CEF负载均衡方式.doc

CEF负载均衡方式研究组网如上，cold我用loopback地址代替，R1上做两条缺省路由，下一跳分别指定R2的F0/1和F1/0，R2反之。形成R1和R2上分别有两条等价缺省路由互指。R1配置：R2配置：实验使用版本是：2600 Software (C2691-ADVSECURITYK9-M), Version 12.4(11)T2, RELEASE SOFTWARE (fc4)第一部分：缺省情况下负载分担怎么处理：在此情况下，我从R1上带源地址往R2的loopback 1接口pingR1#pingProtocol ip: Target IP address: 222.222.222.1Repeat count 5: Datagram size 100: Timeout in seconds 2: Extended commands n: ySource address or interface: 111.111.111.1Type of service 0: Set DF bit in IP header? no: Validate reply data? no: Data pattern 0xABCD: Loose, Strict, Record, Timestamp, Verbosenone: Sweep range of sizes n: Type escape sequence to abort.Sending 5, 100-byte ICMP Echos to 222.222.222.1, timeout is 2 seconds:Packet sent with a source address of 111.111.111.1 !Success rate is 100 percent (5/5), round-trip min/avg/max = 12/38/84 msR1#*Mar 1 00:49:30.319: IP: tableid=0, s=111.111.111.1 (local), d=222.222.222.1 (FastEthernet0/1), routed via FIB*Mar 1 00:49:30.319: IP: s=111.111.111.1 (local), d=222.222.222.1 (FastEthernet0/1), len 100, sending*Mar 1 00:49:30.399: IP: tableid=0, s=222.222.222.1 (FastEthernet1/0), d=111.111.111.1 (Loopback1), routed via RIB*Mar 1 00:49:30.399: IP: s=222.222.222.1 (FastEthernet1/0), d=111.111.111.1, len 100, rcvd 4*Mar 1 00:49:30.403: IP: tableid=0, s=111.111.111.1 (local), d=222.222.222.1 (FastEthernet0/1), routed via FIB*Mar 1 00:49:30.407: IP: s=111.111.111.1 (local), d=222.222.222.1 (FastEthernet0/1), len 100, sending*Mar 1 00:49:30.435: IP: tableid=0, s=222.222.222.1 (FastEthernet1/0), d=111.111.111.1 (Loopback1), routed via RIB*Mar 1 00:49:30.435: IP: s=222.222.222.1 (FastEthernet1/0), d=111.111.111.1, len 100, rcvd 4*Mar 1 00:49:30.439: IP: tableid=0, s=111.111.111.1 (local), d=222.222.222.1 (FastEthernet0/1), routed via FIB*Mar 1 00:49:30.443: IP: s=111.111.111.1 (local), d=222.222.222.1 (FastEthernet0/1), len 100, sending*Mar 1 00:49:30.487: IP: tableid=0, s=222.222.222.1 (FastEthernet1/0), d=111.111.111.1 (Loopback1), routed via RIB*Mar 1 00:49:30.487: IP: s=222.222.222.1 (FastEthernet1/0), d=111.111.111.1, len 100, rcvd 4*Mar 1 00:49:30.487: IP: tableid=0, s=111.111.111.1 (local), d=222.222.222.1 (FastEthernet0/1), routed via FIB*Mar 1 00:49:30.487: IP: s=111.111.111.1 (local), d=222.222.222.1 (FastEthernet0/1), len 100, sending*Mar 1 00:49:30.499: IP: tableid=0, s=222.222.222.1 (FastEthernet1/0), d=111.111.111.1 (Loopback1), routed via RIB*Mar 1 00:49:30.499: IP: s=222.222.222.1 (FastEthernet1/0), d=111.111.111.1, len 100, rcvd 4*Mar 1 00:49:30.499: IP: tableid=0, s=111.111.111.1 (local), d=222.222.222.1 (FastEthernet0/1), routed via FIB*Mar 1 00:49:30.499: IP: s=111.111.111.1 (local), d=222.222.222.1 (FastEthernet0/1), len 100, sending*Mar 1 00:49:30.511: IP: tableid=0, s=222.222.222.1 (FastEthernet1/0), d=111.111.111.1 (Loopback1), routed via RIB*Mar 1 00:49:30.511: IP: s=222.222.222.1 (FastEthernet1/0), d=111.111.111.1, len 100, rcvd 4由此可以看出，请求固定从0/1口发出去，回应从1/0口接收。