I think it is not that simple! I am happy to call it layer 2.5 (as Scott
Morris dose on previous link). There is also a very valuable comment there
that Garry put in and I quote it here:

He says:

"I think we should classify a protocols running *directly* on particular
layer of OSI model (using the *transport services* of  the protocols
running at lower layers and providing the *transport services* for the
protocols running at upper layer), and the protocols running *between layers
* of the OSI model (using the *transport services* of  the protocols
running at lower layers, not providing *transport services* to upper layer
protocols, but *specific supplementary services*).

 For example,
- ARP runs on top of a layer 2 (for instance, ARP using the transport
services of the layer 2 Ethernet and providing a *supplementary services *for
layer 3 IP, *not transport services*)."

and it pretty makes sense.

For ARP it is not only having a specific type field number in layer 2
(0x806) as you compare it with dot1q (in dot1q layer 2 header still
extended after tag); take a look at the link that Ali put in:

http://www.networksorcery.com/enp/protocol/arp.htm

It is defined on the way that can support layer 3-->2 address resolution
for any layer 3 protocols as well as on any layer 2 frame types. (not only
between ethernet in layer 2 and IP in layer 3)

At the end, I am agree with you, who cares!

Cheers,
Pedram.

On Tue, Dec 13, 2011 at 1:34 PM, Matt Hill <[email protected]> wrote:

> Far out... this is confusing.
>
> IP is IP - L3.
> Ethernet is L2.
>
> Lets go further.  IP sits in an L2 frame - Ethertype 0x800 (??)  ARP
> also sits in an L2 frame 0x806 (?? - CBFd googling).  Trunking 802.1q
> is 0x8800 (????)
>
> It really is that simple.  Furthermore, if I got one or even all of
> the ethertypes wrong I dont particularly care.
>
> Cheers,
> Matt
>
> CCIE #22386
> CCSI #31207
>
> On 13 December 2011 12:55, Pedram Zadeh <[email protected]> wrote:
> > ARP is an OSI layer 3 non-routable protocol. It is not layer 3 because it
> > contains IP addresses on its header (as IP also is not the only OSI
> layer 3
> > routed protocol); it is OSI layer 3 because it has its own specific
> header
> > coming after OSI layer 2 header.
> >
> > As you can see on the link you posted, it is defined on the way that can
> > support layer 3-->2 address resolution for other protocols as well as on
> > the other layer 2 frame types.
> >
> > This is long debate you can see on many threads around the net (like
> > following) but I think the key point is the concept of OSI layers that
> > makes it layer 3.
> >
> > https://learningnetwork.cisco.com/thread/36117
> >
> >
> > On Tue, Dec 13, 2011 at 5:20 AM, Imran Ali <[email protected]> wrote:
> >
> >> CORRECTION :
> >>
> >> when i refer layer 3 header . i mean to say their is a field in ARP ,
> that
> >> contains ip address of end host .
> >>
> >> so is ARP layer 2 or layer 3.  debate :-)
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >> On Mon, Dec 12, 2011 at 8:59 PM, Imran Ali <[email protected]> wrote:
> >>
> >> > kid,
> >> >
> >> > if the arp does not contain layer 3 header , then how does the end
> host
> >> > recognises it belongs to him ?
> >> >
> >> > also i would recommend you to learn Layer 2 broadcast address . it is
> all
> >> > F's in destination field not all zero's ..
> >> >
> >> > how does arp works ?
> >> >
> >> > PC1 ----------- SW--------PC2
> >> >
> >> > both belongs to one vlan
> >> >
> >> > .PC1  pings PC2 .
> >> >
> >> > Let say the ip add is 10.0.0.1 and 10.0.0.2 .
> >> >
> >> > arp packet   l3= 10.0.0.2
> >> >                     l2= FFF.-----FFF
> >> >
> >> > SW receives it and sends it to all ports except one port .
> >> >
> >> > it is head by BOB at 10.0.0.3 , TOM at 10.0.0.4 and PC2 ALSO .
> >> >
> >> > BECAUSE IT WAS BROADCAST
> >> >
> >> > NOW IF ARP DOES NOT CONTAIN LAYER 3 HEADER . HOW DOES THE INTENDED
> HOST
> >> > REPLIES ??
> >> >
> >> > WHAT MAKES BOB AND TOM IGNORE THE PACKET ?
> >> >
> >> >
> >> >
> >> >
> >> >
> >> > since i am also a student , i would like you to immediately go to ine
> >> > website , become a member to get Free access to CCNA arp COD . this
> >> > streaming ends in december last day .
> >> >
> >> > also look at apr fields here
> >> >
> >> > http://www.networksorcery.com/enp/protocol/arp.htm
> >> >
> >> > hth
> >> >
> >> >
> >> >
> >> >
> >> > On Mon, Dec 12, 2011 at 10:02 AM, CCIE KID <[email protected]>
> wrote:
> >> >
> >> >> Hi Imran,
> >> >>
> >> >> When router sends a frame , it sends a untagged frame which it
> believes
> >> >> that native vlan is 20 , and that frame reaches the switch and switch
> >> see
> >> >> the frame as untagged as think that it belongs to native vlan 30 and
> >> floods
> >> >> it to all ports which belong to this vlan 300 ( access port for vlan
> 300
> >> >> and trunk ports which carry all vlans ) .
> >> >>
> >> >> I didnt understood the point that ur talking about that ARP is a
> layer 2
> >> >> broadcast i agree. How can u say that it is unicast for Layer 3
> >> >>
> >> >> When a router generates a arp for ip 20.1.1.1 . tthe layer 2 header
> will
> >> >> be the source MAC of its own MAC and the dest MAC as broadcast only
> >> right
> >> >> ..... and inside the ARP header the Source IP is its won IP and
> Target
> >> IP
> >> >> is 20.1.1.1 . and source MAC will be its own MAC and Target MAC will
> be
> >> >> 000000.. So There is no IP header in ARP packet..
> >> >>
> >> >> So where does unicast comes into picture for LAyer 3 ?  Even router
> has
> >> >> to create a broadcast packet for ARP.
> >> >>
> >> >> So now router sends a arp packet to create L2 header . It send a
> >> UNTAGGED
> >> >> frame as it belongs to a native vlan of 20 and it hits switch and it
> >> >> updates the source MAC and sees it is a native vlan and it forwards
> to
> >> all
> >> >> trunk ports and also access ports for vlan 10. , So now another
> switch
> >> >> receives it and sends it to the destined host.
> >> >>
> >> >> SO Imran i guess , I am correct. Correct me if i am wrong
> >> >>
> >> >> Thank You
> >> >>
> >> >>
> >> >>
> >> >>
> >> >> So when the switch receives the frame and see this a broadcast
> frame. it
> >> >> wil broadcast it to all ports except to that port which came in.
> >> >>
> >> >>
> >> >> On Sun, Dec 11, 2011 at 2:54 PM, Imran Ali <[email protected]>
> wrote:
> >> >>
> >> >>> *kid , your question was answered perfectly by Rob.*
> >> >>>
> >> >>> *first off what is the use of trunk . ?*
> >> >>>
> >> >>> *Ans:  to carry traffic of more than one vlan* .
> >> >>>
> >> >>> *can i say if trunk is up , everthing is fine ?*
> >> >>>
> >> >>> *no many factors may prevent proper decapsulation and rechability is
> >> >>> broken*
> >> >>>
> >> >>> *can you give me example when even though trunk is up . end hosts
> are
> >> >>> not talking ?*
> >> >>>
> >> >>> yes . "allowed vlan list " filtering traffiic  and " native vlan
> >> >>> mismatch "
> >> >>>
> >> >>> *ok can you expalin me how native vlan mismatch prevent end host
> >> >>> talking to each other in same vlan ?*
> >> >>>
> >> >>> *look at config provied in above mail . *
> >> >>> **
> >> >>> *router's native vlan is 20 . and switch native vlan is 30. so when
> >> >>> router send packets to an ip in valn 20 . it sends them untagged ,
> and
> >> i
> >> >>> repeat it with diff words  " in its native " form like the one
> received
> >> >>> from PC . *
> >> >>> **
> >> >>> *Swithch  when it receives the packet believes it belongs to Vlan
> 30 ,
> >> >>> because here in switch* vlan 30 is Native .
