IP CEF Cisco

3560 Switch platform

CEF

• show ip cef 0.0.0.0 0.0.0.0 internal

SW1#<input>show cef fib</input>
119 allocated IPv4 entries, 0 failed allocations

SW1#<input>show ip cef switching statistics</input>

       Reason                          Drop       Punt  Punt2Host
RP RIB Packet destined for us             0    1412459          0
RP RIB Total                              0    1412459          0

RP LES No adjacency                    6399          0     100446
RP LES TTL expired                        0          0         36
RP LES Total                           6399          0     100482

All    Total                           6399    1412459     100482

SW1#<input>show ip cef vrf * summary</input>
IPv4 CEF is enabled for distributed and running
VRF Default:
 130 prefixes (130/0 fwd/non-fwd)
 Default network 0.0.0.0/0
 Table id 0, 0 resets
 Database epoch: 1 (130 entries at this epoch)

Heimdal#<input>sh ip cef</input>
Prefix               Next Hop             Interface
0.0.0.0/0            172.16.4.1
0.0.0.0/32           receive
172.16.4.0/24        attached             Vlan1
172.16.4.0/32        receive
172.16.4.1/32        attached             Vlan1
172.16.4.5/32        attached             Vlan1
172.16.4.15/32       attached             Vlan1
172.16.4.16/32       attached             Vlan1
172.16.4.20/32       receive
172.16.4.22/32       attached             Vlan1
172.16.4.233/32      attached             Vlan1
172.16.4.254/32      attached             Vlan1
172.16.4.255/32      receive
192.168.22.0/24      172.16.4.16
192.168.128.0/24     attached             Vlan10
192.168.128.0/32     receive
192.168.128.1/32     receive
192.168.128.255/32   receive
192.168.130.0/24     attached             Vlan12
192.168.130.0/32     receive
192.168.130.1/32     receive
192.168.130.126/32   attached             Vlan12
192.168.138.149/32   attached             Vlan20
192.168.138.255/32   receive
192.168.140.0/24     attached             Vlan22
<notice>...OUTPUT OMITTED...</notice>

Adjacency table

SW1#<input>show adjacency</input>
Protocol Interface                 Address
IP       Vlan1                     172.16.4.5(7)
IP       Vlan1                     stella.tekkom.dk(7)
IP       Vlan1                     mars(9)
IP       Vlan1                     172.16.4.50(9)
IP       Vlan1                     172.16.4.60(9)
IP       Vlan1                     172.16.4.66(7)
IP       Vlan12                    192.168.130.126(7)
IP       Vlan12                    hot-pc-gf.tekkom.local(7)
IP       Vlan28                    192.168.146.145(7)
IP       Vlan28                    192.168.146.146(7)
IP       Vlan28                    192.168.146.149(7)
IP       Vlan28                    192.168.146.150(7)
IP       Vlan28                    192.168.146.151(7)

Looking at details

SW1#<input>show adjacency 172.16.4.16 detail</input>
Protocol Interface                 Address
IP       Vlan1                     mars(9)
                                   0 packets, 0 bytes
                                   epoch 0
                                   sourced in sev-epoch 4874
                                   Encap length 14
                                   <notice>0007E9400ABF</notice>0019E75108C00800
                                   ARP
SW1#<input>sh arp | inc 172.16.4.16</input>
Internet  172.16.4.16             1   <notice>0007.e940.0abf</notice>  ARPA   Vlan1

Notes

If you enable CEF and then create an access list that uses the log keyword, the packets that match the access list are not CEF switched. They are fast switched. Logging disables CEF.

http://www.cisco.com/en/US/docs/ios/12_2/switch/configuration/guide/xcfcef.html

Links

• See [1]