In this CCNA housing study, we'll avow whatever base change and trunking theory and locate it into action. We hit digit routers (R2 and R3) along with digit switches (SW1 and SW2). R2 is adjoining to SW1 at alacritous 0/2, and R3 is adjoining to SW2 at alacritous 0/3. Both routers hit IP addresses on the 172.12.23.0 /24 network.
For these routers to be healthy to sound apiece other, the switches staleness be healthy to communicate. These are digit 2950 switches, and they're adjoining via digit elector cables. Before we vexation most the router connectivity, let's attain trusty the luggage unification is up between the switches with the show programme trunk command.
SW2#show programme trunk
Port Mode Encapsulation Status Native vlan
Fa0/11 delectable 802.1q trunking 1
Fa0/12 delectable 802.1q trunking 1
< production short for clearness >
The choice fashion of these switches is for the ports to removed in impulsive delectable trunking mode, so we didn't modify requirement to indite a plan to hit the luggage modify - it's already there!
Show vlan short reinforces the theory that by default, every alter ports are settled into VLAN 1 (except the luggage ports).
R2 and R3s Ethernet addresses hit already been configured, the luggage distinction is operational, and both ports are in VLAN 1. We'll sound R2s Ethernet programme from R3, and then R3s Ethernet programme from R2 to avow IP connectivity.
R2#ping 172.23.23.3
Type carelessness ordering to abort.
Sending 5, 100-byte ICMP Echos to 172.23.23.3, timeout is 2 seconds:
!!!!!
Success evaluate is 100 proportionality (5/5), round-trip min/avg/max = 4/4/8 ms
R3#ping 172.23.23.2
Type carelessness ordering to abort.
Sending 5, 100-byte ICMP Echos to 172.23.23.2, timeout is 2 seconds:
!!!!!
Success evaluate is 100 proportionality (5/5), round-trip min/avg/max = 4/4/8 ms
With pings, vocalization points inform IP connectivity, and periods inform no connectivity.
So we've got connectivity! Now let's wager if we ease hit that connectivity when the ports are settled into assorted VLANs. Cisco CCNA theory states that devices in assorted VLANs can't transmit without the participation of a Layer 3 device, but let's wager if that's genuine by placing R2 into VLAN 23. (VTP is already streaming on these switches.)
SW1#conf t
Enter plan commands, digit per line. End with CNTL/Z.
SW1(config)#int alacritous 0/2
SW1(config-if)#switchport fashion access
SW1(config-if)#switchport admittance vlan 23
SW1(config-if)#Z
Now that R2 and R3 are in removed VLANs, crapper they ease beam pings backwards and forth?
R2#ping 172.23.23.3
Type carelessness ordering to abort.
Sending 5, 100-byte ICMP Echos to 172.23.23.3, timeout is 2 seconds:
.....
Success evaluate is 0 proportionality (0/5)
R3#ping 172.23.23.2
Type carelessness ordering to abort.
Sending 5, 100-byte ICMP Echos to 172.23.23.2, timeout is 2 seconds:
.....
No, they cant. The disagreement is that theyre today in removed VLANs, and devices in assorted VLANs cant transmit unless routing is attractive locate somewhere. Here, no routing is attractive place, so the pings dont go through.
Put R3s alter opening into VLAN 23, and essay the sound again.
SW2#conf t
Enter plan commands, digit per line. End with CNTL/Z.
SW2(config)#interface fast0/3
SW2(config-if)#switchport fashion access
SW2(config-if)#switchport admittance vlan 23
R3#ping 172.23.23.2
Type carelessness ordering to abort.
Sending 5, 100-byte ICMP Echos to 172.23.23.2, timeout is 2 seconds:
!!!!!
Success evaluate is 100 proportionality (5/5), round-trip min/avg/max = 4/4/8 ms
R2#ping 172.23.23.3
Type carelessness ordering to abort.
Sending 5, 100-byte ICMP Echos to 172.23.23.3, timeout is 2 seconds:
!!!!!
Now that R2 and R3 are in the aforementioned VLAN, pings crapper go through. This meet proves the theory - that inter-VLAN transmit requires a Layer 3 device. Layer 3 switches are decent more and more popular, but router-on-a-stick is ease around - and we'll wager how to configure that in our incoming tutorial!
Chris Bryant, CCIE #12933, is the someone of The Bryant Advantage, bag of liberated CCNA and CCNP tutorials, The Ultimate CCNA Study Package, and Ultimate CCNP Study Packages.
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