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ルートタグを使用して経路ループを防止

以下の例のように外部EIGRP ルートは、R1及びR10の構成によって、OSPFとEIGRPの間に再分配しなければトポロジ内に到達できない。
prevent looping.jpg.png

先ず、各ルータのルーティングテーブルを確認。

R3:
R3#sho ip route
     3.0.0.0/24 is subnetted, 1 subnets
C       3.3.3.0 is directly connected, Loopback0
     10.0.0.0/24 is subnetted, 1 subnets
C       10.1.1.0 is directly connected, FastEthernet1/0
D EX 192.168.1.0/24 [170/2560002816] via 10.1.1.10, 00:00:43, FastEthernet1/0
                    [170/2560002816] via 10.1.1.1, 00:00:42, FastEthernet1/0
     150.1.0.0/24 is subnetted, 1 subnets
C       150.1.1.0 is directly connected, Loopback1

150.1.1.0 R3に直接接続されたネットワークであり、このネットワークは外部EIGRPネットワークとして再配布を宣伝


R1#show ip route 150.1.1.0
Routing entry for 150.1.1.0/24
Known via "ospf 1", distance 110, metric 20
  Tag 190, type extern 2, forward metric 1
  Redistributing via eigrp 10
  Advertised by eigrp 10 metric 1 1 1 1 1
  Last update from 192.168.1.10 on FastEthernet1/0, 00:03:23 ago
  Routing Descriptor Blocks:
  * 192.168.1.10, from 192.168.1.10, 00:03:23 ago, via FastEthernet1/0
      Route metric is 20, traffic share count is 1
      Route tag 190

R10#show ip route 150.1.1.0
Routing entry for 150.1.1.0/24
  Known via "eigrp 10", distance 170, metric 2560002816
  Tag 190, type external
  Redistributing via ospf 1, eigrp 10
  Advertised by ospf 1 subnets tag 190
  Last update from 10.1.1.1 on FastEthernet1/1, 00:03:35 ago
  Routing Descriptor Blocks:
  * 10.1.1.3, from 10.1.1.3, 00:03:35 ago, via FastEthernet1/1
      Route metric is 2560002816, traffic share count is 1
      Total delay is 110 microseconds, minimum bandwidth is 1 Kbit
      Reliability 1/255, minimum MTU 1 bytes
      Loading 1/255, Hops 1
    10.1.1.1, from 10.1.1.1, 00:03:35 ago, via FastEthernet1/1
      Route metric is 2560002816, traffic share count is 1
      Total delay is 110 microseconds, minimum bandwidth is 1 Kbit
      Reliability 1/255, minimum MTU 1 bytes
      Loading 1/255, Hops 1
      Route tag 190


R1とR10の ルーティングテーブルにネットワーク150.1.1.0ループしているに示す。
R1はOSPF を介してAD110とR10でR1及びR3からそれを参照し、ルートループになります 。

R10#ping 150.1.1.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 150.1.1.1, timeout is 2 seconds:
.....
Success rate is 0 percent (0/5)

R1#ping 150.1.1.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 150.1.1.1, timeout is 2 seconds:
.....
Success rate is 0 percent (0/5)

AD 170 のEIGRP は外部ルートを持って、R1 および R10 の間の相互の再配布のためルートループが発生します。
この問題はタグをフィルタリングを使用して解決できる。

R1:
router ospf 1
redistribute eigrp 10 subnets tag 1090

R10:
router ospf 1
redistribute eigrp 10 subnets tag 190


R1#show ip route 150.1.1.0
Routing entry for 150.1.1.0/24
  Known via "ospf 1", distance 110, metric 20
  Tag 190, type extern 2, forward metric 1
  Redistributing via eigrp 10
  Advertised by eigrp 10 metric 1 1 1 1 1
  Last update from 192.168.1.10 on FastEthernet1/0, 00:16:49 ago
  Routing Descriptor Blocks:
  * 192.168.1.10, from 192.168.1.10, 00:16:49 ago, via FastEthernet1/0
      Route metric is 20, traffic share count is 1
      Route tag 190    --- ----AD 190 R10

