Solved

Cisco 891 won't get an ip after a power outage

Posted on 2011-09-16
10
502 Views
Last Modified: 2012-08-13
Hello

I got a Cisco 891 wired to a DOCSIS 3.0 cable modem. Sometimes, we get power outage for several hours and the router and the modem are both shutdown. The problem is when they  both reload the router dont get an IP adress from the modem. I have to reset the interface each time... I am not always there to reset the interface and someone at the job have to connect to the router and reboot it. Is there a way to prevent this ?

Thanks
0
Comment
Question by:metraon
  • 4
  • 3
  • 2
  • +1
10 Comments
 
LVL 3

Expert Comment

by:shbasm
Comment Utility
in router under interface connected tp modem put ip address dhcp command
0
 

Author Comment

by:metraon
Comment Utility
The router have this command already.
0
 
LVL 8

Accepted Solution

by:
gsmartin earned 500 total points
Comment Utility
I would recommend using a UPS with a line conditioner.  This will help to stablize power and keep the router from going down during brief power outages or brown outs.  What is the typical duration of the power outages?    
0
 
LVL 8

Expert Comment

by:gsmartin
Comment Utility
UPS: Depending on how many Watts the router and modem require, will depend on the UPS's Estimated Runtime (i.e. 50Watts with 1300Watt APC UPS - 2:34 min. Est. Runtime.).  The higher the wattage requirement the lower the Estimated Runtime.  FYI... You can also add an external battery pack to support an extended period on select models.
0
 
LVL 8

Expert Comment

by:gsmartin
Comment Utility
After a power outage, the modem would need to come up first an establish it's connection and then bring the router online.  If you don't have control over this process then it makes it difficult.
0
What Should I Do With This Threat Intelligence?

Are you wondering if you actually need threat intelligence? The answer is yes. We explain the basics for creating useful threat intelligence.

 
LVL 3

Expert Comment

by:shbasm
Comment Utility
use static ip address at router interface
0
 
LVL 6

Expert Comment

by:Sanjeevloke
Comment Utility
Do below test when u are there ...

1) Shut modem for sometime and do start it again and check if router gets IP
2) Shut router for sometime and keep modem ON and check again if routers gets IP.
3) When u face IP issue try to restart modem and check if it gets IP.

Can post IOS version many be a IOS bug is there ...
0
 
LVL 8

Assisted Solution

by:gsmartin
gsmartin earned 500 total points
Comment Utility
Static IP Adress would be the best solution to mitigate the issue.  However, DSL and Cable ISP providers typical implementation is DHCP.  

You may need to specifically request a set of Static IP addresses for your Internet connection, which is usually at an additional cost; depending on the ISP.  If for whatever reason, Static IP Addresses are not provided/supportted under the ISP's standard Internet services.  Then you may need to specifically request Business Class Internet services in order to get a set of Static IP addresses.  FYI...  Business Class is usually more expensive than standard DSL or Cable Internet services.  Cost and services will vary from provider to provider.  

Note there are other Internet connectivity options that are more stable, but also more costly (i.e. T1, Frame-Relay, MPLS, eWAN, etc....).  These options typically terminate directly on the router or another device like an external CSU/DSU, but I am sure you already know this.  Anyway, on a T1 circuit you can have it terminate at the router and then avoid any issues with secondary devices such as a modem or external CSU/DSU, as well as have static IPs.    
0
 

Author Comment

by:metraon
Comment Utility
Actually we have business class internet. I will request a static IP, i believe this will help...

I will also test :


1) Shut modem for sometime and do start it again and check if router gets IP
2) Shut router for sometime and keep modem ON and check again if routers gets IP.
3) When u face IP issue try to restart modem and check if it gets IP.

And post the iOS version soon

Many thanks
0
 

Author Closing Comment

by:metraon
Comment Utility
Obviously I need an UPS. I have requested an static IP address also.
0

Featured Post

How to improve team productivity

Quip adds documents, spreadsheets, and tasklists to your Slack experience
- Elevate ideas to Quip docs
- Share Quip docs in Slack
- Get notified of changes to your docs
- Available on iOS/Android/Desktop/Web
- Online/Offline

Join & Write a Comment

New Server 172.16.200.2  was moved from behind Router R2 f0/1 to behind router R1 int f/01 and has now address 172.16.100.2. But we want users still to be able to connected to it by old IP. How to do it ? We can used destination NAT (DNAT).  In DNAT…
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…
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…

771 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

Need Help in Real-Time?

Connect with top rated Experts

10 Experts available now in Live!

Get 1:1 Help Now