Basic Routing on Multilayer Switch 2 - Connected Network - No VLAN

Today, we are enhancing a little bit our previous post

https://activehub2.blogspot.com/2019/03/basic-routing-on-multilayer-switch.html

Earlier we had a single inside laptop.  Now we are placing one more laptop on the inside.  Both laptops are connected to Hub, that in turn connected to the port of the switch.

All the configurations will be same.

Topology

Task Breakup

1. Configuring IP Address on Laptops
2. Configuring IP Address on Switch
3. Analysis before Routing
4. Enable Routing
5. Analysis after Routing
6. Validation

1. Configuring IP address on Laptops

Click on Laptop -> Desktop -> IP Configuration

Inside1 - IP Address - Configuration

Inside2 - IP Address - Configuration

Outside - IP Address - Configuration

2. Configure IP addresses on Switch

As it is a multilayer switch, by default it will act as a switchport.  We have to convert to routing interface, by the command 'no switchport'.  Setting the IP address as mentioned in the Topology

routing(config)#int gig 1/0/1
routing(config-if)#no switchport
routing(config-if)#
%LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/1, changed state to down

%LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/1, changed state to up

routing(config-if)#ip address 172.16.0.1 255.255.0.0
routing(config-if)#no shut
routing(config-if)#exit
routing(config)#int gig1/0/10
routing(config-if)#no switchport
routing(config-if)#
%LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/10, changed state to down

%LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/10, changed state to up

routing(config-if)#ip address 5.0.0.1 255.0.0.0
routing(config-if)#no shut
routing(config-if)#exit

3. Analysis before Routing

Enable Packet Debugging

routing#debug ip packet
Packet debugging is on

Observe the IP Routing table is empty

routing#show ip route 
Default gateway is not set

Host               Gateway           Last Use    Total Uses  Interface
ICMP redirect cache is empty

routing#

4. Enable Routing

I am not sure if Routing is enabled by default.  Even it is enabled, it doesn't hurt to enable with the command 'ip routing'.

routing#conf t
Enter configuration commands, one per line.  End with CNTL/Z.
routing(config)#ip routing 
routing(config)#exit

5. Analysis after Routing

Observe that IP Routing table will show connected networks.  It means, packets can be passed between those networks.

routing#show ip route
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, 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

C    5.0.0.0/8 is directly connected, GigabitEthernet1/0/10
C    172.16.0.0/16 is directly connected, GigabitEthernet1/0/1

6. Validation

Issue a ping from inside2 to outside.  It will be successful.

Successful ping from inside to outside

As packet debug is enabled in step 3, we will observe some routing information that the switch has processed to route packets between inside and outside network.

IP: tableid=0, s=172.16.0.11 (GigabitEthernet1/0/1), d=5.0.0.2 (GigabitEthernet1/0/10), routed via RIB

IP: s=172.16.0.11 (GigabitEthernet1/0/1), d=5.0.0.2 (GigabitEthernet1/0/10), g=5.0.0.2, len 128, forward

IP: tableid=0, s=5.0.0.2 (GigabitEthernet1/0/10), d=172.16.0.11 (GigabitEthernet1/0/1), routed via RIB

IP: s=5.0.0.2 (GigabitEthernet1/0/10), d=172.16.0.11 (GigabitEthernet1/0/1), g=172.16.0.11, len 128, forward

Issue a ping from outside to inside1 laptop.  It will be successful.  Observe the packet debug info.

Successful ping - Outside - Inside1

IP: tableid=0, s=5.0.0.2 (GigabitEthernet1/0/10), d=172.16.0.10 (GigabitEthernet1/0/1), routed via RIB

IP: s=5.0.0.2 (GigabitEthernet1/0/10), d=172.16.0.10 (GigabitEthernet1/0/1), g=172.16.0.10, len 128, forward

IP: tableid=0, s=172.16.0.10 (GigabitEthernet1/0/1), d=5.0.0.2 (GigabitEthernet1/0/10), routed via RIB

IP: s=172.16.0.10 (GigabitEthernet1/0/1), d=5.0.0.2 (GigabitEthernet1/0/10), g=5.0.0.2, len 128, forward