What is Route Leaking
1. When running a multi MPLS network, it can be useful to leak routes between VRFs. A classic use for this would be to leak your link to a management VRF, or assigning a management address to your CE routers as a /32 address and leaking that. Other uses could be leaking public ip addresses to a separate VRF, to be handled by a different router than the LAN addresses. It is necessary to filter your route leaking to make sure that only non-overlapping addresses are leaked, and it is important to make sure that one VRF doesn’t have access to routes of another VRF.
2. 2 ways to leak one vrf to another: –
1. // statically leak a vrf to global routing table and vice versa
2.// using Rd and rt values leak it to mp bgp (other vrfs) and then redistribute to other dynamic routing protocols in that vrf.
3. In ISP environment they use common MPLS core for multiple customer,,if Ur having multiple sites like London-A and Delhi -A and another end London-B and Delhi-B,if u want to make communications between them we can do that, for that isp MPLS core routers use RD and RT concept ,edge router add RT and same applied to both site if they match they successfully communicate without any issue,,and routes of A gives to another end site A only ,,but if RT mismatch then routes will get leak and site A which is london-A route will get into another end site which is Delhi -2.
BGP – ROUTE REFLECTOR
1. Service provider environment – RR are installed to share routes with multiple PEs rather than building igbp with all PEs
2. Generally service provider must have RR. Those RR can be redundant to each other or shared traffic based on Geo location.
3. 1. RR is used to break the ibgp rule.
2. While using RR there are 2 more attributes introduced in bgp which are originator id and cluster id.
3. These two attributes also provide a loop prevention mechanism in ibgp while using RR.