Solved

Reducing a /16 network to a /24

Posted on 2016-08-09
3
57 Views
Last Modified: 2016-08-09
I have a live network that is in the 10.10.0.0/16 range.  I am creating VLANS and subnets and moving most of the nodes out of the range all together.  I was wondering though, is there a way to create a vlan/subnet in the 10.10.1.0/24 range and keep communications up until I can change the grandfathered network to the /24 range?  Right now I'm going to have to take the network down, change the masks change the grandfathered range to a 24 and then create the VLAN that I need.

Anyway to do this with a live network?  Working with a Cisco 6509...
0
Comment
Question by:publicvoid
[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
3 Comments
 
LVL 14

Accepted Solution

by:
SIM50 earned 500 total points
ID: 41748890
I don't see how this would work. Longer prefix will be put in the routing table thus cutting off traffic flow to /16.
0
 

Author Closing Comment

by:publicvoid
ID: 41749470
Thought so but I though maybe there was some ninja solution I didn't know about.
0
 
LVL 37

Expert Comment

by:bbao
ID: 41749767
> a way to create a vlan/subnet in the 10.10.1.0/24 range and keep communications up

there is NO problem for hosts with /16 mask to communicate with others with /24 mask, IF:

1. they are in the same phsicsl network, VLAN or broadcast domain

AND

2. the /16 mask hosts are actually in the range of 10.10.1.0/24.

e.g. 10.10.1.100/16 can talk with. 10.10.1.200/24, but 10.10.2.100 cannot talk to 10.10.1.100/24 (technically the latter can receive the former's packets but will reply to other subsets if a default gateway is available).

does it make sense?

therefore if you carefully plan the IPs, new hosts can communicate with SOME hosts on the grandfathered network, though not all of them.
0

Featured Post

 Database Backup and Recovery Best Practices

Join Percona’s, Architect, Manjot Singh as he presents Database Backup and Recovery Best Practices (with a Focus on MySQL) on Thursday, July 27, 2017 at 11:00 am PDT / 2:00 pm EDT (UTC-7). In the case of a failure, do you know how long it will take to restore your database?

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Auditors face some challenges when reviewing router and firewall configurations.  I'm going to discuss a few of them in this article.  My assumption is that there is a device hardening standard in place, which points out the key elements of configur…
This article is focussed on erradicating the confusion with slash notations. This article will help you identify and understand the purpose and use of slash notations. A deep understanding of this will help you identify networks quicker especially w…
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…

617 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question