> >> >>>
> >> >>> *what made switch believe it belongs to vlan 30 ?*
> >> >>>
> >> >>> *because it is assumed that when ever i received a frame with out
>  any
> >> >>> vlan tag it belongs to native vlan *
> >> >>>
> >> >>> *so it searches vlan 30 . This was a first  packet . *
> >> >>> **
> >> >>> *to build a packet router should know the mac address . so this
> paket
> >> >>> is ARP packet . *
> >> >>> **
> >> >>> *how can you say that ?*
> >> >>> **
> >> >>> *arp cache was empty as this is first time they are talking *
> >> >>>
> >> >>> *ok i agree it was arp packet sourced from router to switch , but
> what
> >> >>> happened to it ?*
> >> >>>
> >> >>> *for the switch its just a frame . and it made an assumption that it
> >> >>> blongs to ITS NATIVE vlan that is vlan 30 .*
> >> >>>
> >> >>> *ok what happened next . ?*
> >> >>>
> >> >>> *arp is broadcast at layer 2 and unicast at layer 3 . so swithch now
> >> >>> prepares for broadcasting the frame IN VLAN 30.*
> >> >>>
> >> >>> *that's fine but why it dint answered ?*
> >> >>>
> >> >>>
> >> >>>
> >> >>> *kid i leave this question to be ansered by you . if you have CCNA
> >> >>> concepts fresh in your mind , you will understand above explantion
> and
> >> >>> also be able to  answer the question* .
> >> >>>
> >> >>> *OH that's why  rechability is broken between the ip that belong to
> >> >>> same vlan due to mismatch in Natve vlan ?*
> >> >>>
> >> >>> *absolutely !*
> >> >>>
> >> >>> *so NATIVE VLAN MISMATCH is  bad ?*
> >> >>>
> >> >>> *exactly
> >> >>> *
> >> >>> On Sat, Dec 10, 2011 at 7:03 PM, CCIE KID <[email protected]>
> wrote:
> >> >>>
> >> >>>> Hi,
> >> >>>>
> >> >>>> Still my issue is not been resolved.
> >> >>>> So what can be the conclusion man
> >> >>>>
> >> >>>> Can any expert can pitch in an answer for that
> >> >>>>
> >> >>>>
> >> >>>> On Sat, Dec 10, 2011 at 8:28 PM, me you <[email protected]>
> wrote:
> >> >>>>
> >> >>>> > *CONCLUSION:  We do NOT have full reachability despite the vlan
> >> >>>> mismatch.*
> >> >>>>
> >> >>>> >
> >> >>>> > I would agree with you that your set up work, but I disagree
> with a
> >> >>>> > general statement that Native Vlan mismatch does not matter
> between
> >> a
> >> >>>> > router and switch.  1 2811, 3 subinterfaces and 1 3750 trunkport
> >> with
> >> >>>> 3
> >> >>>> > vlans. Neither of the native vlans have reachability.
> >> >>>> >
> >> >>>> >
> >> >>>> > interface FastEthernet0/0
> >> >>>> >
> >> >>>> >  no ip address
> >> >>>> >
> >> >>>> >  duplex auto
> >> >>>> >
> >> >>>> >  speed auto
> >> >>>> >
> >> >>>> > !
> >> >>>> >
> >> >>>> > interface FastEthernet0/0.10
> >> >>>> >
> >> >>>> >  encapsulation dot1Q 10
> >> >>>> >
> >> >>>> >  ip address 10.1.1.1 255.255.255.0
> >> >>>> >
> >> >>>> > !
> >> >>>> >
> >> >>>> > interface FastEthernet0/0.20
> >> >>>> >
> >> >>>> >  encapsulation dot1Q 20 native
> >> >>>> >
> >> >>>> >  ip address 20.1.1.1 255.255.255.0
> >> >>>> >
> >> >>>> > !
> >> >>>> >
> >> >>>> > interface FastEthernet0/0.30
> >> >>>> >
> >> >>>> >  encapsulation dot1Q 30
> >> >>>> >
> >> >>>> >  ip address 30.1.1.1 255.255.255.0
> >> >>>> >
> >> >>>> >
> >> >>>> >
> >> >>>> > 3750
> >> >>>> >
> >> >>>> > interface GigabitEthernet1/0/1
> >> >>>> >
> >> >>>> >  switchport trunk encapsulation dot1q
> >> >>>> >
> >> >>>> >  switchport trunk native vlan 30
> >> >>>> >
> >> >>>> >  switchport mode trunk
> >> >>>> >
> >> >>>> > end
> >> >>>> >
> >> >>>> >
> >> >>>> > interface Vlan1
> >> >>>> >
> >> >>>> >  no ip address
> >> >>>> >
> >> >>>> > !
> >> >>>> >
> >> >>>> > interface Vlan10
> >> >>>> >
> >> >>>> >  ip address 10.1.1.2 255.255.255.0
> >> >>>> >
> >> >>>> > !
> >> >>>> >
> >> >>>> > interface Vlan20
> >> >>>> >
> >> >>>> >  ip address 20.1.1.2 255.255.255.0
> >> >>>> >
> >> >>>> > !
> >> >>>> >
> >> >>>> > interface Vlan30
> >> >>>> >
> >> >>>> >  ip address 30.1.1.2 255.255.255.0
> >> >>>> >
> >> >>>> >
> >> >>>> >
> >> >>>> > 3750(config)#do ping 10.1.1.1
> >> >>>> >
> >> >>>> >
> >> >>>> > Type escape sequence to abort.
> >> >>>> >
> >> >>>> > Sending 5, 100-byte ICMP Echos to 10.1.1.1, timeout is 2 seconds:
> >> >>>> >
> >> >>>> > !!!!!
> >> >>>> >
> >> >>>> > Success rate is 100 percent (5/5), round-trip min/avg/max =
> 1/2/9 ms
> >> >>>> >
> >> >>>> > 3750(config)#do ping 20.1.1.1
> >> >>>> >
> >> >>>> >
> >> >>>> > Type escape sequence to abort.
> >> >>>> >
> >> >>>> > Sending 5, 100-byte ICMP Echos to 20.1.1.1, timeout is 2 seconds:
> >> >>>> >
> >> >>>> > .....
> >> >>>> >
> >> >>>> > Success rate is 0 percent (0/5)
> >> >>>> >
> >> >>>> > 3750(config)#do ping 30.1.1.1
> >> >>>> >
> >> >>>> >
> >> >>>> > Type escape sequence to abort.
> >> >>>> >
> >> >>>> > Sending 5, 100-byte ICMP Echos to 30.1.1.1, timeout is 2 seconds:
> >> >>>> >
> >> >>>> > .....
> >> >>>> >
> >> >>>> > Success rate is 0 percent (0/5)
> >> >>>> >
> >> >>>> >
> >> >>>> > Deb ip icmp on *Dec 10 14:36:59.527: ICMP: echo reply sent, src
> >> >>>> 10.1.1.1,
> >> >>>> > dst 10.1.1.2
> >> >>>> >
> >> >>>> > *Dec 10 14:36:59.527: ICMP: echo reply sent, src 10.1.1.1, dst
> >> >>>> 10.1.1.2
> >> >>>> >
> >> >>>> > *Dec 10 14:36:59.531: ICMP: echo reply sent, src 10.1.1.1, dst
> >> >>>> 10.1.1.2
> >> >>>> >
> >> >>>> > *Dec 10 14:36:59.531: ICMP: echo reply sent, src 10.1.1.1, dst
> >> >>>> 10.1.1.2
> >> >>>> >
> >> >>>> > *Dec 10 14:36:59.535: ICMP: echo reply sent, src 10.1.1.1, dst
> >> >>>> 10.1.1.2
> >> >>>> >
> >> >>>> >  --More--
> >> >>>> >
> >> >>>> > *Dec 10 14:37:04.179: ICMP: echo reply sent, src 20.1.1.1, dst
> >> >>>> 30.1.1.2
> >> >>>> >
> >> >>>> >  --More--
> >> >>>> >
> >> >>>> > *Dec 10 14:37:06.183: ICMP: echo reply sent, src 20.1.1.1, dst
> >> >>>> 30.1.1.2
> >> >>>> >
> >> >>>> >  --More--
> >> >>>> >
> >> >>>> > *Dec 10 14:37:08.187: ICMP: echo reply sent, src 20.1.1.1, dst
> >> >>>> 30.1.1.2
> >> >>>> >
> >> >>>> >  --More--
> >> >>>> >
> >> >>>> > *Dec 10 14:37:10.195: ICMP: echo reply sent, src 20.1.1.1, dst
> >> >>>> 30.1.1.2
> >> >>>> >
> >> >>>> >  --More--
> >> >>>> >
> >> >>>> > *Dec 10 14:37:12.199: ICMP: echo reply sent, src 20.1.1.1, dst
> >> >>>> 30.1.1.2
> >> >>>> >
> >> >>>> >
> >> >>>> > To say vlan mismatch between a router and a switch does not
> matter
> >> is
> >> >>>> > misleading or wrong. We could say if "this is that way" then
> "that
> >> is
> >> >>>> this
> >> >>>> > way" "that and this will work":)
> >> >>>> >
> >> >>>> >
> >> >>>> > Rob
> >> >>>> >
> >> >>>> >
> >> >>>> >
> >> >>>> > On Sat, Dec 10, 2011 at 5:39 PM, CCIE KID <[email protected]>
> >> >>>> wrote:
> >> >>>> >
> >> >>>> >> Hi Oyebande,
> >> >>>> >>
> >> >>>> >> Thank u mate. U confirmed my understanding. So from router to
> >> switch
> >> >>>> it
> >> >>>> >> doesnt matter to match the native vlan on both sides.
