Re: router help needed ....urgent
- From: "carlfugate@xxxxxxxxx" <carlfugate@xxxxxxxxx>
- Date: Wed, 04 Jul 2007 14:33:03 -0000
On Jul 1, 9:21 pm, "Brian V" <diespam...@xxxxxxxxxx> wrote:
<carlfug...@xxxxxxxxx> wrote in message
news:1183340116.847975.26120@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
On Jun 30, 1:58 pm, Trendkill <jpma...@xxxxxxxxx> wrote:
On Jun 30, 2:48 pm, TheGoD <tgupt...@xxxxxxxxx> wrote:
Hi Techies....
I'm stuck in a problem....as i'm not very well with cisco routers...
I have a cisco router 1800 series with a 4 port fast ethernet card.
now i have attached both the internet isp's (A and B) over ethernet to
this router, now what i need is that all my traffic for internet from
lan A (192.168.1.0/24) should be routed to isp A and all from lan B
(10.220.16.0/24)should be routed to isp B.
Please ckick the link for the
diagram.http://img248.imageshack.us/my.php?image=drawing1jq5.jpg
Thanks..............
Policy-based routing is your only option. Else all traffic will take
one path, the other, or both (depending on your configuration), but
will not be split based on source network. Search policy-based
routing or PBR on cisco, lots of good documentation.
This only solves one part of the routing equation in that traffic out
to the Internet will indeed leave the connection specified, however it
does not influence the way the traffic will return to your network
which is normally more important (load balancing inbound flows which
are much larger normally than the outbound flows). That cannot be
solved by the end customer without using some very creative routing
and even then you are at the mercy of your provider to make it work.
Normally you would use BGP for that and you would split your IP
address pools in half or more and advertise one half to one provider,
and the other half to the other. At the same time you would advertise
a summary of the entire pool to both providers for failover purposes.
This is a very complex problem in large networks which have large
amounts of IP space that they can use to load balance. Even then, you
have to look at what servers reside in that IP segment (or pool) and
determine if you are truly load balancing (ie if your largest servers
all sit in the same /24 and you are advertising /24 networks to your
upstream provider then most of your traffic will still only use one
link). If both links are to the same ISP router then you can use BGP
MED (communities) to influence it but again provider dependent.
Where did the OP mention redundancy or the need to load balance anything?
They specifically stated that they want this subnet on ISP1 and this subnet
on ISP2. You're refering to corporations/businesses who "own" their own
block of IP's who want to multi-home to different ISP's. The OP mentioned an
1800 series, so thats most likely not the case here. In the OP's case there
is absolutely no need for BGP or any other routing protocol as the IP's will
be nat'd going out their designated interfaces and the return traffic would
follow that same path thru the appropriate ISP. As the first responder
stated already, policy based routing is the only available option without
adding more hardware such as a Radware type solution for what the OP
requested.
Hmm...I guess if I was paying for two links to the Internet even just
for Web browsing, it would be pretty silly not to very easily put in
the ability to use both links. My argument still stands though, it
doesn't matter if you PBR the traffic out one link or the other, your
at the mercy of the Internet routing tables to determine how its going
to come back to you so you may send it out on link 1, but everything
may come back in link 2.
.
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