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1.2.17 Inbound bandwidth optimization
1.2.17.1 Inbound Commit Control #
Starting with version 3.4 IRP introduced optimization of Inbound traffic. Inbound bandwidth control reshapes the traffic from different providers targeting your sub-prefixes.
IRP uses well known and proven BGP mechanisms to instruct your routers to adjust their advertisements of your network segments to upstream providers and subsequently to the World. The adjusted advertisements take advantage of existing BGP policies implemented by edge routers worldwide in order to increase or decrease the preference of your internal network segments as advertised by one or another AS to the world. This allows more traffic to lean towards some of your upstream providers and less towards others. In case of an incident that your multihomed configuration is designed to be resilient against, the entire world still knows of the alternative routes towards your network and will be able to adjust accordingly.
Noction’s IRP Inbound feature:
- advises your edge routers to advertise different prefixes of your network with different counts of BGP prepends to each of your upstream providers;
- monitors inbound and outbound traffic on your network interfaces using standard protocols (SNMP, NetFlow, sFlow) to determine if there is need for action;
- continuously assesses network health and performance to ensure that when overloads are possible it knows good and reliable alternative routes to use;
- uses a proprietary inferring mechanism that takes into account the inertial nature of the Internet to react to inbound preference changes and thus dampens the urge to “act now” and destabilize the network;
- provides you with configuration, monitoring and visualization tools that allow you to cross-check and validate its actions.
The entire Inbound optimization solution covers:
- Segmenting your network into prefixes that are controlled by IRP
- Coordinating communication over BGP between IRP and routers
- Setting network conditions for making Inbound Improvements
- Reviewing Inbound optimization results
Starting with version 3.7 IRP has the capability to also monitor and improve transit routes. Refer Optimization of transiting traffic for details.The use cases below highlight typical scenarios when IRP’s inbound bandwidth control capabilities might come handy:
Lets start with the case of unbalanced inbound and outbound peering. You have a peering agreement with one of your neighbors to exchange traffic. Unfortunately the rest of the neighboring network configuration significantly unbalances the volumes of inbound and outbound traffic.
Figure 1.2.11: Unbalanced inbound/outbound peering
You rely on manipulating prefix announcements towards neighbors in order to shape the traffic. Unfortunately this is a reactive solution and consumes a lot of time while at the same time pushing the balance either one way or another. Often this pushes the network into the second typical scenario.
Fluctuating traffic shape. A multihomed configuration overwhelms some links while other links remain barely used. Your network administrators frequently get alerts during peak network use and they manually add or remove prepends or altogether remove some inbound prefixes from being announced to affected neighboring links. These changes are sometime forgotten or other times just push the bulk of traffic towards other links and the problem re-appears.
Figure 1.2.12: Fluctuating inbound traffic
For both above scenarios Inbound commit control in IRP can automate most of the inbound traffic shaping operations. It uses a typical solution for traffic shaping and specifically manipulates prepend counts announced to different providers and this eventually propagates across the Internet thus diverting traffic as desired. IRP automates your routine day to day traffic shaping actions and probably makes significantly more adjustments than you can afford to. At the same time it offers you reliable reviewing and fine-tuning options that will allow you to adjust IRP’s work in a changing and evolving network.
Refer Inbound Commit Control, Current Inbound Improvement, Inbound Traffic Distribution, Inbound rule for details.