> >> >>>> >> Unlike Switch to Switch to form trunk port ,native vlans should
> >> >>>> match to
> >> >>>> >> form trunk link
> >> >>>> >> to pass data traffic on that link.
> >> >>>> >>
> >> >>>> >> Thanks all for their confirmation
> >> >>>> >>
> >> >>>> >>
> >> >>>> >>
> >> >>>> >> On Sat, Dec 10, 2011 at 5:19 PM, Oluwagbenga Oyebande <
> >> >>>> >> [email protected]> wrote:
> >> >>>> >>
> >> >>>> >>>
> >> >>>> >>> *CONCLUSION:  We have full reachability despite the vlan
> >> mismatch.*
> >> >>>> >>> *
> >> >>>> >>> *
> >> >>>>
> >> >>>> >>> *
> >> >>>> >>> Three routers and one switch.
> >> >>>> >>>
> >> >>>> >>>
> >> >>>> >>> *
> >> >>>> >>> *
> >> >>>> >>>
> >> R2811(Fa0/0.1)-------------TRUNK-LINK-----------------------Cat3550
> >> >>>> >>> (Fa0/1)
> >> >>>> >>> *
> >> >>>> >>> *
> >> >>>> >>> native vlan 20
> >> >>>> >>>                 native vlan 10
> >> >>>> >>>
> >> >>>> >>>
> >> >>>> >>> R3825
> >> >>>> >>> (Gi0/0.1)
> >> >>>> >>> -------------
> >> >>>> >>> TRUNK-LINK
> >> >>>> >>>  -----------------------
> >> >>>> >>> Cat3550 (Gi0/2)
> >> >>>> >>> native vlan 30
> >> >>>> >>>
> >> >>>> >>> native vlan 10
> >> >>>> >>>
> >> >>>> >>> *R2811-forvlan10(Fa0/0)--*
> >> >>>> >>> ACCESS-LINK
> >> >>>> >>> *-----*
> >> >>>> >>> Cat3550 (Fa0/4)
> >> >>>> >>> *
> >> >>>> >>> *
> >> >>>> >>>
> >> >>>> >>>              explicitly configured in vlan 10 as access port
> >> >>>> >>>
> >> >>>> >>> I included the third link to clear all doubts about expected
> >> >>>> behaviour
> >> >>>> >>> of vlan 10 connected devices.
> >> >>>> >>>
> >> >>>> >>>
> >> >>>> >>> *
> >> >>>> >>> *Catalyst 3550 Swicth Spec*
> >> >>>> >>>
> >> >>>> >>> Cat3550(config)#do sh vers | i Model num|RELEA
> >> >>>> >>> Cisco IOS Software, C3550 Software (C3550-IPSERVICESK9-M),
> Version
> >> >>>> >>> 12.2(44)SE3, RELEASE SOFTWARE (fc2)
> >> >>>> >>> Model number: WS-C3550-24-SMI
> >> >>>> >>> *
> >> >>>> >>> *
> >> >>>> >>> *2811 Router Spec*
> >> >>>> >>>
> >> >>>> >>> Router(config)#do sh ver | i image
> >> >>>> >>> System image file is
> >> >>>> "flash:c2800nm-adventerprisek9-mz.124-24.T2.bin"
> >> >>>> >>> *
> >> >>>> >>> *
> >> >>>> >>> *3825 Router Spec*
> >> >>>> >>> *
> >> >>>> >>> *
> >> >>>> >>> R3825(config-subif)#do sh ver | i Software
> >> >>>> >>> Cisco IOS Software, 3800 Software (C3825-ADVENTERPRISEK9-M),
> >> Version
> >> >>>> >>> 12.4(24)T2, RELEASE SOFTWARE (fc2)
> >> >>>> >>>
> >> >>>> >>> *2811 (for vlan 10 ) Router Spec *
> >> >>>> >>> *
> >> >>>> >>> *
> >> >>>>
> >> >>>> >>> R2811-forvlan10(config)#do sh ver | i Software
> >> >>>> >>>  Cisco IOS Software, 2800 Software (C2800NM-ADVENTERPRISEK9-M),
> >> >>>> Version
> >> >>>> >>> 12.4(24)T2, RELEASE SOFTWARE (fc2)
> >> >>>> >>>
> >> >>>> >>>
> >> >>>> >>> *CDP  *(so  we have Fas 0/1 connected to 2811and we have Gig
> 0/2
> >> >>>>
> >> >>>> >>> connected to 3825 and Fa0/4 Connected to R2811-forvlan10)
> >> >>>> >>>
> >> >>>> >>> Cat3550(config-if)#do sh cdp nei | i R2811|R3825|ID
> >> >>>> >>> Device ID        Local Intrfce     Holdtme    Capability
>  Platform
> >> >>>>  Port
> >> >>>> >>> ID
> >> >>>> >>> R2811-forvlan10  Fas 0/4           123          R S I     2811
> >> >>>>  Fas
> >> >>>> >>> 0/0
> >> >>>> >>> R2811            Fas 0/1           139          R S I     2811
> >> >>>>  Fas
> >> >>>> >>> 0/0
> >> >>>> >>> R3825            Gig 0/2           129          R S I     3825
> >> >>>>  Gig
> >> >>>> >>> 0/0
> >> >>>> >>>
> >> >>>> >>>
> >> >>>> >>> *INTERFACE CONFIG*
> >> >>>> >>> *
> >> >>>> >>> *
> >> >>>> >>> Cat3550(config-if)#do sh run int *fa0/1*
> >> >>>> >>> interface FastEthernet0/1
> >> >>>> >>>  description *TRUNK to R2811*
> >> >>>> >>>  switchport trunk encapsulation dot1q
> >> >>>> >>>  switchport trunk native vlan 10
> >> >>>> >>>  switchport mode trunk
> >> >>>> >>> end
> >> >>>> >>>
> >> >>>> >>> Cat3550(config-if)#do sh run int fa0/4
> >> >>>> >>> interface FastEthernet0/4
> >> >>>> >>>  description *ACCESS LINK TO R2811-forvlan10*
> >> >>>>
> >> >>>> >>>  switchport access vlan 10
> >> >>>> >>>  switchport mode access
> >> >>>> >>> end
> >> >>>> >>>
> >> >>>> >>> Cat3550(config-if)#do sh run int gi0/2
> >> >>>> >>> interface GigabitEthernet0/2
> >> >>>> >>>  description *TRUNK to R3825*
> >> >>>>
> >> >>>> >>>  switchport trunk encapsulation dot1q
> >> >>>> >>>  switchport trunk native vlan 10
> >> >>>> >>>  switchport mode trunk
> >> >>>> >>> end
> >> >>>> >>>
> >> >>>> >>> Cat3550(config-if)#do sh run int vlan 10
> >> >>>> >>> interface Vlan10
> >> >>>> >>>  ip address 10.1.1.2 255.255.255.0
> >> >>>> >>> end
> >> >>>> >>>
> >> >>>> >>> Cat3550(config-if)#do sh int status
> >> >>>> >>> Port      Name               Status       Vlan       Duplex
>  Speed
> >> >>>> Type
> >> >>>> >>> Fa0/1     TRUNK to R2811     connected    trunk      a-full
>  a-100
> >> >>>> >>> 10/100BaseTX
> >> >>>> >>> Fa0/4     ACCESS LINK TO R28 connected    10         a-full
>  a-100
> >> >>>> >>> 10/100Base
> >> >>>> >>> Gi0/2     TRUNK to R3825     connected    trunk      a-full
> a-1000
> >> >>>> >>> 1000BaseSX
> >> >>>> >>>
> >> >>>> >>> *VLANS*
> >> >>>> >>> *
> >> >>>>
> >> >>>> >>> *
> >> >>>> >>> VLAN Name                             Status    Ports
> >> >>>> >>> ---- -------------------------------- ---------
> >> >>>> >>> -------------------------------
> >> >>>> >>> 1    default                          active    Fa0/2, Fa0/3,
> >> Fa0/5,
> >> >>>> >>> Fa0/6
> >> >>>> >>>                                                 Fa0/7, Fa0/8,
> >> Fa0/9,
> >> >>>> >>> Fa0/10
> >> >>>> >>>                                                 Fa0/11, Fa0/12,
> >> >>>> Fa0/13,
> >> >>>> >>> Fa0/14
> >> >>>> >>>                                                 Fa0/15, Fa0/16,
> >> >>>> Fa0/17,
> >> >>>> >>> Fa0/18
> >> >>>> >>>                                                 Gi0/1
> >> >>>> >>> 10   VLAN0010                         active    Fa0/4
> >> >>>> >>> 20   VLAN0020                         active
> >> >>>> >>> 30   VLAN0030                         active
> >> >>>> >>>
> >> >>>> >>>
> >> >>>> >>> R2811(config-subif)#do sh run int fa0/0.1
> >> >>>> >>> interface FastEthernet0/0.1
> >> >>>> >>>  description "MISMATCHED NATIVE VLAN 20/10"
> >> >>>> >>>  encapsulation dot1Q 20 native
> >> >>>> >>>  ip address 10.1.1.1 255.255.255.0
> >> >>>> >>> end
> >> >>>> >>>
> >> >>>> >>> R3825(config-subif)#do sh run int gi0/0.1
> >> >>>> >>> interface GigabitEthernet0/0.1
> >> >>>> >>>  description "MISMATCHED NATIVE VLAN 30/10"
> >> >>>> >>>  encapsulation dot1Q 30 native
> >> >>>> >>>  ip address 10.1.1.3 255.255.255.0
> >> >>>> >>> end
> >> >>>> >>>
> >> >>>> >>> R2811-forvlan10(config-if)#do sh run int fa0/0
> >> >>>> >>> interface FastEthernet0/0
> >> >>>> >>>  description "THIS ONE IS AN ACCESS LINK WHICH WE WILL PUT IN
> VLAN
> >> >>>> 10 ON
> >> >>>> >>> THE SWITCH"
> >> >>>> >>>  ip address 10.1.1.4 255.255.255.0
> >> >>>> >>>  duplex auto
> >> >>>> >>>  speed auto
> >> >>>> >>> end
> >> >>>> >>>
> >> >>>> >>>
> >> >>>> >>>
> >> >>>> >>> Cat3550(config-if)#do ping 10.1.1.255
> >> >>>> >>> Type escape sequence to abort.
