fools rush in where angels fear to tread...

a router is a switch, at least in the mls universe...
or a router and switch combined...
or is the switch a router?

these prattlings of mine, are just that, mine... they have their basis in fact but they are sifted through me, and i am a fallible instrument of their conveyance... as always, question everything and  prove the truth for yourself...
in the end the numbers will out...

the l3 switch has the properties of both the router and the switch... it maintains the route table, the arp table, the fib and the adjacency table, among others... cef is built in... the last two tables are considered distinct functional blocks... they are functionally different but make up the whole... they are organized by occurences to the route table and arp table, as we saw in the last submission, and are functionally independant as well as functionally dependant... all four are tables maintained by the mls...

what happens when you show the mac-address-table of a router?


r2620_01#sh mac-add

r2620_01#

nothing...

and the ip route table of a switch...


sw2950_02#sh ip route
                 ^
% Invalid input detected at '^' marker.

sw2950_02#

disaster...
however...


sw3550_01#sh ip route

trimmed

     1.0.0.0/24 is subnetted, 1 subnets

D       1.1.1.0 [90/130816] via 192.168.1.50, 2d16h, Vlan10

                [90/130816] via 172.16.50.50, 2d16h, Vlan50

     2.0.0.0/24 is subnetted, 1 subnets

D       2.2.2.0 [90/2298112] via 192.168.1.50, 2d16h, Vlan10

                [90/2298112] via 172.16.50.50, 2d16h, Vlan50

     100.0.0.0/8 is variably subnetted, 2 subnets, 2 masks

C       100.0.0.0/24 is directly connected, Loopback0

and...


sw3550_01#sh mac-add
          Mac Address Table
-------------------------------------------

Vlan    Mac Address       Type        Ports
----    -----------       --------    -----
 All    000f.8ffe.0980    STATIC      CPU
 All    000f.8ffe.0981    STATIC      CPU
trimmed


the two worlds collide beautifully; synchronicity is achieved...

a diagram that depicts distinct models of a router with a route and arp table, and a separate model of  the mls with fib and adjacency, and the interaction of the two as if they are completely separate entities is misleading...

the router is a switch... the model is a layer 3 switch and it maintains a route table, an arp table, a fib and an adjacency table, among others...