For CCNA and CCNP candidates, it’s tricky not to laugh The 1st time you listen to the phrase “router on a stick”. Enable’s face it, that’s a fairly silly term. But as those who have passed the CCNA and CCNP exams know, it is a essential exam topic which you must learn how to configure and troubleshoot.
Essential Cisco concept states that for hosts in numerous VLANs to communicate, a Layer three unit need to be included to manage the routing amongst the VLANs. That gadget can be a router, and you'll find Distinctive concerns that needs to be taken into consideration for equally the Bodily router itself and also the configuration you’ll be writing.
The router is going to be connected to a change by using a FastEthernet port (or bigger). The router port can not be a regular Ethernet port, For the reason that router port will require the ability to deliver and receive info concurrently.
The configuration in the interface is exactly where factors get attention-grabbing. Let’s say We've got two VLANs that should be employing router-on-a-adhere to communicate.
Here is the VLAN info:
VLAN 20: twenty.twenty.20.0 /24
VLAN forty: forty.forty.forty.0 /24
The port over the switch that could be linked to the router’s FastEthernet port has to be in trunking mode, and you should know the trunking protocol in use. We’ll go While using the Cisco-proprietary ISL in this article.
The physical FE port around the router is not going to have an IP tackle. The usage of router-on-a-adhere mandates the use of sensible subinterfaces. Even though we don’t really have https://en.wikipedia.org/wiki/?search=먹튀검증 to utilize the VLAN numbers with the subinterface numbers, I’ve found this can help you retain the interfaces straight. A single subinterface have to be specified an IP deal with in VLAN 20, and another can have an 먹튀검증커뮤니티 IP tackle in VLAN forty.
After generating subinterfaces rapid 0.20 and fast 0.forty, the config looks like this:
interface fastethernet0
no ip tackle
interface FastEthernet 0.twenty
ip address twenty.twenty.twenty.one 255.255.255.0
interface FastEthernet 0.forty
ip deal with 40.forty.forty.one 255.255.255.0
Believe it or not, you’re almost accomplished! Now we need the encapsulation assertion underneath Each individual subinterface. The subinterface assertion have to replicate both of those the VLAN selection as well as encapsulation variety being used. Whenever we’re finished, the config would look like this:
no ip handle
ip address 20.20.20.one 255.255.255.0
encapsulation isl 20
ip address 40.forty.40.one 255.255.255.0
encapsulation isl forty
And that’s it! Your hosts in VLAN twenty should really now have the capacity to communicate with hosts in VLAN forty, and vice versa.
A handful of closing troubleshooting factors – the commonest error with router-on-a-stick is To place the wrong vlan range from the encapsulation statement. Also, ensure you have configured the router’s IP address in VLAN 20 because the default gateway for hosts in VLAN 20, and do the identical for VLAN forty.
I hope you’ve savored this check out router-on-a-adhere. While the identify might obtain a chuckle from you, it’s continue to used in A good number of networks available, and recognizing tips on how to configure and troubleshoot it will get you that Considerably nearer to earning your CCNA and CCNP.