> >> >>>> >>> Sending 5, 100-byte ICMP Echos to 10.1.1.255, timeout is 2
> >> seconds:
> >> >>>> >>> Reply to request 0 from 10.1.1.3, 1 ms
> >> >>>> >>> Reply to request 0 from 10.1.1.1, 1 ms
> >> >>>> >>> Reply to request 0 from 10.1.1.4, 1 ms
> >> >>>> >>>
> >> >>>> >>> R2811(config-subif)#do ping 10.1.1.255
> >> >>>> >>> Type escape sequence to abort.
> >> >>>> >>> Sending 5, 100-byte ICMP Echos to 10.1.1.255, timeout is 2
> >> seconds:
> >> >>>> >>> Reply to request 0 from 10.1.1.3, 1 ms
> >> >>>> >>> Reply to request 0 from 10.1.1.2, 1 ms
> >> >>>> >>> Reply to request 0 from 10.1.1.4, 1 ms
> >> >>>> >>>
> >> >>>> >>>
> >> >>>> >>> R3825(config-subif)#do ping 10.1.1.255
> >> >>>> >>> Type escape sequence to abort.
> >> >>>> >>> Sending 5, 100-byte ICMP Echos to 10.1.1.255, timeout is 2
> >> seconds:
> >> >>>> >>> Reply to request 0 from 10.1.1.2, 4 ms
> >> >>>> >>> Reply to request 0 from 10.1.1.1, 4 ms
> >> >>>> >>> Reply to request 1 from 10.1.1.2, 1 ms
> >> >>>> >>> Reply to request 1 from 10.1.1.1, 1 ms
> >> >>>> >>> Reply to request 1 from 10.1.1.4, 1 ms
> >> >>>> >>>
> >> >>>> >>> R2811-forvlan10(config-if)#do ping 10.1.1.255
> >> >>>> >>>
> >> >>>> >>> Type escape sequence to abort.
> >> >>>> >>> Sending 5, 100-byte ICMP Echos to 10.1.1.255, timeout is 2
> >> seconds:
> >> >>>> >>>
> >> >>>> >>> Reply to request 0 from 10.1.1.3, 4 ms
> >> >>>> >>> Reply to request 0 from 10.1.1.1, 4 ms
> >> >>>> >>> Reply to request 0 from 10.1.1.2, 4 ms
> >> >>>> >>>
> >> >>>> >>>
> >> >>>> >>> *CONCLUSION:  So we have full reachability despite the vlan
> >> >>>> mismatch.*
> >> >>>>
> >> >>>> >>>
> >> >>>> >>>
> >> >>>> >>> Olugbenga Oyebande
> >> >>>> >>>
> >> >>>> >>>
> >> >>>> >>>
> >> >>>> >>>
> >> >>>> >>>> On Fri, Dec 9, 2011 at 7:38 PM, Oluwagbenga Oyebande <
> >> >>>> >>>> [email protected]> wrote:
> >> >>>> >>>>
> >> >>>> >>>>> Hi CCIE Kid
> >> >>>> >>>>>
> >> >>>> >>>>> I agree with Narottam. I would like to add something to Q2
> >> >>>> >>>>>
> >> >>>> >>>>>
> >> >>>> >>>>> Answ to Q1. The trunk will form as you have already seen.
> >> >>>> >>>>>
> >> >>>> >>>>> Answ to Q2. If by user traffic you mean IP traffic, then the
> >> >>>> answer
> >> >>>> >>>>> depends on the IP configuration of your switch's *VLAN 10
> SVI.
> >> *If
> >> >>>>
> >> >>>> >>>>> you have 10.1.1.0/24 subnet configured on the switch's SVI
> >>  then
> >> >>>> IP
> >> >>>> >>>>> traffic should pass in spite of native vlan mismatch. If you
> >> have
> >> >>>> another
> >> >>>> >>>>> subnet (or no ip address) configured on it then IP traffic
> will
> >> >>>> not pass.
> >> >>>> >>>>> *
> >> >>>>
> >> >>>> >>>>> *
> >> >>>> >>>>>
> >> >>>> >>>>>
> >> >>>> >>>>> On Fri, Dec 9, 2011 at 7:45 AM, Narottam Prajapati <
> >> >>>> >>>>> [email protected]> wrote:
> >> >>>> >>>>>
> >> >>>> >>>>>> HI
> >> >>>> >>>>>>
> >> >>>> >>>>>>     Native VLAN numbering mismatch will not affect to trunk
> >> >>>> forming
> >> >>>> >>>>>> process. Trunk will form between both devics.
> >> >>>> >>>>>>
> >> >>>> >>>>>> Regarding Traffic forwarding traffic will forward without
> any
> >> >>>> tagigng
> >> >>>> >>>>>> due
> >> >>>> >>>>>> to default behaviour of dot1q encapsulation.
> >> >>>> >>>>>>
> >> >>>> >>>>>> When router try to forward traffic to switch frames
> forwards up
> >> >>>> to
> >> >>>> >>>>>> switch
> >> >>>> >>>>>> and switch 2 assume that this traffic is for native VLAN
> >> traffic
> >> >>>> >>>>>> because
> >> >>>> >>>>>> frames are untaged.
> >> >>>> >>>>>>
> >> >>>> >>>>>> Hi Group
> >> >>>> >>>>>>
> >> >>>> >>>>>>  make me correct if any thing is wrong.
> >> >>>> >>>>>>
> >> >>>> >>>>>> Regards,
> >> >>>> >>>>>> Narottam Prajapati
> >> >>>> >>>>>>
> >> >>>> >>>>>> On Fri, Dec 9, 2011 at 11:25 AM, Shaughn Smith <
> >> >>>> [email protected]>
> >> >>>> >>>>>> wrote:
> >> >>>> >>>>>>
> >> >>>> >>>>>> > Your question was answered. A few times.
> >> >>>> >>>>>> >
> >> >>>> >>>>>> > CCIE # 23962 (SP)
> >> >>>> >>>>>> >
> >> >>>> >>>>>> > Sent from my iPhone 4
> >> >>>> >>>>>> >
> >> >>>> >>>>>> > On 09 Dec 2011, at 7:40 AM, CCIE KID <[email protected]
> >
> >> >>>> wrote:
> >> >>>> >>>>>> >
> >> >>>> >>>>>> > > Hi all,
> >> >>>> >>>>>> > >
> >> >>>> >>>>>> > > Still my question has not been answered. What will
> happen
> >> if
> >> >>>> a
> >> >>>> >>>>>> router
> >> >>>> >>>>>> > > connected to a switch is placed in two different native
> >> >>>> Vlans. U
> >> >>>> >>>>>> guys are
> >> >>>> >>>>>> > > all talking about connecting two switches and
> incorporating
> >> >>>> two
> >> >>>> >>>>>> different
> >> >>>> >>>>>> > > native vlans.
> >> >>>> >>>>>> > >
> >> >>>> >>>>>> > > My scenario is simple. R1-----------------------Sw1
> >> >>>> >>>>>> > >
> >> >>>> >>>>>> > > I m using two different native vlans from R1 to Sw1 .
