本帖最后由 碧云天 于 2020-2-7 14:28 编辑
一.测试拓扑
测试总结：
1.非等价负载的条件：
这个链接也有描述：https://packetu.com/2016/07/05/testing-eigrp-feasibility-condition-fc/
二.基本配置
1.R1路由器
hostname R1
interface Loopback0
ip address 1.1.1.1 255.255.255.0
interface FastEthernet0/0
ip address 12.1.1.1 255.255.255.0
no shutdown
interface FastEthernet0/1
ip address 13.1.1.1 255.255.255.0
no shutdown
router eigrp 10
passive-interface Loopback0
network 1.1.1.1 0.0.0.0
network 12.1.1.1 0.0.0.0
network 13.1.1.1 0.0.0.0
no auto-summary
2.R2路由器
hostname R2
interface FastEthernet0/0
ip address 12.1.1.2 255.255.255.0
no shutdown
interface FastEthernet0/1
ip address 23.1.1.2 255.255.255.0
no shutdown
router eigrp 10
network 12.1.1.2 0.0.0.0
network 23.1.1.2 0.0.0.0
no auto-summary
3.R3路由器
hostname R3
interface Loopback0
ip address 3.3.3.3 255.255.255.0
interface FastEthernet0/0
ip address 23.1.1.3 255.255.255.0
no shutdown
interface FastEthernet0/1
ip address 13.1.1.3 255.255.255.0
no shutdown
router eigrp 10
passive-interface Loopback0
network 3.3.3.3 0.0.0.0
network 13.1.1.3 0.0.0.0
network 23.1.1.3 0.0.0.0
no auto-summary
三.用c3725-ik9s-mz.122-15.T9.image dynamips测试
--用c3725-adventerprisek9-mz.124-15.T14.image测试效果也相同,没有找到3725的其他更高的版本
1.上面配置完成后，在R1上面通过show ip eigrp topology命令，到3.3.3.3只有一条路径
R1#show version
Cisco Internetwork Operating System Software
IOS (tm) 3700 Software (C3725-IK9S-M), Version 12.2(15)T9, RELEASE SOFTWARE (fc2)
TAC Support: http://www.cisco.com/tac
Copyright (c) 1986-2003 by cisco Systems, Inc.
Compiled Sat 01-Nov-03 00:53 by ccai
Image text-base: 0x60008954, data-base: 0x61D28000
ROM: ROMMON Emulation Microcode
ROM: 3700 Software (C3725-IK9S-M), Version 12.2(15)T9, RELEASE SOFTWARE (fc2)
R1 uptime is 4 minutes
System returned to ROM by unknown reload cause - suspect boot_data[BOOT_COUNT] 0x0, BOOT_COUNT 0, BOOTDATA 19
System image file is "ftp://255.255.255.255/unknown" TARGET="_blank">tftp://255.255.255.255/unknown"
This product contains cryptographic features and is subject to United
States and local country laws governing import, export, transfer and
use. Delivery of Cisco cryptographic products does not imply
third-party authority to import, export, distribute or use encryption.
