show ip cef

[akhila.pradhan@wipro.com]

Hi,

I have a Cisco 3750 switch and by default CEF is enabled. I just want to know if multiple VLANs are configured in the switch then in show ip cef command o/p all the VLAN information will show.

Please help me to understand this concept. 

Regards

Akhil

[AymanMunassar]

What do you mean by multiple vlans?

[akhila.pradhan@wipro.com]

Hi,

I have following VLAN configured in my 3750 switch and CEF is enabled by default. However, it is not showing any entries for all Vlans in show ip cef command..? only vlan 151 is showing details showing in show ip cef. Please help me to understand.

UPELKONDS01C3750#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

192.169.0.0/24       attached             Vlan151

192.169.0.0/32       receive              Vlan151

192.169.0.50/32      receive              Vlan151

192.169.0.255/32     receive              Vlan151

224.0.0.0/4          drop

224.0.0.0/24         receive             

240.0.0.0/4          drop

255.255.255.255/32   receive             

UPELKONDS01C3750#

Vlan1 is up, line protocol is down
  Hardware is EtherSVI, address is 0024.1337.ed40 (bia 0024.1337.ed40)
  Internet address is 10.10.10.1/30
  MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec,
     reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation ARPA, loopback not set
  Keepalive not supported
  ARP type: ARPA, ARP Timeout 04:00:00
  Last input never, output 4w4d, output hang never
  Last clearing of "show interface" counters 3d00h
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
  Queueing strategy: fifo
  Output queue: 0/40 (size/max)
  5 minute input rate 0 bits/sec, 0 packets/sec
  5 minute output rate 0 bits/sec, 0 packets/sec
     0 packets input, 0 bytes, 0 no buffer
     Received 0 broadcasts (0 IP multicasts)
     0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
     0 packets output, 0 bytes, 0 underruns
     0 output errors, 0 interface resets
     0 output buffer failures, 0 output buffers swapped out
Vlan150 is up, line protocol is up
  Hardware is EtherSVI, address is 0024.1337.ed50 (bia 0024.1337.ed50)
  Description: Flexi internal
  MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec,
     reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation ARPA, loopback not set
  Keepalive not supported
  ARP type: ARPA, ARP Timeout 04:00:00
  Last input never, output never, output hang never
  Last clearing of "show interface" counters 3d00h
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
  Queueing strategy: fifo
  Output queue: 0/40 (size/max)
  5 minute input rate 0 bits/sec, 0 packets/sec
  5 minute output rate 0 bits/sec, 0 packets/sec
     0 packets input, 0 bytes, 0 no buffer
     Received 0 broadcasts (0 IP multicasts)
     0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
     0 packets output, 0 bytes, 0 underruns
     0 output errors, 0 interface resets
     0 output buffer failures, 0 output buffers swapped out
Vlan151 is up, line protocol is up
  Hardware is EtherSVI, address is 0024.1337.ed51 (bia 0024.1337.ed51)
  Description: Flexi MGMT
  Internet address is 192.169.0.50/24
  MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec,
     reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation ARPA, loopback not set
  Keepalive not supported
  ARP type: ARPA, ARP Timeout 04:00:00
  Last input 15:10:04, output 15:10:16, output hang never
  Last clearing of "show interface" counters 3d00h
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
  Queueing strategy: fifo
  Output queue: 0/40 (size/max)
  5 minute input rate 0 bits/sec, 0 packets/sec
  5 minute output rate 0 bits/sec, 0 packets/sec
     3 packets input, 180 bytes, 0 no buffer
     Received 0 broadcasts (0 IP multicasts)
     0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
     8 packets output, 512 bytes, 0 underruns
     0 output errors, 0 interface resets
     0 output buffer failures, 0 output buffers swapped out
Vlan160 is up, line protocol is up
  Hardware is EtherSVI, address is 0024.1337.ed52 (bia 0024.1337.ed52)
  Description: Site internal data
  MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec,
     reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation ARPA, loopback not set
  Keepalive not supported
  ARP type: ARPA, ARP Timeout 04:00:00
  Last input 4w4d, output never, output hang never
  Last clearing of "show interface" counters 3d00h
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
  Queueing strategy: fifo
  Output queue: 0/40 (size/max)
  5 minute input rate 0 bits/sec, 0 packets/sec
  5 minute output rate 0 bits/sec, 0 packets/sec
     0 packets input, 0 bytes, 0 no buffer
     Received 0 broadcasts (0 IP multicasts)
     0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
     0 packets output, 0 bytes, 0 underruns
     0 output errors, 0 interface resets
     0 output buffer failures, 0 output buffers swapped out
Vlan200 is up, line protocol is up
  Hardware is EtherSVI, address is 0024.1337.ed53 (bia 0024.1337.ed53)
  Description: External Applictions
  Internet address is 10.155.59.2/26
  MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec,
     reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation ARPA, loopback not set
  Keepalive not supported
  ARP type: ARPA, ARP Timeout 04:00:00
  Last input 00:00:00, output 00:00:00, output hang never
  Last clearing of "show interface" counters 3d00h
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
  Queueing strategy: fifo
  Output queue: 0/40 (size/max)
  5 minute input rate 1000 bits/sec, 3 packets/sec
  5 minute output rate 2000 bits/sec, 3 packets/sec
     946039 packets input, 58628132 bytes, 0 no buffer
     Received 0 broadcasts (0 IP multicasts)
     0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
     936366 packets output, 61793516 bytes, 0 underruns
     0 output errors, 0 interface resets
     0 output buffer failures, 0 output buffers swapped out
Vlan201 is up, line protocol is up
  Hardware is EtherSVI, address is 0024.1337.ed54 (bia 0024.1337.ed54)
  Description: External OAM
  Internet address is 10.155.58.2/25
  MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec,
     reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation ARPA, loopback not set
  Keepalive not supported
  ARP type: ARPA, ARP Timeout 04:00:00
  Last input 00:00:00, output 00:00:00, output hang never
  Last clearing of "show interface" counters 3d00h
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
  Queueing strategy: fifo
  Output queue: 0/40 (size/max)
  5 minute input rate 21000 bits/sec, 45 packets/sec
  5 minute output rate 23000 bits/sec, 45 packets/sec
     11925604 packets input, 717402180 bytes, 0 no buffer
     Received 0 broadcasts (0 IP multicasts)
     0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
     11906058 packets output, 763853788 bytes, 0 underruns
     0 output errors, 0 interface resets
     0 output buffer failures, 0 output buffers swapped out
Vlan202 is up, line protocol is up
  Hardware is EtherSVI, address is 0024.1337.ed55 (bia 0024.1337.ed55)
  Description: External One-NDS replication
  Internet address is 10.155.58.130/25
  MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec,
     reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation ARPA, loopback not set
  Keepalive not supported
  ARP type: ARPA, ARP Timeout 04:00:00
  Last input 00:00:00, output 00:00:00, output hang never
  Last clearing of "show interface" counters 3d00h
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
  Queueing strategy: fifo
  Output queue: 0/40 (size/max)
  5 minute input rate 1000 bits/sec, 3 packets/sec
  5 minute output rate 1000 bits/sec, 3 packets/sec
     943194 packets input, 58457424 bytes, 0 no buffer
     Received 0 broadcasts (0 IP multicasts)
     0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
     933842 packets output, 61632218 bytes, 0 underruns
     0 output errors, 0 interface resets
     0 output buffer failures, 0 output buffers swapped out

