of some of the more important bits of the output is in order; most comments refer to a
highlighted portion of an example. First, the legend at the beginning of Example 6-20 defines
the letter codes that identify the source of the routing information--for instance, C for
connected routes, R for RIP, and I for IGRP. Each of the Class A, B, and C networks is listed,
along with each of the subnets of that network. If a static mask is used within that network, then
R 10.1.11.0/24 [120/1] via 172.16.3.252, 00:00:22, Serial0.1
R 10.1.10.0/24 [120/1] via 172.16.3.252, 00:00:22, Serial0.1
R 10.1.9.0/24 [120/1] via 172.16.3.252, 00:00:22, Serial0.1
R 10.1.8.0/24 [120/1] via 172.16.3.252, 00:00:22, Serial0.1
Albuquerque#show ip route igrp
10.0.0.0/8 is variably subnetted, 5 subnets, 2 masks
D 10.1.4.0/22 [90/2185984] via 172.16.1.253, 00:29:42, Serial0.2
172.16.0.0/24 is subnetted, 3 subnets
C 172.16.1.0 is directly connected, Serial0.2
C 172.16.2.0 is directly connected, Ethernet0
C 172.16.3.0 is directly connected, Serial0.1
10.0.0.0/8 is variably subnetted, 5 subnets, 2 masks
R 10.1.11.0/24 [120/1] via 172.16.3.252, 00:00:22, Serial0.1
R 10.1.10.0/24 [120/1] via 172.16.3.252, 00:00:22, Serial0.1
R 10.1.9.0/24 [120/1] via 172.16.3.252, 00:00:22, Serial0.1
R 10.1.8.0/24 [120/1] via 172.16.3.252, 00:00:22, Serial0.1
D 10.1.4.0/22 [90/2185984] via 172.16.1.253, 00:29:58, Serial0.2
Route Source Networks Subnets Overhead Memory (bytes)
connected 0 3 156 420
static 0 0 0 0
rip 0 4 208 560
eigrp 9 0 1 52 140
internal 2 2320
Total 2 8 416 3440
Codes: C - connected, S - static, I - IGRP, 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, E - EGP
i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, * - candidate default
U - per-user static route, o - ODR