As Cloud technologies come of age, business leaders grapple with the impact it has on their team's skills and the gap associated with the use of a cloud platform.
Join experts from 451 Research and Concerto Cloud Services on July 27th where we will examine fact and fiction.
Course Of The Month
8 days, 18 hours left to enrollBecome a Premium Member and unlock a new, free course in leading technologies each month.
Solved
VLANs Design
Posted on 2016-08-16
If I understand VLANs are Layer 2 concept , and they are the Broadcast boundary, which means the Broadcast on one Vlan does not propagate to another VLAN. However I would like an Expert to clarify some dark areas about VLANs.
-- are VLANs the boundary of STP. I mean if there is a Switching Loop on one VLAN, the Loop will stay just on that VLAN and it does go to other VLANs ?
--If we have VLAN10 on a Switch in Building1 and 10 miles away in Building 2 we have another Switch that has VLAN10 and both VLANs are in the same VTP domain. is that considered Bad practice ?
--if we need to make Vlan2050 with 510 or 508 hosts has subnets 192.168.20.0 to 192.168.20.254 and 192.168.50.0 to 192.168.50.254 , to make it one VLAN for all wireless Access Points.
in other words, is it possible to have one VLAN for 2 subnets ?
Thank you
-- are VLANs the boundary of STP. I mean if there is a Switching Loop on one VLAN, the Loop will stay just on that VLAN and it does go to other VLANs ?
--If we have VLAN10 on a Switch in Building1 and 10 miles away in Building 2 we have another Switch that has VLAN10 and both VLANs are in the same VTP domain. is that considered Bad practice ?
--if we need to make Vlan2050 with 510 or 508 hosts has subnets 192.168.20.0 to 192.168.20.254 and 192.168.50.0 to 192.168.50.254 , to make it one VLAN for all wireless Access Points.
in other words, is it possible to have one VLAN for 2 subnets ?
Thank you
[X]
Welcome to Experts Exchange
Add your voice to the tech community where 5M+ people just like you are talking about what matters.
- Help others & share knowledge
- Earn cash & points
- Learn & ask questions
-
4
3
7 Comments
Active today
are VLANs the boundary of STP. I mean if there is a Switching Loop on one VLAN, the Loop will stay just on that VLAN and it does go to other VLANs ?Yes, but it will most likely skyrocket CPU of the switch and all VLANs will be affected in the end.
If we have VLAN10 on a Switch in Building1 and 10 miles away in Building 2 we have another Switch that has VLAN10 and both VLANs are in the same VTP domain. is that considered Bad practice ?Typically it is considered bad practice. Having the same VLAN number is not a problem, but VTP typically should be stay local. Max STP diameter is 7 "hops". That looks like:
Switch1 - Switch2 - Switch3 - VTP server switch - Switch4 - Switch5 - Switch6
BPDUs can be too slowly propagated from end to end (10 miles distance does not help at all).
Please read article.
in other words, is it possible to have one VLAN for 2 subnets ?Yes. You can use secondary IP address for for other range in the same VLAN (and not even just one secondary ip address range)
interface vlan 10
ip address 192.168.20.1 255.255.255.0
ip address 192.168.50.1 255.255.255.0 secondary
ip helper-address x.x.x.x
Addresses from secondary IP address range will be assigned by DHCP when primary IP address pool is wasted.
But, on the other hand it is not recommended to have 1000 hosts in one VLAN.
Active 1 day ago
are VLANs the boundary of STP. I mean if there is a Switching Loop on one VLAN, the Loop will stay just on that VLAN and it does go to other VLANs ?
Yes, but it will most likely skyrocket CPU of the switch and all VLANs will be affected in the end.
But the problem will impact only hosts connected to that single switch ? other switches will be OK ?
![[Live Webinar] The Cloud Skills Gap](https://filedb.experts-exchange.com/files/public/2017/5/29/3249c5dc-214e-4f8f-afab-ef354630e19f.png)
Active 1 day ago
So if it impacts only switches where that one VLAN exist, there is nothing you can do to prevent the Loop to happen.
Active 1 day ago
Also if I am not wrong, it is better to not spread one VLAN across several switches.
for instance if you can have VLAN 10 on Switch 1 only, if there is a Loop it will impact jut that Switch is better than having VLAN 10 span 2 or more Switches.
for instance if you can have VLAN 10 on Switch 1 only, if there is a Loop it will impact jut that Switch is better than having VLAN 10 span 2 or more Switches.
Active today
So if it impacts only switches where that one VLAN exist, there is nothing you can do to prevent the Loop to happen.You need to separate 2 things - preventing loop and effects of a loop. You can prevent loop for sure. On newer devices you can control effects of a loop by using :
storm-control broadcast level <level>
storm-control multicast level <level>
storm-control unicast level <level>
But, it is better to prevent loop than using network equipment to control it, Typically loops can be prevented by choosing proper network design and using STP, RSTP or MSTP with enhancements that are needed.
Also if I am not wrong, it is better to not spread one VLAN across several switches.Everything is moving into that direction, but if I remember correctly Cisco's current recommendation is that VLAN should stay inside rack (I still do not see that reflected in productions, typically VLANs are spreading through building).
Featured Post
Veeam is happy to provide a free NFR license (for 1 year, up to 10 users). This license allows for the non‑production use of Veeam Backup for Microsoft Office 365 in your home lab without any feature limitations.
Question has a verified solution.
If you are experiencing a similar issue, please ask a related question
There are two basic ways to configure a static route for Cisco IOS devices. I've written this article to highlight a case study comparing the configuration of a static route using the next-hop IP and the configuration of a static route using an outg…
Tired of waiting for your show or movie to load? Are buffering issues a constant problem with your internet connection? Check this article out to see if these simple adjustments are the solution for you.
After creating this article (http://www.experts-exchange.com/articles/23699/Setup-Mikrotik-routers-with-OSPF.html), I decided to make a video (no audio) to show you how to configure the routers and run some trace routes and pings between the 7 sites…
After creating this article (http://www.experts-exchange.com/articles/23699/Setup-Mikrotik-routers-with-OSPF.html), I decided to make a video (no audio) to show you how to configure the routers and run some trace routes and pings between the 7 sites…
Suggested Courses
Earn Certification
HTML5 Specialist - Certification
Free withPremium
Course of the Month8 days, 18 hours left to enroll
615 members asked questions and received personalized solutions in the past 7 days.
Join the community of 500,000 technology professionals and ask your questions.