NYCPHP Meetup

[nycphp-talk] multiple gateways and linux

Jim Suto jim at alliedtours.com
Tue Jun 4 13:29:14 EDT 2002


Actually the circuits in question are not at the location you mentioned but
I could make address DNS records for www.alliedtours.com to point to
X.X.X.X, Y.Y.Y.Y, Z.Z.Z.Z where x,y,z represent public IPs that I got from
the three T1s and have all those IPs each assigned to one of three NICS in
the server.  This doesn't require bgp to work, right?



> -----Original Message-----
> From: Larry Chuon [mailto:LarryC at indexstock.com]
> Sent: Tuesday, June 04, 2002 1:17 PM
> To: NYPHP Talk
> Subject: RE: [nycphp-talk] multiple gateways and linux
>
>
> That won't solve your redundancy problem if your services are
> residing on a
> subnet that goes down.  The rest of the world won't know how to
> automatically get to your domain.  For instance, alliedtours.com's IP@ is
> 208.193.190.3. AlliedTours has three T1 and at least one circuit
> comes from
> another provider.  You need a way to tell all the routing tables
> around the
> world how to get to you when the circuit for 208.193.109.3 is down.  Going
> out won't be a problem. One way to solve that problem is by
> implementing BGP
> or IS-IS.
>
>
> -----Original Message-----
> From: Chalu Kim [mailto:chalu at egenius.com]
> Sent: Tuesday, June 04, 2002 12:59 PM
> To: NYPHP Talk
> Subject: Re: [nycphp-talk] multiple gateways and linux
>
>
> Why not check out IPROUTE which does fail-over and packet balancing? It is
> available on Linux...
> Instead of going the circuitous way of HSRP and VRRP or BGP, this
> is more in
> the localized first step to high availability to the intranet.
>
> ----- Original Message -----
> From: "Jim Suto" <jim at alliedtours.com>
> To: "NYPHP Talk" <talk at nyphp.org>
> Sent: Tuesday, June 04, 2002 12:14 PM
> Subject: RE: [nycphp-talk] multiple gateways and linux
>
>
> > We have 3 T1s, 2 are from Worldcom, one is from Cable & Wireless.  These
> are
> > already in place with each provider having its own CISCO router.  If we
> use
> > HSRP, we are only going to be using one single router at any
> time and the
> > other one will sit by idle, right?  It's good for redundancy but not for
> > maximizing usage of the available bandwidth.  I was thinking of using
> > roundrobing DNS for incoming connections to our server using
> the 3 IPs (1
> > from each T1 block).  The outgoing connections could be returned via
> source
> > routing perhaps?  And if a gateway is down, use another gateway even if
> that
> > will create an assymetrical route?
> > In your point (e) if we got two routers for each circuit we
> would need to
> > have 6 routers, do you think the cost would be justified for slightly
> > reduced failover risk?  I think the company could live in a
> pinch even on
> > just a single working T1 but it seems like a waste to have all
> that other
> > bandwidth just sitting there unused.  Let me know what you think.
> >
> > regards,
> > Jim
> >
> > -----Original Message-----
> > From: Larry Chuon [mailto:LarryC at indexstock.com]
> > Sent: Tuesday, June 04, 2002 11:55 AM
> > To: NYPHP Talk
> > Subject: RE: [nycphp-talk] multiple gateways and linux
> >
> >
> > Keep in mind that when you have multiple circuits, you're running into
> some
> > complecity with your network design.  Here is a general guideline.
> > 1. Are you planning to subscribe the add'l T1 from the same ISP
> of from a
> > different one?
> > Same:
> > a. Easy to loadbalance (LB) your package both inbound and outbound
> > b. You don't require to have a heavy duty router.  This way you
> can accept
> > partial BGP route.  As a result your, hardware requirement is much less.
> > c. Use vendor assigned Autonymous System Number (ASN).
> > d. If the ISP is down, assuming both T1 are from the same c/o,
> you're out!
> > e. I recommend that you have two separate routers for each circuit.
> >
> > Different:
> > a. You must apply for you own ASN from ARIN.
> > b. Tedious BGP configuration
> > c. Setup of LB might be difficult depends on your environment, but not
> > impossible
> > d. Complete ISP redundancy - due to two separate path in and out
> > e. Same as 1e above.
> >
> > With the two routers as your gateway, you can configure
> HSRP/VSRP (depends
> > on the vendors).  Essentially, you have two real gateways and
> one virtual
> > one that everyone is pointing to.  When any of the real
> gateways is down,
> it
> > won't affect your connectivity at all.  Linux has something to
> that affect
> > as well.  I don't have experience with it nor do I know what it calls.
> >
> >
> > -----Original Message-----
> > From: Jim Suto [mailto:jim at alliedtours.com]
> > Sent: Tuesday, June 04, 2002 11:10 AM
> > To: NYPHP Talk
> > Subject: [nycphp-talk] multiple gateways and linux
> >
> >
> > I am looking for any ideas people might have to maximize the value of
> having
> > multiple T1s from different providers and being able to provide
> redundancy
> > and possibly performance gains from having a linux server utilize these
> > multiple gateways.  Some ideas I was thinking about:
> > 1) enable linux to do dead gateway detection and avoid using a
> gateway if
> it
> > is not up
> > 2) enable linux to distribute traffic among the gateways to
> whichever one
> is
> > least busy (this might be a little bit more difficult)
> > 3) enable linux to figure out from a list of hosts which gateway would
> allow
> > connection to a specific host with minimum lag and/or hops
> >
> > I guess some shell scripts could accomplish some of these tasks unless
> > someone knows a better way?
> >
> > regards,
> > Jim
> >
> >
> >
> >
> >
> >
>
>
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