而换另外一个接口对R2另外一个loopback地址ping，结果如下：R1#pingProtocol ip: Target IP address: 2.2.2.2Repeat count 5: Datagram size 100: Timeout in seconds 2: Extended commands n: ySource address or interface: 1.1.1.2Type of service 0: Set DF bit in IP header? no: Validate reply data? no: Data pattern 0xABCD: Loose, Strict, Record, Timestamp, Verbosenone: Sweep range of sizes n: Type escape sequence to abort.Sending 5, 100-byte ICMP Echos to 2.2.2.2, timeout is 2 seconds:Packet sent with a source address of 1.1.1.2 !Success rate is 100 percent (5/5), round-trip min/avg/max = 12/41/72 msR1#*Mar 1 00:58:20.371: IP: tableid=0, s=1.1.1.2 (local), d=2.2.2.2 (FastEthernet0/1), routed via FIB*Mar 1 00:58:20.371: IP: s=1.1.1.2 (local), d=2.2.2.2 (FastEthernet0/1), len 100, sending*Mar 1 00:58:20.439: IP: tableid=0, s=2.2.2.2 (FastEthernet0/1), d=1.1.1.2 (FastEthernet0/0), routed via RIB*Mar 1 00:58:20.439: IP: s=2.2.2.2 (FastEthernet0/1), d=1.1.1.2, len 100, rcvd 4*Mar 1 00:58:20.443: IP: tableid=0, s=1.1.1.2 (local), d=2.2.2.2 (FastEthernet0/1), routed via FIB*Mar 1 00:58:20.443: IP: s=1.1.1.2 (local), d=2.2.2.2 (FastEthernet0/1), len 100, sending*Mar 1 00:58:20.499: IP: tableid=0, s=2.2.2.2 (FastEthernet0/1), d=1.1.1.2 (FastEthernet0/0), routed via RIB*Mar 1 00:58:20.499: IP: s=2.2.2.2 (FastEthernet0/1), d=1.1.1.2, len 100, rcvd 4*Mar 1 00:58:20.503: IP: tableid=0, s=1.1.1.2 (local), d=2.2.2.2 (FastEthernet0/1), routed via FIB*Mar 1 00:58:20.503: IP: s=1.1.1.2 (local), d=2.2.2.2 (FastEthernet0/1), len 100, sending*Mar 1 00:58:20.519: IP: tablR1#eid=0, s=2.2.2.2 (FastEthernet0/1), d=1.1.1.2 (FastEthernet0/0), routed via RIB*Mar 1 00:58:20.519: IP: s=2.2.2.2 (FastEthernet0/1), d=1.1.1.2, len 100, rcvd 4*Mar 1 00:58:20.519: IP: tableid=0, s=1.1.1.2 (local), d=2.2.2.2 (FastEthernet0/1), routed via FIB*Mar 1 00:58:20.519: IP: s=1.1.1.2 (local), d=2.2.2.2 (FastEthernet0/1), len 100, sending*Mar 1 00:58:20.567: IP: tableid=0, s=2.2.2.2 (FastEthernet0/1), d=1.1.1.2 (FastEthernet0/0), routed via RIB*Mar 1 00:58:20.567: IP: s=2.2.2.2 (FastEthernet0/1), d=1.1.1.2, len 100, rcvd 4*Mar 1 00:58:20.567: IP: tableid=0, s=1.1.1.2 (local), d=2.2.2.2 (FastEthernet0/1), routed via FIB*Mar 1 00:58:20.567: IP: s=1.1.1.2 (local), d=2.2.2.2 (FastEthernet0/1), len 100, sending*Mar 1 00:58:20.579: IP: tableid=0, s=2.2.2.2 (FastEthernet0/1), d=1.1.1.2 (FastEthernet0/0), routed via RIB*Mar 1 00:58:20.579: IP: s=2.2.2.2 (FastEthernet0/1), d=1.1.1.2, len 100, rcvd 4请求固定从0/1口发出，固定从0/1口收回。怀疑接口缺省是per-destination方式，查看接口FastEthernet0/1 is up (if_number 4) Corresponding hwidb fast_if_number 4 Corresponding hwidb firstsw-if_number 4 Internet address is 12.0.0.1/30 ICMP redirects are always sent Per packet load-sharing is disabled IP unicast RPF check is disabled Inbound access list is not set Outbound access list is not set Hardware idb is FastEthernet0/1 Fast switching type 1, interface type 18 IP CEF switching enabled IP CEF Fast switching turbo vector Input fast flags 0x0, Input fast flags2 0x0, Output fast flags 0x0, Output fast flags2 0x0 ifindex 3(3) Slot 0 Slot unit 1 Unit 1 VC -1 Transmit limit accumulator 0x0 (0x0) IP MTU 1500FastEthernet1/0 is up (if_number 5) Corresponding hwidb fast_if_number 5 Corresponding hwidb firstsw-if_number 5 Internet address is 12.0.0.5/30 