Cisco Help Required - 1841 Programing

[adznight]

I have a client that I'm looking to setup 5-6 Cisco 1841 Routers for and I'd like to have the fitted WIC's failover but it's not something I have experience with. I was hoping someone here might be good with Cisco IOS as I'm only self taught.

What I'm looking to do is install an 1841 with two WIC's, 1 ADSL and one SHDSL and if interface 1 go's down it will fail over to interface 2. I have experience with setting up the interfaces to work independently but there is some tricky routing involved with failing over and I'm a bit out of my depth.

Has anyone done this that can help? I'm happy to pay. Cheers

PS - If you don't understand what I've just said don't fill my thread with garbage

[DogKnight]

I understand what your trying to arrange. Its been a few years since i studied the CCNA so I would only be looking through a manual myself.

Now youve got me thinking constantly about how to do this >.<

[adznight]

Yeah it's a bit of a tricky one for me too. It's just a job I'm outsourcing not a full time position but it would be good to have a relationship with someone with a strong Cisco knowledge that we could call on for work as we sometimes have drama’s with VPN and Crypto too. If you think you can do this sort of stuff we can talk $

[paulr33]

hsrp attached to the wan interface will do it

both routers run hsrp between each other and send echo packets

they also share a virtual ip between them

if one of them doesn't respond to the echo within set timeout the other router takes over the virtual ip

there's always a master and a slave in the hsrp

ive got a book / pdf if you want to do it yourself, its easy

[paulr33]

or the other ip logical way is ip routing, so use ospf, eigrp to provide logical route redundancy

[CeJay]

I'm only learning cisco atm, but wouldn't a gateway of last resort do the trick? (ie default network etc)

[paulr33]

ah i didnt see it was on one device, well yeah just set to two gateways with different metric

the lower metric being the primary route, and the secondary with the higher metric

i assumed you had two routers

[adznight]

It's 50/50 one one device atm. It may just stay 1 866 and 1 837 so yes your'e right HSRP would do the trick.

[paulr33]

yeah if you have two routers, then HSRP is spot on

will give you want you need, just make sure you set it to watch the serial or dialer/0 interface for the dsl connection

and test it of course, also make sure to set the priority, dont assume defaults

[paulr33]

for those interested in similar topics check out;

network warrior

http://www.amazon.com/Network-Warrior-Gary...7458&sr=8-1

a recommended read

it covers advanced and commonly used scenarios of networking and networking concepts

the pdf version is on bit torrent if you want a sneek peek, but the paper back is recommended

http://www.mininova.org/tor/860447

i purchased mine from amazon.com delivered in about 1.5 weeks for $49 new

[evade]

adz,

get cisco's packet tracer.

setup your routers in it, test it all out..configurations/layouts/etc and use the book resources to help you if needed!

router simulation easiest way to go about it

let me know if you want a copy

[justin911]

what if the interface stays up but theres no ip connectivity, twill never swap over

best way is to setup object tracking/EEM applet on the cisco so it automaticaly pings the default gateway every few seconds then if it fails it swaps over by itsself.

[Random Dude]

justin911 makes a good point - and the main point why traditional interface down detection methods won't work with ADSL.

The ADSL line sync (layer2 of the OSI model) will be the main interface that the detection will work on. What you'll find is that most of the time, the PPP layer (layer 3 of the OSI model) will be the one failing, and you'll lose your PPP link - which means no traffic. This PPP fail won't trigger the interface as being down.

The default gateway idea is the most logical however not always reliable. I suspect that depending on the routing protocol it might not always detect the ADSL/SHDSL fail and keep pumping out packets to the default gateway with the lowest metric which will result in lost packets and no connectivity.

Not having any live cisco equipment I can't say for sure (and I don't work on the equipment on a daily basis anymore) but being a good cisco tech I did some googling and found the following:

http://wiki.ittoolbox.com/index.php/Cisco_Failover

This is an IOS feature (sla monitor/rtr?) that tests a particular IP address for certain criteria, ie:

IP sla monitor 1

type echo protocol ipIcmpEcho your_first_test_ip source-ipaddr your_source_ip

timeout 2000

threshold 2000

frequency 3

IP sla monitor schedule 1 life forever start-time now

Basically the above will ping a particular IP through a particular interface and make sure it meets the SLA of 'a timeout of no longer than 2000ms' and 'no more than 3 failures in a row' or something to that effect.

Look at the website above and the rest of the commands will set up the routes etc. Its a start but I don't know how useful it is - and you're right, it's probably out of your depth - heck its even out of mine and I'm a CCNA/CCDA/VOIP etc.

Like i said mate i'm not working on the stuff full time anymore but I can still get my head around most of the stuff. You'll be able to find my ph number. Gimmie a call anytime - don't feel afraid to chuck me a config file either

[Random Dude]

More info for you here Adz:

http://www.velocityreviews.com/forums/t552...cisco-2801.html

And as Justin mentioned above, object tracking sounds like what I found above, however i havn't worked on it before:

http://www.cisco.com/en/US/docs/ios/12_3/1...e/dbackupx.html

[adznight]

Thanks for all the input guys Much appreciated!