10-07-2012 12:04 AM - edited 03-07-2019 09:19 AM
Hi,
I want to connect 2 ISP links into one Gigabit-interface on my Router 2921, can any one tell me how to do that ? sub-interface creation is not possible on cisco 2921
plz help me
Solved! Go to Solution.
10-07-2012 02:28 AM
Hi Imran,
I didn't realize that the switch doesn't even have a login option :-( So it would be more of like a HUB then. It worth checking (google it) if your switch model understand 802.1q tagged frames.More likely they wouldn't be. In that case you will have go with a manageable switch. Also it worth trying to have your router configured with sub interface and connecting the port to your unmanageable switch and see if you are able to ping your service providers router.
As updated before another option you could try is secondary ip address but again that is not a scalable option and i wouldn't recommend the same for a long run.
Regards
Najaf
10-07-2012 02:42 AM
No i can not connect 2-isps into 2 gi0/1 and gi0/0, because that is used for other purposes. we have only one Gigiabit-int availble that has to be connected into 2-isps .
Then you have to use a different switch or a module in the router. I would go for the module as there will be one device less to manage.
--
Don't stop after you've improved your network! Improve the world by lending money to the working poor:
http://www.kiva.org/invitedby/karsteni
10-07-2012 12:22 AM
Hi Imran,
Are you sure that sub-interface creation is not possible in 2921?
Also if you have 2 ISP links I would assume there would be two physical cables coming from these ISP's as well. Is that not the case????
Not sure if secondary ip address on the interface will do the job for you as below even though it is not a good practice.
interface FastEthernet0/0
ip address 192.168.10.10 255.255.255.0 secondary
ip address 10.10.10.10 255.255.255.0
shutdown
Regards
Najaf
CCIE (R&S) 25070
10-07-2012 12:33 AM
Subinterfaces can also be configured on a 2921. Here is an example:
interface GigabitEthernet0/1
no ip address
duplex auto
speed auto
!
interface GigabitEthernet0/1.16
encapsulation dot1Q 116
ip address 172.16.1.1 255.255.255.0
...
!
interface GigabitEthernet0/1.10
encapsulation dot1Q 10
ip address 10.10.10.1 255.255.255.0
...
--
Don't stop after you've improved your network! Improve the world by lending money to the working poor:
http://www.kiva.org/invitedby/karsteni
10-07-2012 12:43 AM
Thanks Karsten, yes after your example, it is possible to configure sub-interfaces on 2921. because i didnt know that
can you tell me after adding those 2-sub-interfaces into 2-vlans (116 & 10) , then the Router interface GigabitEthernet0/1 should be physically connected into a switch which must be a managable switch ? and should configure that switch port as TRUNK LINK for vlans (116&10) ?
im asking the question, because i dont have cisco switch in between my 2-ISPs and my Router, that is a normal D-Link switch (Un-Managable Switch)
Please tell me what is the solution ? my d-link switch is not configurable, it is plug&play
10-07-2012 12:52 AM
Hi Imran,
You dont need a managable switch. You can use a un managable switch and put two ISP's in different VLAN (116 & 10) and configure the switch port as trunk which is getting connected to yout 2921 router.
Hopet his helps
Regards
Najaf
CCIE (R&S) 25070
10-07-2012 01:13 AM
Hi Najaf,
But how to configure un-managable switch-port as Trunk ?
10-07-2012 01:08 AM
Yes, you need a managed switch in that case. The Port to the router has to be a trunk port and the two ports to the ISP-routers have to be in their VLANs as an access-port. A cheap SG300-8 would do that job.
Two other ways to solve that:
1) Use gig 0/0 and gig 0/1 for your ISPs and gig 0/2 for your internal connection. There you probably have a managed switch if you need more logical interfaces.
2) Use a switch module that you install in one of the slots and configure vlans for the ISPs there:
http://www.cisco.com/en/US/products/ps10537/products_relevant_interfaces_and_modules.html#esm
--
Don't stop after you've improved your network! Improve the world by lending money to the working poor:
http://www.kiva.org/invitedby/karsteni
10-07-2012 01:20 AM
No i can not connect 2-isps into 2 gi0/1 and gi0/0, because that is used for other purposes. we have only one Gigiabit-int availble that has to be connected into 2-isps .
Najaf , you suggested me to configure the Un-Manageble switch-port as Trunk. but how to do that, un-managable switch means that isnot configurable . i can not login or enter to that d-link siwtch
10-07-2012 02:28 AM
Hi Imran,
I didn't realize that the switch doesn't even have a login option :-( So it would be more of like a HUB then. It worth checking (google it) if your switch model understand 802.1q tagged frames.More likely they wouldn't be. In that case you will have go with a manageable switch. Also it worth trying to have your router configured with sub interface and connecting the port to your unmanageable switch and see if you are able to ping your service providers router.
As updated before another option you could try is secondary ip address but again that is not a scalable option and i wouldn't recommend the same for a long run.
Regards
Najaf
10-07-2012 03:17 AM
Hi Imran,
Najaf is correct please consider him, in this scenario you should need layer 3 switch or Manageble swtich to got the subinterfaces with trunking between the different Local VLANS.
Thanks to Imran
Regards
Naresh
10-07-2012 02:42 AM
No i can not connect 2-isps into 2 gi0/1 and gi0/0, because that is used for other purposes. we have only one Gigiabit-int availble that has to be connected into 2-isps .
Then you have to use a different switch or a module in the router. I would go for the module as there will be one device less to manage.
--
Don't stop after you've improved your network! Improve the world by lending money to the working poor:
http://www.kiva.org/invitedby/karsteni
10-07-2012 04:02 AM
Thank you all for your support. i will go for manageable switch , i think i will go with Kareten suggeted cheap switch SG300-8
Discover and save your favorite ideas. Come back to expert answers, step-by-step guides, recent topics, and more.
New here? Get started with these tips. How to use Community New member guide