[AymanMunassar]

Now I know, you mean the SVI.

Look, if you want to watch the active SVI in your switch, use show ip interfaces brief

All the SVIs that you have instantiated will be shown mostly at the end of the command.

[Richard Burts]

The original poster tells us it is a 3750 switch but does not tell us whether it is operating as a layer 2 switch (ip routing not enabled) or as a layer 3 switch (ip routing is enabled). Knowing this would be helpful in understanding the situation.

I agree that it would be helpful if we saw the output of 

show ip interface brief and of

show ip route

HTH

Rick

[akhila.pradhan@wipro.com]

Hi Richard,

please find the requested command o/p.

Regards

Akhil

[AymanMunassar]

All the access ports that you assigned the VLANs to are in the down down state.

no shut down them

[akhila.pradhan@wipro.com]

Hi Ayman,

Just answer to my query, what is the relevant of no shut down here.

Regards

Akhil

[AymanMunassar]

If an SVI does not have a port that is assigned to it and it is up, it will not work

[AymanMunassar]

Try with the 1/0/8 and check the output

[Richard Burts · Accepted solution]

Thank you for the outputs that you have posted. They do clarify the issue. I note that the config shows that ip routing is enabled. This means that the switch can have multiple layer 3 interfaces active and functioning. And the output of show ip interface brief does confirm that multiple layer 3 interfaces are active. But the output of show ip route shows that only one subnet, associated with one interface, is in the routing table. Looking more closely at the config we find that most of your layer 3 interfaces are assigned to vrfs. This explains the output that you are seeing for sh ip cef. There is only one subnet active in the main ip routing tabel. And there are cef entries for that subnet shown in the output of show ip cef. I expect that there are cef entries for the other interfaces but that you would need to specify the vrf in the show ip cef command to see them.

HTH

Rick

[Richard Burts]

I am glad that you found my explanation helpful. Thank you for marking this question as solved. This will help other participants in the forum to identify discussions that have helpful information. These forums are excellent places to ask questions and to learn about networking. I hope to see you continue to be active in the forum.

HTH

Rick