> >> Whether
> >> >>>> >>>>>> trunk will
> >> >>>> >>>>>> > > form.?  Or if the trunk forms, whether user traffic
> will be
> >> >>>> able
> >> >>>> >>>>>> to pass
> >> >>>> >>>>>> > > through or not.
> >> >>>> >>>>>> > >
> >> >>>> >>>>>> > > Please reply to my questions
> >> >>>> >>>>>> > >
> >> >>>> >>>>>> > > Thank You
> >> >>>> >>>>>> > >
> >> >>>> >>>>>> > > On Fri, Dec 9, 2011 at 4:23 AM, George J. Sanchez <
> >> >>>> >>>>>> [email protected]
> >> >>>> >>>>>> > >wrote:
> >> >>>> >>>>>> > >
> >> >>>> >>>>>> > >> I've seen plenty of customers networks with native vlan
> >> >>>> >>>>>> mismatches,
> >> >>>> >>>>>> > >> traffic will pass.  With that being said, newer code
> may
> >> fix
> >> >>>> >>>>>> different
> >> >>>> >>>>>> > >> "features" that previous codes had issues with.
> >> >>>> >>>>>> > >>
> >> >>>> >>>>>> > >> Regards,
> >> >>>> >>>>>> > >> Joe Sanchez
> >> >>>> >>>>>> > >>
> >> >>>> >>>>>> > >> On Dec 8, 2011, at 1:28 PM, Narbik Kocharians <
> >> >>>> [email protected]
> >> >>>> >>>>>> >
> >> >>>> >>>>>> > wrote:
> >> >>>> >>>>>> > >>
> >> >>>> >>>>>> > >>> This is what i was referring to:
> >> >>>> >>>>>> > >>>
> >> >>>> >>>>>> > >>>
> >> >>>> >>>>>> > >>> R1 s F0/0 is connected to SW1 s port F0/1
> >> >>>> >>>>>> > >>>
> >> >>>> >>>>>> > >>> R2 s F0/1 is connected to SW2 s port F0/2
> >> >>>> >>>>>> > >>>
> >> >>>> >>>>>> > >>>
> >> >>>> >>>>>> > >>> SW1 s F0/19 is connected to SW2 s F0/19
> >> >>>> >>>>>> > >>>
> >> >>>> >>>>>> > >>>
> >> >>>> >>>>>> > >>> *SW1#sh run int f0/19 | B inter*
> >> >>>> >>>>>> > >>>
> >> >>>> >>>>>> > >>> interface FastEthernet0/19
> >> >>>> >>>>>> > >>>
> >> >>>> >>>>>> > >>> switchport trunk encapsulation dot1q
> >> >>>> >>>>>> > >>>
> >> >>>> >>>>>> > >>> switchport trunk native vlan 10
> >> >>>> >>>>>> > >>>
> >> >>>> >>>>>> > >>> switchport mode trunk
> >> >>>> >>>>>> > >>>
> >> >>>> >>>>>> > >>> end
> >> >>>> >>>>>> > >>>
> >> >>>> >>>>>> > >>> *
> >> >>>> >>>>>> > >>> *
> >> >>>> >>>>>> > >>>
> >> >>>> >>>>>> > >>> *SW2#sh run int f0/19 | B inter*
> >> >>>> >>>>>> > >>>
> >> >>>> >>>>>> > >>> interface FastEthernet0/19
> >> >>>> >>>>>> > >>>
> >> >>>> >>>>>> > >>> switchport trunk encapsulation dot1q
> >> >>>> >>>>>> > >>>
> >> >>>> >>>>>> > >>> switchport mode trunk
> >> >>>> >>>>>> > >>>
> >> >>>> >>>>>> > >>> end
> >> >>>> >>>>>> > >>>
> >> >>>> >>>>>> > >>>
> >> >>>> >>>>>> > >>> *NOTE: The trunk is UP*
> >> >>>> >>>>>> > >>>
> >> >>>> >>>>>> > >>>
> >> >>>> >>>>>> > >>> *SW1#Show int trunk*
> >> >>>> >>>>>> > >>>
> >> >>>> >>>>>> > >>>
> >> >>>> >>>>>> > >>> Port        Mode         Encapsulation  Status
> >> >>>>  Native
> >> >>>> >>>>>> vlan
> >> >>>> >>>>>> > >>>
> >> >>>> >>>>>> > >>> Fa0/19      on           802.1q         trunking
>  10
> >> >>>> >>>>>> > >>>
> >> >>>> >>>>>> > >>>
> >> >>>> >>>>>> > >>> Port        Vlans allowed on trunk
> >> >>>> >>>>>> > >>>
> >> >>>> >>>>>> > >>> Fa0/19      1-4094
> >> >>>> >>>>>> > >>>
> >> >>>> >>>>>> > >>>
> >> >>>> >>>>>> > >>> Port        Vlans allowed and active in management
> domain
> >> >>>> >>>>>> > >>>
> >> >>>> >>>>>> > >>> Fa0/19      1,10,80
> >> >>>> >>>>>> > >>>
> >> >>>> >>>>>> > >>>
> >> >>>> >>>>>> > >>> Port        Vlans in spanning tree forwarding state
> and
> >> not
> >> >>>> >>>>>> pruned
> >> >>>> >>>>>> > >>>
> >> >>>> >>>>>> > >>> Fa0/19      1,10,80
> >> >>>> >>>>>> > >>>
> >> >>>> >>>>>> > >>>
> >> >>>> >>>>>> > >>>
> >> >>>> >>>>>> > >>> *SW2#sh spanning-tree blockedports *
> >> >>>> >>>>>> > >>>
> >> >>>> >>>>>> > >>>
> >> >>>> >>>>>> > >>> Name                 Blocked Interfaces List
> >> >>>> >>>>>> > >>>
> >> >>>> >>>>>> > >>> --------------------
> ------------------------------------
> >> >>>> >>>>>> > >>>
> >> >>>> >>>>>> > >>> VLAN0001             Fa0/19
> >> >>>> >>>>>> > >>>
> >> >>>> >>>>>> > >>> VLAN0010             Fa0/19
> >> >>>> >>>>>> > >>>
> >> >>>> >>>>>> > >>>
> >> >>>> >>>>>> > >>> Number of blocked ports (segments) in the system : 2
> >> >>>> >>>>>> > >>>
> >> >>>> >>>>>> > >>>
> >> >>>> >>>>>> > >>> *All Traffic is blocked for the two Vlans.*
> >> >>>> >>>>>> > >>>
> >> >>>> >>>>>> > >>> *And sure you can get around it, and one way to do
> this
> >> is
> >> >>>> to
> >> >>>> >>>>>> filter
> >> >>>> >>>>>> > >> BPDUs
> >> >>>> >>>>>> > >>> that carry the VLANs as you mentioned:*
> >> >>>> >>>>>> > >>>
> >> >>>> >>>>>> > >>>
> >> >>>> >>>>>> > >>> SW1(config)#int f0/19
> >> >>>> >>>>>> > >>>
> >> >>>> >>>>>> > >>> SW1(config-if)#spanning-tree bpdufilter en
> >> >>>> >>>>>> > >>>
> >> >>>> >>>>>> > >>>
> >> >>>> >>>>>> > >>> *SW1#sh spannin blockedports   *
> >> >>>> >>>>>> > >>>
> >> >>>> >>>>>> > >>>
> >> >>>> >>>>>> > >>> Name                 Blocked Interfaces List
> >> >>>> >>>>>> > >>>
> >> >>>> >>>>>> > >>> --------------------
> ------------------------------------
> >> >>>> >>>>>> > >>>
> >> >>>> >>>>>> > >>>
> >> >>>> >>>>>> > >>> Number of blocked ports (segments) in the system : 0
> >> >>>> >>>>>> > >>>
> >> >>>> >>>>>> > >>>
> >> >>>> >>>>>> > >>> *And I am sure there are other ways. But remember
> this is
> >> >>>> the
> >> >>>> >>>>>> default
> >> >>>> >>>>>> > >>> behavior BUT not on all IOSes, on some IOSes, it will
> >> >>>> complain
> >> >>>> >>>>>> that
> >> >>>> >>>>>> > there
> >> >>>> >>>>>> > >>> is a Native VLAN mismatch, but it will NOT block the
> >> VLANs
> >> >>>> >>>>>> configured
> >> >>>> >>>>>> > as
> >> >>>> >>>>>> > >>> Native*
> >> >>>> >>>>>> > >>>
> >> >>>> >>>>>> > >>>
> >> >>>> >>>>>> > >>> On Thu, Dec 8, 2011 at 10:35 AM, Narbik Kocharians <
> >> >>>> >>>>>> [email protected]
> >> >>>> >>>>>> > >>> wrote:
> >> >>>> >>>>>> > >>>
> >> >>>> >>>>>> > >>>> Yes, you are correct, you can get around it, i was
> >> >>>> referring
> >> >>>> >>>>>> to the
> >> >>>> >>>>>> > >>>> default behavior.
