From: Guyler, Rik (rguyler@shp-dayton.org)
Date: Wed Mar 01 2006 - 15:14:25 GMT-3
Exactly. Avoiding long convergence times is the real goal here. Our
network using L2 in the access layer is very dependable and with STP
enhancements such as Backbonefast and uplinkfast, our convergence is still
pretty quick. I think L3 convergence may speed it up a bit, though, and in
a medical environment that little bit may be critical.
We are just looking at this conceptually for now so we don't know all the
details. I do believe that we would not include every access switch in the
routing domain but certainly every access layer. Before we made any
commitment to this design we would have to do some pretty thorough testing
in a lab environment.
Rik
-----Original Message-----
From: Church, Chuck [mailto:cchurch@netcogov.com]
Sent: Wednesday, March 01, 2006 11:18 AM
To: Guyler, Rik; ccielab@groupstudy.com
Subject: RE: To route or not to route.....
It's going to take careful planning of your IGP then if you're going to
include every access layer switch. If you're using NSF on your distribution
and core layers, you might need to make sure it's available on the access
layer devices now to take advantage of it. Avoiding long reconvergence
times after a sup failure/switchover is the goal after all, right?
Chuck Church
Network Engineer
CCIE #8776, MCNE, MCSE
Netco Government Services
Enterprise Network Engineering
Home Office - 864-335-9473
Cell - 864-266-3978
cchurch@netcogov.com
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Guyler, Rik
Sent: Wednesday, March 01, 2006 11:00 AM
To: 'ccielab@groupstudy.com'
Subject: RE: To route or not to route.....
I didn't say we wouldn't use L2 within the access layer. This design just
does not extend the L2 domain up to the distribution layer where
traditionally the L3 function takes place. The access layer could use just
one of the switches to run L3 or a concentrator of sorts.
We haven't worked out all the details as it's in a conceptual stage for us
at this time so we're just kicking it around in a pro/con discussion right
now. If Cisco is pushing this I have no idea but this design is not new.
Many Cisco docs talk about L3 ACL's in the access layer so how else would
this be accomplished?
I see more and more intelligence being pushed down to the access layer so
it's just a matter of time before this becomes mainstream design.
Just my .02
Rik
-----Original Message-----
From: Venkataramanaiah.R [mailto:vramanaiah@gmail.com]
Sent: Wednesday, March 01, 2006 10:50 AM
To: Guyler, Rik
Cc: ccielab@groupstudy.com
Subject: Re: To route or not to route.....
I have not heard about this myself that Cisco is pushing L3 upto Access, but
i can foresee few other issues in doing this..
For eg., what will happen to the Voice network. Will you have one subnet per
Access switch for IP Phones.. Guess this will become unmanageable if you
have just a couple of IP Phones per closet. Same with Wireless APs, the
wired side is usually on the Access switches.
Vlan management for these services w/o L2 upto Distribution might become
cumbersome..
Just my 2 cents
-Venkat
On 3/1/06, Guyler, Rik <rguyler@shp-dayton.org> wrote:
> Well, what I meant (sorry for not being specific enough) was to create
> a
> *second* link between switches and closets that all participate in a
> single VLAN dedicated for RSPAN only. If you have extra fiber
> pairs/copper between closets then this shouldn't be too expensive.
> Might have to buy some media converters or other assorted hardware but
> I think it's still a good solution. I would want to lab it up with 2
> or 3 switches first though just to see what unexpected little
> surprises may exist. ;-)
>
> Rik
>
> -----Original Message-----
> From: Leigh Harrison [mailto:ccileigh@gmail.com]
> Sent: Wednesday, March 01, 2006 9:40 AM
> To: Guyler, Rik
> Cc: 'ccielab@groupstudy.com'
> Subject: Re: To route or not to route.....
>
> Hey there Rik,
>
> I'd had a thought about that and leaving one vlan for rspan
> specifically, but the problem there is that on the uplink interfaces,
> you have to throw in the commands: "no switchport, ip address 1.2.3.4"
> which means that no vlans will be passed over!!
>
> LH
>
>
> Guyler, Rik wrote:
>
> >Leigh, I haven't run into this but we're considering L3 at the access
> >layer as well for future design. The problem I see is once you go
> >with
> >L3 you no longer have a path to really setup the RSPAN. What about
> >creating a separate L2 link between all switches dedicated just for
> >the
> RSPAN session?
> >I really like the L3 access layer design but it certainly makes
> >things like this much more interesting... ;-)
> >
> >Rik
> >
> >-----Original Message-----
> >From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf
> >Of Leigh Harrison
> >Sent: Wednesday, March 01, 2006 7:48 AM
> >To: FORUM
> >Subject: To route or not to route.....
> >
> >All,
> >
> >I'm currently working on a design for a customer. Straight forward
> >design with Access and a Core. 3750's in the access layer and a 6513
> >in the core (yes there is only 1, but the customer already has it, it
> >has dual sup cards and dual power supplies...) the 3750's are in
> >stacks and there is dual gig links back to the core.
> >
> >I was at a Cisco seminar recently where Cisco said that the best
> >practice is to route, rather than use spanning tree and switch,
> >essentially turn off spanning tree. I'm quite happy to run either
> >way, but I do have a
> >question:-
> >
> >We are running VoIP on the network and there is call recording
> >software going in. This needs to have the ports of the gatekeepers
> >span'd to it so that it can do the recording. If I'm routing my
> >network, what are the options for accomplishing this if my
> >gatekeepers are not connected to the same switch?
> >
> >I presume that someone out there has run into a similar issue, so any
> >insight would be greatly appreciated.
> >
> >Best Regards
> >LH
> >#15331
> >
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