R10#show ip route 150.1.1.0
Routing entry for 150.1.1.0/24
  Known via "eigrp 10", distance 170, metric 2560002816
  Tag 190, type external
  Redistributing via ospf 1, eigrp 10
  Advertised by ospf 1 subnets tag 190
  Last update from 10.1.1.1 on FastEthernet1/1, 00:17:49 ago
  Routing Descriptor Blocks:
  * 10.1.1.3, from 10.1.1.3, 00:17:49 ago, via FastEthernet1/1
      Route metric is 2560002816, traffic share count is 1
      Total delay is 110 microseconds, minimum bandwidth is 1 Kbit
      Reliability 1/255, minimum MTU 1 bytes
      Loading 1/255, Hops 1
    10.1.1.1, from 10.1.1.1, 00:17:49 ago, via FastEthernet1/1
      Route metric is 2560002816, traffic share count is 1
      Total delay is 110 microseconds, minimum bandwidth is 1 Kbit
      Reliability 1/255, minimum MTU 1 bytes
      Loading 1/255, Hops 1
      Route tag 190 --- (tag 190)


R1:
route-map EIGRP deny 10 
match tag 190
!
route-map EIGRP permit 20   -- permit anything else

router eigrp 10
redistribute ospf 1 metric 1 1 1 1 1 route-map EIGRP

R10:

route-map EIGRP deny 10
match tag 1090
!
route-map EIGRP permit 20
router eigrp 10
redistribute ospf 1 metric 1 1 1 1 1 route-map EIGRP

lets pig now :

R1#ping 150.1.1.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 150.1.1.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 92/137/188 ms

R10#ping 150.1.1.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 150.1.1.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 28/64/156 ms


R10#show ip route 150.1.1.0
Routing entry for 150.1.1.0/24
  Known via "eigrp 10", distance 170, metric 2560002816, type external
  Redistributing via ospf 1, eigrp 10
  Advertised by ospf 1 subnets tag 190
  Last update from 10.1.1.3 on FastEthernet1/1, 00:03:46 ago
  Routing Descriptor Blocks:
  * 10.1.1.3, from 10.1.1.3, 00:03:46 ago, via FastEthernet1/1
      Route metric is 2560002816, traffic share count is 1
      Total delay is 110 microseconds, minimum bandwidth is 1 Kbit
      Reliability 1/255, minimum MTU 1 bytes
      Loading 1/255, Hops 1

R1#show ip route 150.1.1.0
Routing entry for 150.1.1.0/24
Known via "ospf 1", distance 110, metric 20
  Tag 190, type extern 2, forward metric 1
  Redistributing via eigrp 10
  Last update from 192.168.1.10 on FastEthernet1/0, 00:30:37 ago
  Routing Descriptor Blocks:
  * 192.168.1.10, from 192.168.1.10, 00:30:37 ago, via FastEthernet1/0
      Route metric is 20, traffic share count is 1
      Route tag 190
 
router ospf 1
distribute-list route-map EIGRP in

R1#show ip route 150.1.1.0
Routing entry for 150.1.1.0/24
  Known via "eigrp 10", distance 170, metric 2560002816, type external
  Redistributing via ospf 1, eigrp 10
  Advertised by ospf 1 subnets tag 1090
  Last update from 10.1.1.3 on FastEthernet1/1, 00:00:36 ago
  Routing Descriptor Blocks:
  * 10.1.1.3, from 10.1.1.3, 00:00:36 ago, via FastEthernet1/1
      Route metric is 2560002816, traffic share count is 1
      Total delay is 110 microseconds, minimum bandwidth is 1 Kbit
      Reliability 1/255, minimum MTU 1 bytes
      Loading 1/255, Hops 1

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最終更新:
‎07-31-2010 10:36 PM
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