What is native vlan in the context of IEEE 802.1Q trunk restriction ?
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FAQ
Benny,
Try thinking of trunking as a "service" that runs on the access links,
multiplexing traffic from multiple vlans. Those links have a native VLAN
that they revert to if trunking breaks down. For example, if you reboot a
switch and it's unable to negotiate the trunking due t
Also, and importantly: While ISL tags *all* frames with VLAN info, 802.1Q
does *not*: Traffic on the "native" VLAN is forwarded unaltered. So, an
802.1Q trunk will not work at all if the native VLANs are not identical,
whereas an ISL trunk can if nothing goes wrong.
-Gabriel McCall,
Group,
What is the significance of deciding what vlan to use for the "native vlan"
when setting up a trunk. Presently, I use "native vlan 1" when setting up
a trunk. Could I use any other vlan that is established on both switches as
the "native vlan"? I'll
Hi all
Can someone tell me what is the purpose of the native vlan in Csico Switch?
What is the feature & main usage on that?
I am wondering if it is a proprietary feature, it will only work through
Cisco Switches only?
Thanks.
Cheers
Stephen
Message Posted at:
http://www.groupstudy.com/
I am kinda new to VLANs and need some advice.
I have a router which I have broken an interface into FastEthernet
subinterfaces. Each subinterface defines the VLAN. This has worked very
well. But I am wondering if it is possible to make this port a trunk port
and have other non-tagged traffic arrive
One of the things related to native VLAN was VTP updates. I think they go
over the "native" VLAN, so you'll need to make sure its the same for all the
switches in the same VTP domain.
Jeffrey Reed
Classic Networking, Inc.
-Original Message-
From: [EMAIL PROTECTED]
we use native vlan 1 on our switches as well...you can use
any other vlan if you like. We tried that once and had problems
with inserting a new redundant sup card, which when installed
hot, puts its ports in vlan 1 by default and then causing vlan mismatch's
which caused stp re-calc loop i
I think the only significance is that they must match. In 802.1q the
native VLAN has no tag so the VLANs must match on each end so the
endpoints can deduce which VLAN the tagless packets belong.
Dave
"Lopez, Robert" wrote:
>
> Group,
>
> What is the significance of
The only thing I know from the switching exam, is that it is the vlan number
the trunk uses in case the trunk feature fails.
Regards.
Message Posted at:
http://www.groupstudy.com/form/read.php?f=7&i=45156&t=45146
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FAQ, list archives, and subscr
Packets sent on the native VLAN do not have the VLAN tag in them, so they
can be read by non-vlan aware devices.
Ron
""Chan Stephen"" wrote in message
[EMAIL PROTECTED]">news:[EMAIL PROTECTED]...
> Hi all
>
> Can someone tell me what is the purpose of the n
When Ports are configured as trunk in Catalyst switches, they still belong
to VLAN 1 in native column eventhough the ports can span all VLANs. What's
the drawback of changing the port from Native VLAN 1 to some other VLANs?
Regards, Teza
___
I'm confused on native vlan and trunking. Can I assign a port to a trunk
(for all the vlans), then assign that port to a vlan100? Does that port
belong to native vlan100? What means native vlan? Thanks. Yoshi
Message Posted at:
http://www.groupstudy.com/form/read.php?f=7&i=6330
Hey Jim
Supposing you take a new switch out of the box and don't configure any
vlan's etc, all the ports will still be using a vlan. That vlan is called
vlan1 and all ports are on vlan1 by default. The devices on those ports
wouldn't need any router to route traffic since they all belong to the sam
ell.
- Original Message -
From: "Bill"
To:
Sent: Tuesday, March 04, 2003 8:19 PM
Subject: Re: Native VLAN question [7:64431]
> Hey Jim
> Supposing you take a new switch out of the box and don't configure any
> vlan's etc, all the ports will still be using
: Native VLAN question [7:64431]
Hey Jim
Supposing you take a new switch out of the box and don't configure any
vlan's etc, all the ports will still be using a vlan. That vlan is called
vlan1 and all ports are on vlan1 by default. The devices on those ports
wouldn't need any
]
Sent: Tuesday, March 04, 2003 7:49 PM
Subject: Native VLAN question [7:64431]
I am kinda new to VLANs and need some advice.
I have a router which I have broken an interface into FastEthernet
subinterfaces. Each subinterface defines the VLAN. This has worked very
well. But I am wondering
Jim,
When you encapsulate your router interface with dot1q you are turning it
into a trunk port. All of the traffic coming out of that port will be
tagged with a vlan id except for traffic generated on the native vlan. By
default, any subinterface encapped with vlan 1 will be native and its
CTED]
> Subject: Native VLAN 1 [7:55743]
>
>
> When Ports are configured as trunk in Catalyst switches, they still belong
> to VLAN 1 in native column eventhough the ports can span all
> VLANs. What's
> the drawback of changing the port from Native VL
m: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On
> Behalf Of
> > Azhar Teza
> > Sent: Wednesday, October 16, 2002 3:21 PM
> > To: [EMAIL PROTECTED]
> > Subject: Native VLAN 1 [7:55743]
> >
> >
> > When Ports are configured as trunk in Catalyst switc
Pris,
In our 6509's we used to make the native vlan and the data vlan
the same and it was something other than 1...if a blade fails and
we put in a new one , it defaults to vlan 1 for all ports. If the
blade has trunk ports in it, they get set to native vlan 1. The other
end is se
""Larry Letterman"" wrote in message
[EMAIL PROTECTED]">news:[EMAIL PROTECTED]...
> Pris,
>
> In our 6509's we used to make the native vlan and the data vlan
> the same and it was something other than 1...if a blade fails and
> we put in a new o
Comments inline...
