Layer3 counter for SVI on 4900M

Answered Question
Jun 9th, 2010

Hi,

I am testing a Catalyst 4900M for ipv4/ipv6 routing between SVI (int vlan xxx)

and found that the interface counters are not reflecting the real amount of traffic.

I believe that only the traffic to the processor is counted (for example ospf traffic),

but i am missing counters for the hardware-forwarded packets/bytes for those vlans.

Any hints? Is there a special snmp-variable/table for it

(the "normal" interface counter thru snmp

show the same values as the show interface vlan xxx command).

currently tested image is cat4500e-entservicesk9-mz.122-53.SG1.bin,

example for show interface is

Vlan501 is up, line protocol is up
  Hardware is Ethernet SVI, address is 0022.56ba.897f (bia 0022.56ba.897f)
  Description: XXXXX

   Internet address is xxx.XXX.xxx.XXX/28
  MTU 2018 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 never, output hang never
  Last clearing of "show interface" counters never
  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
  L3 in Switched: ucast: 0 pkt, 0 bytes - mcast: 0 pkt, 0 bytes
  L3 out Switched: ucast: 0 pkt, 0 bytes - mcast: 0 pkt, 0 bytes
    0 packets input, 0 bytes, 0 no buffer
     Received 1602141 broadcasts (0 IP multicasts)
     0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
    1345389 packets output, 122115475 bytes, 0 underruns
     0 output errors, 0 interface resets
     0 output buffer failures, 0 output buffers swapped out

Sure, there are flowing more than  1 MBit/s in and out.

Any suggestions ?

Thank you ,

Jürgen Marenda.

I have this problem too.
0 votes
Correct Answer by Chad Peterson about 3 years 8 months ago

Under your SVI, try entering the command "counters".

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Calin Chiorean Wed, 06/09/2010 - 02:47

This story is very unclear for me also.

It seems that SVI (vlan interface) traffic counters don't show  much traffic because it only counts traffic that hits the CPU, not  traffic that is hardware-switched as sustained by some Cisco reports and users.

On the other hand I see a lot of traffic on some on my SVI interfaces, and almost nothing on others. Maybe is IOS related.

I will check some more into this.

Calin


Giuseppe Larosa Wed, 06/09/2010 - 05:51

Hello Jurgen,

you  see CEF multilayer switching in action here

higher platforms like C6500 in modern IOS images are able to report correct stats on SVIs

It wasn't so in C6500 Hybrid mode, where you had a scenario similar to what you see on the C4900M

I think it is platform and IOS version dependent the capability to show current counters under SVI interfaces

I agree it would be handy to have correct statistics under SVI interfaces.

Hope to help

Giuseppe

glen.grant Wed, 06/09/2010 - 07:56

  Try using "show interface summary "  , this kind of breaks it out into whats hitting the SVI what is going to the interface statitstics .

j-marenda Fri, 06/11/2010 - 00:34

no, show int sum does not do the trick:

  Interface               IHQ   IQD  OHQ   OQD  RXBS RXPS  TXBS TXPS TRTL
-------------------------------------------------------------------------
* Vlan501                  0     0    0     0     0    0     0    0    0

while the physical interfaces show byte/packets.

(at least on the current ios).

Jürgen.

j-marenda Tue, 08/10/2010 - 01:05

Yes,

that is the trick;

they are also readable thru snmp.

(hope that it works also long-term;

ip verify unicast.... did work fine for approx. 3 weeks on those switches but stopped accepting traffic .

Searching, i found the release note saying it's not working/unsupported command)

Any know issues with that command, cpu-load ?

Thank you for this!

Jürgen.

#sh run int vlan 501
Building configuration...

Current configuration : 165 bytes
!
interface Vlan501
description xxxxxxxx
mtu 2018
ip address xxx.xxx.xxx.xxx 255.255.255.xxx
ip broadcast-address xxx.xxx.xxx.xxx
no ip proxy-arp
counter
end

!

