MPLS Question

Unanswered Question
Feb 28th, 2008
User Badges:

Just want to know if the CIR that providers give to customers have burst just like FR? example, they give me 128k for my link. Do it has a burst like 256k if your using MPLS VPN. Please enlighten me. Tnx a lot!

  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 0 (0 ratings)
rahul0904 Fri, 02/29/2008 - 01:27
User Badges:


Its depends on provider to provider. Also it depends lot on what rate-limit or bandwidth is alloted to your VPN link.

s.ganguly Fri, 02/29/2008 - 05:17
User Badges:


A CIR can and usually have burst sizes vonfigured either as a PIR or Bc and Be depending on what kind of configuration the ISP are applying (rate limiting, policing etc.). This may not have a lot to do with MPLS VPN as per se.

Best Regards


Joseph W. Doherty Fri, 02/29/2008 - 05:31
User Badges:
  • Super Bronze, 10000 points or more

Keep in mind each provider can do whatever they want; my experience has with a couple of the largest MPLS providers is the MPLS CIR equivalent has little impact besides price and except where it might control how real-time traffic bandwidth is controlled. For instance, one vendor's real-time bandwidth class is sold as a percentage of MPLS CIR equivalent. You exceed that classes's allocation, traffic is dropped.

Mohamed Sobair Fri, 02/29/2008 - 11:13
User Badges:
  • Gold, 750 points or more


burst is burst whether its an MPLS-VPN service or Fram-relay service.

The point here is that up to which limit you can burst? and this should be agreed with the SP.

As for Bc, Be calculation, If you just a CIR value provided by the provider, Cisco routers will calculate (Bc, Be) values, unless you manually change it.

It depends on which method you use, single token bucket or dual token bucket.





This Discussion