O'Reilly logo

JUNOS Cookbook by Aviva Garrett

Stay ahead with the world's most comprehensive technology and business learning platform.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, tutorials, and more.

Start Free Trial

No credit card required

14.13. Automatically Allocating Bandwidth

Problem

You want an automatic way to optimize the amount of bandwidth allocated to each LSP to minimize or eliminate any contention for the available bandwidth on the shared links.

Solution

MPLS can automatically allocate bandwidth for an LSP and can automatically adjust the allocation as necessary from time to time. The configuration has two parts. First, MPLS must gather bandwidth statistics:

	[edit protocols mpls]
	aviva@R1#  
set statistics auto-bandwidth
	aviva@R1# set statistics file mpls-bandwidth-stats world-readable

Second, configure the LSP to automatically allocate and adjust the bandwidth for an LSP:

	[edit protocols mpls]
	aviva@R1# set label-switched-path R1-to-R5 auto-bandwidth minimum-bandwidth 50m

Discussion

In a network with bandwidth constraints, it can be difficult for RSVP to set up LSPs when insufficient bandwidth is available. If you choose to allocate LSP bandwidth manually (see Recipe 14.11), it can be challenging to figure out how much bandwidth to set aside for an individual LSP or for a series of LSPs so that they are always available to carry your customer's traffic. MPLS autobandwidth is a JUNOS mechanism that automatically allocates bandwidth for an LSP. It works by monitoring the rate of traffic flow through an LSP and periodically resizing the allocated bandwidth to match the flow rate. In effect, autobandwidth adaptively requests bandwidth reservations based on actual LSP usage.

When MPLS resizes the bandwidth, it ...

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, interactive tutorials, and more.

Start Free Trial

No credit card required