#

#sh int vlan 501

Vlan501 is up, line protocol is up

  Hardware is Ethernet SVI, address is XXXX.XXXX.XXXX (bia XXXX.XXXX.XXXX)
  Description: xxxxxxx
  Internet address is xxx.xxx.xxx.xxx/xx
  MTU 2018 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 never, output hang never
  Last clearing of "show interface" counters 00:23:11
  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 7116000 bits/sec, 1123 packets/sec
  5 minute output rate 4035000 bits/sec, 955 packets/sec
L3 in Switched: ucast: 1545430 pkt, 1080705148 bytes - mcast: 0 pkt, 0 bytes
  L3 out Switched: ucast: 1356423 pkt, 792911416 bytes - mcast: 0 pkt, 0 bytes
    1545430 packets input, 1080705148 bytes, 0 no buffer
     Received 701 broadcasts (0 IP multicasts)
     0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
     1363458 packets output, 793401879 bytes, 0 underruns
     0 output errors, 0 interface resets
     0 output buffer failures, 0 output buffers swapped out
#

Chad Peterson Wed, 08/11/2010 - 09:32

There isn't any impact to the CPU.  In the command reference it covers this command a bit:

http://www.cisco.com/en/US/docs/switches/lan/catalyst4500/12.2/54sg/command/reference/ch2a_ins.html#wp1036313

Honestly I'm not sure why this isn't just on by default.  I'm looking into that a bit now.  There is a total number of switchports that can have counter collection, 4092.  I'm assuming that this could be the though as to why we don't enable it by default.

babloo@123 Tue, 01/21/2014 - 05:57

Hello Peter,

Today I have seen very abnormal behaviour in 4500X. I have created SVI and advertised in OSPF. Everything is working fine but when I see the traffic counter , I am surprised to see that on INPUT there is a traffic but on OUTPUT there is no traffic whereas I see hits for output too. INPUT Traffic I see on my primary switch & Output traffic I see it on secondary switch. For other vlans its working fine. Please find the below output and suggest with recommendation.

HTAINNOI08INTDS0001#sh int vlan 977
Vlan977 is up, line protocol is up
  Hardware is Ethernet SVI, address is c067.af87.0d1f (bia c067.af87.0d1f)
  Description: MANAGE ** CLARIANT-INT **
  Internet address is 192.8.184.106/29
  MTU 1500 bytes, BW 128 Kbit/sec, DLY 10 usec,
     reliability 255/255, txload 1/255, rxload 105/255
  Encapsulation ARPA, loopback not set
  Keepalive not supported
  ARP type: ARPA, ARP Timeout 04:00:00
  Last input 00:00:00, output never, output hang never
  Last clearing of "show interface" counters never
  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 53000 bits/sec, 56 packets/sec
  5 minute output rate 0 bits/sec, 0 packets/sec
  L3 in Switched: ucast: 1377161 pkt, 172430132 bytes - mcast: 0 pkt, 0 bytes
  L3 out Switched: ucast: 173529 pkt, 43272564 bytes - mcast: 0 pkt, 0 bytes
  IPv6 L3 in Switched: ucast: 0 pkt, 0 bytes - mcast: 0 pkt, 0 bytes
  IPv6 L3 out Switched: ucast: 0 pkt, 0 bytes - mcast: 0 pkt, 0 bytes
     1377161 packets input, 172430132 bytes, 0 no buffer
     Received 40829 broadcasts (0 IP multicasts)
     0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
     211532 packets output, 45117721 bytes, 0 underruns
     0 output errors, 2 interface resets
     0 unknown protocol drops
     0 output buffer failures, 0 output buffers swapped out
HTAINNOI08INTDS0001#


HTAINNOI08INTDS0002#sh int vlan 977
Vlan977 is up, line protocol is up
  Hardware is Ethernet SVI, address is f0f7.55c4.887f (bia f0f7.55c4.887f)
  Description: MANAGE ** CLARIANT-INT **
  Internet address is 192.8.184.107/29
  MTU 1500 bytes, BW 128 Kbit/sec, DLY 10 usec,
     reliability 255/255, txload 193/255, rxload 1/255
  Encapsulation ARPA, loopback not set
  Keepalive not supported
  ARP type: ARPA, ARP Timeout 04:00:00
  Last input 00:00:01, output never, output hang never
  Last clearing of "show interface" counters 03:56:52
  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 97000 bits/sec, 47 packets/sec
  L3 in Switched: ucast: 102 pkt, 4980 bytes - mcast: 0 pkt, 0 bytes
  L3 out Switched: ucast: 564933 pkt, 139790509 bytes - mcast: 0 pkt, 0 bytes
  IPv6 L3 in Switched: ucast: 0 pkt, 0 bytes - mcast: 0 pkt, 0 bytes
  IPv6 L3 out Switched: ucast: 0 pkt, 0 bytes - mcast: 0 pkt, 0 bytes
     102 packets input, 4980 bytes, 0 no buffer
     Received 5141 broadcasts (0 IP multicasts)
     0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
     570680 packets output, 140065481 bytes, 0 underruns
     0 output errors, 1 interface resets
     0 unknown protocol drops
     0 output buffer failures, 0 output buffers swapped out
HTAINNOI08INTDS0002#

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Posted June 9, 2010 at 2:07 AM
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