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tech:network:cef:cef

CEF

Cisco Express Forwarding

Home Physical Lab Topologies

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