採用VRF的GRE通道組態範例

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已更新: 2006 年 1 月 16 日
文件 ID:46252

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關於此翻譯

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簡介

本檔案將提供在通用路由封裝(GRE)通道介面下的VPN路由和轉送(VRF)例項的範例組態。

必要條件

需求

嘗試此組態之前，請確保符合以下要求：

本文檔的讀者應瞭解以下主題：

採用元件

本檔案中的資訊是根據3725系列路由器上的Cisco IOS®軟體版本12.3(4)T1。

使用Cisco Feature Navigator II(僅供註冊客戶使用)並搜尋GRE通道IP來源和目的地VRF成員資格功能，以獲得所需的其他軟體和硬體要求。

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。如果您的網路正在作用，請確保您已瞭解任何指令可能造成的影響。

慣例

如需文件慣例的詳細資訊，請參閱思科技術提示慣例。

設定

本節提供用於設定本文件中所述功能的資訊。

配置按以下方式設定：

  • R1-CE和R2-CE位於VRF BLUE中。

  • R1-CE也位於VRF GREEN中（通過使用通往R3-PE的GRE隧道）。

R1-CE使用靜態主機路由到達R3-PE（隧道目標），這可確保GRE隧道不會發生遞迴路由（通過隧道學習隧道目標地址）。

VRF BLUE和VRF GREEN由兩個不同的公司擁有，它們之間不會發生路由洩漏。此外，R1-CE和R2-CE之間的介面上的訪問控制清單(ACL)只能用於允許它們之間的GRE流量。

注意：要查詢有關本文檔中使用的命令的其他資訊，請使用命令查詢工具(僅限註冊客戶)。

網路圖表

本檔案會使用以下網路設定：

圖1 — 物理拓撲

grewithvrf_01.gif

圖2 — 邏輯VRF拓撲

grewithvrf_02.gif

組態

本檔案會使用以下設定：

R3-PE（隧道端點） 
R3-PE# show running-config

Building configuration...
.
!
no ip domain lookup
!
ip vrf blue
 rd 1:1
 route-target export 311:311
 route-target import 411:411
!
ip vrf green
 rd 2:2
 route-target export 322:322
 route-target import 422:422
!
ip cef
!
interface Tunnel0
 ip vrf forwarding green
 ip address 200.200.200.3 255.255.255.0
 tunnel source Ethernet0/0
 tunnel destination 10.10.10.1
 tunnel vrf blue

!--- Tunnel 0 is part of VRF GREEN; but it uses the tunnel !--- destination and source addresses from the routing !--- table of VRF BLUE, because of this tunnel vrf blue !--- command.

!
interface Ethernet0/0
 ip vrf forwarding blue
 ip address 20.20.20.3 255.255.255.0

!--- Connection to the VRF BLUE network and the VRF GREEN !--- network using the GRE tunnel.

!
interface Ethernet1/0
 ip address 30.30.30.3 255.255.255.0
 tag-switching ip
!
router bgp 1
 no bgp default ipv4-unicast
 bgp log-neighbor-changes
 neighbor 30.30.30.4 remote-as 1
 !
 address-family vpnv4
 neighbor 30.30.30.4 activate
 neighbor 30.30.30.4 send-community extended
 exit-address-family
 !
 address-family ipv4 vrf green
 redistribute connected
 no auto-summary
 no synchronization
 exit-address-family
 !
 address-family ipv4 vrf blue
 redistribute connected
 no auto-summary
 no synchronization
 exit-address-family
!
ip classless
ip route vrf blue 10.10.10.1 255.255.255.255 20.20.20.2

!--- Static Host route to ensure that recursive routing !--- does not occur.
 
no ip http server
!
.
end

R4-PE 
R4-PE# show running-config

Building configuration...
.
.
.
no ip domain lookup
!
ip vrf blue
 rd 1:1
 route-target export 411:411
 route-target import 311:311
!
ip vrf green
 rd 2:2
 route-target export 422:422
 route-target import 322:322
!
ip cef
!
interface Ethernet0/0
 ip address 30.30.30.4 255.255.255.0
 tag-switching ip
!
interface Ethernet1/0
 ip vrf forwarding green
 ip address 100.100.100.4 255.255.255.0
!
interface Ethernet2/0
 ip vrf forwarding blue
 ip address 40.40.40.4 255.255.255.0
!
router bgp 1
 no bgp default ipv4-unicast
 bgp log-neighbor-changes
 neighbor 30.30.30.3 remote-as 1
 !
 address-family vpnv4
 neighbor 30.30.30.3 activate
 neighbor 30.30.30.3 send-community extended
 exit-address-family
 !
 address-family ipv4 vrf green
 redistribute connected
 no auto-summary
 no synchronization
 exit-address-family
 !
 address-family ipv4 vrf blue
 redistribute connected
 no auto-summary
 no synchronization
 exit-address-family
!
ip classless
.
.
end

