Ahh weird.. I never knew that about the gateway when specifying an
interface.. hrm never looked or noticed..
CEF gives you per packet and equal cost allows for source/destination load
balancing. Ive done this a million times and graph utilization at about
49% to 51% per 2 T1's. Ive never enabled CEF on anything smaller than a
7513 so I wouldn't feel comfortable suggesting on a 3640 as Im unaware of
the ramifications from doing so or how it operates or even if it would.
The 2640 are just WIC's right? Im not implying it would be a bad thing
just not sure of the specifics as Ive never thought to do so.
There are other optimizations you can use as well like "down-when-looped"
so the route goes away in the case of a loop in the circuit (which it wont
do by default etc etc etc). The beauty of this business is there are 1000
ways to skin a cat.. :)
-blair
AT&T CERFnet
Backbone Engineering and Planning
| PGP Public Key: www.hfh.com/blair/pgp.txt |
On Fri, 19 Nov 1999, Keoseyan, Scott wrote:
> Actually that "Gateway set to 0.0.0.0" is what you end up with when you
> specify your default gateway as an interface in the IP route statement...
> goofy, but true.
>
> What you propose will give him per-packet load balancing... but wouldn't it
> just be better to turn on CEF and run multiple default route statements
> pointing down each T1?
>
> One question I had about that strategy is... does CEF work when you specify
> interfaces as gateways in your static route statements... or does one need
> to put IP addresses in for it to work correctly... or does it matter at all?
>
> Scott
>
> -----Original Message-----
> From: Scot Donovan Blair [mailto:sblair@cerf.net]
> Sent: Thursday, November 18, 1999 11:08 PM
> To: cisco-nsp@puck.nether.net
> Cc: cisco-nsp@puck.nether.net
> Subject: Re: static routing
>
>
> Paul,
>
> Equal cost static routes should work fine to balance between your T1's.
> I would note turning route-cache off the interface may be useful as well
> (this is always debatable). Something that looks odd to me is the below
> snipet of your info..
>
> "Gateway of last resort is 0.0.0.0 to network 0.0.0.0"
>
> Without seeing the config I would be just guessing but it appears as if
> maybe you have default-gateway set to 0.0.0.0.. it's a guess. Im not sure
> what your problems are *exactly* but if you are trying to load balance
> between multiple T1's it should be more than OK to have equal costs
> statics to multiple interfaces .
>
>
> -blair
> AT&T CERFnet
> Backbone Engineering and Planning
>
> | PGP Public Key: www.hfh.com/blair/pgp.txt |
>
> On Thu, 18 Nov 1999, Paul Jacobs wrote:
>
> > I have a simple question (I hope).....
> >
> > I now have 3 T-1's in my 3640 Cisco and need to place static routes to
> > different T-1's so all traffic does not go out 1 single T-1..
> >
> > Below is my current ip route statements:
> >
> > ip route 0.0.0.0 0.0.0.0 Serial1/0:1.1
> > ip route 127.0.0.0 255.0.0.0 Null0
> > ip route 0.0.0.0 0.0.0.0 serial 0/0
> >
> >
> > And my 'sh ip route' output:
> >
> > Gateway of last resort is 0.0.0.0 to network 0.0.0.0
> >
> > C 208.239.156.0/24 is directly connected, FastEthernet1/0
> > S 127.0.0.0/8 is directly connected, Null0
> > 63.0.0.0/24 is subnetted, 1 subnets
> > C 63.64.44.0 is directly connected, Ethernet0/1
> > S* 0.0.0.0/0 is directly connected, Serial1/0:1.1
> >
> > I am doing something wrong because if I define my routes via ip route
> > statement(s) and remove the 0.0.0.0 0.0.0.0 ip route traffic gets in but
> > not out??
> >
> > Any help any one can offer is welcome...
> >
> > Paul Jacobs
> > Network admin
> > http://www.netpacq.com
> >
> >
>
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