我們在接口配置過程中，幀中繼的DLCI號和IP映射時也沒有配置broadcast 參數，這類問題該如何解決?下面小編給你帶來的內容回答以上疑問。
EIGRP路由協議的配置拓撲圖
EIGRP路由協議的配置實例解析
R1(config)#router eigrp 100
R1(config-router)#no auto-summary //關閉自動彙總
R1(config-router)#net //宣告路由條目
R1(config-router)#end
R2(config)#router eigrp 100
R2(config-router)#no auto-summary
R2(config-router)#net
R2(config-router)#net //宣告路由條目
R2(config-router)#end
R3(config)#router eigrp 100
R3(config-router)#no auto-summary
R3(config-router)#net
R3(config-router)#net
R3(config-router)#end
檢查：
R1#show ip eigrp neighbors //查看eigrp 鄰居表，發現並沒有鄰居
IP-EIGRP neighbors for process 100
R1#show ip eigrp topology //查看EIGRP 拓撲表，並沒有學習到任何的路由
IP-EIGRP Topology Table for AS(100)/ID()
Codes: P – Passive, A – Active, U – Update, Q – Query, R – Reply,
r – reply Status, s – sia Status
P , 1 successors, FD is 2169856
via Connected, Serial0/0
因爲幀中繼默認爲NBMA 模式，也就是非廣播的多路訪問模式，它會阻止廣播數據和組播數據，我們在接口配置過程中，幀中繼的DLCI 號和IP 映射時也沒有配置broadcast 參數，而EIGRP 路由協議通過組播地址 來發送相應的路由信息(比如hello、update 等數據包)，所以R1 並沒有發現任何的鄰居路由器。
爲了能讓EIGRP的路由信息通過幀中繼傳播，在沒有配置broadcast 參數的情況下，我們可以通過單播的形式來發送EIGRP 數據包，我們對以上的配置進行改進：
R1(config)#router eigrp 100
R1(config-router)#neighbor serial 0/0 //手工指定鄰居，實現單播方式
R1(config-router)#neighbor serial 0/0
R1(config-router)#end
R2(config)#router eigrp 100
R2(config-router)#neighbor serial 0/0 //手工指定鄰居，實現單播方式
R2(config-router)#end
R3(config)#router eigrp 100
R3(config-router)#neighbor serial 0/0 //手工指定鄰居，實現單播方式
R3(config-router)#end
驗證：
*Mar 1 00:29:18.955: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor (Serial0/0) is up: new adjacency
*Mar 1 00:29:19.115: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor (Serial0/0) is up: new adjacency
R1#show ip eigrp neighbors
IP-EIGRP neighbors for process 100
H Address Interface Hold Uptime SRTT RTO Q Seq
(sec) (ms) Cnt Num
1 Se0/0 156 00:01:19 99 594 0 3
0 Se0/0 154 00:01:19 137 822 0 3
R2#
*Mar 1 00:29:18.979: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor (Serial0/0) is up: new adjacency
R2#
R2#show ip eigrp neighbor
IP-EIGRP neighbors for process 100
H Address Interface Hold Uptime SRTT RTO Q Seq
(sec) (ms) Cnt Num
0 Se0/0 138 00:02:31 171 1026 0 7
R1#show ip route eigrp 100 //查看路由表，可以看到R1 能夠學習到R2 和R3 相應的網絡
is subnetted, 4 subnets
D [90/2297856] via , 00:03:45, Serial0/0
D [90/2297856] via , 00:03:45, Serial0/0
D [90/2297856] via , 00:03:45, Serial0/0
D [90/2297856] via , 00:03:45, Serial0/0
is subnetted, 4 subnets
D [90/2297856] via , 00:03:45, Serial0/0
D [90/2297856] via , 00:03:45, Serial0/0
D [90/2297856] via , 00:03:45, Serial0/0
D [90/2297856] via , 00:03:45, Serial0/0
R1#ping //驗證是否可以訪問R2 的網絡
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to , timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 20/56/104 ms
R1#ping //驗證是否可以訪問R3 的網絡
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to , timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 8/52/124 ms
查看R2 的路由表：
R2#show ip route
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
is subnetted, 4 subnets
C is directly connected, Loopback3
C is directly connected, Loopback2
C is directly connected, Loopback1
C is directly connected, Loopback0
C is directly connected, Serial0/0
發現R2 並沒有學習到R3 的 網絡， R1 通過S0/0 接口學習到R3 宣告的網絡，因爲R1 s0/0 接口的水平分割機制導致R1 不會再由這個接口S0/0 發佈出去，所以R2無法學習到R3 宣告的網絡，同理，R3 也無法學習到R2 宣告的網絡。
