配置具有接口故障转移的 IP 监控
通过使用具有接口故障转移的 IP 监控，您可以通过实时性能监控 （RPM） 探测来跟踪一个 IP 地址或一组 IP 地址。如果 RPM 探测失败，您可以启用通常处于稳定状态的备份接口。RPM 探针成功到达其目标后，备份接口再次被禁用。
图 1 显示了配置示例中使用的拓扑结构以及 IP 监控的工作原理。
图 1：实时性能监控拓扑
在稳定状态下，接口 fe-0/0/2 处于链路关闭状态。但是，当 RPM 探测失败时，系统将启用接口，并且流量会流经接口 fe-0/0/2。当 RPM 探针成功到达其目标时，系统将关闭接口 fe-0/0/2，并且流量会通过 fe-0/0/1。
要实现此结果，请定义一个 RPM 探针来监控 IP 地址 5.1.1.2。输入以下配置：
set services rpm probe Probe-Payment-Server test paysvr target address 5.1.1.2 set services rpm probe Probe-Payment-Server test paysvr probe-count 5 set services rpm probe Probe-Payment-Server test paysvr probe-interval 5 set services rpm probe Probe-Payment-Server test paysvr test-interval 3 set services rpm probe Probe-Payment-Server test paysvr thresholds successive-loss 5 set services rpm probe Probe-Payment-Server test paysvr destination-interface fe- 0/0/1.0 set services rpm probe Probe-Payment-Server test paysvr hardware-timestamp set services rpm probe Probe-Payment-Server test paysvr next-hop 1.1.1.2
此外，将 IP 监控策略配置为在 RPM 探测失败时启用备份接口 fe-0/0/2。输入以下配置：
set services ip-monitoring policy test-remote-server match rpm-probe Probe-Payment-Server set services ip-monitoring policy test-remote-server then interface fe-0/0/2 enable
在此示例中，接口 fe-0/0/2 具有静态 IP 地址。因此，您需要指定到所有目标的静态路由，以便 fe-0/0/2 始终是首选路由（较低的优先级值）。您还需要指定到所有目标的路由，以便下一跃点路由器指向下一跃点 fe-0/0/1（更高的优先级值）。使用这种方法，当接口 fe-0/0/2 在稳定状态下被禁用时，所有流量都将流经 fe-0/0/1。当接口 fe-0/0/2 建立时，所有流量都流经 fe-0/0/2。输入以下配置：
set routing-options static route 5.1.1.0/24 qualified-next-hop 2.1.1.2 metric 1 set routing-options static route 5.1.1.0/24 qualified-next-hop 1.1.1.2 metric 10
如果备份接口的 IP 地址是使用动态主机配置协议 （DHCP） 分配的，则您不知道通过备份接口的下一跃点是什么，也无法添加与前面所述类似的静态路由。有关此方案的详细信息，请参阅 使用 DHCP 备份接口配置 IP 监控。
在稳定状态下，您可以通过 IP 地址为 1.1.1.2 的链接到达 IP 地址 5.1.1.1，RPM 探测成功。备份接口 fe-0/0/2 已关闭。要验证稳定状态，请输入以下命令：
root# run traceroute 5.1.1.1 source 10.1.1.1 traceroute to 5.1.1.1 (5.1.1.1) from 10.1.1.1, 30 hops max, 40 byte packets 1 1.1.1.2 (1.1.1.2) 8.807 ms 14.808 ms 9.279 ms 2 5.1.1.1 (5.1.1.1) 3.517 ms 9.609 ms 3.804 ms
在以下show命令输出中Status，PASS字段中的结果指示探测成功：
root# run show services ip-monitoring status
Policy - test-remote-server
RPM Probes:
Probe name Address Status
---------------------- ---------------- ---------
Probe-Payment-Server 5.1.1.2 PASS
root# run show interfaces fe-0/0/2 terse
Interface Admin Link Proto Local Remote
fe-0/0/2 down down
fe-0/0/2.0 up down inet 2.1.1.1/24
在以下 show 命令输出中， Probes sent count 和 Probes received count 相等，且为 Loss percentage 0。这表示探测成功。
root# run show services rpm probe-results
Owner: Probe-Payment-Server, Test: paysvr
Target address: 5.1.1.2, Probe type: icmp-ping
Destination interface name: fe-0/0/1.0
Test size: 5 probes
Probe results:
Response received, Wed Sep 21 06:24:05 2011, No hardware timestamps
Rtt: 1838 usec
Results over current test:
Probes sent: 4, Probes received: 4, Loss percentage: 0
Measurement: Round trip time
Samples: 4, Minimum: 1674 usec, Maximum: 2006 usec, Average: 1805 usec,
Peak to peak: 332 usec, Stddev: 132 usec, Sum: 7220 usec
Results over last test:
Probes sent: 5, Probes received: 5, Loss percentage: 0
Test completed on Wed Sep 21 06:23:47 2011
Measurement: Round trip time
Samples: 5, Minimum: 1632 usec, Maximum: 7599 usec, Average: 4226 usec,
Peak to peak: 5967 usec, Stddev: 2719 usec, Sum: 21128 usec
Results over all tests:
Probes sent: 54, Probes received: 54, Loss percentage: 0
Measurement: Round trip time
Samples: 54, Minimum: 1524 usec, Maximum: 97845 usec,
Average: 5422 usec, Peak to peak: 96321 usec, Stddev: 13438 usec,