Importers, exporters, distributors and users are responsible for
compliance with U.S. and local country laws. By using this product you
R1#show ip eigrp topology
IP-EIGRP Topology Table for AS(10)/ID(1.1.1.1)
Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply,
r - reply Status, s - sia Status
P 1.1.1.0/24, 1 successors, FD is 128256
via Connected, Loopback0
P 3.3.3.0/24, 1 successors, FD is 156160
via 13.1.1.3 (156160/128256), FastEthernet0/1
P 12.1.1.0/24, 1 successors, FD is 28160
via Connected, FastEthernet0/0
P 13.1.1.0/24, 1 successors, FD is 28160
via Connected, FastEthernet0/1
P 23.1.1.0/24, 2 successors, FD is 30720
via 13.1.1.3 (30720/28160), FastEthernet0/1
via 12.1.1.2 (30720/28160), FastEthernet0/0
R1#
2.在R1上面通过show ip eigrp topology all-links命令，到3.3.3.3有两条路径的FD差不多，但后者AD等于前者FD
R1#show ip eigrp topology all-links
IP-EIGRP Topology Table for AS(10)/ID(1.1.1.1)
Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply,
r - reply Status, s - sia Status
P 1.1.1.0/24, 1 successors, FD is 128256, serno 1
via Connected, Loopback0
P 3.3.3.0/24, 1 successors, FD is 156160, serno 19
via 13.1.1.3 (156160/128256), FastEthernet0/1
via 12.1.1.2 (158720/156160), FastEthernet0/0
P 12.1.1.0/24, 1 successors, FD is 28160, serno 2
via Connected, FastEthernet0/0
P 13.1.1.0/24, 1 successors, FD is 28160, serno 4
via Connected, FastEthernet0/1
P 23.1.1.0/24, 2 successors, FD is 30720, serno 20
via 13.1.1.3 (30720/28160), FastEthernet0/1
via 12.1.1.2 (30720/28160), FastEthernet0/0
R1#
3.在R1上面修改variance为2，并确认最大路径数为默认的4
R1#show ip protocols
*** IP Routing is NSF aware ***
Routing Protocol is "eigrp 10"
Outgoing update filter list for all interfaces is not set
Incoming update filter list for all interfaces is not set
Default networks flagged in outgoing updates
Default networks accepted from incoming updates
EIGRP-IPv4 Protocol for AS(10)
Metric weight K1=1, K2=0, K3=1, K4=0, K5=0
NSF-aware route hold timer is 240
Router-ID: 192.168.11.1
Topology : 0 (base)
Active Timer: 3 min
Distance: internal 90 external 170
Maximum path: 4
Maximum hopcount 100
Maximum metric variance 2
Automatic Summarization: disabled
Maximum path: 4
Routing for Networks:
1.1.1.1/32
12.1.1.1/32
13.1.1.1/32
Routing Information Sources:
Gateway Distance Last Update
13.1.1.3 90 00:00:09
12.1.1.2 90 00:00:09
Distance: internal 90 external 170
R1#
4.R1查看路由，到3.3.3.0仍然只有一条路径
R1#show ip route eigrp
3.0.0.0/24 is subnetted, 1 subnets
D 3.3.3.0 [90/156160] via 13.1.1.3, 00:04:30, FastEthernet0/1
23.0.0.0/24 is subnetted, 1 subnets
D 23.1.1.0 [90/30720] via 12.1.1.2, 00:04:30, FastEthernet0/0
[90/30720] via 13.1.1.3, 00:04:30, FastEthernet0/1
R1#
5.改小R2的F0/1接口的延时
R2(config)#int f0/1
R2(config-if)#delay 9
R2(config-if)#do show int f0/1
FastEthernet0/1 is up, line protocol is up
Hardware is Gt96k FE, address is c202.4cf2.0001 (bia c202.4cf2.0001)
Internet address is 23.1.1.2/24
MTU 1500 bytes, BW 100000 Kbit, DLY 90 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
6.在R1上面通过show ip eigrp topology命令，到3.3.3.3出现了两条路径
R1#show ip eigrp topology
IP-EIGRP Topology Table for AS(10)/ID(1.1.1.1)
Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply,
r - reply Status, s - sia Status
P 1.1.1.0/24, 1 successors, FD is 128256
via Connected, Loopback0
P 3.3.3.0/24, 1 successors, FD is 156160
via 13.1.1.3 (156160/128256), FastEthernet0/1
via 12.1.1.2 (158464/155904), FastEthernet0/0
P 12.1.1.0/24, 1 successors, FD is 28160
via Connected, FastEthernet0/0
P 13.1.1.0/24, 1 successors, FD is 28160
via Connected, FastEthernet0/1
P 23.1.1.0/24, 1 successors, FD is 30464
via 12.1.1.2 (30464/27904), FastEthernet0/0
via 13.1.1.3 (30720/28160), FastEthernet0/1
R1#
7.R1路由表到3.3.3.0/24也有两条路由
R1#show ip route eigrp
3.0.0.0/24 is subnetted, 1 subnets
D 3.3.3.0 [90/156160] via 13.1.1.3, 00:04:50, FastEthernet0/1
[90/158464] via 12.1.1.2, 00:04:50, FastEthernet0/0
23.0.0.0/24 is subnetted, 1 subnets
D 23.1.1.0 [90/30464] via 12.1.1.2, 00:05:00, FastEthernet0/0
[90/30720] via 13.1.1.3, 00:05:00, FastEthernet0/1
R1#
四.用c7200-advipservicesk9-mz.152-4.S2.image dynamips测试
---相同的拓扑，相同的基本配置，只是f0/1改成f1/0
1.配置完成后，在R1上面通过show ip eigrp topology命令，到3.3.3.3只有一条路径
R1#show version
Cisco IOS Software, 7200 Software (C7200-ADVIPSERVICESK9-M), Version 15.2(4)S2, RELEASE SOFTWARE (fc1)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2012 by Cisco Systems, Inc.
