From: CCIE 4 Me (ccie4me@inbox.lv)
Date: Fri Feb 24 2006 - 00:34:50 GMT-3
By default your trunk ports will carry traffics for all VLANs configured on
your switched network. So, configuring "switchport trunk allowed vlan 8'
accomplish nothing.
Alternatively, if you first configure 'switchport trunk allowed vlan none'
and then configure 'switchport trunk allowed vlan 8'. this again will not
fulfil the task and you would have created more problem eg removing all
other VLANs from fa0/13 including the native vlan 36 and these were not
asked for.
Simply configure the other two trunks ie fa0/14&fa0/15 and remove vlan 8.
!
Interface range fa0/14 - 15
switchport trunk allowed vlan remove 8
!
Note, that this is different from pruning eligible list. All VLANs are prune
eligible except VLAN1, which is a Switch's way of telling the other switches
that, 'Do not keep sending me VLAN information about a particular VLAN, if I
donot have any traffic for it' You can see that, if you remove a VLAN from a
trunk port, it will also be remove from the prunning eligibility list for
that Trunk port kind of saying...'what is the point in keeping in the prune
eligibility list, a VLAN for which you will never receive any traffic?'
On the other hand, if you make VLAN 8 pruning ineligible, you are saying, do
not prune traffics sent to this VLAN 'ie keep sending me this VLAN
information even if, I do not have traffic for it' All VLANs are pruning
eligible by default except for VLAN 1, but you have to enable vtp pruning
'vtp pruning' for prunning to start working.
HTH
CCIE 4 Me.
----- Original Message -----
From: "jellyboy" <jellyboy@gmail.com>
To: <ccielab@groupstudy.com>
Sent: Thursday, February 23, 2006 3:34 PM
Subject: IEWB Lab4 1.3 Traffic Control
> Hi all, The task asks for traffic belonging to Vlan8 to be assigned to
port
> fa0/13 and all other trunk links should not receive Vlan8. The Brians
> solution involves removing Vlan8 from the prune eligible list:
>
> #switchport trunk pruning vlan 2-7,9-1001
>
> I can understand the logic behind this, but I originally came up with:
>
> interface FastEthernet0/13
> switchport trunk encapsulation dot1q
> switchport trunk native vlan 36
> switchport trunk allowed vlan 8 <<
> switchport mode trunk
> !
> interface FastEthernet0/14
> switchport trunk encapsulation dot1q
> switchport trunk native vlan 36
> switchport trunk allowed vlan 1-7,9-4094 <<
> switchport mode trunk
> !
> interface FastEthernet0/15
> switchport trunk encapsulation dot1q
> switchport trunk native vlan 36
> switchport trunk allowed vlan 1-7,9-4094 <<
> switchport mode trunk
>
> I am wondering if what I did accomplishes the same thing?
> If not what are the suttle (or obvious!!) differences? Apart from the
static
> allocation of vlans on a trunk.
>
>
> Many Thanks,
>
> JB
>
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