Control plane: Responsible for Exchanging layer 3 routing
information and labels.
Control plane consists complex mechanism to exchange routing information
such as OSPF, EIGRP, IS-IS, and BGP and to exchange label such as TDP, LDP, BGP
and RSVP.
Data plane: Responsible to forward packet based on labels
and IP header.
Data plane has simple forwarding engine it maintains LFIB and FIB.
Control Plane:
Routing protocol: Responsible for exchange of routing
information .It prepares IP routing table.
IP routing table: Responsible to build IP forwarding table
(FIB) in Data Plane (Forwarding plane).
LDP: Responsible for exchange of labels between the peers. After
exchanging the labels with LDP peer LFIB is formed in Data Plane (Forwarding
Plane).
Data Plane:
- As the IP packet comes in it
will do a IP routing lookup and check is any label is associated with
particular FEC. If yes then label is imposed in the packet and process by
LFIB as labeled packet.
- If
no label is associated with IP Packet then it is processed as normal IP
Packet by FIB.
- If
incoming packet is labeled then by using LFIB the label is swapped and the
packet is processed
RIB Table
show ip
route
CEF Table
show ip
cef - shows the cef table. The major difference is
that the next hop is figured out in the cef output.
LIB Table
show mpls
ldp bindings - shows all
the labels bounded to the networks, contains all good and bad networks labels. Here
Liberal retention mode is used. That means even not the best labels are
remembered
LFIB Table
# show
mpls forwarding – LFIB is
winner circle. Best paths for the label forwarding go in the LFIB
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