tech:network:cef:cef
CEF
Cisco Express Forwarding
R1#sh run | i cef
ip cef
no ipv6 cef
R1#conf t
Enter configuration commands, one per line. End with CNTL/Z.
R1(config)#ip cef
R1(config)#^Z
R1#
*Mar 4 00:30:52.783: %SYS-5-CONFIG_I: Configured from console by console
R1#sh ip cef
Prefix Next Hop Interface
0.0.0.0/0 no route
0.0.0.0/8 drop
0.0.0.0/32 receive
127.0.0.0/8 drop
172.16.1.0/24 attached FastEthernet0/1
172.16.1.0/32 receive FastEthernet0/1
172.16.1.1/32 receive FastEthernet0/1
172.16.1.255/32 receive FastEthernet0/1
172.16.2.0/24 attached FastEthernet0/0
172.16.2.0/32 receive FastEthernet0/0
172.16.2.1/32 receive FastEthernet0/0
172.16.2.2/32 attached FastEthernet0/0
172.16.2.250/32 attached FastEthernet0/0
172.16.2.255/32 receive FastEthernet0/0
172.16.3.0/24 172.16.2.2 FastEthernet0/0
224.0.0.0/4 drop
224.0.0.0/24 receive
240.0.0.0/4 drop
255.255.255.255/32 receive
R1#sh ad
R1#sh adjacency de
R1#sh adjacency detail
Protocol Interface Address
IP FastEthernet0/0 172.16.2.2(11)
0 packets, 0 bytes
epoch 0
sourced in sev-epoch 0
Encap length 14
0024C431126E001B2A7766D20800
ARP
IP FastEthernet0/0 172.16.2.250(7)
0 packets, 0 bytes
epoch 0
sourced in sev-epoch 0
Encap length 14
B827EB1F4500001B2A7766D20800
ARP
R1#sh run | i cef
ip cef
no ipv6 cef
R2#sh run | i cef
ip cef
no ipv6 cef
R2#conf t
Enter configuration commands, one per line. End with CNTL/Z.
R2(config)#ip cef
R2(config)#^Z
R2#
*Mar 4 01:41:03.315: %SYS-5-CONFIG_I: Configured from console by console
R2#sh ip cef
Prefix Next Hop Interface
0.0.0.0/0 no route
0.0.0.0/8 drop
0.0.0.0/32 receive
127.0.0.0/8 drop
172.16.1.0/24 172.16.2.1 FastEthernet0/0
172.16.2.0/24 attached FastEthernet0/0
172.16.2.0/32 receive FastEthernet0/0
172.16.2.1/32 attached FastEthernet0/0
172.16.2.2/32 receive FastEthernet0/0
172.16.2.255/32 receive FastEthernet0/0
172.16.3.0/24 attached FastEthernet0/1
172.16.3.0/32 receive FastEthernet0/1
172.16.3.2/32 receive FastEthernet0/1
172.16.3.255/32 receive FastEthernet0/1
224.0.0.0/4 drop
224.0.0.0/24 receive
240.0.0.0/4 drop
255.255.255.255/32 receive
R2#sh ad
R2#sh adjacency de
R2#sh adjacency detail
Protocol Interface Address
IP FastEthernet0/0 172.16.2.1(11)
0 packets, 0 bytes
epoch 0
sourced in sev-epoch 0
Encap length 14
001B2A7766D20024C431126E0800
ARP
R2#sh run | i cef
ip cef
no ipv6 cef
Let's ping to TFTP server on R2.
R2#ping 172.16.2.250
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 172.16.2.250, timeout is 2 seconds:
.!!!!
Success rate is 80 percent (4/5), round-trip min/avg/max = 1/1/4 ms
R2#sh ip cef
Prefix Next Hop Interface
0.0.0.0/0 no route
0.0.0.0/8 drop
0.0.0.0/32 receive
127.0.0.0/8 drop
172.16.1.0/24 172.16.2.1 FastEthernet0/0
172.16.2.0/24 attached FastEthernet0/0
172.16.2.0/32 receive FastEthernet0/0
172.16.2.1/32 attached FastEthernet0/0
172.16.2.2/32 receive FastEthernet0/0
172.16.2.250/32 attached FastEthernet0/0
172.16.2.255/32 receive FastEthernet0/0
172.16.3.0/24 attached FastEthernet0/1
172.16.3.0/32 receive FastEthernet0/1
172.16.3.2/32 receive FastEthernet0/1
172.16.3.255/32 receive FastEthernet0/1
224.0.0.0/4 drop
224.0.0.0/24 receive
240.0.0.0/4 drop
255.255.255.255/32 receive
R2#sh adjac
R2#sh adjacency deta
R2#sh adjacency detail
Protocol Interface Address
IP FastEthernet0/0 172.16.2.1(11)
0 packets, 0 bytes
epoch 0
sourced in sev-epoch 0
Encap length 14
001B2A7766D20024C431126E0800
ARP
IP FastEthernet0/0 172.16.2.250(7)
0 packets, 0 bytes
epoch 0
sourced in sev-epoch 0
Encap length 14
B827EB1F45000024C431126E0800
ARP
R2#sh adjacency
Protocol Interface Address
IP FastEthernet0/0 172.16.2.1(11)
IP FastEthernet0/0 172.16.2.250(7)
Now, 172.16.2.250 entry appeared on R2 FIB table, Adjacency table.
References
tech/network/cef/cef.txt · Last modified: 2018/04/02 02:52 by 5.9.98.130
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