Configuring A Trunk Port on 2800 ISR

Answered Question
Apr 14th, 2010

I'm lost here.  I popped open my brand new 2821 ISR router yesterday and went to configure it and something just isn't right.  Half of the commands I'm trying to use aren't available.  So the only recourse I have is to find out what the router can do and then solve the issue I'm having with it.  Here's my issue:

I have a trunk port coming from my ISP's router.  They split the traffic into two VLANS: 360 and 560.  VLAN 560 shoots everything to the Internet and VLAN 360 dumps everything into our MPLS cloud.  I have two gigabit ports (G0/0 and G0/1).  G0/0 will connect to the LAN and G0/1 will be the trunk port.  I need to be able to tag traffic coming off of G0/1 as either VLAN 360 or VLAN 560.  What do I need to do?

Correct Answer by Giuseppe Larosa about 6 years 10 months ago

Hello Frank,

the only alternate way would be to add an external LAN switch and to use three ports on it:

port 1  is a trunk carrying vlan 360 and vlan560 and connects to provider

port 2  is an access port in vlan 360 and connects to C2800:g0/0

port 3 is an access port in vlan 560 and connects to C2800:g0/1

you cannot use a serial port as a LAN interface

you could consider to use an HWIC that gives some switch ports like etherswitch module

But I strongly recommend to upgrade the IOS.

you need to go to download SW -> Branch routers - > C2851 - > 12.4T

for example a 12.4 20T2 ip base

http://tools.cisco.com/support/downloads/go/SftAdvisory.x?defAdv=N&sftAdv=Y&filename=c2800nm-ipbasek9-mz.124-20.T2.bin&advUrl=http://www.cisco.com/web/software/DefTracker/280805679/SA/ac104262.html&defInd=N&mdfid=279120798&sftType=IOS+Software&optPlat=&relVer=12.4.20T2&md5=e678cff3e3e8574b71281cebbb2b1ddc&relmdfid=279978467&modifmdfid=279120798&imname=&hybrid=&modelName=Cisco+2821+Integrated+Services+Router&fsd=IP+BASE&wc=N&hasfsd=Y&imageGuId=4E86F355C765F90457FBC8775D74B99300B4862A&treeMdfId=268437899&treeName=Wireless&edesignator=ED&nodecount=19&action=d&isLatestRel=&refUrl=I&offsetTop=2166

you cannot use the link as it is

the first thing to do is to add to your CCO login the service contract of the router in order to be able to download sotfware

Hope to help

Giuseppe

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Jerry Ye Wed, 04/14/2010 - 12:50

Assuming both VLAN 360 and VLAN 560 are tagged

interfce g0/0

no ip address

interface g0/0.360

encap dot1q 360

ip address x.x.x.x x.x.x.x

interface g0/0.560

encap dot1q 560

ip address y.y.y.y y.y.y.y

HTH,

jerry

Shahaludeen N Wed, 04/14/2010 - 13:15

Just to make sure that you are doing it right.

The encapsulation dot1q is only available on the subinterface and it makes sense only on the subinterface. So are you checking the command on the main interface and finding it not there?.

Regards,

Shahal.

frivers@myatlan... Wed, 04/14/2010 - 13:30


Cisco IOS Software, 2800 Software (C2800NM-IPBASE-M), Version 12.4(15)T12, RELEASE SOFTWARE (fc3)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2010 by Cisco Systems, Inc.
Compiled Fri 22-Jan-10 02:04 by prod_rel_team

ROM: System Bootstrap, Version 12.4(13r)T11, RELEASE SOFTWARE (fc1)

ABT_OPS uptime is 1 day, 1 hour, 14 minutes
System returned to ROM by power-on
System restarted at 15:11:28 PCTime Tue Apr 13 2010
System image file is "flash:c2800nm-ipbase-mz.124-15.T12.bin"

Cisco 2821 (revision 53.51) with 514048K/10240K bytes of memory.
Processor board ID FTX1413AJTF
2 Gigabit Ethernet interfaces
1 Serial interface
DRAM configuration is 64 bits wide with parity enabled.
239K bytes of non-volatile configuration memory.
126976K bytes of ATA CompactFlash (Read/Write)

Configuration register is 0x2102

frivers@myatlan... Wed, 04/14/2010 - 13:35

shahaludeen wrote:

Just to make sure that you are doing it right.

The encapsulation dot1q is only available on the subinterface and it makes sense only on the subinterface. So are you checking the command on the main interface and finding it not there?.

