Additional BGP Process on Single Router

[Carlton Patterson]

Hello Experts,

I have a problem with my lab. I need to be able to  run more than one BGP routing process on my lab router. I have over   connected BGP routers connected to my live production network and I  need to emulate the production network with GNS3. However, BGP rules  only allow a single BGP routing process on a single router.

Can someone please tell me how to overcome this limitation for my lab?

Cheers

Carlton

[Peter Paluch]

Hi Carlton,

Indeed, only a single BGP process can be running on a single router.

I am not sure if that would help but perhaps you could use the local-as feature to talk to specific neighbors as if you were in a different AS than the ASN you are currently running with. For example:

router bgp 1

  neighbor 1.2.3.4 remote-as 5

  neighbor 1.2.3.4 local-as 2

This would cause your BGP to talk to the peer 1.2.3.4 as if you were placed in AS number 2.

My two cents...

Best regards,

Peter

[fb_webuser]

Hello,

Mr. Peter has given you the solution, just to add, make sure you have prefix-list present on your border router (router between your production and your lab network) to avoid funny routes propagation into your production network.

Regards

Musab

---

Posted by WebUser Musab Kiani from Cisco Support Community App

[milan.kulik]

Hi,

I'm not sure if I understand your request 100%.

Do you need to achieve a second (separate) BGP table on your router?

Assigning a port to a VRF and

address-family ipv4 vrf ...

command in your config BGP section might help you possibly?

HTH,

Milan

[Peter Paluch]

Hello Milan,

I was thinking about using VRFs as well. However, it occured to me that a BGP running in VRF still inherits the ASN of the main BGP process so it does not really behave like two independent BGP instance. Therefore I suggested using the local-as instead.

Best regards,

Peter

[milan.kulik]

Hi Peter,

well, what does the sentence "I need to be able to  run more than one BGP routing process on my lab router." mean in fact?

Is a separate BGP table requested (VRF) or is the clashing AS number (local-as) the root problem?

With local-as used, the BGP procsess also does not behave like two independent BGP instances, does it?

It's just masking the AS number, but creating a single BGP table.

BR,

Milan

[Peter Paluch]

Hello Milan,

Well, you're right as always No matter what solution we suggest, there is a drawback. local-as will get a shared BGP table, VRFs will get a shared ASN. It is simply not possible to run two totally separate instances of BGP on a single device to my best knowledge.

Best regards,

Peter

[Joseph W. Doherty]

Disclaimer

The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.

Liability Disclaimer

In no event shall Author be liable for any damages whatsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.

Posting

It is simply not possible to run two totally separate instances of BGP on a single device to my best knowledge.

I believe it's possible on those routers that support virtual routers (not just VRF) on a single device, but then it's logically two devices.

[Peter Paluch]

Joseph,

You're right, I did not think about this option. Still, this is supported only in IOS-XR, am I correct?

Best regards,

Peter

[Joseph W. Doherty]

Disclaimer

The  Author of this posting offers the information contained within this  posting without consideration and with the reader's understanding that  there's no implied or expressed suitability or fitness for any purpose.  Information provided is for informational purposes only and should not  be construed as rendering professional advice of any kind. Usage of this  posting's information is solely at reader's own risk.

Liability Disclaimer

In  no event shall Author be liable for any damages whatsoever (including,  without limitation, damages for loss of use, data or profit) arising out  of the use or inability to use the posting's information even if Author  has been advised of the possibility of such damage.

Posting

Still, this is supported only in IOS-XR, am I correct?

Peter, I believe that's correct too.