Load Sharing works by splitting the visitors after which distributing the load throughout a number of hyperlinks. eBGP (Flavour of BGP protocol) is the perfect reply which makes use of Load Sharing mechanism for incoming visitors by using AS- Path attribute. On this article we are going to find out about load sharing and beneath are subjects:
- Idea of Load Sharing
- Load sharing utilizing eBGP
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- BGP Load Sharing When Twin-Homed to One Web Service Supplier (ISP) By means of a Single Native Router
- BGP Load Sharing When Multi homed to Two ISPs by way of a Single Native Router
- BGP Load Sharing When Multi homed to Two ISPs by way of A number of Native Routers
Idea of Load Sharing
Load sharing is the forwarding technique of a router to share the visitors if the routing desk has a number of paths to a vacation spot. This nonetheless bears the opportunity of unbalanced forwarding. If unequal paths, the visitors is distributed inversely proportionally to the price of the routes. Paths with decrease prices will carry extra visitors and paths with increased prices will carry much less visitors.
Load sharing utilizing BGP (eBGP)
BGP Load Sharing is a typical state of affairs nonetheless it’s normally executed in two or extra hyperlinks linked to a novel Autonomous System (ISP). If we’ve got two or extra ASs, a personalized configuration is required to distribute visitors throughout AS.
i) BGP Load Sharing When Twin-Homed to One Web Service Supplier (ISP) By means of a Single Native Router
This state of affairs exhibits learn how to obtain load sharing in BGP when a number of hyperlinks exist between a distant AS and a neighborhood AS. These hyperlinks are terminated on one router on the native AS and on a number of routers at distant AS in a single-homed BGP setting. This pattern configuration makes use of the maximum-paths command. By default, BGP chooses one greatest path among the many attainable equal-cost paths which can be discovered from one AS. Nevertheless, you’ll be able to change the utmost variety of parallel equal-cost paths which can be allowed. In an effort to make this transformation, embody the maximum-paths paths command underneath the BGP protocol configuration. Use a quantity between 1 and 6 for the paths argument.
ii) BGP Load Sharing When Multi homed to Two ISPs by way of a Single Native Router
On this state of affairs, reaching load balancing utilizing BGP protocol will not be an possibility (for a multi homed setting), so you’ll be able to solely do load sharing. Load balancing will not be attainable as a result of BGP selects solely a single greatest path to a vacation spot among the many BGP routes which can be discovered from the totally different ASs. The thought is to set a greater attribute worth (weight or Native Desire) for the routes which can be discovered from ISP(A) and a greater attribute worth for the remainder of the routes which can be discovered from ISP(B).
Within the above config, weight attribute is used to control outgoing visitors path from Router A in the direction of Router B and Router C. By setting weight 100 in Route Map, Router A to B hyperlink turns into most well-liked path for Community 150.150.15.0/24 and Router A to C Hyperlink turns into most well-liked path for Community 160.160.16.0/24.
Comment – It was assumed that networks 150.150.15.0/24 and 160.160.16.0/24 each are marketed by Router B and C.
iii) BGP Load Sharing When Multi homed to Two ISPs by way of A number of Native Routers
Load balancing will not be attainable in a multi homed setting with two ISPs. BGP selects solely the only greatest path to a vacation spot among the many BGP paths which can be discovered from totally different ASs, which makes load balancing inconceivable. However, load sharing is feasible in such multi homed BGP networks. On the idea of predetermined insurance policies (utilizing attribute manipulation), visitors movement is managed with totally different BGP attributes.
Within the above config, native desire attribute is used to control outgoing visitors path from Router A to Router C and Router B to Router D. By setting native desire to 200 by way of Route Map, Router A to C hyperlink turns into most well-liked path for Community 150.150.15.0/24 and Router B to D Hyperlink turns into most well-liked path for Community 160.160.16.0/24.
Comment – It was assumed that networks 150.150.15.0/24 and 160.160.16.0/24 each are marketed by Router C and D.
Conclusion
Load sharing is distributing the load throughout a number of hyperlinks. That is being attainable by utilizing attributes of BGP (eBGP) and leveraging NAT-ACL method.
