Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. And see here for current known issues.

New Member

Cisco vg224 FastEthernet 0/0 not reachable every about 5 hours


i have a problem with some vg224, i configered it as following:

vg224-1      protocol sccp, eth0 speed 100, duplex full, ip adress IOS 15.0(1)M7

vg224-2      protocol sccp, eth0 speed auto, duplex auto, ip address, IOS 15.1(4)M2

on both voicegateway everything works fine for a couple of hours, then it unregisters all ports from the cucm and isn't reachable any more via telnet or ping.

if i look at the switch (Catalyst WS-C3750G), everything is fine:

GigabitEthernet1/0/22 is up, line protocol is up (connected)

  Hardware is Gigabit Ethernet, address is 0018.73ac.7e8a (bia 0018.73ac.7e8a)

  Description: VG224-1 VoiceGateway

  MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec,

     reliability 255/255, txload 1/255, rxload 1/255

  Encapsulation ARPA, loopback not set

  Keepalive set (10 sec)

  Full-duplex, 100Mb/s, media type is 10/100/1000BaseTX

  input flow-control is off, output flow-control is unsupported

  ARP type: ARPA, ARP Timeout 04:00:00

  Last input 00:00:41, output 00:00:00, 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

     460662 packets input, 56902140 bytes, 0 no buffer

     Received 3365 broadcasts (0 multicasts)

     0 runts, 0 giants, 0 throttles

     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored

     0 watchdog, 3000 multicast, 0 pause input

     0 input packets with dribble condition detected

     388734 packets output, 54869618 bytes, 0 underruns

     0 output errors, 0 collisions, 7 interface resets

     0 babbles, 0 late collision, 0 deferred

     0 lost carrier, 0 no carrier, 0 PAUSE output

     0 output buffer failures, 0 output buffers swapped out

here is the switch config:

interface GigabitEthernet1/0/22

description VG224-1 Gateway

switchport access vlan 358

switchport mode access

speed 100

duplex full

srr-queue bandwidth share 20 9 1 70

priority-queue out

spanning-tree portfast

service-policy input VOICEMARK


here is the vg224-1 config:

interface FastEthernet0/0

ip address

duplex full

speed 100

even it is not reachable i see the cdp packets from the vg224 with the correct ip address:

sw-musik-01#show cdp neig Gig 1/0/22 det


Device ID: vg224-1

Entry address(es):

  IP address:

Platform: Cisco VG224,  Capabilities: Router

Interface: GigabitEthernet1/0/22,  Port ID (outgoing port): FastEthernet0/0

Holdtime : 126 sec

Version :

Cisco IOS Software, vg224 Software (vg224-I6S-M), Version 15.0(1)M7, RELEASE SOFTWARE (fc2)

Technical Support:

Copyright (c) 1986-2011 by Cisco Systems, Inc.

Compiled Fri 05-Aug-11 02:47 by prod_rel_team

advertisement version: 2

Duplex: full

Management address(es):

if i shutdown the ethernet port of the switch, and no shutdown the port ofthe switch, everything works great again for the next few hours.

the show log displays no error message, i only see the last thing i did bevor it happend, and the port shutdown when i recofigured the switch... (i configured logging buffer)

both are on different switches and i already changed the switch port

any ideas?

if i can't find other reasons i assume that both must have a hardware fault...

Everyone's tags (1)
Hall of Fame Super Gold

Re: Cisco vg224 FastEthernet 0/0 not reachable every about 5 hou

You should begin tremoving the QoS command that are absolutely unnecessary despite whatever has been said to you.

Other than thta you can have a duplicate IP, or other stuff thta can only be diagnosed while it happens.

Re: Cisco vg224 FastEthernet 0/0 not reachable every about 5 hou

I would check:

  • Interface counters on the vg224 during the error condition. (you will need a console connectiont to the system). You may be able to check counters after you resolve the condition too. They shouldn't clear.
  • Check the CAM address table and arp cache during the condition.
  • Ping the vg224 from the 3750 (source from the SVI) during error condition. Check CAM/ARP again and see if you can ping vg224 from an upstream (l3 hops) device.
  • During normal condition, traceroute to vg224 from cucm
  • During error condition, traceroute to vg224 from cucm and look for differences between error and normal
  • Check Tx/Rx on 3750 interface when in error condition
  • Check ping, arp cache, etc. on vg224 when in error condition
  • Check ping to default gateway assigned to the vg224 (maybe SVI on 3750) during outage

Other thoughts:

  • Based purely on elapsed time, I am not sure I follow Paolo on the dup IP but it may be possible this is occurring if you have tweaked timers on ARP, CACHE, or your routing protocol. It is an easy test. Shutdown the 3750 interface that connects to the vg224. Ping the vg224 IP address. If you get a response, you have a dup. If you don't then you don't. When I have seen dup IP addresses on a system, it usually manifests with intermittent connectivity not a complete drop in traffic response.
  • I highly doubt this is related to QoS. The symptoms just don't line up. It wouldn't work for a period and then just stop without self-recovering. It is another easy test but I think your issue may be in the physical layer, l2 address cache, or l3 routing. I would at least exclude these before exploring other factors.




HTH -Bill (b) (t) @ucguerrilla

Please remember to rate helpful responses and identify

New Member

Cisco vg224 FastEthernet 0/0 not reachable every about 5 hours

Well thank you for your answers, i wasn't able to find the reason until now.

Layer 2 and 3 seems to be o.k.

If the error occurs and i'm in the same vlan as the vg224 i can't even ping it or get an arp answer.

The only devices that are in the same vlan are 4 Cisco IP Phones.

the switch mac-table is o.k. i see on this port only the correct mac and if i ping the ip address of the vg224 i get no arp response, not from the vg and not from another device, so there is no dublicate ip address.

i have a second location with a vg224 which has ios 12.4(15)T10 and MGCP as Protocol to the cucm with works without problems since several weeks.

i changed my vg224 so that it has the same ios, protocol and the same configuration (of course not the same ip) as the other location. on my location i use the same switch model with the same configuration, just another ip and another voice vlan. but: it didn't solve my problem, in this location every 2 hours and really all 2 hours the error returns.  Just like Michael Myers returns on every Halloween Movie

i removed the qos config when the error occured, and it didn't help, i rebootet all systems and disabled power inline and i will see tomorrow what this did, but i don't think it helps.

i also changed the hardware of the vg224 without a positive result. and: the old hardware works on another location without this problem, which make me thinkig that i't more likely something with the patch kabel or the switch.

i also checked the show-techsupport on the switch and the vg, i couldn't find errors...strange...

New Member

Cisco vg224 FastEthernet 0/0 not reachable every about 5 hours

So after capturing some packets when the error occurs i found the problem, it was the ios of the switch which has several bugs with cef and arp resolution. i don't know why it happens only on 2 of more than 20 switches with the same affected ios...