Sum: 292762 usec
当 IP 地址 5.1.1.2 无法访问时，RPM 探测失败，接口 fe-0/0/2 启用。现在，所有流量都通过接口 fe-0/0/2 进行路由。探针仍会从接口 fe-0/0/1 发出。
在该部分下的以下show命令输出中，它显示Probes sent计数为2，Probes received计数为 0。Results over current test:它还表明是 Loss percentage 100.这表示探测失败。
root# run show services rpm probe-results
Owner: Probe-Payment-Server, Test: paysvr
Target address: 5.1.1.2, Probe type: icmp-ping
Destination interface name: fe-0/0/1.0
Test size: 5 probes
Probe results:
Request timed out, Thu Sep 22 01:18:25 2011
Results over current test:
Probes sent: 2, Probes received: 0, Loss percentage: 100
Results over last test:
Probes sent: 5, Probes received: 5, Loss percentage: 0
Test completed on Thu Sep 22 01:18:17 2011
Measurement: Round trip time
Samples: 5, Minimum: 1635 usec, Maximum: 7528 usec, Average: 4055 usec,
Peak to peak: 5893 usec, Stddev: 2819 usec, Sum: 20273 usec
Results over all tests:
Probes sent: 22, Probes received: 20, Loss percentage: 9
Measurement: Round trip time
Samples: 20, Minimum: 1439 usec, Maximum: 9427 usec, Average: 3355 usec,
Peak to peak: 7988 usec, Stddev: 2650 usec, Sum: 67099 usec
要进一步验证失败状态，请使用以下命令：
root# run show services ip-monitoring status
Policy - test-remote-server
RPM Probes:
Probe name Address Status
---------------------- ---------------- ---------
Probe-Payment-Server 5.1.1.2 FAIL
要验证接口 fe-0/0/2 是否已启用，请使用以下命令：
root# run show interfaces fe-0/0/2 terse Interface Admin Link Proto Local Remote fe-0/0/2 up up fe-0/0/2.0 up up inet 2.1.1.1/24
要验证 IP 地址 5.1.1.1 现在是否可通过 IP 地址为 2.1.1.2 的设备访问，请使用以下命令：
root# run traceroute 5.1.1.1 source 10.1.1.1 traceroute to 5.1.1.1 (5.1.1.1) from 10.1.1.1, 30 hops max, 40 byte packets 1 2.1.1.2 (2.1.1.2) 9.031 ms 8.575 ms 15.450 ms 2 5.1.1.1 (5.1.1.1) 10.120 ms 10.581 ms 3.553 ms
当再次可访问 IP 地址 5.1.1.2 时，RPM 探测成功到达目标，接口 fe-0/0/2 被禁用。现在，所有流量都流经接口 fe-0/0/1。
若要验证还原稳态的作，请使用以下命令，并验证结果是否与前面所述的稳态结果相似：
root# run show services rpm probe-results
Owner: Probe-Payment-Server, Test: paysvr
Target address: 5.1.1.2, Probe type: icmp-ping
Destination interface name: fe-0/0/1.0
Test size: 5 probes
Probe results:
Response received, Thu Sep 22 01:22:01 2011, No hardware timestamps
Rtt: 2258 usec
Results over current test:
Probes sent: 2, Probes received: 2, Loss percentage: 0
Measurement: Round trip time
Samples: 2, Minimum: 1847 usec, Maximum: 2258 usec, Average: 2053 usec,
Peak to peak: 411 usec, Stddev: 206 usec, Sum: 4105 usec
Results over last test:
Probes sent: 5, Probes received: 5, Loss percentage: 0
Test completed on Thu Sep 22 01:21:53 2011
Measurement: Round trip time
Samples: 5, Minimum: 1614 usec, Maximum: 3752 usec, Average: 2213 usec,
Peak to peak: 2138 usec, Stddev: 782 usec, Sum: 11064 usec
Results over all tests:
Probes sent: 62, Probes received: 31, Loss percentage: 50
Measurement: Round trip time
Samples: 31, Minimum: 1439 usec, Maximum: 9427 usec, Average: 3076 usec,
Peak to peak: 7988 usec, Stddev: 2426 usec, Sum: 95345 usec
root# run show services ip-monitoring status
Policy - test-remote-server
RPM Probes:
Probe name Address Status
---------------------- ---------------- ---------
Probe-Payment-Server 5.1.1.2 PASS
root# run show interfaces fe-0/0/2 terse
Interface Admin Link Proto Local Remote
fe-0/0/2 down down
fe-0/0/2.0 up down inet 2.1.1.1/24
root# run traceroute 5.1.1.1 source 10.1.1.1
traceroute to 5.1.1.1 (5.1.1.1) from 10.1.1.1, 30 hops max, 40 byte packets
1 1.1.1.2 (1.1.1.2) 8.818 ms 8.573 ms 9.847 ms
2 5.1.1.1 (5.1.1.1) 3.384 ms 15.888 ms 3.640 ms