Regards,

Shahal.

I've drilled down as deep as I could and still nothing.  All I see is "dot1q".

Giuseppe Larosa Wed, 04/14/2010 - 13:43

Hello Frank,

I'm afraid it is a question of feature set

I've checked on one of our 2821

sh ver | inc image
System image file is "flash:c2800nm-spservicesk9-mz.124-3i.bin"

Here I can use enc dot1q XX under a subinterface

you have the IP base feature set

Hope to help

Giuseppe

Jerry Ye Wed, 04/14/2010 - 13:50

I was thinking the same thing Giuseppe said, about the feature set. However, the Software Advisor off CCO said 802.1q is supported in IP Base.

About getting full feature set, legally, you have to pay for it.

Regards,

jerry

Giuseppe Larosa Wed, 04/14/2010 - 14:00

Hello Frank,

taking in account Jerry's note, you can try to upgrade to  later 12.4T IP Base image for free and see if this solves

Hope to help

Giuseppe

frivers@myatlan... Thu, 04/15/2010 - 06:32

Well, I want to see if I can do what I need to do with the software I have.  I do know that I may have to replace the serial card with another LAN card.  Here are the requirements:

  • Ethernet trunk port carries dot1q tagged traffic from VLAN 360 and VLAN 560
  • 2800 needs to assign VLAN 560 to G0/0 and VLAN 360 to G0/1
  • 2800 needs to tag all packets coming out of G0/0 with dot1q 560 and G0/1 with dot1q 360

Currently the config looks like:

interface GigabitEthernet0/0

ip address x.x.x.x 255.255.255.0

vlan-id dot1q 360

duplex auto

speed auto

vlan-id dot1q 560

     exit-vlan-config

interface GigabitEthernet0/1

ip address x.x.x.x 255.255.255.0

duplex auto

speed auto

vlan-id dot1q 360

     exit-vlan-config

Will this do the trick?  The only problem is that my router has a Serial HWIC card when I really need an extra 10/100 card.  It's probably a dumb question, but there's no way I can configure the serial HWIC to just be Ethernet, right?  It's a shot in the dark, but I just need to know before I send it back.  What's a good replacement HWIC for what I need.  I need something with 10/100 ports and relatively inexpensive.

So again, will the config above do what I need it to do?

Correct Answer
Giuseppe Larosa Thu, 04/15/2010 - 08:28

Hello Frank,

the only alternate way would be to add an external LAN switch and to use three ports on it:

port 1  is a trunk carrying vlan 360 and vlan560 and connects to provider

port 2  is an access port in vlan 360 and connects to C2800:g0/0

port 3 is an access port in vlan 560 and connects to C2800:g0/1

you cannot use a serial port as a LAN interface

you could consider to use an HWIC that gives some switch ports like etherswitch module

But I strongly recommend to upgrade the IOS.

you need to go to download SW -> Branch routers - > C2851 - > 12.4T

for example a 12.4 20T2 ip base

http://tools.cisco.com/support/downloads/go/SftAdvisory.x?defAdv=N&sftAdv=Y&filename=c2800nm-ipbasek9-mz.124-20.T2.bin&advUrl=http://www.cisco.com/web/software/DefTracker/280805679/SA/ac104262.html&defInd=N&mdfid=279120798&sftType=IOS+Software&optPlat=&relVer=12.4.20T2&md5=e678cff3e3e8574b71281cebbb2b1ddc&relmdfid=279978467&modifmdfid=279120798&imname=&hybrid=&modelName=Cisco+2821+Integrated+Services+Router&fsd=IP+BASE&wc=N&hasfsd=Y&imageGuId=4E86F355C765F90457FBC8775D74B99300B4862A&treeMdfId=268437899&treeName=Wireless&edesignator=ED&nodecount=19&action=d&isLatestRel=&refUrl=I&offsetTop=2166

you cannot use the link as it is

the first thing to do is to add to your CCO login the service contract of the router in order to be able to download sotfware

Hope to help

Giuseppe

frivers@myatlan... Thu, 04/15/2010 - 10:15

I was afraid of this.  We have a Procurve switch that I guess I can configure the trunk port on.  So I take it my dot1q setups are useless and won't do what I need them to.

Guiseppe, if I use the switch, do I still have to upgrade the IOS to do what I want.

Giuseppe Larosa Thu, 04/15/2010 - 14:51

Hello Frank,

good news and don't worry these kind of things happen everyday to everyone

Hope to help

Giuseppe

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