What is fib and LFIB?

2021-02-15 john

What is fib and LFIB?

LFIB is the Label Forwarding Information Base. It is the MPLS table that has got labels against IP prefixes along with outgoing interfaces and it is used to forward labelled packets. The FIB is the Forwarding Information Base that is an optimized version of RIB.

What is rib in MPLS?

RIB: This is a routing protocols database of routing prefixes that could potentially be installed in the routing table. LIB is the equivalent to RIB but for MPLS labels. It contains all the labels received from adjacent routers, usually over LDP. The LFIB has the best labels installed and is used for forwarding.

What is the role of label forwarding information base LFIB in MPLS?

MPLS creates its own database for lookups called the Label Forwarding Information Base (LFIB), but it uses the CEF FIB as a source of this information. If CEF cannot resolve a route, the label cannot switch to a destination either. Multiple paths known through different routers can result in one label for each path.

What is Lib table?

Label Information Base (LIB) is the software table maintained by IP/MPLS capable routers to store the details of port and the corresponding MPLS router label to be popped/pushed on incoming/outgoing MPLS packets. Entries are populated from label-distribution protocols.

What is difference between LIB and LFIB in Mpls?

The LIB maintains the mapping between the IP prefix, the assigned label, and the assigning label. The LFIB is part of the data plane and provides the database used in forwarding labeled packets. The IGP is used to populate the routing tables in all MPLS routers throughout the network.

What are two differences between the RIB and the fib?

What are two differences between the RIB and the FIB? (Choose two.) A. FIB is a database of routing prefixes, and the RIB is the information used to choose the egress interface for each packet. The RIB is a database of routing prefixes, and the FIB is the information used to choose the egress interface for each packet.

How does RIB differ from fib?

The RIB is used to create network topologies and routing tables. The FIB is a list of routes to particular network destinations. The RIB includes many routes to the same destination prefix. The FIB contains only the best route.

How many bits is an MPLS label?

MPLS Label. A label is a 20-bit identifier that uniquely identifies a FEC to which a packet belongs. Upon receipt of an IP packet from a non-MPLS network, the ingress of an LSP creates an MPLS header in the packet and inserts a specific label into this field.

What is Cisco FIB table?

The FIB is conceptually similar to a routing table or information base. It maintains a mirror image of the forwarding information contained in the IP routing table. When routing or topology changes occur in the network, the IP routing table is updated, and those changes are reflected in the FIB.

What is VRF Lite?

VRF-lite is a feature that enables a service provider to support two or more VPNs, where IP addresses can be overlapped among the VPNs. VRF-lite uses input interfaces to distinguish routes for different VPNs and forms virtual packet-forwarding tables by associating one or more Layer 3 interfaces with each VRF.

How is the LFib used in the MPLS network?

The LFIB is essentially the label routing table. Labels are shared through distribution protocols, but the information is built based on the IP routing table information. If the IP network experiences convergence issues or other types of instability, the MPLS network will be affected in a like manner.

What is the difference between LFib and Lib?

Like RIB, LIB is a Control-Plane MPLS table and is not used for the actual forwarding of the MPLS packets. Label Forwarding Information Base or LFIB, like FIB, is a Data-Plane MPLS forwarding table. LFIB is used to forward the MPLS packets. LIB aids in creating the LFIB table with the help of the IP Routing table.

Is the Lib the same as the MPLS table?

What are the labels in fib and LFib?

FIB and LFIB only contains labels for best path to a prefix, LIB contains all labels regardless if they’re used or not. To choose what label to apply the router depends on the routing protocols decision about the best route.