Compiled Tue 11-Dec-12 13:33 by prod_rel_team
ROM: ROMMON Emulation Microcode
BOOTLDR: 7200 Software (C7200-ADVIPSERVICESK9-M), Version 15.2(4)S2, RELEASE SOFTWARE (fc1)
R1 uptime is 4 minutes
System returned to ROM by unknown reload cause - suspect boot_data[BOOT_COUNT] 0x0, BOOT_COUNT 0, BOOTDATA 19
System image file is "ftp://255.255.255.255/unknown" TARGET="_blank">tftp://255.255.255.255/unknown"
Last reload reason: Unknown reason
This product contains cryptographic features and is subject to United
States and local country laws governing import, export, transfer and
use. Delivery of Cisco cryptographic products does not imply
third-party authority to import, export, distribute or use encryption.
Importers, exporters, distributors and users are responsible for
R1#show ip eigrp topology
EIGRP-IPv4 Topology Table for AS(10)/ID(1.1.1.1)
Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply,
r - reply Status, s - sia Status
P 13.1.1.0/24, 1 successors, FD is 28160
via Connected, FastEthernet1/0
via Rconnected (28160/0)
P 23.1.1.0/24, 1 successors, FD is 30720
via 13.1.1.3 (30720/28160), FastEthernet1/0
P 3.3.3.0/24, 1 successors, FD is 156160
via 13.1.1.3 (156160/128256), FastEthernet1/0
P 12.1.1.0/24, 1 successors, FD is 28160
via Connected, FastEthernet0/0
via Rconnected (28160/0)
P 1.1.1.0/24, 1 successors, FD is 128256
via Connected, Loopback0
2.在R1上面通过show ip eigrp topology all-links命令，到3.3.3.3有两条路径的FD差不多，但后者AD等于前者FD
R1#show ip eigrp topology all-links
EIGRP-IPv4 Topology Table for AS(10)/ID(1.1.1.1)
Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply,
r - reply Status, s - sia Status
P 13.1.1.0/24, 1 successors, FD is 28160, serno 4
via Connected, FastEthernet1/0
via 12.1.1.2 (33280/30720), FastEthernet0/0
via Rconnected (28160/0)
P 23.1.1.0/24, 1 successors, FD is 30720, serno 6
via 13.1.1.3 (30720/28160), FastEthernet1/0
P 3.3.3.0/24, 1 successors, FD is 156160, serno 5
via 13.1.1.3 (156160/128256), FastEthernet1/0
via 12.1.1.2 (158720/156160), FastEthernet0/0
P 12.1.1.0/24, 1 successors, FD is 28160, serno 3
via Connected, FastEthernet0/0
via Rconnected (28160/0)
P 1.1.1.0/24, 1 successors, FD is 128256, serno 2
via Connected, Loopback0
R1#
3.在R1上面修改variance为2，并确认最大路径数为默认的4
R1(config)#router eigrp 10
R1(config-router)#variance 2
R1(config-router)#do show ip protocols
*** IP Routing is NSF aware ***
Routing Protocol is "eigrp 10"
Outgoing update filter list for all interfaces is not set
Incoming update filter list for all interfaces is not set
Default networks flagged in outgoing updates
Default networks accepted from incoming updates
EIGRP-IPv4 Protocol for AS(10)
Metric weight K1=1, K2=0, K3=1, K4=0, K5=0
NSF-aware route hold timer is 240
