[cisco-voip] IOS VG Link redundancy

Mon Jan 26 21:51:00 EST 2009

If it works, you're turning the two routed ports into two switch ports.  So
yes, you'd be able to connect to two different switches.  The following
caveats come to mind though.

1. The switches you connect to should be equidistant from the STP root. You
want STP to block one of the ports on the router so that other traffic
doesn't flow through the router
2. STP convergence is on the order of 30-50s, you'd want RSTP for sub 5
seconds.  The feature navigator is mum on the issue, other than it supports
IRB. I'm going to guess it probably doesn't.

http://www.cisco.com/en/US/tech/tk389/tk815/technologies_tech_note09186a0080094663.shtml

Personally, we run them on one interface. It's easier to troubleshoot, and
our analogue stuff isn't that important to us.  If I needed redundancy, I'd
run a routing protocol and go the anycast route on the /32.

Sean

On Mon, Jan 26, 2009 at 8:39 PM, Lelio Fulgenzi <lelio at uoguelph.ca> wrote:

>
> looks like i can enter "interface bvi ?" on the command line, so i'm
> guessing it supports it.
>
> i didn't have much luck searching on CCO and finding something to describe
> it, so I'm not sure how it would apply here, i.e. can you run the two
> interfaces to two different uplink switches?
>
> definately something to consider for the future though, that's for sure.
>
> actually, i think i recall seeing BVI interfaces on the old 350APs!
>
> ----- Original Message -----
> From: "Sean Walberg" <sean at ertw.com>
> To: "Lelio Fulgenzi" <lelio at uoguelph.ca>, nikola at att.net,
> cisco-voip at puck.nether.net
> Sent: Monday, January 26, 2009 9:21:24 PM GMT -05:00 US/Canada Eastern
> Subject: Re: [cisco-voip] IOS VG Link redundancy
>
> Do the vg224s support BVI?  Turn the two interfaces into a bridge with
> the bvi int holding the IP and let STP sort it out.  Would work a lot
> better if it supports rstp.
>
> Sean
>
> On 1/26/09, Lelio Fulgenzi <lelio at uoguelph.ca> wrote:
> > That's an interesting document - something I'll file for future
> reference.
> >
> > However, I'm not sure how it helps here. The VGWs are routers themselves
> > with two uplinks. Since you can't have two interfaces on the same network
> > they have to be separate layer three routes to the upstream router.
> That's
> > the only I see this work (confirmed by a few others).
> >
> > Whether it's static or dynamic, somewhere on the network (and the device)
> > you have to configure routing to get back/forth. Especially if you are
> using
> > loopbacks. I don't think you can avoid this.
> >
> > If you want to use only one interface, then routing is not required,
> > however, I think that was the original post - making use of the two
> > interfaces.
> >
> > I'd be glad to hear alternatives.
> >
> > ---
> > Lelio Fulgenzi, B.A.
> > Senior Analyst (CCS) * University of Guelph * Guelph, Ontario N1G 2W1
> > (519) 824-4120 x56354 (519) 767-1060 FAX (JNHN)
> > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> > "Bad grammar makes me [sic]" - Tshirt
> >
> >
> > ----- Original Message -----
> > From: "Nikola Stojsin" <nikolastojsin at gmail.com>
> > To: "Brandon Bennett" <bennetb at gmail.com>, "Jason Aarons (US)"
> > <jason.aarons at us.didata.com>
> > Cc: cisco-voip at puck.nether.net
> > Sent: Monday, January 26, 2009 8:41:42 PM GMT -05:00 US/Canada Eastern
> > Subject: Re: [cisco-voip] IOS VG Link redundancy
> >
> >
> >
> >
> > As long as you do not need load balancing between voice gateways, HSRP
> would
> > work really well here, I think. I do not know what your OSPF topology
> looks
> > like, but something along the lines of HSRP with totally stubby OSPF area
> > would be my choice here. It is about as simple as it gets.
> >
> >
> >
> > If you do need load balancing, you can use Multigroup HRSP (
> >
> http://www.cisco.com/en/US/tech/tk648/tk362/technologies_configuration_example09186a0080094e90.shtml
> > ), with one caveat: some NICs cannot handle multiple MAC addresses, so,
> > depending on the router model, MHRSP may or may not work.
> >
> >
> >
> > Actually, it would be interesting to see which – HSRP, OSPF or EIGRP –
> would
> > converge/failover the fastest.
> >
> >
> >
> > HTH,
> >
> > Nikola
> >
> >
> >
> >
> >
> >
> >
> >
> >
> > -------------------------------------------
> >
> > Nikola Stojsin
> >
> > PhD CCIE #12888
> >
> > President
> >
> > Network Makers LLC
> >
> > 110 Wall Street, 11th Floor
> >
> > New York, NY 10005
> >
> > (212) 709-8201
> >
> > (212) 706-2986 (fax)
> >
> > nikolas at networkmakers.com
> >
> > -------------------------------------------
> >
> >
> >
> >
> > From: cisco-voip-bounces at puck.nether.net
> > [mailto:cisco-voip-bounces at puck.nether.net] On Behalf Of Brandon Bennett
> > Sent: Monday, January 26, 2009 7:38 PM
> > To: Jason Aarons (US)
> > Cc: cisco-voip at puck.nether.net
> > Subject: Re: [cisco-voip] IOS VG Link redundancy
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> > Wh at makes you want to change it?
> >
> >
> >
> > Well it's mostly a political thing. We are trying to remove the network
> team
> > from the gateways and remove the voice team from the network.
> >
> > Also 12.4(15)T8 which is required for our CVP install has proven itself
> so
> > completely unstable that the idea of having it in my routing domain
> scares
> > me and probably the less services running on it the better.
> >
> > I am doing max-metric, and a separate OSPF area for the VGs so that they
> > will never try to route traffic not for them, but it seems to me there
> > should be a better way to have an IOS device that doesn't have to
> > participate with a RP with the rest of the network.
> >
> >
> >
> > -Brandon
> > _______________________________________________ cisco-voip mailing list
> > cisco-voip at puck.nether.net
> > https://puck.nether.net/mailman/listinfo/cisco-voip
>
> --
> Sent from my mobile device
>
> Sean Walberg <sean at ertw.com>    http://ertw.com/
>

-- 
Sean Walberg <sean at ertw.com>    http://ertw.com/
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