| Author |
Trunking, InterVLAN Routing
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| paul_tribe 2002-05-20, 10:31 am |
| I Recently purchased routers (2500s) on the basis you could trunk 802.1q on ethernet and it doesn't seem to work.
This is on a 2501 with 12.1 IOS (IP Plus, 16MB DRAM & 16MB FLASH.
Any one know where I can get a cheap 2620 ?
Cisco does state you can do this but it probably only works on 2600 routers (ethernet versions not fast ethernet), not 2500's. They never made this clear though, typical. | |
| mcoates 2002-05-27, 4:10 pm |
| Have you been through the troubleshooting methodologies described by Cisco in Support exam book?
Have you contacted the TAC? | |
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| jgaudon 2002-06-11, 12:53 pm |
| You can only trunk on a 100Mb interface, and then not all 100Mb interfaces. The 1720 10/100 Interface can do it, would be cheaper than a 2620/21.
Hope this helps | |
| paul_tribe 2002-06-11, 1:30 pm |
| What about this then cut from the URL below, can you explain?
http://www.cisco.com/warp/public/cc...78_pp.htm#16764
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IEEE 802.1Q Virtual LAN
Description
By definition, virtual LANs, (VLANs) perform network partitioning and traffic separation at Layer 2, and communications beyond a single VLAN topology requires a Layer 3 routing function. The Cisco IOS Software offers the industry's most comprehensive VLAN services, supporting multiple VLAN protocols optimized for different media—Cisco's Inter-Switch Link (ISL) for Fast/Gigabit Ethernet, IEEE 802.10 for Fiber Distributed Data Interface (FDDI) backbones, and via LAN Emulation over ATM. Software Release 12.0T adds support for the IEEE 802.1Q VLAN standard such that the IOS software is able to perform full-feature routing of 802.1Q-tagged IP and Novell Internetwork Packet Exchange (IPX) VLAN traffic on Ethernet media.
Benefits
As switched networks evolve to standards-based virtual LANs, the feature-rich Cisco IOS Software is able to provide key inter-VLAN communications for multiple protocols thus allowing the network infrastructure to scale.
Platforms/Considerations
IEEE 802.1Q VLAN routing is available across IOS-based platforms capable of supporting the appropriate media. The Cisco IOS 802.1Q support is designed to perform a VLAN routing function; therefore, it does not participate in the VLAN or Multicast Registration Protocol GARP VLAN Registration Protocol/GARP Multicast Registration Protocol (GVRP/GMRP) aspects of 802.1Q.
First appearance in a Cisco IOS Software "T" release: 12.0(1)T.
Product Marketing Contact
Martin McNealis
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I know it works on ethernet, its whether it works on 2501 platform, CISCO says it does. ISL is fastethernet only.
http://www.cisco.com/warp/public/cc/pd/iosw/prodlit/1078_pp.htm#16764 | |
| jgaudon 2002-06-11, 2:21 pm |
| With reference to 12.0T, this doc is dated May 2001
http://www.cisco.com/univercd/cc/td...m#xtocid1367310
(Let me know if you can't read it, I have a CCO account as a reseller and this doc may be in the permission-required zone)
It states the supported platforms for 802.1q (2500 not on the list) and references Fastethernet interfaces all over the place.
One base requirement for VLAN trunking on a router is the ability to sub-interface the "Ethernet" interface. I have been working with 2500 series routers since 1993 and I have yet to see a sub interface on an ethernet interface, only serial interfaces for Frame-Relay DLCI's. The only sub-interfacing I have seen is on "LAN" side interfaces are Fast-Ethernet/FDDI/ and ATM interfaces so far.
Hope this helps you out. | |
| paul_tribe 2002-06-11, 2:45 pm |
| You can definately create sub interfaces on 2501 running IOS 12.0(T) IP Plus, and above on the ethernet interface. Once created though there is no option to encapsulate it with 802.1q like the "cut" in my message above from Cisco suggests.
Just read again:
Software Release 12.0T adds support for the IEEE 802.1Q VLAN standard such that the IOS software is able to perform full-feature routing of 802.1Q-tagged IP and Novell Internetwork Packet Exchange (IPX) VLAN traffic on Ethernet media.