Router-ID: 1.1.1.1
Topology : 0 (base)
Active Timer: 3 min
Distance: internal 90 external 170
Maximum path: 4
Maximum hopcount 100
Maximum metric variance 2
Automatic Summarization: disabled
Maximum path: 4
Routing for Networks:
1.1.1.1/32
12.1.1.1/32
13.1.1.1/32
Passive Interface(s):
Loopback0
Routing Information Sources:
Gateway Distance Last Update
12.1.1.2 90 00:01:06
13.1.1.3 90 00:01:06
Distance: internal 90 external 170
R1(config-router)#
4.在R2上面不需要做任何配置，R1有两条到3.3.3.0/24的非等价路由
R1#show ip route eigrp | begin Gate
Gateway of last resort is not set
3.0.0.0/24 is subnetted, 1 subnets
D 3.3.3.0 [90/156160] via 13.1.1.3, 00:02:37, FastEthernet1/0
[90/158720] via 12.1.1.2, 00:02:37, FastEthernet0/0
23.0.0.0/24 is subnetted, 1 subnets
D 23.1.1.0 [90/30720] via 13.1.1.3, 00:02:37, FastEthernet1/0
R1#
5.甚至将R2的f1/0接口延时改大,AD比FD要大一点，R1到3.3.3.0/24的两条非对称路由依然存在
---下面时将R2的f1/0的delay设置成19的情况，（100+19+500）*256= 158464
R1#show ip eigrp topology all-links
EIGRP-IPv4 Topology Table for AS(10)/ID(1.1.1.1)
Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply,
r - reply Status, s - sia Status
P 13.1.1.0/24, 1 successors, FD is 28160, serno 4
via Connected, FastEthernet1/0
via 12.1.1.2 (35584/33024), FastEthernet0/0
P 23.1.1.0/24, 1 successors, FD is 30720, serno 6
via 13.1.1.3 (30720/28160), FastEthernet1/0
P 3.3.3.0/24, 2 successors, FD is 156160, serno 9
via 13.1.1.3 (156160/128256), FastEthernet1/0
via 12.1.1.2 (161024/158464), FastEthernet0/0
P 12.1.1.0/24, 1 successors, FD is 28160, serno 3
via Connected, FastEthernet0/0
P 1.1.1.0/24, 1 successors, FD is 128256, serno 2
via Connected, Loopback0
via Rconnected (128256/0)
R1#
R1#clear ip route *
R1#show ip route ei
R1#show ip route eigrp | begin Gate
Gateway of last resort is not set
3.0.0.0/24 is subnetted, 1 subnets
D 3.3.3.0 [90/156160] via 13.1.1.3, 00:00:09, FastEthernet1/0
[90/158976] via 12.1.1.2, 00:00:09, FastEthernet0/0
23.0.0.0/24 is subnetted, 1 subnets
D 23.1.1.0 [90/30720] via 13.1.1.3, 00:00:09, FastEthernet1/0
R1#
6.把R2的f1/0接口延时改为20，比较奇怪的是R1上执行show ip eigrp topology all-links都看不到第二条了
R1#show ip eigrp topology all-links
EIGRP-IPv4 Topology Table for AS(10)/ID(1.1.1.1)
Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply,
r - reply Status, s - sia Status
P 13.1.1.0/24, 1 successors, FD is 28160, serno 4
via Connected, FastEthernet1/0
via 12.1.1.2 (35840/33280), FastEthernet0/0
P 23.1.1.0/24, 1 successors, FD is 30720, serno 6
via 13.1.1.3 (30720/28160), FastEthernet1/0
P 3.3.3.0/24, 1 successors, FD is 156160, serno 10
via 13.1.1.3 (156160/128256), FastEthernet1/0
P 12.1.1.0/24, 1 successors, FD is 28160, serno 3
via Connected, FastEthernet0/0
P 1.1.1.0/24, 1 successors, FD is 128256, serno 2
