Hello Praveen -
In my experience (and IMHO) discovering routers and trying to use this data isn't worth the hassle. With redundant routes, complex network setups, large number of routers (in a typical enterprise) and questionable valuable for Service Mapping, the issues out-weigh the value (again in my opinion).
And finally, the network team/engineers are very unlikely to use, trust or rely upon the CMDB data for any network infrastructure data. Instead when issues arrive and they will want the real-time "the source of truth" they will very likely go to their native administrative tools (Cisco, etc.). When it comes down to dealing with real issues, the network team is unlikely to refer to CMDB as their 'go to' tool.
Other folks here will likely have other opinions, but in my experience trying to bring in the lower layer network architecture stuff into the CMDB may not provide sufficient value to be worth it...