R1-CE（隧道端點） 
R1-CE# show running-config 
Building configuration...
.
.
no ip domain lookup

!
ip cef
!         
interface Tunnel0
 ip address 200.200.200.1 255.255.255.0
 tunnel source Ethernet0/0
 tunnel destination 20.20.20.3

!--- Both the tunnel source and destination address are in !--- the VRF BLUE, to provide transport for the VRF GREEN !--- network.

!
interface Ethernet0/0
 description Connection to R2-CE router
 ip address 10.10.10.1 255.255.255.0
 ip access-group 100 in
 ip access-group 100 out

!--- Access-group to allow only GRE packets through the !--- R2-CE network. However, R1-CE networks data is in the !--- GRE packet.

!
!
ip classless
ip route 0.0.0.0 0.0.0.0 Tunnel0
ip route 20.20.20.3 255.255.255.255 10.10.10.2

!--- Static Host route to ensure that recursive routing !--- does not occur.

no ip http server
!
access-list 100 permit gre host 10.10.10.1 host 20.20.20.3
access-list 100 permit gre host 20.20.20.3 host 10.10.10.1

!--- Permits only GRE packets between the endpoints.

!         
.
.
end

R2-CE 
R2-CE# show running-config

Building configuration...
.
.
no ip domain lookup

!
ip cef
!
interface Ethernet0/0
 description Connection to R1-CE router
 ip address 10.10.10.2 255.255.255.0
 ip access-group 100 in
 ip access-group 100 out
!
interface Ethernet1/0
 ip address 20.20.20.2 255.255.255.0
!
ip classless
ip route 0.0.0.0 0.0.0.0 20.20.20.3
no ip http server
!
access-list 100 permit gre host 10.10.10.1 host 20.20.20.3
access-list 100 permit gre host 20.20.20.3 host 10.10.10.1

!--- Permits only GRE packets between the endpoints.

.
!
end

R5-CE 
R5-CE# show running-config

Building configuration...
.
.
no ip domain lookup

!
interface Ethernet0/0
 ip address 100.100.100.5 255.255.255.0
!
!
ip classless
ip route 0.0.0.0 0.0.0.0 100.100.100.4
no ip http server
!
.
end

R6-CE 
R6-CE# show running-config

Building configuration...
.
.
no ip domain lookup

!
interface Ethernet0/0
 ip address 40.40.40.6 255.255.255.0
!
!
ip classless
ip route 0.0.0.0 0.0.0.0 40.40.40.4
no ip http server
!
.
end

驗證

本節提供的資訊可用於確認您的組態是否正常運作。

輸出直譯器工具(僅供註冊客戶使用)支援某些show命令，此工具可讓您檢視show命令輸出的分析。

  • show ip route , show ip route vrf — 在通道端點上發出這些命令，以確保通道目的地可連線。這可確保通道介面將啟動。

  • ping — 從CE的另一端發出此命令，以確保可以從CE訪問隧道。

  • show ip bgp vpnv4 all labels — 在PE裝置上發出此命令，以檢視通過邊界網關協定(BGP)分配給其他PE裝置的VPN標籤。

R3-PE# show ip route vrf blue 10.10.10.1

   Routing entry for 10.10.10.1/32
   Known via "static", distance 1, metric 0
   Routing Descriptor Blocks:
   * 20.20.20.2
   Route metric is 0, traffic share count is 1

R3-PE# show ip route vrf green

Routing Table: green
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

C    200.200.200.0/24 is directly connected, Tunnel0
     100.0.0.0/24 is subnetted, 1 subnets
B       100.100.100.0 [200/0] via 30.30.30.4, 01:11:45