via Connected, Loopback0
via Rconnected (128256/0)
R1#show ip route eigrp | begin Gate
Gateway of last resort is not set
3.0.0.0/24 is subnetted, 1 subnets
D 3.3.3.0 [90/156160] via 13.1.1.3, 00:00:45, FastEthernet1/0
23.0.0.0/24 is subnetted, 1 subnets
D 23.1.1.0 [90/30720] via 13.1.1.3, 00:22:35, FastEthernet1/0
R1#
一.测试拓扑
测试总结：
1.非等价负载的条件：
- Maximum path > 1
- Maximum metric variance 合适的倍数关系
- 存在备用路径（满足FC限制）
- 低版本：备用路径的AD应该严格小于最优路径的FD
- 高版本：备用路径的AD可以小于、等于、略微大于最优路径的FD（虽然AD等于或略大于FD时在拓扑表中不显示，但不妨碍成为非等价路径）
- 或许这么描述可能更合适，FC的限制还是一样的，需要AD严格小于FD，但是能成为备用路径的条件放松了
这个链接也有描述：https://packetu.com/2016/07/05/testing-eigrp-feasibility-condition-fc/
二.基本配置
1.R1路由器
hostname R1
interface Loopback0
ip address 1.1.1.1 255.255.255.0
interface FastEthernet0/0
ip address 12.1.1.1 255.255.255.0
no shutdown
interface FastEthernet0/1
ip address 13.1.1.1 255.255.255.0
no shutdown
router eigrp 10
passive-interface Loopback0
network 1.1.1.1 0.0.0.0
network 12.1.1.1 0.0.0.0
network 13.1.1.1 0.0.0.0
no auto-summary
2.R2路由器
hostname R2
interface FastEthernet0/0
ip address 12.1.1.2 255.255.255.0
no shutdown
interface FastEthernet0/1
ip address 23.1.1.2 255.255.255.0
no shutdown
router eigrp 10
network 12.1.1.2 0.0.0.0
network 23.1.1.2 0.0.0.0
no auto-summary
3.R3路由器
hostname R3
interface Loopback0
ip address 3.3.3.3 255.255.255.0
interface FastEthernet0/0
ip address 23.1.1.3 255.255.255.0
no shutdown
interface FastEthernet0/1
ip address 13.1.1.3 255.255.255.0
no shutdown
router eigrp 10
passive-interface Loopback0
network 3.3.3.3 0.0.0.0
network 13.1.1.3 0.0.0.0
network 23.1.1.3 0.0.0.0
no auto-summary
三.用c3725-ik9s-mz.122-15.T9.image dynamips测试
--用c3725-adventerprisek9-mz.124-15.T14.image测试效果也相同,没有找到3725的其他更高的版本
1.上面配置完成后，在R1上面通过show ip eigrp topology命令，到3.3.3.3只有一条路径
R1#show version
Cisco Internetwork Operating System Software
IOS (tm) 3700 Software (C3725-IK9S-M), Version 12.2(15)T9, RELEASE SOFTWARE (fc2)
TAC Support: http://www.cisco.com/tac
Copyright (c) 1986-2003 by cisco Systems, Inc.
Compiled Sat 01-Nov-03 00:53 by ccai
Image text-base: 0x60008954, data-base: 0x61D28000
ROM: ROMMON Emulation Microcode
ROM: 3700 Software (C3725-IK9S-M), Version 12.2(15)T9, RELEASE SOFTWARE (fc2)
R1 uptime is 4 minutes
System returned to ROM by unknown reload cause - suspect boot_data[BOOT_COUNT] 0x0, BOOT_COUNT 0, BOOTDATA 19
System image file is "ftp://255.255.255.255/unknown" TARGET="_blank">tftp://255.255.255.255/unknown"
This product contains cryptographic features and is subject to United
States and local country laws governing import, export, transfer and
use. Delivery of Cisco cryptographic products does not imply
third-party authority to import, export, distribute or use encryption.
