From: Justin Menga (Justin.Menga@xxxxxxxxxxxxxxxxxx)
Date: Wed Feb 21 2001 - 17:14:38 GMT-3
The problem with HSRP is it is an Active/Passive technology, so you won't be
able to load balance between the two. To get a fully redundant load sharing
topology without using BGP you would probably need:
DSL Cable
R1 R2
| |
|---------------|
|
Ethernet
|
|---------------|
| |
R3 R4
| |
-----------------
Internal
Hosts
You would use dynamic routing on R1 and R2 to announce default routes to R3
and R4.
R3 and R4 would run HSRP on the internal network side. This means that say
R3 becomes the primary HSRP router, and then would load balance traffic
between R1 and R2. If R3 fails, R4 will become primary router and will also
load balance between R1 and R2. If R1 or R2 fail, only 1 default route is
announced. In this scenario, the network provides reduncancy for a single
router failure and also a double router failure (provided the failures are
not both R1 and R2 or both R3 and R4). The network also load balances
between the cable and DSL connections, which would not be possible if the
cable and DSL routers were running HSRP.
Also, for a cheaper alternative for DSL, you could use Cisco 827, which also
supports FW/IPsec/VoIP...
Regards,
Justin Menga CCIE #6640 MCSE+I CCSE
WAN Specialist
Computerland New Zealand
PO Box 3631, Auckland
DDI: (+64) 9 360 4864 Mobile: (+64) 25 349 599
mailto: justin.menga@computerland.co.nz
-----Original Message-----
From: Peter [mailto:peter@web53.com]
Sent: Wednesday, February 21, 2001 6:08 PM
To: Foster, Kristopher; 'Paul Thomas'; ccielab@groupstudy.com
Subject: Re: off topic: redundant internet connections for small clients
For the Cable connection, get a CiscoUBR924. This is a SOHO IOS router with
a cable interface, it even supports VoIP. For the DSL, get a 1700 with the
new WIC-DSL card. You can run HSRP between the two, track the WAN link,
creat equal cost routes out for load balancing, etc. You still may have
problems with point #2 below.
Peter
----- Original Message -----
From: "Foster, Kristopher" <KFoster@C1Communications.com>
To: "'Paul Thomas'" <psthomas@telusplanet.net>; <ccielab@groupstudy.com>
Sent: Tuesday, February 20, 2001 1:37 PM
Subject: RE: off topic: redundant internet connections for small clients
> You may need to look into a hardware solution (www.fatpipeinc.com may have
> what you need). The major problem with trying to load balance with your
way
> is inconsistency:
>
> 1. you are doing per destination load balancing, in which case if one
> provider goes down, or a problem farther up the path occurs, you will
> continue to forward traffic in that direction. The only way it will fail
> over properly is if the connected interface goes down.
>
> 2. you are doing per packet load balancing, other then your packets
arriving
> out of order or at very inconsistent rates, NAT isn't going to work
properly
> (which I can't see anyway of getting around having to do NAT without
having
> your own advertisable address space).
>
> If someone can come up with a decent solution I'd like to hear it too.
This
> is a problem I've seen come up before without resolution.
>
> Kris,
>
> -----Original Message-----
> From: Paul Thomas [mailto:psthomas@telusplanet.net]
> Sent: Tuesday, February 20, 2001 2:02 PM
> To: ccielab@groupstudy.com
> Subject: off topic: redundant internet connections for small clients
>
>
> Hi all,
> Does anyone have any suggestions on configurations to improve =
> interent redundancy for small clients that cannot run BGP. For example a =
> 50-100 user company with both a Cable modem and ADSL connection. I could =
> see how setting up internal servers with an address from each ISP's =
> range would allow access to them from the internet if one link went down =
> (as long as both addresses are listed in DNS). What could you do for =
> internal client pc's to ensure internet connectivity? A router connected =
> to both the cable and ADSL modems could have both listed as default =
> gateways and load balance between the two links to optimize bandwidth =
> utilization. It would only fail over to the other link if the connection =
> between the client company and the ISP went down though. It would be =
> unable to sense a failure in the ISP connection to the Internet backbone =
> for example. Any suggestions of how to optimize this setup further? =
> Without BGP of course ;-)
>
> Thanks everyone,
>
> Paul Thomas
>
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