AND:
IEEE 802.1Q VLAN routing is available across IOS-based platforms capable of supporting the appropriate media.
" Capable of supporting the appropriate media " to me says, An IOS router that supports ethernet. I realise now 2501s are not supported, all I'm saying is that Cisco should make it more clear when we are trying to study etc £300 for a router is a lot of cash. I'm not a multi million pound company I'm trying to learn and these guys should be more accurate. Cisco's website although very good has a lot of contradictions.
Fortunately I purchased routers mainly for the routing course anyway, and have finished switching which covers inter VLAN routing.
NOTE: You do need 16MB flash for IP Plus and above I believe.Software Release 12.0T adds support for the IEEE 802.1Q VLAN standard such that the IOS software is able to perform full-feature routing of 802.1Q-tagged IP and Novell Internetwork Packet Exchange (IPX) VLAN traffic on Ethernet media. IEEE 802.1Q VLAN routing is available across IOS-based platforms capable of supporting the appropriate media. | |
| jgaudon 2002-06-13, 7:02 am |
| Hey Paul..
I tried sub interfaces on an ethernet interface on a 1601 at home, and indeed you can, however if I try to use them it starts screaming about the interface needing to be configured as an ISL or 802.1q trunk.
I have a 2610, and I am going to flash the right software into it and try again. I will let you know.
On a philosophical note, the guys and I had a conversation (we are an engineering group at a Canadian telco - not operations though) and we talked about making a 10Mb port a trunk and said - Why?
The purpose of a trunk is to aggregate many VLANs over a single facility. When you think that the minimum for a vlan is 10Mb, why would you put many 10Mb over a single 10Mb trunk?
To counter that, recently we heard that Bell may start using 10Mb sub-interfaces as a limiting factor for DSL trunks.. I am looking for more info on that.
Joe | |
| paul_tribe 2002-06-13, 1:49 pm |
| Hello
I never knew there was a limit/suggeston of 10MB per VLAN to be honest. I just really wanted to do this in a LAB environment where it wouldn't make any difference.
10MB per VLAN seems strange actaully considering we used to have several 64KBit/s links so who made this figure up? If I have a small remote office with 3 users on a 10MBit circuit why not trunk ?
Where I work we use BT LES (LAN Extended Services) circuits which are a minimum of 10MB/s and we have asked them if we can trunk over 10 MB circuits. Reason being, we want all network devices to be in a mangement VLAN so at 10 MBit remote sites we would need to trunk to carry user VLAN and management VLAN traffic.
Any thoughts would be useful. I am trying to learn all about Cisco due to my organisation moving to a totally managed service. I want to keep my eye on BT.
OH for 3COM ! | |
| jgaudon 2002-06-13, 2:15 pm |
| Must keep an eye on the outsourcer! I know from experience that once they know more about your network than you do, it is a license to ... (whatever, but I don't want to get sued)
I actually have access to my home lab over the Internet and configured a 10Mb Ethernet interface for 802.1Q on my 2610 at home. The sub interface took an IP address without complaining.
I have a Nortel Baystack 450-24T (supports 802.1q) at home that I will connect to it to see if the trunks negociate. I will then put a workstation on it and see if I can get to the net after.
(I don't have deep pockets, I just borrow returned equipment from customers while I am studying for CCNA-on the way to CCDP) | |
| jgaudon 2002-06-13, 2:16 pm |
| send your email address to my hotmail account
throttle_up34@hotmail.com
Let's not clog up this forum with our little evaluation.
Joe | |
| wirechild 2002-06-13, 3:14 pm |
| It says "Ethernet media" which does not imply an 10baseT ethernet interface nor does imply all ethernet interfaces.
Trunking requires a 100Mb/s or faster link on all Cisco gear and I have seen some 100Mb interfaces that does not support ISL.
Bell uses ATM for their DSL backbone and this is what is getting limited to 10mb. | |
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| quote:
Originally posted by paul_tribe
we have asked them if we can trunk over 10 MB circuits
Paul,
Your LES 10 cct is essentially a dedicated cct between your 2 sites, and you can do whatever you wish with it, there are datasheets available on BT's site (search for "short haul data services" are similar).
Tho I have misinformed you before  |
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