Importers, exporters, distributors and users are responsible for
compliance with U.S. and local country laws. By using this product you
R1#show ip eigrp topology
IP-EIGRP Topology Table for AS(10)/ID(1.1.1.1)
Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply,
r - reply Status, s - sia Status
P 1.1.1.0/24, 1 successors, FD is 128256
via Connected, Loopback0
P 3.3.3.0/24, 1 successors, FD is 156160
via 13.1.1.3 (156160/128256), FastEthernet0/1
P 12.1.1.0/24, 1 successors, FD is 28160
via Connected, FastEthernet0/0
P 13.1.1.0/24, 1 successors, FD is 28160
via Connected, FastEthernet0/1
P 23.1.1.0/24, 2 successors, FD is 30720
via 13.1.1.3 (30720/28160), FastEthernet0/1
via 12.1.1.2 (30720/28160), FastEthernet0/0
R1#
2.在R1上面通过show ip eigrp topology all-links命令，到3.3.3.3有两条路径的FD差不多，但后者AD等于前者FD
R1#show ip eigrp topology all-links
IP-EIGRP Topology Table for AS(10)/ID(1.1.1.1)
Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply,
r - reply Status, s - sia Status
P 1.1.1.0/24, 1 successors, FD is 128256, serno 1
via Connected, Loopback0
P 3.3.3.0/24, 1 successors, FD is 156160, serno 19
via 13.1.1.3 (156160/128256), FastEthernet0/1
via 12.1.1.2 (158720/156160), FastEthernet0/0
P 12.1.1.0/24, 1 successors, FD is 28160, serno 2
via Connected, FastEthernet0/0
P 13.1.1.0/24, 1 successors, FD is 28160, serno 4
via Connected, FastEthernet0/1
P 23.1.1.0/24, 2 successors, FD is 30720, serno 20
via 13.1.1.3 (30720/28160), FastEthernet0/1
via 12.1.1.2 (30720/28160), FastEthernet0/0
R1#
3.在R1上面修改variance为2，并确认最大路径数为默认的4
R1#show ip protocols
*** IP Routing is NSF aware ***
Routing Protocol is "eigrp 10"
Outgoing update filter list for all interfaces is not set
Incoming update filter list for all interfaces is not set
Default networks flagged in outgoing updates
Default networks accepted from incoming updates
EIGRP-IPv4 Protocol for AS(10)
Metric weight K1=1, K2=0, K3=1, K4=0, K5=0
NSF-aware route hold timer is 240
Router-ID: 192.168.11.1
Topology : 0 (base)
Active Timer: 3 min
Distance: internal 90 external 170
Maximum path: 4
Maximum hopcount 100
Maximum metric variance 2
Automatic Summarization: disabled
Maximum path: 4
Routing for Networks:
1.1.1.1/32
12.1.1.1/32
13.1.1.1/32
Routing Information Sources:
Gateway Distance Last Update
13.1.1.3 90 00:00:09
12.1.1.2 90 00:00:09
Distance: internal 90 external 170
R1#
4.R1查看路由，到3.3.3.0仍然只有一条路径
R1#show ip route eigrp
3.0.0.0/24 is subnetted, 1 subnets
D 3.3.3.0 [90/156160] via 13.1.1.3, 00:04:30, FastEthernet0/1
23.0.0.0/24 is subnetted, 1 subnets
D 23.1.1.0 [90/30720] via 12.1.1.2, 00:04:30, FastEthernet0/0
[90/30720] via 13.1.1.3, 00:04:30, FastEthernet0/1
R1#
5.改小R2的F0/1接口的延时
R2(config)#int f0/1
R2(config-if)#delay 9
R2(config-if)#do show int f0/1
FastEthernet0/1 is up, line protocol is up
Hardware is Gt96k FE, address is c202.4cf2.0001 (bia c202.4cf2.0001)
Internet address is 23.1.1.2/24
MTU 1500 bytes, BW 100000 Kbit, DLY 90 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
6.在R1上面通过show ip eigrp topology命令，到3.3.3.3出现了两条路径
R1#show ip eigrp topology
IP-EIGRP Topology Table for AS(10)/ID(1.1.1.1)
Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply,
r - reply Status, s - sia Status
P 1.1.1.0/24, 1 successors, FD is 128256
via Connected, Loopback0
P 3.3.3.0/24, 1 successors, FD is 156160
via 13.1.1.3 (156160/128256), FastEthernet0/1
via 12.1.1.2 (158464/155904), FastEthernet0/0
P 12.1.1.0/24, 1 successors, FD is 28160
via Connected, FastEthernet0/0
P 13.1.1.0/24, 1 successors, FD is 28160
via Connected, FastEthernet0/1
P 23.1.1.0/24, 1 successors, FD is 30464
via 12.1.1.2 (30464/27904), FastEthernet0/0
via 13.1.1.3 (30720/28160), FastEthernet0/1
R1#
7.R1路由表到3.3.3.0/24也有两条路由
R1#show ip route eigrp
3.0.0.0/24 is subnetted, 1 subnets
D 3.3.3.0 [90/156160] via 13.1.1.3, 00:04:50, FastEthernet0/1
[90/158464] via 12.1.1.2, 00:04:50, FastEthernet0/0
23.0.0.0/24 is subnetted, 1 subnets
D 23.1.1.0 [90/30464] via 12.1.1.2, 00:05:00, FastEthernet0/0
[90/30720] via 13.1.1.3, 00:05:00, FastEthernet0/1
R1#
四.用c7200-advipservicesk9-mz.152-4.S2.image dynamips测试
---相同的拓扑，相同的基本配置，只是f0/1改成f1/0
1.配置完成后，在R1上面通过show ip eigrp topology命令，到3.3.3.3只有一条路径
R1#show version
Cisco IOS Software, 7200 Software (C7200-ADVIPSERVICESK9-M), Version 15.2(4)S2, RELEASE SOFTWARE (fc1)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2012 by Cisco Systems, Inc.
