I have a branch site connected to my main office using a 128 Kbps FR link. The FR link is terminated on a 2621 router at the branch and on a 3640 at the central office. Now i need to avoid single point of failures for both hardware and connectivity . My idea is to implement standby routers at both ends using HSRP and ISDN as redundancy for FR.
Is this a good design? When the FR interface on router-A at the central office goes down , the ISDN on router-B would initiate a call to router-B at remote office and establish connection . This is my logical thinking. Is there a better way fo doing this? What are the things which i should keep in mind while going ahead with this?
When the Primary 2 MB link goes down how does the ISDN dialer interface on the second router get a trigger to initiate dialing. As far as i understand , when the primary circuit goes down HSRP has to inform secondary router to become active and also initiate the dialing of ISDN. Could you throw some light on how you have accomplished this. I am not very experienced with ISDN DDR configuration and setup
I've been doing this since circa IOS 11.0! There are several example configurations in my book High Availability Networking with Cisco (listings are on my web site). See Chapter 5 "Multiple Routers at a Single Site" which has a section on "Dial Backup by One Router for a Line on Another." You can do it with dialer watch (use IOS 12.1(5) or later only) or with BGP (any IOS with DDR and BGP support). Note that since I wrote the book, Cisco has fixed dialer watch to work with all routing protocols, so ignore that comment in the book.
HSRP should be configured independently of the dial backup, because the dialer link never goes down (so you can't track it) and the serial line may not go down at the link level (particularly if frame relay) even though all traffic has been forced over to the backup path. Configure a dynamic routing protocol (EIGRP or OSPF) between the routers so that all routers can find the working path, regardless of the mode of failure. That way, while HSRP will protect you from router failure and may eliminate extra hops during link failure conditions, you are not dependent on it working under all conditions for your backup plan to work. (been there, done that, been burnt...)
This is actually a pretty cool feature, i didn't even know it existed until I was looking for a solution to advertise a subnet (prefix in BGP talk), only if a certain condition existed. This is exactly what conditional advertisements does
j ai une question j ai achete un routeur cisco 887VA-k9 , je le configuré avec la configuration ci- dessous
si je le lier avec mon pc portable sur l un de ses ports directement ça marche toute est bien ( la connexion internet + m...
Attached policy provides CLI access to the Cisco 4G router over text messaging. Two files are in the attached .tar file:
2. PDF with instructions on how to load and use the .tcl file.