系已建立，并达到Established状态。

6. 在PE之间建立SRv6 BE路径

# 配置PE1。

[~PE1] segment-routing ipv6
[*PE1-segment-routing-ipv6] encapsulation source-address 1::1
[*PE1-segment-routing-ipv6] locator as1 ipv6-prefix 10:: 64 static 32
[*PE1-segment-routing-ipv6-locator] quit
[*PE1-segment-routing-ipv6] quit
[*PE1] bgp 100
[*PE1-bgp] ipv4-family vpnv4
[*PE1-bgp-af-vpnv4] peer 3::3 prefix-sid
[*PE1-bgp-af-vpnv4] quit
[*PE1-bgp] ipv4-family vpn-instance vpna
[*PE1-bgp-vpna] segment-routing ipv6 best-effort
[*PE1-bgp-vpna] segment-routing ipv6 locator as1
[*PE1-bgp-vpna] commit
[~PE1-bgp-vpna] quit
[~PE1-bgp] quit
[~PE1] isis 1
[~PE1-isis-1] segment-routing ipv6 locator as1
[*PE1-isis-1] commit
[~PE1-isis-1] quit

# 配置PE2。

[~PE2] segment-routing ipv6
[*PE2-segment-routing-ipv6] encapsulation source-address 3::3
[*PE2-segment-routing-ipv6] locator as1 ipv6-prefix 30:: 64 static 32
[*PE2-segment-routing-ipv6-locator] quit
[*PE2-segment-routing-ipv6] quit
[*PE2] bgp 100
[*PE2-bgp] ipv4-family vpnv4
[*PE2-bgp-af-vpnv4] peer 1::1 prefix-sid
[*PE2-bgp-af-vpnv4] quit
[*PE2-bgp] ipv4-family vpn-instance vpna
[*PE2-bgp-vpna] segment-routing ipv6 best-effort
[*PE2-bgp-vpna] segment-routing ipv6 locator as1
[*PE2-bgp-vpna] commit
[~PE2-bgp-vpna] quit
[~PE2-bgp] quit
[~PE2] isis 1
[~PE2-isis-1] segment-routing ipv6 locator as1
[*PE2-isis-1] commit
[~PE2-isis-1] quit

7. 检查配置结果

执行命令display ip routing-table vpn-instance vpna ip-address verbose查看VPN路由信息。以PE1的显示为例：

[~PE1] display ip routing-table vpn-instance vpna 22.22.22.22 32 verbose 
Route Flags: R - relay, D - download to fib, T - to vpn-instance, B - black hole route          
------------------------------------------------------------------------------  
Routing Table : vpna        
Summary Count : 1           

Destination: 22.22.22.22/32 
     Protocol: IBGP               Process ID: 0 
   Preference: 255                      Cost: 0 
      NextHop: 30::1:0:20          Neighbour: 3::3 
        State: Active Adv Relied         Age: 00h00m23s 
          Tag: 0                    Priority: low     
        Label: 3                     QoSInfo: 0x0       
   IndirectID: 0x10000C7            Instance:             
 RelayNextHop: 30::1:0:20          Interface: SRv6 BE     
     TunnelID: 0x0                     Flags: RD

从以上显示信息可以看出，VPN路由22.22.22.22/32迭代到SRv6 BE路径。

以路由下一跳30::1:0:20为目的地址查看IPv6路由的详细信息。

[~PE1] display ipv6 routing-table 30::1:0:20 verbose  
Route Flags: R - relay, D - download to fib, T - to vpn-instance, B - black hole route 
------------------------------------------------------------------------------  
Routing Table : _public_    
Summary Count : 2           

Destination  : 30::                                    PrefixLength : 64        
NextHop      : FE80::3A92:6CFF:FE31:307                Preference   : 15        
Neighbour    : ::                                      ProcessID    : 1         
Label        : NULL                                    Protocol     : ISIS-L2   
State        : Active Adv                              Cost         : 20        
Entry ID     : 0                                       EntryFlags   : 0x00000000
Reference Cnt: 0                                       Tag          : 0         
Priority     : medium                                  Age          : 132sec    
IndirectID   : 0x1000085                               Instance     :           
RelayNextHop : ::                                      TunnelID     : 0x0       
Interface    : GigabitEthernet1/0/0                    Flags        : D         

Destination  : 30::                                    PrefixLength : 64        
NextHop      : FE80::3A92:6CFF:FE41:305                Preference   : 15        
Neighbour    : ::                                      ProcessID    : 1         
Label        : NULL                                    Protocol     : ISIS-L2   
State        : Active Adv                              Cost         : 20        
Entry ID     : 0                                       EntryFlags   : 0x00000000
Reference Cnt: 0                                       Tag          : 0         
Priority     : medium                                  Age          : 132sec    
IndirectID   : 0x1000087                               Instance     :           
RelayNextHop : ::                                      TunnelID     : 0x0       
Interface    : GigabitEthernet2/0/0                    Flags        : D

从以上显示信息可以看出，路由30::1:0:20具有两个出接口，转发时将形成ECMP。

同一VPN的CE能够相互Ping通，例如：

[~CE1] ping -a 11.11.11.11 22.22.22.22
  PING 22.22.22.22: 56  data bytes, press CTRL_C to break
    Reply from 22.22.22.22: bytes=56 Sequence=1 ttl=253 time=7 ms
    Reply from 22.22.22.22: bytes=56 Sequence=2 ttl=253 time=5 ms
    Reply from 22.22.22.22: bytes=56 Sequence=3 ttl=253 time=4 ms
    Reply from 22.22.22.22: bytes=56 Sequence=4 ttl=253 time=5 ms
    Reply from 22.22.22.22: bytes=56 Sequence=5 ttl=253 time=5 ms

  --- 22.22.22.22 ping statistics ---
    5 packet(s) transmitted
    5 packet(s) received
    0.00% packet loss
    round-trip min/avg/max = 4/5/7 ms