對幀中繼配置進行修正，使用broadcast 參數：
R1(config)#router eigrp 100
R1(config-router)#no neighbor s0/0 //取消手工指定鄰居
*Mar 1 00:42:29.807: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor (Serial0/0) is down:
R1(config-router)#no neighbor s0/0
*Mar 1 00:42:32.623: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor (Serial0/0) is down:
R1(config-router)#exit
R1(config)#int s0/0
R1(config-if)#no fram map ip 102 //取消之前不帶broadcast 參數的靜態映射
R1(config-if)#no fram map ip 103
R1(config-if)#frame map ip 102 broadcast
R1(config-if)#frame map ip 103 broadcast
R1(config-if)#end
R2(config)#router eigrp 100
R2(config-router)#no neighbor Serial0/0
R2(config-router)#int s0/0
R2(config-if)#no frame-relay map ip 201
R2(config-if)# frame-relay map ip 201 broadcast
R3(config)#router eigrp 100
R3(config-router)#no neighbor Serial0/0
R3(config-router)#int s0/0
R3(config-if)#no
*Mar 1 00:47:58.943: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor (Serial0/0) is up: new adjacency
R3(config-if)#no frame-relay map ip 301
R3(config-if)#frame-relay map ip 301 broadcast
R3(config-if)#end
驗證結果：
可以看到添加了broadcast 後，幀中繼可以正常的.傳遞組播數據了，R1 就可以和R2 和R3 建立鄰居關係並正常學習到路由。
R1#show ip eigrp neighbors
IP-EIGRP neighbors for process 100
H Address Interface Hold Uptime SRTT RTO Q Seq
(sec) (ms) Cnt Num
1 Se0/0 178 00:00:03 906 5000 0 7
0 Se0/0 178 00:01:57 1040 5000 0 6
R1#show ip route eigrp 100
is subnetted, 4 subnets
D [90/2297856] via , 00:00:53, Serial0/0
D [90/2297856] via , 00:00:53, Serial0/0
D [90/2297856] via , 00:00:53, Serial0/0
D [90/2297856] via , 00:00:53, Serial0/0
is subnetted, 4 subnets
D [90/2297856] via , 00:02:46, Serial0/0
D [90/2297856] via , 00:02:46, Serial0/0
D [90/2297856] via , 00:02:46, Serial0/0
D [90/2297856] via , 00:02:46, Serial0/0
查看R3 的路由表，發現R3 並沒有學習到R2 的網絡，這是因爲R1 默認情況下接口有水平。
R3#show ip route
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
is subnetted, 4 subnets
C is directly connected, Loopback0
C is directly connected, Loopback1
C is directly connected, Loopback2
C is directly connected, Loopback3
C is directly connected, Serial0/0
將R1 接口的水平分割關閉：
R1(config)#interface serial 0/0
R1(config-if)#no ip split-horizon eigrp 100
R1(config-if)#end
當R1 的水平分割關閉後，EIGRP 進程會出現相應提示：
*Mar 1 00:52:25.055: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor (Serial0/0) is resync: split horizon changed
*Mar 1 00:52:25.055: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor (Serial0/0) is resync: split horizon changed
查看R1 接口S0/0 的情況：
R1#show ip int s0/0 | include Split
Split horizon is disabled
查看R2 的路由表：
R2#show ip route eigrp 100
is subnetted, 4 subnets
D [90/2809856] via , 00:08:03, Serial0/0
D [90/2809856] via , 00:08:03, Serial0/0
D [90/2809856] via , 00:08:03, Serial0/0
D [90/2809856] via , 00:08:03, Serial0/0
雖然R2 路由表中有 網絡，但R2 並沒有ping 通，這是什麼原因?
因爲R3 的串行口幀中繼配置時，只做了IP 和DLCI 號的對應，沒有做IP 192。168.1.2 和DLCI 號的映射，所以R2 ping 時，採用的源地址爲，通過路由表發現目的地址 具有符合的條目，轉發接口爲，於是由R1 轉發到R3，R3 在回包過程時，源地址爲，而目標地址爲，但它不知道這個地址怎麼轉發於是就丟棄。
R3(config)#int s0/0
R3(config-if)#frame-relay map ip 301 broadcast
R2(config-if)#end
R2(config)#int s0/0
R2(config-if)#frame-relay map ip 201 broadcast
R2(config-if)#end
驗證結果：
R2#ping
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to , timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 44/88/160 ms
