Login | Register For Free | Help
Search for: (Advanced)

Mailing List Archive: Cisco: NSP

vlan across a routed link

 

 

Cisco nsp RSS feed   Index | Next | Previous | View Threaded


teklish76 at yahoo

Nov 18, 2009, 5:03 AM

Post #1 of 7 (1095 views)
Permalink
vlan across a routed link

i work in a university which has three campuses. on each campuse, there is one cisco 6509 switch as a core switch. all other switches (L2) are in vtp client except the core switches. the campuses are connected with a routed link. so, one campuse, has 10.128.0.0/16 subnet and the others have a subnet of 10.129.0.0/16 and 10.130.0.0/16. rip v2 is used on the intercampuse links to advertise individaul vlans.

here is my problem.

i'm asked to create a vlan with a subnet id of 192.168.1.0/24. but computers in this vlan are located in the 10.128.0.0/16 campuse and 10.130.0.0/16 campuse.the link between the 10.128.0.0/16 and 10.130.0.0/16 is not trunk it is routed with ip address.
so can any body suggest me how to implement such senario which allows one vlan (in this case 192.168.1.0/24) to be visible from the two campuses? i.e to propage that specific valn across a routed link not a trunk link.
thanks





_______________________________________________
cisco-nsp mailing list cisco-nsp [at] puck
https://puck.nether.net/mailman/listinfo/cisco-nsp
archive at http://puck.nether.net/pipermail/cisco-nsp/


p.mayers at imperial

Nov 18, 2009, 6:25 AM

Post #2 of 7 (1067 views)
Permalink
Re: vlan across a routed link [In reply to]

teklay gebremichael wrote:
> i work in a university which has three campuses. on each campuse,
> there is one cisco 6509 switch as a core switch. all other switches
> (L2) are in vtp client except the core switches. the campuses are
> connected with a routed link. so, one campuse, has 10.128.0.0/16
> subnet and the others have a subnet of 10.129.0.0/16 and
> 10.130.0.0/16. rip v2 is used on the intercampuse links to advertise
> individaul vlans.
>
> here is my problem.
>
> i'm asked to create a vlan with a subnet id of 192.168.1.0/24. but
> computers in this vlan are located in the 10.128.0.0/16 campuse and
> 10.130.0.0/16 campuse.the link between the 10.128.0.0/16 and
> 10.130.0.0/16 is not trunk it is routed with ip address. so can any
> body suggest me how to implement such senario which allows one vlan
> (in this case 192.168.1.0/24) to be visible from the two campuses?
> i.e to propage that specific valn across a routed link not a trunk
> link. thanks

You will need to convert the link from routed to switchport. That is,
transform this:

interface Gi1/1
ip address a.b.c.d

...to:

interface Gi1/1
switchport
switchport mode trunk
switchport trunk native vlan 4000
switchport trunk allowed vlan yourvlan,4000

int Vlan4000
ip address a.b.c.d
_______________________________________________
cisco-nsp mailing list cisco-nsp [at] puck
https://puck.nether.net/mailman/listinfo/cisco-nsp
archive at http://puck.nether.net/pipermail/cisco-nsp/


oboehmer at cisco

Nov 18, 2009, 6:39 AM

Post #3 of 7 (1059 views)
Permalink
Re: vlan across a routed link [In reply to]

> teklay gebremichael wrote:
> > i work in a university which has three campuses. on each campuse,
> > there is one cisco 6509 switch as a core switch. all other switches
> > (L2) are in vtp client except the core switches. the campuses are
> > connected with a routed link. so, one campuse, has 10.128.0.0/16
> > subnet and the others have a subnet of 10.129.0.0/16 and
> > 10.130.0.0/16. rip v2 is used on the intercampuse links to advertise
> > individaul vlans.
> >
> > here is my problem.
> >
> > i'm asked to create a vlan with a subnet id of 192.168.1.0/24. but
> > computers in this vlan are located in the 10.128.0.0/16 campuse and
> > 10.130.0.0/16 campuse.the link between the 10.128.0.0/16 and
> > 10.130.0.0/16 is not trunk it is routed with ip address. so can any
> > body suggest me how to implement such senario which allows one vlan
> > (in this case 192.168.1.0/24) to be visible from the two campuses?
> > i.e to propage that specific valn across a routed link not a trunk
> > link. thanks
>
> You will need to convert the link from routed to switchport. That is,
> transform this:

right, but think about the implications before doing so. You will extend
your spanning tree domain over all the different sites, so this just
asks for disaster to happen. And don't mention "hey, I only do this for
a single Vlan". Once you start offering this "service", users will ask
for it, and you end up doing this for many.

Please consider technologies for this where you don't need to extend
spanning tree. for example L2VPN (EoMPLS, VPLS), or loop-free topologies
using VSS where you can disable STP between campuses..

oli
_______________________________________________
cisco-nsp mailing list cisco-nsp [at] puck
https://puck.nether.net/mailman/listinfo/cisco-nsp
archive at http://puck.nether.net/pipermail/cisco-nsp/


masood at nexlinx

Nov 18, 2009, 7:10 AM

Post #4 of 7 (1056 views)
Permalink
Re: vlan across a routed link [In reply to]

what’s wrong in extending your spanning-tree domain, as long as numbers of
nodes are not too many? People are using trunk links between different
sites across the world in an enterprise environment, and this is for what
you use a trunk link. I would prefer the usage of trunk links and routed
VLAN interfaces over EoMPLS and VPLS. (keeping in mind the throughput
issues on EoMPLS, mtu problems and overall network complexity)

