12-19-2007 09:57 AM - edited 03-05-2019 08:05 PM
hiya
what is the best ios for 2500s in a home lab to practus vlan cfg
i have 2 2514s and a 2501
serial links in delta config using frame
"simulated wan links"
and 6 1924s running V9.00.06
passed intro going for icnd2
to fill ccna
thanks in advance for your help
jeff larson
12-19-2007 10:17 AM
Jeff
I am not sure that any 2500 router supports VLANs. This is mostly a restriction of the chip set used in the Ethernet interfaces. To practice VLAN I believe that you would need a different router model.
HTH
Rick
12-22-2007 08:58 AM
hiya rick
thanks for the info
im looking at a 2600 now
jeff
12-20-2007 12:55 AM
Jeff,
I can confirm that: 2500s do not support VLANs in any way. They can be great for other things, but not for VLANs. (The best IOS I know for testing other stuff on a 2500 is 12.2(15)T17 IP-Plus, 'cos it supports things like IPv6, OSPFv3, IPv6 BGP, etc., but it does have some bugs.)
When I was using mainly 2500s, I used to adapt test scenarios as far as possible. I had a full-msh FR switch connecting all my routers. Where the scenario had a VLAN with only two members, I could replace it with a FR P2P link, with the necessary frame maps and OSPF tweaks. Where the scenario had more than two members on a VLAN, and one of them was a 2500, I would have to workaround with FR P2P links and a bridge. It's an ingenuity test!
Nowadays, 2600s are becoming so cheap on eBay that it is not really worth struggling with 2500s, except perhaps as hosts, or FR switches, or as backbone route generators. I finally passed my 2500s down the chain a couple of weeks ago, replacing them with 2611 XMs.
Kevin Dorrell
Luxembourg
12-22-2007 08:56 AM
hiya kevin
well time to get off my wallet
i am looking at some 2600s now
by looking at current cfg "atached"
can my 2500s remain as backbone and route
vlan packets to a 2600 that would handle
the vlan traffic and acls for the all the 1924s ?
this is the stuff upgrades are made of keeping
what works in place and adding one 2600 to the stack to get inter-vlan routing wich really is a small amount of traffic
only high level administrative nodes will have access to other vlans or be a member of multiple vlans i think??
thanks in advance for your help
jeff larson
12-22-2007 02:28 PM
Jeff
Perhaps I am not understanding well what you are proposing to do and perhaps could understand better if I could see where the 2600 were going to go. I am having trouble seeing how this could work. If the switches connected to the 2500 are doing more than 1 VLAN I think that you will have trouble. The 2500s should recognize the frames in the native VLAN (because they are not tagged) but I think that the 2500s will have problems with frames in the other VLANs and will probably drop them.
If you want to experiment with VLANs I think that you need to get your 2600 and to re-think the topology of the network. There may be some useful things to do with the 2500s but forwarding when more than one VLAN is directly connected will not work.
As I think about it there is a topology which might work (and not need a 2600) if 3 VLANs were enough. Instead of a topology with routers in the middle and switches at the edges connected to the routers to talk to other switches, what if you put the switches into a cloud in the middle. Configure 3 VLANs on the switches and trunking between the switches. Then connect the 2501 to one switch in an access port in one VLAN. Then connect 2514-1 to another switch on an access port in the second VLAN. And connect 2514-2 to another switch on an access port in the third VLAN. Then connect the 3 routers by their serial ports (as you have in the diagram) with the serial links as routed subnets. In this way you will have each 2500 as the default gateway for one VLAN and will have routed access between the 3 VLANs.
HTH
Rick
12-22-2007 02:33 PM
Jeff
After reading through the thread again I come back to your expression in the response to Kevin where you advocate keeping what works and building on that. It seems to me that we need some clarification about what your real objectives are for this lab which will help us recognize what works - or does not work.
If your objective with VLANs focuses on configuration of VLANs and trunking between VLANs on the switches then my suggestion of an alternate topology would work. But if your objective for this lab is to get experience with inter-vlan routing on a router (to do subinterfaces and trunking to the router) then 2500s do not work and you need to replace them with 2600s.
HTH
Rick
12-24-2007 10:43 AM
hiya rick
lets just think of this topology as a existing
small bizz
theay want to keep in place there existing net
wan links and all
now theay want inter vlan routeing
can this be done by adding 1 2600 to 1 site
and this one router handles all inter-vlan
routing at all sites through wan links
can the 2500s forward the ip vlan packets to
the 2600 for intervlan routing decisions ?
i see myself contracting small upgrades like this in the future
not all bizz will want to tear it all down and start over
theay will probly want a patch to get them by
or replace one pice at a time
to minimize downtime and cost$$
thanks for your help
jeff larson
12-24-2007 11:00 AM
Jeff
Given the situation that you describe I do not see much practical alternative to replacing the 2500s with something capable of processing VLANs.
As I tried to explain in a previous post the 2500s will not understand (and will not forward) any VLAN tagged frames. So no - placing a single 2600 into the network will not allow it to process intervlan routing for all the sites.
In your original post I assumed that we were talking about a lab situation, and attempts to extend the usefulness of the 2500s is appropriate. But in the context of any small bizz that wants to get into a VLAN environment, they should face the reality that an upgrade of their routers would be necessary to support the VLAN capability at each site.
If the small bizz does not want to start over they should recognize that they will not have VLANs. If no VLANs is adequate to their current business environment then their current routers are ok. If their business environment needs VLAN capability then their business environment needs upgraded routers (it part of the cost of growth).
HTH
Rick
12-24-2007 12:29 PM
hiya rick
so i figured that isl framing would not work
but i thought dotq would be routed based on ip
but your saying the little dotq tag in the type field prevents even the dotq ip packets from being routed to a 2600 for intervlan routing
is that what you are saying here ?
12-24-2007 10:35 PM
Jeff
The only thing that the 2500 can understand and route is a simple Ethernet frame - no VLAN information. Any Ethernet frame that has VLAN identification (either ISL or dot1Q) coming into the 2500 Ethernet interface will be dropped.
HTH
Rick
12-25-2007 06:30 AM
hiya rick
ok got it
ill just fiddle around with other things
untill i get some 2600s
thanks for the help
jeff
12-25-2007 03:40 AM
122-12b
12-25-2007 06:35 AM
hiya csco11331076
122-12b is ??
the best os for icnd2 labs ??
jeff
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