> >> >>>> >>>>>> > >>>>
> >> >>>> >>>>>> > >>>>
> >> >>>> >>>>>> > >>>> On Thu, Dec 8, 2011 at 9:23 AM, Paul Cocker <
> >> >>>> >>>>>> [email protected]>
> >> >>>> >>>>>> > >> wrote:
> >> >>>> >>>>>> > >>>>
> >> >>>> >>>>>> > >>>>> Spanning-tree...
> >> >>>> >>>>>> > >>>>>
> >> >>>> >>>>>> > >>>>> I'm guessing the vlan is in the bpdu.
> >> >>>> >>>>>> > >>>>>
> >> >>>> >>>>>> > >>>>> with this config...
> >> >>>> >>>>>> > >>>>>
> >> >>>> >>>>>> > >>>>> SW1
> >> >>>> >>>>>> > >>>>> interface FastEthernet0/13
> >> >>>> >>>>>> > >>>>> switchport trunk encapsulation dot1q
> >> >>>> >>>>>> > >>>>> switchport trunk native vlan 10
> >> >>>> >>>>>> > >>>>> switchport mode trunk
> >> >>>> >>>>>> > >>>>> switchport nonegotiate
> >> >>>> >>>>>> > >>>>>
> >> >>>> >>>>>> > >>>>> SW2
> >> >>>> >>>>>> > >>>>> interface FastEthernet0/13
> >> >>>> >>>>>> > >>>>> switchport access vlan 20
> >> >>>> >>>>>> > >>>>> switchport trunk encapsulation dot1q
> >> >>>> >>>>>> > >>>>> switchport trunk native vlan 20
> >> >>>> >>>>>> > >>>>> switchport mode trunk
> >> >>>> >>>>>> > >>>>> switchport nonegotiate
> >> >>>> >>>>>> > >>>>> no cdp enable
> >> >>>> >>>>>> > >>>>>
> >> >>>> >>>>>> > >>>>>
> >> >>>> >>>>>> > >>>>> you get this...
> >> >>>> >>>>>> > >>>>>
> >> >>>> >>>>>> > >>>>> *Mar  1 00:18:26.994: %SPANTREE-2-RECV_PVID_ERR:
> >> Received
> >> >>>> >>>>>> BPDU with
> >> >>>> >>>>>> > >>>>> inconsistent peer vlan id 10 on FastEthernet0/13
> >> VLAN20.
> >> >>>> >>>>>> > >>>>> *Mar  1 00:18:26.994: %SPANTREE-2-BLOCK_PVID_LOCAL:
> >> >>>> Blocking
> >> >>>> >>>>>> > >>>>> FastEthernet0/13 on VLAN0020. Inconsistent local
> vlan.
> >> >>>> >>>>>> > >>>>>
> >> >>>> >>>>>> > >>>>> You can disable spanning tree, or use bpdufilter to
> get
> >> >>>> >>>>>> around it.
> >> >>>> >>>>>> > >>>>>
> >> >>>> >>>>>> > >>>>>
> >> >>>> >>>>>> > >>>>> On 08/12/2011 16:58, Carlos G Mendioroz wrote:
> >> >>>> >>>>>> > >>>>>
> >> >>>> >>>>>> > >>>>>> What mechanism is responsible for such blocking ?
> >> >>>> >>>>>> > >>>>>>
> >> >>>> >>>>>> > >>>>>> -Carlos
> >> >>>> >>>>>> > >>>>>>
> >> >>>> >>>>>> > >>>>>> Narbik Kocharians @ 08/12/2011 13:34 -0300 dixit:
> >> >>>> >>>>>> > >>>>>>
> >> >>>> >>>>>> > >>>>>>> Between any two switch if the Native VLAN is
> >> >>>> mismatched the
> >> >>>> >>>>>> trunk
> >> >>>> >>>>>> > >> will
> >> >>>> >>>>>> > >>>>>>> come up but you won't be able to pass any traffic
> >> >>>> through
> >> >>>> >>>>>> it, and
> >> >>>> >>>>>> > you
> >> >>>> >>>>>> > >>> can
> >> >>>> >>>>>> > >>>>>>> see that with a "Show spanning block".
> >> >>>> >>>>>> > >>>>>>> On Thu, Dec 8, 2011 at 4:31 AM, David Bass
> >> >>>> >>>>>> > >>> <[email protected]<mailto:
> >> >>>> >>>>>> > >>>>>>> [email protected]**>> wrote:
> >> >>>> >>>>>> > >>>>>>>
> >> >>>> >>>>>> > >>>>>>>  We are talking about CCIE lab, so best practice
> and
> >> >>>> >>>>>> "working"
> >> >>>> >>>>>> > >> status
> >> >>>> >>>>>> > >>>>>>>  all go out the window :).  In his scenario he's
> >> >>>> talking
> >> >>>> >>>>>> about
> >> >>>> >>>>>> > >> router
> >> >>>> >>>>>> > >>>>>>>  to switch trunk, so no VTP or STP (if you do this
> >> >>>> switch
> >> >>>> >>>>>> to switch
> >> >>>> >>>>>> > >>>>>>>  you'll definitely have issues though, so very
> good
> >> to
> >> >>>> >>>>>> know)...CDP
> >> >>>> >>>>>> > >>>>>>>  will definitely bark non-stop though which is
> very
> >> >>>> >>>>>> irritating.
> >> >>>> >>>>>> > >>>>>>>
> >> >>>> >>>>>> > >>>>>>>
> >> >>>> >>>>>> > >>>>>>>
> >> >>>> >>>>>> > >>>>>>>  On Dec 8, 2011, at 6:08 AM, Carlos G Mendioroz
> >> wrote:
> >> >>>> >>>>>> > >>>>>>>
> >> >>>> >>>>>> > >>>>>>>> May be depending on the equipment, the trunk will
> >> >>>> "form"
> >> >>>> >>>>>> just
> >> >>>> >>>>>> > fine,
> >> >>>> >>>>>> > >>>>>>>> if VLAN hopping is not considered to be a
> problem :)
> >> >>>> >>>>>> > >>>>>>>> CDP may barf. If VLAN 1 is involved, other griefs
> >> >>>> will pop.
> >> >>>> >>>>>> > >>>>>>>>
> >> >>>> >>>>>> > >>>>>>>> Different problems:
> >> >>>> >>>>>> > >>>>>>>> -framing: no problem, but "native VLAN" frames do
> >> not
> >> >>>> >>>>>> signal
> >> >>>> >>>>>> > >>>>>>>  which VLAN
> >> >>>> >>>>>> > >>>>>>>> they belong to, so if they do not match, frames
> will
> >> >>>> hop
> >> >>>> >>>>>> from one
> >> >>>> >>>>>> > >>>>>>>  VLAN
> >> >>>> >>>>>> > >>>>>>>> to the other.
> >> >>>> >>>>>> > >>>>>>>>
> >> >>>> >>>>>> > >>>>>>>> -signalling (DTP): AFAIK, VLANs are not part of
> the
> >> >>>> info
> >> >>>> >>>>>> > >>>>>>>  interchanged, so the trunk will form even if
> native
> >> >>>> is not
> >> >>>> >>>>>> the
> >> >>>> >>>>>> > >> same.
> >> >>>> >>>>>> > >>>>>>>>
> >> >>>> >>>>>> > >>>>>>>> -control: (CDP/VTP/STP/...): well, you may have a
> >> >>>> problem
> >> >>>> >>>>>> here.
> >> >>>> >>>>>> > >>>>>>>> In particular, CDP/VTP go on VLAN 1, so if this
> is
> >> >>>> one of
> >> >>>> >>>>>> the
> >> >>>> >>>>>> > VLANs
> >> >>>> >>>>>> > >>>>>>>> involved in the crossing, it won't work.
> >> >>>> >>>>>> > >>>>>>>>
> >> >>>> >>>>>> > >>>>>>>> -Others ?
> >> >>>> >>>>>> > >>>>>>>>
> >> >>>> >>>>>> > >>>>>>>> -Carlos
> >> >>>> >>>>>> > >>>>>>>>
> >> >>>> >>>>>> > >>>>>>>>
> >> >>>> >>>>>> > >>>>>>>> David Bass @ 08/12/2011 08:25 -0300 dixit:
> >> >>>> >>>>>> > >>>>>>>>> The trunk will come up fine, but you won't have
> IP
> >> >>>> >>>>>> connectivity
> >> >>>> >>>>>> > >>>>>>>  between the 2 devices on the VLANs/subnets you
> are
> >> >>>> >>>>>> expecting
> >> >>>> >>>>>> > >> because
> >> >>>> >>>>>> > >>>>>>>  the 2 native VLANs are being bridged.  Do some
> >> >>>> research on
> >> >>>> >>>>>> how
> >> >>>> >>>>>> > >> dot1q
> >> >>>> >>>>>> > >>>>>>>  trunks work and you should be able to figure it
> out.