--- The Long and Winding Road
wrote:
> ""Larry Letterman"" wrote in message
> [EMAIL PROTECTED]">news:[EMAIL PROTECTED]...
> > Pris,
> >
> > In our 6509's we used to make the native vlan and
> the data vlan
> &g
Network Engineer
Cisco Systems Inc.
> -Original Message-
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of
> The Long and Winding Road
> Sent: Wednesday, October 16, 2002 11:08 PM
> To: [EMAIL PROTECTED]
> Subject: Re: Native VLAN 1 [7:55743]
>
>
>
I personally changed out a secondary sup card, when I was new in the lan
team..
the redundant sup came up with with the trunk port 2/1 config'd for native
vlan
1. this caused the vtp management to issue a vlan mismatch...which then
started
a stp recalc, which caused utilization on the gatew
yes...which is why a new one comes up as default
on vlan 1 as the native vlan for all ports...
Larry Letterman
Network Engineer
Cisco Systems Inc.
> -Original Message-
> From: [EMAIL PROTECTED] [mailto:nobody@;groupstudy.com]On Behalf Of
> Ken Diliberto
> Sent: Thursday
Don't want to beat this to death but if you pull out the redundant sup
the primary keeps running the show. After you reinstall the new
redundant sup it "should" sync up with the primary, including the native
VLAN info.
Dave
Priscilla Oppenheimer wrote:
>
> Thanks Lar
Ok this just didn't jive with my understanding so I went back to the
lab and tried something.
I have a 6509 with redundant supII's. On the redundant sup I have a
trunk to a 3550 and the native VLAN is 64. I pulled out the active SUP,
slot1. The redundant sup came active, all is go
I disagree with that. If native vlan is changed on only one end of the
link, you will get native vlan mismatch which can be bad. There are
some cases when changing native vlans is needed by design. Case in
point. A PC is plugged into an IP phone, the configuration of Cat 3524
is below
Since the config for the line cards resides on the sup there should be
no problem swapping out same line cards, if the native VLAN was changed,
the change will be employed on the new card also.
When you swapped out a standby sup in your example below I don't quite
understand what hapened.
""Larry Letterman"" wrote in message
news:200210170727.HAA2@;groupstudy.com...
> I personally changed out a secondary sup card, when I was new in the lan
> team..
> the redundant sup came up with with the trunk port 2/1 config'd for native
> vlan
> 1. t
TECTED] [mailto:nobody@;groupstudy.com]On Behalf Of
> MADMAN
> Sent: Thursday, October 17, 2002 7:35 AM
> To: [EMAIL PROTECTED]
> Subject: Re: Native VLAN 1 [7:55743]
>
>
> Since the config for the line cards resides on the sup there should be
> no problem swapping out same line cards,
> > From: [EMAIL PROTECTED] [mailto:nobody@;groupstudy.com]On
> Behalf Of
> > MADMAN
> > Sent: Thursday, October 17, 2002 7:35 AM
> > To: [EMAIL PROTECTED]
> > Subject: Re: Native VLAN 1 [7:55743]
> >
> >
> > Since the config for the line cards resid
; MADMAN
> Sent: Thursday, October 17, 2002 7:35 AM
> To: [EMAIL PROTECTED]
> Subject: Re: Native VLAN 1 [7:55743]
>
>
> Since the config for the line cards resides on the sup there should
be
> no problem swapping out same line cards, if the native VLAN was
changed,
> the
Native VLAN is the vlan which is is "untagged" with VLAN information or
tags. IE, by default, VLAN 1 is untagged, meaning other devices which do not
understand vlan's, can understand traffic from a vlan 1 port (for example).
Message Posted at:
http://www.groupstudy.com/form/read.
A native VLAN is the VLAN that that port uses when trunking breaks down.
Thats it. If you don't set it to a specific VLAN in the config, then the
native VLAN will be the default vlan. On cisco, this is VLAN 1.
Normally, the trunk is up and running and the native vlan doesn't come
r
> old Cabletron MMAC. (we're in the process of upgrading and
> have most of the
> network still on the MMAC side of the house).. here's my dilemma...
>
> Every once in awhile I get the following error:
> Native vlan mismatch detected on port [dec]/[dec]
>
>
Hi all,in a trunk,both sides setting as :
trunk mode:desirable
encapsulation:isl
i only try one side native vlan as 1 and the other is 2,except some
error messages,everything is still working
Console> (enable) 2001 Aug 25 20:29:03 %CDP-4-NVLANMISMATCH:Native vlan
mismatch d
etected on port 2
both ends agree that the untagged VLAN is the native VLAN.
Since both ends believe that any untagged frames belong to the VLAN that is
configured as the native VLAN, you can see this could cause some serious
problems if different VLANs are configured as the native VLAN at each end of
the trunk
Dave,
what you wrote is correct for 802.1q trunks. However, ISL tags
all frames, and 'native vlan' in ISL context is vlan to which
the port will be assigned if trunking is disabled (by DISL,
DTP, or via CLI).
See: http://www.cisco.com/warp/public/793/lan_switching/2.html
Regards,
Sa
" you can see this could cause some serious
problems if different VLANs are configured as the native VLAN at each end of
the trunk."
i still can not imaging what type of problem will occur,can you show me some
examples?
now i have enough switch to prove it ,this problem has confused m
Imagine that you use 802.1q trunk, with different native vlan on
switches. Traffic from two different vlans will mix between those
two switches, and will flow to the rest of the network. It will
be two IP subnets on one LAN.
BTW, see:
http://www.cisco.com/univercd/cc/td/doc/product/software
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