Redundancy and path selection

[josedelpino]

Hey guys

Currently I need to implement a redundancy scheme consists of two roads one primary and one secondary, basically the idea is that if you drop the primary traffic go by the secondary

This is the first time I do something like this, so I'm looking at a help in that technology could be used to accomplish this.

Greetings to all

Any comments will be well recieved

[Vasileios Bouloukos MSc, ITIL, CCIE]

Hi Jose,

This is a common scenario for LAN setup.

I would recommend to configure the 2950 and 2651 routers with either HSRP or GLBP in order to achieve reundancy in case of a link LAN failure. Your server will be configured with a default route to the HSRP/GLBP IP.

Moreover, I would suggest, in case that you select HSRP to configure the 2950 router as active since has better performance than 2651(I assume that the wan links are equal). GLBP could be prefered in case that you have to balance the traffic to the LAN.

Finally, you should configure to the HSRP/GLBP setup to track the status of the WAN interface in order to avoid any blackholing traffic issues.

If you are not familiar with this technology I would suggest to read the next.

http://www.cisco.com/en/US/tech/tk648/tk362/technologies_tech_note09186a0080094a91.shtml

http://www.youtube.com/watch?v=2-EtRgAEHiE

Hope that helps!

Vasilis

[Joseph W. Doherty]

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Posting

The first "tricky" part is do you intend to have your server connect to both switches, i.e. multi-homed?  If so, you'll need to trunk between your two switch so that both server subnets have a path to both routers.  Both routers would run HSRP for this two subnets with the active gateways being on your 2951.  I'm also assuming both routers are sharing routing information, so if the primary WAN path fails the primary router knows to redirect traffic to the secondary path (NB: you might also configure HSRP that the active gateway moves to the secondary router).

If your server only has a single connection to one of your two switches, you'll see need to extend the subnet across both switches and to both routers.  HSRP like above except only one subnet instead of two.

[Parvesh Paliwal]

Dear Friend,

I would recommend you to have both of the links at the same router and have static routes to the same destinations with different Administrative Distances and define the exit interfaces.

This would lead the traffic to another interface if the first one goes down.

If this is still not possible to have both of the interfaces on the same router.. you can have routes to the other router as well.

Hope it helps.

Regards,

Parvesh

[Crypt0]

@Parvesh having everything go out of ONE device kind of defeats the purpose of REDUNDANCY.

I'd def go with HSRP & remember to setup preempt

[josedelpino]

Thank you very much to all,
I tried HSRP and exactly what I've been looking, but I have some problems.
This project is to implement redundancy in a small ISP in my country and the problem is that I have several public addresses in my router and are / 30 the first valid address for my router and the second to the client obviously, but want to add another router the topology does not suffice me a / 30 and need a / 29 for HSRP.before:
Core1: 10.0.0.1/30
Client: 10.0.0.2/30&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&now:
Core1: 10.0.0.3/29
Core2: 10.0.0.4/29
Virtual Router: 10.0.0.1/29
Client: 10.0.0.2/29
Wasted addresses: 10.0.0.5, 10.0.0.6
There are over one hundred clients with public address
This represents a waste of hundreds of public addresses.There any way around this?regards