From: Antonio Soares (amsoares@netcabo.pt)
Date: Sun Nov 18 2007 - 17:08:35 ART
The error is see is due to a Cosmetic Bug someone said a few weeks ago. I
did a search in Bug Toolkit but i wasn't able to find it. Nevertheless, you
can forget it safely. You can always confirm if the switch has accepted your
config:
SW1(config-if)#switchport voice vlan dot1p
% Voice VLAN does not exist. Creating vlan 0
SW1(config-if)#
18:12:44: %PM-2-VLAN_ADD: Failed to add VLAN 0 - VLAN not found.
SW1(config-if)#
SW1(config-if)#do sh int g0/1 switch | inc Voice
Voice VLAN: dot1p
SW1(config-if)#
Regarding the other questions, see the packet captures bellow. I think it is
self explanatory:
++++++++++++++++++++++++++++++++++++++++++++++++++
Packet received from the PC attached to the IP Phone:
++++++++++++++++++++++++++++++++++++++++++++++++++
No. Time Source Destination Protocol
Info
13 2.733968 10.10.10.10 10.10.10.1 ICMP
Echo (ping) reply
Frame 13 (114 bytes on wire, 114 bytes captured)
Ethernet II, Src: Cisco_92:f4:73 (00:00:0c:92:f4:73), Dst: Cisco_93:45:43
(00:13:c4:93:45:43)
Destination: Cisco_93:45:43 (00:13:c4:93:45:43)
Source: Cisco_92:f4:73 (00:00:0c:92:f4:73)
Type: IP (0x0800)
Internet Protocol, Src: 10.10.10.10 (10.10.10.10), Dst: 10.10.10.1
(10.10.10.1)
Internet Control Message Protocol
++++++++++++++++++++++++++++++++++++++++++++++++++
Packet received from the IP Phone:
++++++++++++++++++++++++++++++++++++++++++++++++++
No. Time Source Destination Protocol
Info
11 0.394817 192.168.100.100 192.168.100.1 ICMP
Echo (ping) reply
Frame 11 (118 bytes on wire, 118 bytes captured)
Ethernet II, Src: Cisco_f6:f1:65 (00:17:0e:f6:f1:65), Dst: Cisco_c3:0d:38
(00:15:63:c3:0d:38)
Destination: Cisco_c3:0d:38 (00:15:63:c3:0d:38)
Source: Cisco_f6:f1:65 (00:17:0e:f6:f1:65)
Type: 802.1Q Virtual LAN (0x8100)
802.1Q Virtual LAN
000. .... .... .... = Priority: 0
...0 .... .... .... = CFI: 0
.... 0000 0000 0000 = ID: 0
Type: IP (0x0800)
Internet Protocol, Src: 192.168.100.100 (192.168.100.100), Dst:
192.168.100.1 (192.168.100.1)
Internet Control Message Protocol
+++++++++++++++++++++++++
You see that the data packet is untagged and the voice packet is tagged with
VLAN=0.
Regards,
Antonio Soares
CCIE #18473 (R&S),CCNP,CCIP,JNCIA-ER
http://pwp.netcabo.pt/amsoares/
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Gregory Gombas
Sent: domingo, 18 de Novembro de 2007 17:21
To: Cisco certification
Subject: Problems with Dot1p
I tried configuring the voice port on a Cat3560 with dot1p tagging but
get the following error message:
SW1(config-if)# switchport voice vlan dot1p
% Voice VLAN does not exist. Creating vlan 0
SW1(config-if)#
09:23:29: %PM-2-VLAN_ADD: Failed to add VLAN 0 - VLAN not found.
Here is my config:
interface FastEthernet0/22
switchport mode dynamic desirable
switchport voice vlan dot1p
mls qos trust cos
spanning-tree portfast
!
Couple questions:
1. Why did I get the error message?
2. What is the purpose of vlan 0? I obviously can't add it to my
switch because vlan numbering starts at 1.
3. Why would someone use dot1p instead of manually specifying the
voice vlan number?
4. Documentation states with dot1p configuration the voice and data is
carried in the same vlan, yet from the config examples I've seen the
access vlan is usually configured to be some arbitrary number (say
vlan5) while dot1p is in vlan 0. So how are they in the same vlan?
Thanks,
Greg
This archive was generated by hypermail 2.1.4 : Sat Dec 01 2007 - 06:37:30 ART