> >> >>>> On
> >> >>>> >>>>>> Dec 7,
> >> >>>> >>>>>> > >> 2011,
> >> >>>> >>>>>> > >>>>>>>  at 11:40 PM, CCIE KID <[email protected]
> >> >>>> >>>>>> > >>>>>>> <mailto:[email protected]>> wrote:
> >> >>>> >>>>>> > >>>>>>>>>> Hi fellas,
> >> >>>> >>>>>> > >>>>>>>>>>
> >> >>>> >>>>>> > >>>>>>>>>> I tested a scenario where the Native vlan
> differs
> >> >>>> from
> >> >>>> >>>>>> the
> >> >>>> >>>>>> > >>>>>>>  router port to
> >> >>>> >>>>>> > >>>>>>>>>> the switch port. I understood that if the
> NAtive
> >> >>>> vlan
> >> >>>> >>>>>> > >>>>>>>  mismatches on a trunk
> >> >>>> >>>>>> > >>>>>>>>>> port , then appropriate trunking wont be
> formed.
> >> >>>> >>>>>> > >>>>>>>>>> But when i connect my router to a switch and in
> >> the
> >> >>>> >>>>>> router
> >> >>>> >>>>>> > >>>>>>>  subinterface . I
> >> >>>> >>>>>> > >>>>>>>>>> am having a native vlan of 20 and in the switch
> >> >>>> port it
> >> >>>> >>>>>> is
> >> >>>> >>>>>> > >>>>>>>  having a native
> >> >>>> >>>>>> > >>>>>>>>>> vlan of 10 , but still the trunk is forming
> >> >>>> perfectly
> >> >>>> >>>>>> > >>>>>>>>>>
> >> >>>> >>>>>> > >>>>>>>>>> Can someone correct me
> >> >>>> >>>>>> > >>>>>>>>>>         fa0/1.1
> >> >>>>  fa0/1
> >> >>>> >>>>>> > >>>>>>>>>>
> >> >>>> >>>>>>
> Router1-----------------------**------------------------Switch
> >> 1
> >> >>>> >>>>>> > >>>>>>>>>>
> >> >>>> >>>>>> > >>>>>>>>>> Router 1
> >> >>>> >>>>>> > >>>>>>>>>>
> >> >>>> >>>>>> > >>>>>>>>>> inter fa 0/1.1
> >> >>>> >>>>>> > >>>>>>>>>> encap dot1q 20 native
> >> >>>> >>>>>> > >>>>>>>>>> ip add 10.1.1.1 255.255.255.0
> >> >>>> >>>>>> > >>>>>>>>>> no sh
> >> >>>> >>>>>> > >>>>>>>>>>
> >> >>>> >>>>>> > >>>>>>>>>>
> >> >>>> >>>>>> > >>>>>>>>>> Switch 1
> >> >>>> >>>>>> > >>>>>>>>>>
> >> >>>> >>>>>> > >>>>>>>>>> int fa 0/1
> >> >>>> >>>>>> > >>>>>>>>>> enc dot1q 10 native
> >> >>>> >>>>>> > >>>>>>>>>> swi trunk enc dot
> >> >>>> >>>>>> > >>>>>>>>>> swi mo trunk
> >> >>>> >>>>>> > >>>>>>>>>> no sh
> >> >>>> >>>>>> > >>>>>>>>>>
> >> >>>> >>>>>> > >>>>>>>>>>
> >> >>>> >>>>>> > >>>>>>>>>> But s
> >> >>>> >>>>>> > >>>>>>>>>>
> >> >>>> >>>>>> > >>>>>>>>>> --
> >> >>>> >>>>>> > >>>>>>>>>> With Warmest Regards,
> >> >>>> >>>>>> > >>>>>>>>>>
> >> >>>> >>>>>> > >>>>>>>>>> CCIE KID
> >> >>>> >>>>>> > >>>>>>>>>> CCIE#29992 (Security)
> >> >>>> >>>>>> > >>>>>>>>>>
> >> >>>> >>>>>> > >>>>>>>>>>
> >> >>>> >>>>>> > >>>>>>>>>> Blogs and organic groups at
> http://www.ccie.net
> >> >>>> >>>>>> > >>>>>>>>>>
> >> >>>> >>>>>> > >>>>>>>>>>
> >> >>>> >>>>>> > >>>>>>>
> >> >>>> >>>>>>
> >>  ______________________________**______________________________**
> >> >>>> >>>>>> > >>>>>>> ___________
> >> >>>> >>>>>> > >>>>>>>>>> Subscription information may be found at:
> >> >>>> >>>>>> > >>>>>>>
> >> >>>> >>>>>> > >>> http://www.groupstudy.com/**list/CCIELab.html<
> >> >>>> >>>>>> > >> http://www.groupstudy.com/list/
> >> >>>> >>>>>> > >>> CCIELab.html>
> >> >>>> >>>>>> > >>>>>>>>> Blogs and organic groups at http://www.ccie.net
> >> >>>> >>>>>> > >>>>>>>>>
> >> >>>> >>>>>> > >>>>>>>
> >> >>>> >>>>>>
> >>  ______________________________**______________________________**
> >> >>>> >>>>>> > >>>>>>> ___________
> >> >>>> >>>>>> > >>>>>>>>> Subscription information may be found at:
> >> >>>> >>>>>> > >>>>>>>
> >> >>>> >>>>>> > >>> http://www.groupstudy.com/**list/CCIELab.html<
> >> >>>> >>>>>> > >> http://www.groupstudy.com/list/
> >> >>>> >>>>>> > >>> CCIELab.html>
> >> >>>> >>>>>> > >>>>>>>>
> >> >>>> >>>>>> > >>>>>>>> --
> >> >>>> >>>>>> > >>>>>>>> Carlos G Mendioroz <[email protected] <mailto:
> >> >>>> >>>>>> [email protected]>>
> >> >>>> >>>>>> > >>>>>>>   LW7 EQI  Argentina
> >> >>>> >>>>>> > >>>>>>>
> >> >>>> >>>>>> > >>>>>>>
> >> >>>> >>>>>> > >>>>>>>  Blogs and organic groups at http://www.ccie.net
> >> >>>> >>>>>> > >>>>>>>
> >> >>>> >>>>>> > >>>>>>>
> >> >>>> >>>>>>
> >>  ______________________________**______________________________**
> >> >>>> >>>>>> > >>>>>>> ___________
> >> >>>> >>>>>> > >>>>>>>  Subscription information may be found at:
> >> >>>> >>>>>> > >>>>>>>
> >> >>>> >>>>>> > >>> http://www.groupstudy.com/**list/CCIELab.html<
> >> >>>> >>>>>> > >> http://www.groupstudy.com/list/
> >> >>>> >>>>>> > >>> CCIELab.html>
> >> >>>> >>>>>> > >>>>>>>
> >> >>>> >>>>>> > >>>>>>>
> >> >>>> >>>>>> > >>>>>>>
> >> >>>> >>>>>> > >>>>>>>
> >> >>>> >>>>>> > >>>>>>>
> >> >>>> >>>>>> > >>>>>>>
> >> >>>> >>>>>> > >>>>>>>
> >> >>>> >>>>>> > >>>>>>>
> >> >>>> >>>>>> > >>>>>>>
> >> >>>> >>>>>> > >>>>>>>
> >> >>>> >>>>>> > >>>>>>> --
> >> >>>> >>>>>> > >>>>>>> *Narbik Kocharians
> >> >>>> >>>>>> > >>>>>>> *CCSI#30832, CCIE# 12410 (R&S, SP, Security)
> >> >>>> >>>>>> > >>>>>>> *www.MicronicsTraining.com*
> >> >>>> >>>>>> > >>> <http://www.micronicstraining.**com/<
> >> >>>> >>>>>> http://www.micronicstraining.com/
> >> >>>> >>>>>> > >
> >> >>>> >>>>>> > >>>>>>>>
> >> >>>> >>>>>> > >>>>>>> Sr. Technical Instructor
> >> >>>> >>>>>> > >>>>>>> YES! We take Cisco Learning Credits!
