a few useful show IP command..

sh ip route


R1#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


     172.16.0.0/30 is subnetted, 2 subnets
C       172.16.1.0 is directly connected, Serial0/1
C       172.16.2.0 is directly connected, Serial0/0
     10.0.0.0/24 is subnetted, 1 subnets
D       10.1.1.0 [90/2195456] via 172.16.1.2, 00:02:01, Serial0/1
C    192.168.1.0/24 is directly connected, Loopback1

• type of network ; static, connected
• or how the router learn it ; EIGRP, OSPF.from which interface it learned

let's be more specific

show ip route [address]

R1#sh ip rou 10.1.1.1

Routing entry for 10.1.1.0/24

  Known via "eigrp 1", distance 90, metric 2195456, type internal

  Redistributing via eigrp 1

  Last update from 172.16.1.2 on Serial0/1, 00:07:16 ago

  Routing Descriptor Blocks:

  * 172.16.1.2, from 172.16.1.2, 00:07:16 ago, via Serial0/1

      Route metric is 2195456, traffic share count is 1

      Total delay is 21000 microseconds, minimum bandwidth is 1544 Kbit

      Reliability 255/255, minimum MTU 1500 bytes

      Loading 1/255, Hops 1

• how it's learned . ex; EIGRP, static or connected..
• how long since the route learned, this can be useful when you want to check how long link down, up time.. etc,
• the bandwidth information are reflected by the value configured on the interface .. what ever value you put, it's gonna show the same in here

show ip route connected

show ip route static

• issue this two cmd if you want to filter or be more specific on the type of route

show ip route summary

R1#sh ip rou sum

IP routing table name is Default-IP-Routing-Table(0)

IP routing table maximum-paths is 16

Route Source    Networks    Subnets     Overhead    Memory (bytes)

connected       1           2           216         408

static               0           0           0           0

eigrp 1            0           1           72          136

internal            2                                   2312

Total               3           3           288         2856

Removing Queue Size 0

• this will summarize all you information base on Net, Subnet, Overhead(other memory used) and Memory