R3-PE# show interfaces tunnel 0

   Tunnel0 is up, line protocol is up
   Hardware is Tunnel
   Internet address is 200.200.200.3/24
   MTU 1514 bytes, BW 9 Kbit, DLY 500000 usec,
   reliability 255/255, txload 1/255, rxload 1/255
   Encapsulation TUNNEL, loopback not set
   Keepalive not set
   Tunnel source 20.20.20.3 (Ethernet0/0), destination 10.10.10.1
   Tunnel protocol/transport GRE/IP, key disabled, sequencing disabled
   Tunnel TTL 255
   Checksumming of packets disabled, fast tunneling enabled
   Last input 00:44:05, output 00:26:16, output hang never
   Last clearing of "show interface" counters never
   Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
   Queueing strategy: fifo
   Output queue: 0/0 (size/max)
   5 minute input rate 0 bits/sec, 0 packets/sec
   5 minute output rate 0 bits/sec, 0 packets/sec
   105 packets input, 11964 bytes, 0 no buffer
   Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
   0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
   83 packets output, 10292 bytes, 0 underruns
   0 output errors, 0 collisions, 0 interface resets
   0 output buffer failures, 0 output buffers swapped out

R3-PE# show ip bgp vpnv4 all labels

      Network          Next Hop      In label/Out label
Route Distinguisher: 1:1 (blue)
   20.20.20.0/24    0.0.0.0         16/aggregate(blue)
Route Distinguisher: 2:2 (green)
   100.100.100.0/24 30.30.30.4      nolabel/16
   200.200.200.0    0.0.0.0         17/aggregate(green)

R4-PE# show ip route vrf blue

Routing Table: blue
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

     20.0.0.0/24 is subnetted, 1 subnets
B       20.20.20.0 [200/0] via 30.30.30.3, 01:14:05

R4-PE# show ip route vrf green

Routing Table: green
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

B    200.200.200.0/24 [200/0] via 30.30.30.3, 01:14:10
     100.0.0.0/24 is subnetted, 1 subnets
C       100.100.100.0 is directly connected, Ethernet1/0

R1-CE# show ip route 20.20.20.3

   Routing entry for 20.20.20.3/32
   Known via "static", distance 1, metric 0
   Routing Descriptor Blocks:
   * 10.10.10.2
   Route metric is 0, traffic share count is 1

R1-CE# show interfaces tunnel 0

   Tunnel0 is up, line protocol is up
   Hardware is Tunnel
   Internet address is 200.200.200.1/24
   MTU 1514 bytes, BW 9 Kbit, DLY 500000 usec,
   reliability 255/255, txload 1/255, rxload 1/255
   Encapsulation TUNNEL, loopback not set
   Keepalive not set
   Tunnel source 10.10.10.1 (Ethernet0/0), destination 20.20.20.3
   Tunnel protocol/transport GRE/IP, key disabled, sequencing disabled
   Tunnel TTL 255
   Checksumming of packets disabled, fast tunneling enabled
   Last input 00:26:57, output 00:26:57, output hang never
   Last clearing of "show interface" counters never
   Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
   Queueing strategy: fifo
   Output queue: 0/0 (size/max)
   5 minute input rate 0 bits/sec, 0 packets/sec
   5 minute output rate 0 bits/sec, 0 packets/sec
   83 packets input, 10292 bytes, 0 no buffer
   Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
   0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
   106 packets output, 12088 bytes, 0 underruns
   0 output errors, 0 collisions, 0 interface resets
   0 output buffer failures, 0 output buffers swapped out

R5-CE# ping 200.200.200.1

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 200.200.200.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 40/54/80 ms

R5-CE# ping 200.200.200.3

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 200.200.200.3, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 20/36/72 ms

疑難排解

目前尚無適用於此組態的具體疑難排解資訊。

注意事項

這些已知警告針對此功能的配置進行了標識。您可以使用Bug工具包(僅供註冊客戶使用)搜尋錯誤。

  • CSCea81266(僅限註冊客戶) — 已解決(R)GRE:clear ip route *後流量停止流動。

  • CSCdx74855(僅限註冊客戶) — 已解決(R)無法ping本地GRE通道介面的IP地址。

  • CSCdx57718(僅限註冊客戶) — 在傳出介面上停用Cisco Express Forwarding(CEF)時，已解決(R)GRE通道中的IP封包遺失。

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