> >> >>>> >>>>>> > >>>>>>> Training & Remote Racks available
> >> >>>> >>>>>> > >>>>>>>
> >> >>>> >>>>>> > >>>>>>
> >> >>>> >>>>>> > >>>>>
> >> >>>> >>>>>> > >>>>> Blogs and organic groups at http://www.ccie.net
> >> >>>> >>>>>> > >>>>>
> >> >>>> >>>>>> > >>>>>
> >> >>>> >>>>>>
> >> ______________________________**______________________________**
> >> >>>> >>>>>> > >>>>> ___________
> >> >>>> >>>>>> > >>>>> Subscription information may be found at:
> >> >>>> >>>>>> > http://www.groupstudy.com/**
> >> >>>> >>>>>> > >>>>> list/CCIELab.html <
> >> >>>> >>>>>> http://www.groupstudy.com/list/CCIELab.html>
> >> >>>> >>>>>> > >>>>>
> >> >>>> >>>>>> > >>>>>
> >> >>>> >>>>>> > >>>>>
> >> >>>> >>>>>> > >>>>>
> >> >>>> >>>>>> > >>>>>
> >> >>>> >>>>>> > >>>>>
> >> >>>> >>>>>> > >>>>>
> >> >>>> >>>>>> > >>>>>
> >> >>>> >>>>>> > >>>>
> >> >>>> >>>>>> > >>>>
> >> >>>> >>>>>> > >>>> --
> >> >>>> >>>>>> > >>>> *Narbik Kocharians
> >> >>>> >>>>>> > >>>> *
> >> >>>> >>>>>> > >>>> CCSI#30832, CCIE# 12410 (R&S, SP, Security)
> >> >>>> >>>>>> > >>>> *www.MicronicsTraining.com* <
> >> >>>> http://www.micronicstraining.com/
> >> >>>> >>>>>> >
> >> >>>> >>>>>> > >>>> Sr. Technical Instructor
> >> >>>> >>>>>> > >>>> YES! We take Cisco Learning Credits!
> >> >>>> >>>>>> > >>>> Training & Remote Racks available
> >> >>>> >>>>>> > >>>>
> >> >>>> >>>>>> > >>>>
> >> >>>> >>>>>> > >>>
> >> >>>> >>>>>> > >>>
> >> >>>> >>>>>> > >>> --
> >> >>>> >>>>>> > >>> *Narbik Kocharians
> >> >>>> >>>>>> > >>> *CCSI#30832, CCIE# 12410 (R&S, SP, Security)
> >> >>>> >>>>>> > >>> *www.MicronicsTraining.com* <
> >> >>>> http://www.micronicstraining.com/>
> >> >>>> >>>>>> > >>> Sr. Technical Instructor
> >> >>>> >>>>>> > >>> YES! We take Cisco Learning Credits!
> >> >>>> >>>>>> > >>> Training & Remote Racks available
> >> >>>> >>>>>> > >>>
> >> >>>> >>>>>> > >>>
> >> >>>> >>>>>> > >>> Blogs and organic groups at http://www.ccie.net
> >> >>>> >>>>>> > >>>
> >> >>>> >>>>>> > >>>
> >> >>>> >>>>>>
> >> >>>>
> >> _______________________________________________________________________
> >> >>>> >>>>>> > >>> Subscription information may be found at:
> >> >>>> >>>>>> > >>> http://www.groupstudy.com/list/CCIELab.html
> >> >>>> >>>>>> > >>
> >> >>>> >>>>>> > >>
> >> >>>> >>>>>> > >> Blogs and organic groups at http://www.ccie.net
> >> >>>> >>>>>> > >>
> >> >>>> >>>>>> > >>
> >> >>>> >>>>>>
> >> >>>>
> >> _______________________________________________________________________
> >> >>>> >>>>>> > >> Subscription information may be found at:
> >> >>>> >>>>>> > >> http://www.groupstudy.com/list/CCIELab.html
> >> >>>> >>>>>> > >>
> >> >>>> >>>>>> > >>
> >> >>>> >>>>>> > >>
> >> >>>> >>>>>> > >>
> >> >>>> >>>>>> > >>
> >> >>>> >>>>>> > >>
> >> >>>> >>>>>> > >>
> >> >>>> >>>>>> > >>
> >> >>>> >>>>>> > >
> >> >>>> >>>>>> > >
> >> >>>> >>>>>> > > --
> >> >>>> >>>>>> > > With Warmest Regards,
> >> >>>> >>>>>> > >
> >> >>>> >>>>>> > > CCIE KID
> >> >>>> >>>>>> > > CCIE#29992 (Security)
> >> >>>> >>>>>> > >
> >> >>>> >>>>>> > >
> >> >>>> >>>>>> > > Blogs and organic groups at http://www.ccie.net
> >> >>>> >>>>>> > >
> >> >>>> >>>>>> > >
> >> >>>> >>>>>>
> >> >>>>
> >> _______________________________________________________________________
> >> >>>> >>>>>> > > Subscription information may be found at:
> >> >>>> >>>>>> > > http://www.groupstudy.com/list/CCIELab.html
> >> >>>> >>>>>> >
> >> >>>> >>>>>> >
> >> >>>> >>>>>> > Blogs and organic groups at http://www.ccie.net
> >> >>>> >>>>>> >
> >> >>>> >>>>>> >
> >> >>>> >>>>>>
> >> >>>>
> >> _______________________________________________________________________
> >> >>>> >>>>>> > Subscription information may be found at:
> >> >>>> >>>>>> > http://www.groupstudy.com/list/CCIELab.html
> >> >>>> >>>>>>
> >> >>>> >>>>>>
> >> >>>> >>>>>> Blogs and organic groups at http://www.ccie.net
> >> >>>> >>>>>>
> >> >>>> >>>>>>
> >> >>>> >>>>>>
> >> >>>>
> >> _______________________________________________________________________
> >> >>>> >>>>>> Subscription information may be found at:
> >> >>>> >>>>>> http://www.groupstudy.com/list/CCIELab.html
> >> >>>> >>>>>>
> >> >>>> >>>>>>
> >> >>>> >>>>>>
> >> >>>> >>>>>>
> >> >>>> >>>>>>
> >> >>>> >>>>>>
> >> >>>> >>>>>>
> >> >>>> >>>>>>
> >> >>>> >>>>>
> >> >>>> >>>>>
> >> >>>> >>>>> --
> >> >>>> >>>>> --
> >> >>>> >>>>> Olugbenga Oyebande
> >> >>>> >>>>> MD, DAIT
> >> >>>> >>>>> 234-803-302-5287
> >> >>>> >>>>> http://www.dait-ng.com
> >> >>>> >>>>> Cisco Unified Network, VPN
> >> >>>> >>>>> DAIT Enterprise Network Servers
> >> >>>> >>>>> Broadband Internet Deployment & ISP Consultancy
> >> >>>> >>>>>
> >> >>>> >>>>>
> >> >>>> >>>>
> >> >>>> >>>
> >> >>>> >>>
> >> >>>> >>> --
> >> >>>> >>> --
> >> >>>> >>> Olugbenga Oyebande
> >> >>>> >>> MD, DAIT
> >> >>>> >>> 234-803-302-5287
> >> >>>> >>> http://www.dait-ng.com
> >> >>>> >>> Cisco Unified Network, VPN
> >> >>>> >>> DAIT Enterprise Network Servers
> >> >>>> >>> Broadband Internet Deployment & ISP Consultancy
> >> >>>> >>>
> >> >>>> >>>
> >> >>>> >>
> >> >>>> >>
> >> >>>> >> --
> >> >>>> >> With Warmest Regards,
> >> >>>> >>
> >> >>>> >> CCIE KID
> >> >>>> >> CCIE#29992 (Security)
> >> >>>> >>
> >> >>>> >>
> >> >>>> >>
> >> >>>> >
> >> >>>>
> >> >>>>
> >> >>>> --
> >> >>>> With Warmest Regards,
> >> >>>>
> >> >>>> CCIE KID
> >> >>>> CCIE#29992 (Security)
> >> >>>> _______________________________________________
> >> >>>> For more information regarding industry leading CCIE Lab training,
> >> >>>> please visit www.ipexpert.com
> >> >>>>
> >> >>>> Are you a CCNP or CCIE and looking for a job? Check out
> >> >>>> www.PlatinumPlacement.com
> >> >>>>
> >> >>>> http://onlinestudylist.com/mailman/listinfo/ccie_rs
> >> >>>>
> >> >>>
> >> >>>
> >> >>
> >> >>
> >> >> --
> >> >> With Warmest Regards,
> >> >>
> >> >> CCIE KID
> >> >> CCIE#29992 (Security)
> >> >>
> >> >>
> >> >>
> >> >
> >> _______________________________________________
> >> For more information regarding industry leading CCIE Lab training,
> please
> >> visit www.ipexpert.com
> >>
> >> Are you a CCNP or CCIE and looking for a job? Check out
> >> www.PlatinumPlacement.com
> >>
> >> http://onlinestudylist.com/mailman/listinfo/ccie_rs
> >>
> > _______________________________________________
> > For more information regarding industry leading CCIE Lab training,
> please visit www.ipexpert.com
> >
> > Are you a CCNP or CCIE and looking for a job? Check out
> www.PlatinumPlacement.com
> >
> > http://onlinestudylist.com/mailman/listinfo/ccie_rs
>
_______________________________________________
For more information regarding industry leading CCIE Lab training, please visit 
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Are you a CCNP or CCIE and looking for a job? Check out 
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