MPLS has the following configuration constraints:
- IP flow redirection—IP flow redirection commands and MPLS are mutually exclusive functions. Both functions cannot be enabled simultaneously.
- IGMP snooping—OSPF and LDP session establishment require the switch to receive and process IP multicast frames. Therefore, IGMP snooping must be enabled to support MPLS.
- VPLS—VPLS requires that IGMP snooping be disabled on customer-facing VLANs.