set vlan CFI and TPID

set vlan CFI and TPID

[hong zhiyi]

Hi All,

May I ask how to set the 1 bit CFI and 2 bytesTPID in the VLAN header
by vconfig? and what is the meaning of the egress map and ingress map?

I hope someone can help me.

Best Regards,
Hong Zhiyi

Re: set vlan CFI and TPID

[Jesse Gross]

On Tue, Dec 7, 2010 at 8:04 PM, hong zhiyi <zhiyi.hong@gmail.com> wrote:
> Hi All,
>
> May I ask how to set the 1 bit CFI and 2 bytesTPID in the VLAN header
> by vconfig?

You can't change them using vconfig.  For 802.1q/Ethernet, the TPID is
0x8100 and the CFI is 0.

> and what is the meaning of the egress map and ingress map?

These convert between the PCP bits found in the vlan header and the
priority field that is used internally for QoS, which you access
through tc.

Re: set vlan CFI and TPID

[hong zhiyi]

On Mon, Dec 13, 2010 at 8:20 AM, Jesse Gross <jesse@nicira.com> wrote:
> On Tue, Dec 7, 2010 at 8:04 PM, hong zhiyi <zhiyi.hong@gmail.com> wrote:
>> Hi All,
>>
>> May I ask how to set the 1 bit CFI and 2 bytesTPID in the VLAN header
>> by vconfig?
>
> You can't change them using vconfig.  For 802.1q/Ethernet, the TPID is
> 0x8100 and the CFI is 0.
>
>> and what is the meaning of the egress map and ingress map?
>
> These convert between the PCP bits found in the vlan header and the
> priority field that is used internally for QoS, which you access
> through tc.
>

Hi Jesse,

Thank you for your reply.

Then how can it set the value of the TPID and the CFI? Also, I do not
understand you mentioned the *tc* means, what is the tc?

Best Regards
Hong Zhiyi

Re: set vlan CFI and TPID

[Jesse Gross]

On Sun, Dec 12, 2010 at 6:20 PM, hong zhiyi <zhiyi.hong@gmail.com> wrote:
> On Mon, Dec 13, 2010 at 8:20 AM, Jesse Gross <jesse@nicira.com> wrote:
>> On Tue, Dec 7, 2010 at 8:04 PM, hong zhiyi <zhiyi.hong@gmail.com> wrote:
>>> Hi All,
>>>
>>> May I ask how to set the 1 bit CFI and 2 bytesTPID in the VLAN header
>>> by vconfig?
>>
>> You can't change them using vconfig.  For 802.1q/Ethernet, the TPID is
>> 0x8100 and the CFI is 0.
>>
>>> and what is the meaning of the egress map and ingress map?
>>
>> These convert between the PCP bits found in the vlan header and the
>> priority field that is used internally for QoS, which you access
>> through tc.
>>
>
> Hi Jesse,
>
> Thank you for your reply.
>
> Then how can it set the value of the TPID and the CFI? Also, I do not
> understand you mentioned the *tc* means, what is the tc?

You can't really.  Like I said, the values are fixed by the standard
for basic 802.1q, which is what Linux implements.  You could, of
course, directly send/receive packets through a raw socket with
whatever values you like.  However, other components of the kernel
that deal with vlans won't recognize them.

tc is a userspace program that (among other things) handles QoS
settings.  Google should be able to turn up information on how to use
it.