Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
Community Member

Why do you need bgp for MPLS vpns

Hi all

Am I right in saying that you need BGP for MPLS vpn's ?

why do we need BGP for this, what does BGP do that the other IGP's cant , as you can use VRF's with Eigrp?

Hope someone can explain this to me ?

cheers

Carl

3 REPLIES
Super Bronze

Why do you need bgp for MPLS vpns

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

Am I right in saying that you need BGP for MPLS vpn's ?

No.

what does BGP do that the other IGP's cant , as you can use VRF's with Eigrp?

Perhaps the principle advantage is BGP's ability to manage routing among your locations and/or with the MPLS VPN vendor and/or the problem of running many IGPs across a MPLS VPN when multicast isn't supported.

Possibly the biggest issue using BGP is when you're inexperienced with it.

Gold

Why do you need bgp for MPLS vpns

To go along with the comments by our esteemed Mr. Doherty,

BGP is the mechanisim to manage routes based on route distinguisher through a carrier (usually)

network. This allows for multiple instances of the same ip addresses to be routed sucessfully.

here is a bit from netcraftsmen, there is more available.

http://www.netcraftsmen.net/resources/archived-articles/373.html

Community Member

Why do you need bgp for MPLS vpns

Am I right in saying that you need BGP for MPLS vpn's ?

Yes. For Layer 3 MPLS VPNs we use MPBGP to send the traffic from one site to the other.

why do we need BGP for this, what does BGP do that the other IGP's cant , as you can use VRF's with Eigrp?

In this situation we use BGP's VPNv4 address family (which uses 96bits) to tunnel the traffic. This helps us to send multiple overlapping addresses of different vrfs through the same vpnv4 tunnel.

1108
Views
0
Helpful
3
Replies
CreatePlease to create content