In-Switch Routing vs Centralized Routing | Centralised vs Distributed Routing
In-Switch Routing and Centralised Routing both are routing methods used in network platforms in Telecommunication industries. If you take a telecom switching element, when a call hits the switch, the switch should make the decision where to send the call, how to send the call and find the path by considering a lot of parameters including commercial arrangements. Finding the path will depend on least cost based or quality based or both.
In-Switch routing is basically the routing logic and routing database is residing in the switching element itself. The database structure, creating routing logic, populating the logic, feeding the external logic, feeding external rates and carriers would be different from vendor to vendor. Vendor will provide a tool to load this logic from your IT systems. Assume you have couple of different switches in your network; you need to do the same for all the switches. If any changes occurred on the rates or carriers or suppliers, you need to update the routing database of each switch with different tools thus lot of manpower and expertise required.
Centralized routing concept came out by considering the disadvantages of the In-Switching routing and the scalability of the network. In Centralized routing, routing database will be kept in a central place and each switching element will communicate with the centralized routing database to find the exact outgoing route or route choices depend on the defined criteria. Switching elements can use AIN, INAP, MAP, ENUM, SIP, WIN, etc. to communicate to the centralized routing database. So the centralized routing database will have all the routing data, number breakouts, routing logic, and instant update with daily rate changes (user input) with carriers and supplier, carrier information and commercial arrangement to perform the best routing. The centralized database can connect to external systems to get more information if required, like number portability correction, destination group data or any other data. The main advantage over centralized database is, vendor independent centralized routing engine with interconnect options to any standard interfaces thus results less maintenance and easy integration of new switching elements with instant activation.
Difference Between In-Switch Routing and Centralized Routing
(1) Service provisioning is centralized in Centralized Routing whereas in in-switch routing each switching element has to be provisioned seperately.
(2) Centralized Routing database method is vendor independent and common interface for interconnection of switching elements thus scalability is very easy whereas in In-Switch Routing network scalability require more manpower and expertise.
(3) In-Switch Routing, switch may have database limitations and that has to be managed whereas in Centralized database system there will not be any limitations and easy to expandable as well.
(4) Real-time Traffic Management System and Routing Decision Making System based on least cost basis, quality basis or both can feed the LCR or Best routes to centralized database with single interface or format whereas as in In-Switch Routing, we need to load LCR or routing decisions to each switch via different interfaces and formats depend on vendor formats.
(5) In Centralized Routing, the database availability is more important since the whole network rely on a single point, whereas in In-Switch Routing database in independent to network and in case of failures it affects the particular box only. But in Centralized Routing, we can replicate master database with multiple boxes as required and make active sync with master.
(6) In Centralized Routing, we don’t need technical expert or vendor experience to load the data whereas in In-Switch Routing you need skilled resources to load the data.
(7) In Centralized Routing, route backup , routing history backups and producing reports against the database is easy whereas in In-Switch Routing , it difficult to produce reports or keeping records of the routing information is difficult.