Regards,
Masood


>> teklay gebremichael wrote:
>> > i work in a university which has three campuses. on each campuse,
>> > there is one cisco 6509 switch as a core switch. all other switches
>> > (L2) are in vtp client except the core switches. the campuses are
>> > connected with a routed link. so, one campuse, has 10.128.0.0/16
>> > subnet and the others have a subnet of 10.129.0.0/16 and
>> > 10.130.0.0/16. rip v2 is used on the intercampuse links to advertise
>> > individaul vlans.
>> >
>> > here is my problem.
>> >
>> > i'm asked to create a vlan with a subnet id of 192.168.1.0/24. but
>> > computers in this vlan are located in the 10.128.0.0/16 campuse and
>> > 10.130.0.0/16 campuse.the link between the 10.128.0.0/16 and
>> > 10.130.0.0/16 is not trunk it is routed with ip address. so can any
>> > body suggest me how to implement such senario which allows one vlan
>> > (in this case 192.168.1.0/24) to be visible from the two campuses?
>> > i.e to propage that specific valn across a routed link not a trunk
>> > link. thanks
>>
>> You will need to convert the link from routed to switchport. That is,
>> transform this:
>
> right, but think about the implications before doing so. You will extend
> your spanning tree domain over all the different sites, so this just
> asks for disaster to happen. And don't mention "hey, I only do this for
> a single Vlan". Once you start offering this "service", users will ask
> for it, and you end up doing this for many.
>
> Please consider technologies for this where you don't need to extend
> spanning tree. for example L2VPN (EoMPLS, VPLS), or loop-free topologies
> using VSS where you can disable STP between campuses..
>
> oli
> _______________________________________________
> cisco-nsp mailing list cisco-nsp [at] puck
> https://puck.nether.net/mailman/listinfo/cisco-nsp
> archive at http://puck.nether.net/pipermail/cisco-nsp/
>


_______________________________________________
cisco-nsp mailing list cisco-nsp [at] puck
https://puck.nether.net/mailman/listinfo/cisco-nsp
archive at http://puck.nether.net/pipermail/cisco-nsp/


p.mayers at imperial

Nov 18, 2009, 7:36 AM

Post #5 of 7 (1056 views)
Permalink
Re: vlan across a routed link [In reply to]

masood [at] nexlinx wrote:
> what’s wrong in extending your spanning-tree domain, as long as numbers of
> nodes are not too many? People are using trunk links between different
> sites across the world in an enterprise environment, and this is for what
> you use a trunk link. I would prefer the usage of trunk links and routed
> VLAN interfaces over EoMPLS and VPLS. (keeping in mind the throughput
> issues on EoMPLS, mtu problems and overall network complexity)

Well, I think it depends on your existing setup and requirements.

The original poster states that they currently have *no* vlans between
sites; therefore any move to do this is a new service, with all the
learning experiences and issues associated.

The OP also says they're using VTP.

I agree with Oli: It makes sense to avoid this if possible. But it's a
matter of personal opinion.
_______________________________________________
cisco-nsp mailing list cisco-nsp [at] puck
https://puck.nether.net/mailman/listinfo/cisco-nsp
archive at http://puck.nether.net/pipermail/cisco-nsp/


mtinka at globaltransit

Nov 18, 2009, 6:45 PM

Post #6 of 7 (1036 views)
Permalink
Re: vlan across a routed link [In reply to]

On Wednesday 18 November 2009 10:39:42 pm Oliver Boehmer
(oboehmer) wrote:

> Please consider technologies for this where you don't
> need to extend spanning tree. for example L2VPN (EoMPLS,
> VPLS), or loop-free topologies using VSS where you can
> disable STP between campuses..

Or just IP, if all locations are being connected to forward
IP traffic.

Cheers,

Mark.
Attachments: signature.asc (0.82 KB)


mtinka at globaltransit

Nov 18, 2009, 6:54 PM

Post #7 of 7 (1037 views)
Permalink
Re: vlan across a routed link [In reply to]

On Wednesday 18 November 2009 11:10:22 pm
masood [at] nexlinx wrote:

> what’s wrong in extending your spanning-tree domain, as
> long as numbers of nodes are not too many?

You can't know that the number of nodes or VLAN's won't
grow. And chances are, they will.

> People are
> using trunk links between different sites across the
> world in an enterprise environment, and this is for what
> you use a trunk link.

Fair point.

Digressing a little from the OP's post, control planes for
Ethernet in the LAN (and small WAN) have different
characteristics from various points of view when considered
for large scale, probably Metro deployments.

> I would prefer the usage of trunk
> links and routed VLAN interfaces over EoMPLS and VPLS.

YMMV, but the performance of IP and EoMPLS shouldn't be that
different since it's all done in hardware. VPLS is a little
more complex by its nature.

> (keeping in mind the throughput issues on EoMPLS, mtu
> problems and overall network complexity)

I'm not sure increased MTU requirements makes a network any
more complex. Besides, in a campus LAN/WAN with your own
fibre, you can control the MTU on each of the links, which
is great.

Cheers,

Mark.
Attachments: signature.asc (0.82 KB)

Cisco nsp RSS feed   Index | Next | Previous | View Threaded
 
 


Interested in having your list archived? Contact Gossamer Threads
 
  Web Applications & Managed Hosting Powered by Gossamer Threads Inc.