You are mixing layer 2 and layer 3 - they are on the same vlan - meaning
same broadcast domain - so that they will see broadcasts for anything in
that VLAN - that is all layer 2 broadcasts - but at layer 3 there is no
network connection between the addresses so they need to use a gateway to
communicate between the 2 different networks.
On Feb 8, 2002 Angelo De Guzman spake:
> Thanks for the reply! 8-)
>
> I have a follow up question regarding these native
> VLAN.I have a client who has two 6509 and the connection
> in between the two is through a trunk port. What keeps
> me wondering is that each VLAN 1 one on both switch has
> a different ip network.
>
> Set-up:
>
> Cisco_ 3640
> / \
> / \
> / \
> / \
> / \
> 7206_Old 7206_New
> | 192.168.21.2 |
> | |
> | |
> Catalyst6509A --(trunk)-------Catalyst6509B
>
>
>
>
> Sample Config:
>
> Catalyst6509A
>
> interface Vlan 21
> ip address 192.168.21.1 255.255.255.0
>
> Catalyst6509B
>
> interface Vlan 21
> ip address 197.77.77.1 255.255.255.0
>
> Why dont I get errors on these? Like conflict vlan
> id or something weird..(just guessing). I also notice
> that when I try to ping from Catalyst6509A the ip
> address 197.77.77.1 it goes around the network first.
> Meaning the next hop is from another router.
> (I assumed that it would be one hop away because
> of the trunk connection!!!)
> Now this is the tricky part, I wanted to implement
> HSRP. Since 192.168.21.2 is the default gateway it
> would be the virtual ip address for the HSRP. Is this
> possible? Especially with VLAN 21 of Catalyst 6509
> belongs to a different network. (i'm thinking of
> assigning 197.77.77.0 to a different vlan and re-assigning
> Vlan 21 0f Cat__B to 192.168.1.x). What is important for
> me to achieve right now, is for users in the Catalyst 6509A
> would be able to access the 3640 router even if 7206_Old is down.
> TIA,
> Angelo
> Nash Darukhanawalla (2/8/02 9:58 AM):
> >Angelo,
> >
> >A trunk port configured with 802.1Q tagging can receive both tagged and
> >untagged traffic. By default, the switch forwards untagged traffic with the
> >native VLAN configured for the port. The native VLAN is VLAN 1 by default
> >or is the vlan that the port was a member of before it was configured as a
> >trunk.
> >
> >If a packet has a VLAN ID the same as the outgoing port native VLAN ID, the
> >packet is transmitted untagged; otherwise, the switch transmits the packet
> >with a dot1q tag.
> >
> >"encapsulation isl 1 native" essentially configures VLAN 1 that is sending
> >and receiving untagged traffic on the trunk port.
> >
> >We do not care about the native vlan when encapsulation is isl because all
> >packets are tagged. But that's not the case with dot1q encap and so native
> >vlan should match at both the ends of the link.
> >
> >-- Nash
> >
> >
> >At 09:24 AM 2/8/2002 +0800, Angelo De Guzman wrote:
> >>Hi To All,
> >> I'm using 2948G-L3.
> >> interface port-channel 1.1
> >> encapsulation isl 1 native
> >> What does it mean when the native command is added? Please enlighten me on
> >>this matter!
> >>TIA,
> >>Angelo
> >
>
-- Rich Sena - ras@thick.net ThickNET Consulting "On the way to understanding; you understand, and forget."
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