[c-nsp] 7940 VLAN's

[Gert Doering]

Hi,

to close down this thread...

On Thu, Feb 03, 2005 at 12:42:43PM +0100, Brian Turnbow wrote:
> It depends on the platform ,
> For switches it's usually the "auxilary vlan"  or switchport voice vlan that you can set manually. 

Tried it on a 3750G - it's "switchport voice vlan <n>" to set the Voice
VLAN, which will then be advertised via CDP.

Tcpdump 3.8 already knows how to decode this :-) - the following is
from a "Fedora Core 2" Linux system, tcpdump as shipped:

SwitchX(config)#int g1/0/6               
SwitchX(config-if)#switchport voice vlan 456

$ tcpdump -i eth0 -n -v -s0 ether dst 1:0:c:cc:cc:cc
...
  Platform (0x06), length: 20 bytes: 'cisco WS-C3750G-24TS'
...
  Port-ID (0x03), length: 20 bytes: 'GigabitEthernet1/0/6'
  Capability (0x04), length: 4 bytes: (0x00000029): Router, L2 Switch, IGMP snooping
...
  Native VLAN ID (0x0a), length: 2 bytes: 1
  ATA-186 VoIP VLAN request (0x0e), length: 3 bytes: app 1, vlan 456   <<<<<
  AVVID trust bitmap (0x12), length: 1 byte: 0x00
  AVVID untrusted ports CoS (0x13), length: 1 byte: 0x00


gert
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Gert Doering - Munich, Germany                             gert at greenie.muc.de
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