In this video, Todd Lammle continues with his subnetting practice, but this time he moves the block sizes we use for finding our subnets from the fourth octet to the third octet. You'll use the same block sizes and answers you used in the fourth octet, and the fourth octet.
- [Narrator] Let's take a look at some examples…not Class C.…Here I've got in this graphic…a network address of 172.16.0.0.…Notice this is an RFC 19/18 address for Class B 172.16…through 31 are my available networks…but in this case here we're using the first one.…My mask is 255.255.128…which is a slash 17…but the 128 here…isn't that important in the sense that we're Class B.…It doesn't make it any harder.…
My subnets are in the third octet: zero and 128.…The fourth octet are all host bits.…So as you already know,…what do you do with host bits to get your network address?…You turn them all off.…To find your broadcast address,…what do you do with host bits?…You turn them all on.…So in this case here,…my fourth octet is all host bits so I just turn them all off…to get my network address and all on so the answer is:…zero and 255 in the fourth octet here always.…
Okay, so my first subnet is zero.…My next subnet is 128.…So I put a 127 down here under the zero.…I add a dot zero and a dot 255 which is so easy to do.…My valid hosts are the numbers in between…
For more information on the CCENT exam, visit Cisco's website.
- Overview of internetworking
- The TCP/IP networking model
- Easy subnetting
- Managing Cisco IOS
- Managing Cisco networks and devices
- IP routing
- Layer 2 switching
- VLANs and InterVLAN routing
- Network address translation
Skill Level Intermediate
Internetworking devices4m 20s
3. Introduction to TCP/IP
4. Easy Subnetting
5. VLSM, Summarization, and Troubleshooting TCP/IP
6. Cisco Internetworking Operating System (IOS)
7. Managing a Cisco Internetwork
8. IP Routing
9. Layer 2 Switching
10. VLANs and InterVLAN Routing (IVR)
12. Network Address Translation (NAT)
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