From: Brian McGahan (bmcgahan@internetworkexpert.com)
Date: Wed Feb 02 2005 - 16:33:33 GMT-3
Cisco has an informative white paper titled "Gigabit Campus
Network Design- Principles and Architecture". Based on the product
matrix at the end you can see it is slightly dated, but still gives a
lot of good information on comparing different switch block design
models.
http://www.cisco.com/en/US/netsol/ns340/ns394/ns147/ns17/networking_solu
tions_white_paper09186a00800a3e16.shtml
HTH,
Brian McGahan, CCIE #8593
bmcgahan@internetworkexpert.com
Internetwork Expert, Inc.
http://www.InternetworkExpert.com
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> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf
Of
> Conte, Charles
> Sent: Tuesday, February 01, 2005 9:29 PM
> To: Church, Chuck; Scott Morris; Brant I. Stevens; asadovnikov;
> ccielab@groupstudy.com
> Subject: RE: Simple Design Question
>
> Chuck,
>
> I guess if I was to use OSPF with NSF I might as well go with
> IS-IS :). IS-IS on Cisco's white paper seemed to yield great results.
I
> agree with you on L2 versus L3 if convergence may be the argument.
What
> do you think in the situation of loop avoidance? Thanks!
>
> Charles
>
> -----Original Message-----
> From: Church, Chuck [mailto:cchurch@netcogov.com]
> Sent: Tuesday, February 01, 2005 10:05 PM
> To: Scott Morris; Brant I. Stevens; asadovnikov; Conte, Charles;
> ccielab@groupstudy.com
> Subject: RE: Simple Design Question
>
> I agree. The NSF (graceful restart) OSPF stuff with sub-second hellos
> make for wicked-fast OSPF convergence. Still, I'd rather have 100
> devices participating in spanning tree vs. SPF. It's much simpler to
> compute. Realistically though, with the fast CPUs in both routers and
> switches these days, re-computing SPF vs. recomputing RSTP can't be
more
> than a second difference one way or another. Both are huge advances
> over the 'old' way of doing things...
>
>
> Chuck Church
> Lead Design Engineer
> CCIE #8776, MCNE, MCSE
> Netco Government Services - Design & Implementation Team
> 1210 N. Parker Rd.
> Greenville, SC 29609
> Home office: 864-335-9473
> Cell: 703-819-3495
> cchurch@netcogov.com
> PGP key: http://pgp.mit.edu:11371/pks/lookup?op=get&search=0x4371A48D
>
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf
Of
> Scott Morris
> Sent: Tuesday, February 01, 2005 9:33 AM
> To: 'Brant I. Stevens'; 'asadovnikov'; 'Conte, Charles';
> ccielab@groupstudy.com
> Subject: RE: Simple Design Question
>
> On the flip side, you can do OSPF fast hellos and make things equal to
> rapid
> spanning tree!
>
>
> Scott Morris, MCSE, CCDP, CCIE4 (R&S/ISP-Dial/Security/Service
Provider)
> #4713, JNCIP, CCNA-WAN Switching, CCSP, Cable Communications
Specialist,
> IP
> Telephony Support Specialist, IP Telephony Design Specialist, CISSP
> CCSI #21903
> swm@emanon.com
>
>
>
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf
Of
> Brant I. Stevens
> Sent: Tuesday, February 01, 2005 1:15 AM
> To: asadovnikov; 'Conte, Charles'; ccielab@groupstudy.com
> Subject: Re: Simple Design Question
>
> I happen to disagree with this direction for the following reasons:
>
> 1. Using an IGP as opposed to L2 trunking for an
access-to-distribution
> link can actually INCREASE reconvergence time, especially when you
> consider
> the performance of Rapid-PVST and 802.1w. The only exception I've
seen
> to
> this is using EIGRP stub areas @ each access switch, but that means
you
> have
> to run EIGRP, as opposed to OSPF.
> 2. You will no longer be able to have the same VLAN spread across
> multiple
> switches (short of using software bridging, which defeats the purpose
of
> using switches.)
>
> I agree that reducing reliance on STP (even if you could, NEVER
disable
> it... =)) is always a good idea, but I think L3 to the closet
eliminates
> some of the benefits that VLANs provide.
>
> On 02/01/2005 12:57 AM, "asadovnikov" <asadovnikov@comcast.net> wrote:
>
> > I like the approach. If access switches are L3 capable you should
run
>
> > them as routers not switches. Although there are always corner
cases
> > when L2 may be better option, I strongly agree that benefits of
> > avoiding L2 generally greater then any potential downside.
> >
> > Best Regards,
> > Alexei
> >
> >
> > -----Original Message-----
> > From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf
> > Of Conte, Charles
> > Sent: Monday, January 31, 2005 7:29 PM
> > To: ccielab@groupstudy.com
> > Subject: OT:Simple Design Question
> >
> > Hello,
> >
> >
> >
> > If MSFC's are available at the access-layer, can anybody
> > tell me why we wouldn't run L3 to the access layer if the primary
and
> > secondary access switches are available in convenient locations?
Also
>
> > for the attached gifs can anybody provide any opinions on why one
> > wouldn't extend L3 to the access instead of having L2 only Access
> > switches [Example 1 L3] V.S. [Example 2 L2]? I like avoiding L2 in
> > any situations that I can. I can understand if the requirement is
to
> > have the vlan available at every switch to go with example 2, but if
> > not it wouldn't make sense to extend L2 everywhere. Any opinions
> appreciated!
> > Thanks!
> >
> >
> >
> > Charles
> >
> > [GroupStudy removed an attachment of type image/gif which had a name
> > of example_gif_2.gif]
> >
> > [GroupStudy removed an attachment of type image/gif which had a name
> > of example_gif_1.gif]
> >
> >
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