Compiled Tue 11-Dec-12 13:33 by prod_rel_team
ROM: ROMMON Emulation Microcode
BOOTLDR: 7200 Software (C7200-ADVIPSERVICESK9-M), Version 15.2(4)S2, RELEASE SOFTWARE (fc1)
R1 uptime is 4 minutes
System returned to ROM by unknown reload cause - suspect boot_data[BOOT_COUNT] 0x0, BOOT_COUNT 0, BOOTDATA 19
System image file is "ftp://255.255.255.255/unknown" TARGET="_blank">tftp://255.255.255.255/unknown"
Last reload reason: Unknown reason
This product contains cryptographic features and is subject to United
States and local country laws governing import, export, transfer and
use. Delivery of Cisco cryptographic products does not imply
third-party authority to import, export, distribute or use encryption.
Importers, exporters, distributors and users are responsible for
R1#show ip eigrp topology
EIGRP-IPv4 Topology Table for AS(10)/ID(1.1.1.1)
Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply,
r - reply Status, s - sia Status
P 13.1.1.0/24, 1 successors, FD is 28160
via Connected, FastEthernet1/0
via Rconnected (28160/0)
P 23.1.1.0/24, 1 successors, FD is 30720
via 13.1.1.3 (30720/28160), FastEthernet1/0
P 3.3.3.0/24, 1 successors, FD is 156160
via 13.1.1.3 (156160/128256), FastEthernet1/0
P 12.1.1.0/24, 1 successors, FD is 28160
via Connected, FastEthernet0/0
via Rconnected (28160/0)
P 1.1.1.0/24, 1 successors, FD is 128256
via Connected, Loopback0
2.在R1上面通过show ip eigrp topology all-links命令，到3.3.3.3有两条路径的FD差不多，但后者AD等于前者FD
R1#show ip eigrp topology all-links
EIGRP-IPv4 Topology Table for AS(10)/ID(1.1.1.1)
Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply,
r - reply Status, s - sia Status
P 13.1.1.0/24, 1 successors, FD is 28160, serno 4
via Connected, FastEthernet1/0
via 12.1.1.2 (33280/30720), FastEthernet0/0
via Rconnected (28160/0)
P 23.1.1.0/24, 1 successors, FD is 30720, serno 6
via 13.1.1.3 (30720/28160), FastEthernet1/0
P 3.3.3.0/24, 1 successors, FD is 156160, serno 5
via 13.1.1.3 (156160/128256), FastEthernet1/0
via 12.1.1.2 (158720/156160), FastEthernet0/0
P 12.1.1.0/24, 1 successors, FD is 28160, serno 3
via Connected, FastEthernet0/0
via Rconnected (28160/0)
P 1.1.1.0/24, 1 successors, FD is 128256, serno 2
via Connected, Loopback0
R1#
3.在R1上面修改variance为2，并确认最大路径数为默认的4
R1(config)#router eigrp 10
R1(config-router)#variance 2
R1(config-router)#do show ip protocols
*** IP Routing is NSF aware ***
Routing Protocol is "eigrp 10"
Outgoing update filter list for all interfaces is not set
Incoming update filter list for all interfaces is not set
Default networks flagged in outgoing updates
Default networks accepted from incoming updates
EIGRP-IPv4 Protocol for AS(10)
Metric weight K1=1, K2=0, K3=1, K4=0, K5=0
NSF-aware route hold timer is 240
Router-ID: 1.1.1.1
Topology : 0 (base)
Active Timer: 3 min
Distance: internal 90 external 170
Maximum path: 4
Maximum hopcount 100
Maximum metric variance 2