ICMP redirects are always sent Per packet load-sharing is disabled IP unicast RPF check is disabled Inbound access list is not set Outbound access list is not set Hardware idb is FastEthernet1/0 Fast switching type 1, interface type 18 IP CEF switching enabled IP CEF Fast switching turbo vector Input fast flags 0x0, Input fast flags2 0x0, Output fast flags 0x0, Output fast flags2 0x0 ifindex 1(1) Slot 1 Slot unit 0 Unit 2 VC -1 Transmit limit accumulator 0x0 (0x0) IP MTU 1500确实端口per-packet已经disabled，但未显示per-destination，应该是工作在destination方式。这也是很多资料上所说的，CEF缺省基于目标进行负载均衡，什么是基于目标负载均衡呢？举例说明：到达目标1-10都有两条等值路径，分别是A和B两个出口，第一条走A，第二条就走B，第三条再走A，第四条又走B，依次类推。第二部分：基于数据包（per-packet）的负载均衡如何处理首先在接口下打开基于数据包的负载均衡interface FastEthernet0/1 ip address 12.0.0.1 255.255.255.252 ip load-sharing per-packet duplex auto speed auto!interface FastEthernet1/0 ip address 12.0.0.5 255.255.255.252 ip load-sharing per-packet duplex auto speed autoshow cef interface显示端口的per-packet已经打开此时，再用源地址111.111.111.1来ping 222.222.222.1看看R1#pingProtocol ip: Target IP address: 222.222.222.1Repeat count 5: Datagram size 100: Timeout in seconds 2: Extended commands n: ySource address or interface: 111.111.111.1Type of service 0: Set DF bit in IP header? no: Validate reply data? no: Data pattern 0xABCD: Loose, Strict, Record, Timestamp, Verbosenone: Sweep range of sizes n: Type escape sequence to abort.Sending 5, 100-byte ICMP Echos to 222.222.222.1, timeout is 2 seconds:Packet sent with a source address of 111.111.111.1 !Success rate is 100 percent (5/5), round-trip min/avg/max = 8/44/92 msR1#*Mar 1 01:23:31.055: IP: tableid=0, s=111.111.111.1 (local), d=222.222.222.1 (FastEthernet0/1), routed via FIB*Mar 1 01:23:31.055: IP: s=111.111.111.1 (local), d=222.222.222.1 (FastEthernet0/1), len 100, sending*Mar 1 01:23:31.143: IP: tableid=0, s=222.222.222.1 (FastEthernet1/0), d=111.111.111.1 (Loopback1), routed via RIB*Mar 1 01:23:31.143: IP: s=222.222.222.1 (FastEthernet1/0), d=111.111.111.1, len 100, rcvd 4*Mar 1 01:23:31.147: IP: tableid=0, s=111.111.111.1 (local), d=222.222.222.1 (FastEthernet1/0), routed via FIB*Mar 1 01:23:31.147: IP: s=111.111.111.1 (local), d=222.222.222.1 (FastEthernet1/0), len 100, sending*Mar 1 01:23:31.175: IP: tableid=0, s=222.222.222.1 (FastEthernet1/0), d=111.111.111.1 (Loopback1), routed via RIB*Mar 1 01:23:31.175: IP: s=222.222.222.1 (FastEthernet1/0), d=111.111.111.1, len 100, rcvd 4*Mar 1 01:23:31.179: IP: tableid=0, s=111.111.111.1 (local), d=222.222.222.1 (FastEthernet0/1), routed via FIB*Mar 1 01:23:31.179: IP: s=111.111.111.1 (local), d=222.222.222.1 (FastEthernet0/1), len 100, sending*Mar 1 01:23:31.191: IP: tableid=0, s=222.222.222.1 (FastEthernet1/0), d=111.111.111.1 (Loopback1), routed via RIB*Mar 1 01:23:31.191: IP: s=222.222.222.1 (FastEthernet1/0), d=111.111.111.1, len 100, rcvd 4*Mar 1 01:23:31.191: IP: tableid=0, s=111.111.111.1 (local), d=222.222.222.1 (FastEthernet1/0), routed via FIB*Mar 1 01:23:31.191: IP: s=111.111.111.1 (local), d=222.222.222.1 (FastEthernet1/0), len 100, sending*Mar 1 01:23:31.199: IP: tableid=0, s=222.222.222.1 (FastEthernet1/0), d=11