It can be quite confusing to work out what all these terms are exactly referring to. I’ll try and put a concise answer for all of them here with an example.
RIB – Routing Information Base
This is the route table. i.e. When you do a show ip route, the RIB is what you see
This is the route table. i.e. When you do a show ip route, the RIB is what you see
AR1#sh ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route
Gateway of last resort is not set
10.0.0.0/32 is subnetted, 1 subnets
C 10.255.255.5 is directly connected, Loopback0
A router may have many separate RIB’s. If you’re running vrf’s with customer, then each vrf will have a separate RIB:
AR1#sh ip route vrf CUS1 | begin Gateway
Gateway of last resort is not set
C 192.168.1.0/24 is directly connected, FastEthernet0/0
AR1#sh ip route vrf CUS2 | begin Gateway
Gateway of last resort is not set
172.16.0.0/24 is subnetted, 1 subnets
C 172.16.1.0 is directly connected, FastEthernet2/0
FIB – Forwarding Information Base
The FIB is an optimised version of the RIB. Or more correctly it’s the table a router looks at when deciding where to actually forward traffic. In Cisco land, the CEF table is a FIB.
The FIB is an optimised version of the RIB. Or more correctly it’s the table a router looks at when deciding where to actually forward traffic. In Cisco land, the CEF table is a FIB.
AR1#sh ip cef Prefix Next Hop Interface 0.0.0.0/0 drop Null0 (default route handler entry) 0.0.0.0/8 drop 0.0.0.0/32 receive 10.255.255.5/32 receive 127.0.0.0/8 drop 224.0.0.0/4 drop 224.0.0.0/24 receive 240.0.0.0/4 drop 255.255.255.255/32 receive
Like the RIB, there can be multiple FIB tables on a router:
AR1#sh ip cef vrf CUS1 Prefix Next Hop Interface 0.0.0.0/0 drop Null0 (default route handler entry) 0.0.0.0/32 receive 192.168.1.0/24 attached FastEthernet0/0 192.168.1.0/32 receive 192.168.1.1/32 receive 192.168.1.255/32 receive 224.0.0.0/24 receive 255.255.255.255/32 receive AR1#sh ip cef vrf CUS2 Prefix Next Hop Interface 0.0.0.0/0 drop Null0 (default route handler entry) 0.0.0.0/32 receive 172.16.1.0/24 attached FastEthernet2/0 172.16.1.0/32 receive 172.16.1.1/32 receive 172.16.1.255/32 receive 224.0.0.0/24 receive 255.255.255.255/32 receive
LIB – Label Information Base
The LIB is an MPLS table. This is the place where the router will keep all known MPLS labels. To take a look, you just need to use show mpls ldp bindings:
The LIB is an MPLS table. This is the place where the router will keep all known MPLS labels. To take a look, you just need to use show mpls ldp bindings:
AR1#sh mpls ldp bindings
tib entry: 10.0.0.0/30, rev 18
local binding: tag: 21
remote binding: tsr: 10.255.255.1:0, tag: imp-null
remote binding: tsr: 10.255.255.2:0, tag: imp-null
tib entry: 10.0.0.4/30, rev 16
local binding: tag: 20
remote binding: tsr: 10.255.255.1:0, tag: 32
remote binding: tsr: 10.255.255.2:0, tag: imp-null
tib entry: 10.0.0.8/30, rev 44
local binding: tag: 34
remote binding: tsr: 10.255.255.1:0, tag: 31
remote binding: tsr: 10.255.255.2:0, tag: 32
tib entry: 10.0.0.12/30, rev 42
local binding: tag: 33
remote binding: tsr: 10.255.255.1:0, tag: imp-null
remote binding: tsr: 10.255.255.2:0, tag: 31
tib entry: 10.1.0.0/30, rev 5
local binding: tag: imp-null
remote binding: tsr: 10.255.255.1:0, tag: imp-null
remote binding: tsr: 10.255.255.2:0, tag: 30
tib entry: 10.2.0.0/30, rev 4
local binding: tag: imp-null
remote binding: tsr: 10.255.255.1:0, tag: 30
remote binding: tsr: 10.255.255.2:0, tag: imp-null
tib entry: 10.7.0.0/30, rev 36
local binding: tag: 30
remote binding: tsr: 10.255.255.1:0, tag: 25
remote binding: tsr: 10.255.255.2:0, tag: 26
tib entry: 10.8.0.0/30, rev 34
local binding: tag: 29
remote binding: tsr: 10.255.255.1:0, tag: imp-null
remote binding: tsr: 10.255.255.2:0, tag: 25
tib entry: 10.255.255.1/32, rev 30
local binding: tag: 27
remote binding: tsr: 10.255.255.1:0, tag: imp-null
remote binding: tsr: 10.255.255.2:0, tag: 23
tib entry: 10.255.255.2/32, rev 10
local binding: tag: 17
remote binding: tsr: 10.255.255.1:0, tag: 23
remote binding: tsr: 10.255.255.2:0, tag: imp-null
tib entry: 10.255.255.3/32, rev 28
local binding: tag: 26
remote binding: tsr: 10.255.255.1:0, tag: 22
remote binding: tsr: 10.255.255.2:0, tag: 22
tib entry: 10.255.255.4/32, rev 26
local binding: tag: 25
remote binding: tsr: 10.255.255.1:0, tag: 21
remote binding: tsr: 10.255.255.2:0, tag: 21
tib entry: 10.255.255.5/32, rev 6
local binding: tag: imp-null
remote binding: tsr: 10.255.255.1:0, tag: 20
remote binding: tsr: 10.255.255.2:0, tag: 20
tib entry: 10.255.255.7/32, rev 24
local binding: tag: 24
remote binding: tsr: 10.255.255.1:0, tag: 18
remote binding: tsr: 10.255.255.2:0, tag: 18
AR1#
LFIB – Label Forwarding Instance Base
The LFIB is another MPLS table. This is the table that the router uses to forward labelled packets going through the network. Much like the RIB uses the FIB to forward traffic, so the LIB uses the LFIB to forward traffic. This is how you view it:
The LFIB is another MPLS table. This is the table that the router uses to forward labelled packets going through the network. Much like the RIB uses the FIB to forward traffic, so the LIB uses the LFIB to forward traffic. This is how you view it:
AR1#sh mpls forwarding-table
Local Outgoing Prefix Bytes tag Outgoing Next Hop
tag tag or VC or Tunnel Id switched interface
17 Pop tag 10.255.255.2/32 0 Se1/2 point2point
20 Pop tag 10.0.0.4/30 0 Se1/2 point2point
21 Pop tag 10.0.0.0/30 0 Se1/2 point2point
Pop tag 10.0.0.0/30 0 Se1/0 point2point
24 18 10.255.255.7/32 0 Se1/0 point2point
25 21 10.255.255.4/32 0 Se1/2 point2point
26 22 10.255.255.3/32 0 Se1/0 point2point
27 Pop tag 10.255.255.1/32 0 Se1/0 point2point
29 Pop tag 10.8.0.0/30 0 Se1/0 point2point
30 25 10.7.0.0/30 0 Se1/0 point2point
33 Pop tag 10.0.0.12/30 0 Se1/0 point2point
34 32 10.0.0.8/30 0 Se1/2 point2point
31 10.0.0.8/30 0 Se1/0