Automatic Summarization: disabled
Maximum path: 4
Routing for Networks:
1.1.1.1/32
12.1.1.1/32
13.1.1.1/32
Passive Interface(s):
Loopback0
Routing Information Sources:
Gateway Distance Last Update
12.1.1.2 90 00:01:06
13.1.1.3 90 00:01:06
Distance: internal 90 external 170
R1(config-router)#
4.在R2上面不需要做任何配置，R1有两条到3.3.3.0/24的非等价路由
R1#show ip route eigrp | begin Gate
Gateway of last resort is not set
3.0.0.0/24 is subnetted, 1 subnets
D 3.3.3.0 [90/156160] via 13.1.1.3, 00:02:37, FastEthernet1/0
[90/158720] via 12.1.1.2, 00:02:37, FastEthernet0/0
23.0.0.0/24 is subnetted, 1 subnets
D 23.1.1.0 [90/30720] via 13.1.1.3, 00:02:37, FastEthernet1/0
R1#
5.甚至将R2的f1/0接口延时改大,AD比FD要大一点，R1到3.3.3.0/24的两条非对称路由依然存在
---下面时将R2的f1/0的delay设置成19的情况，（100+19+500）*256= 158464
R1#show ip eigrp topology all-links
EIGRP-IPv4 Topology Table for AS(10)/ID(1.1.1.1)
Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply,
r - reply Status, s - sia Status
P 13.1.1.0/24, 1 successors, FD is 28160, serno 4
via Connected, FastEthernet1/0
via 12.1.1.2 (35584/33024), FastEthernet0/0
P 23.1.1.0/24, 1 successors, FD is 30720, serno 6
via 13.1.1.3 (30720/28160), FastEthernet1/0
P 3.3.3.0/24, 2 successors, FD is 156160, serno 9
via 13.1.1.3 (156160/128256), FastEthernet1/0
via 12.1.1.2 (161024/158464), FastEthernet0/0
P 12.1.1.0/24, 1 successors, FD is 28160, serno 3
via Connected, FastEthernet0/0
P 1.1.1.0/24, 1 successors, FD is 128256, serno 2
via Connected, Loopback0
via Rconnected (128256/0)
R1#
R1#clear ip route *
R1#show ip route ei
R1#show ip route eigrp | begin Gate
Gateway of last resort is not set
3.0.0.0/24 is subnetted, 1 subnets
D 3.3.3.0 [90/156160] via 13.1.1.3, 00:00:09, FastEthernet1/0
[90/158976] via 12.1.1.2, 00:00:09, FastEthernet0/0
23.0.0.0/24 is subnetted, 1 subnets
D 23.1.1.0 [90/30720] via 13.1.1.3, 00:00:09, FastEthernet1/0
R1#
6.把R2的f1/0接口延时改为20，比较奇怪的是R1上执行show ip eigrp topology all-links都看不到第二条了
R1#show ip eigrp topology all-links
EIGRP-IPv4 Topology Table for AS(10)/ID(1.1.1.1)
Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply,
r - reply Status, s - sia Status
P 13.1.1.0/24, 1 successors, FD is 28160, serno 4
via Connected, FastEthernet1/0
via 12.1.1.2 (35840/33280), FastEthernet0/0
P 23.1.1.0/24, 1 successors, FD is 30720, serno 6
via 13.1.1.3 (30720/28160), FastEthernet1/0
P 3.3.3.0/24, 1 successors, FD is 156160, serno 10
via 13.1.1.3 (156160/128256), FastEthernet1/0
P 12.1.1.0/24, 1 successors, FD is 28160, serno 3
via Connected, FastEthernet0/0
P 1.1.1.0/24, 1 successors, FD is 128256, serno 2
via Connected, Loopback0
via Rconnected (128256/0)
R1#show ip route eigrp | begin Gate
Gateway of last resort is not set
3.0.0.0/24 is subnetted, 1 subnets
D 3.3.3.0 [90/156160] via 13.1.1.3, 00:00:45, FastEthernet1/0
23.0.0.0/24 is subnetted, 1 subnets
D 23.1.1.0 [90/30720] via 13.1.1.3, 00:22:35, FastEthernet1/0
R1#
