From: Balaji Siva (bsivasub@gmail.com)
Date: Tue Feb 01 2005 - 21:38:58 GMT-3
Yes that is correct. There is no speed penalty for L2 or L3 switching.
For example on cat4k, it is all done in hw asic and if the packet is
not routed, that function is "no opearation".. So whether you turn on
routing/acl/qos, it all is same.
On Tue, 1 Feb 2005 19:34:32 -0500, Conte, Charles
<Charles.Conte@nasdaq.com> wrote:
> Hello Phase,
>
> My reason would be to avoid spanning-tree. With Layer 3
> switching there is practically no difference in latency. Spanning-tree
> is a lot harder to troubleshoot in situations of a loop. I like the
> document below on how it talks about some aspects of spanning tree. I
> guess everything has the "it depends" attached to it. :)
>
> http://www.cisco.com/en/US/tech/tk389/tk621/technologies_tech_note09186a
> 00800951ac.shtml
>
> CISCO DOCUMENTATION:
> High-end Cisco Layer 3 switches are now able to perform this second
> function, at the same speed as the Layer 2 switching function. There is
> no speed penalty in introducing a routing hop and creating an additional
> segmentation of the network.
>
>
> -----Original Message-----
> From: phase90 [mailto:phase90@comcast.net]
> Sent: Tuesday, February 01, 2005 7:17 PM
> To: asadovnikov; Conte, Charles; ccielab@groupstudy.com
> Subject: Re: Simple Design Question
>
> Yes but what if your access switch / router is one hop from your core,
> why
> would you route that hop and have the additional latency in the routing
> process?
>
> Jerry
> ----- Original Message -----
> From: "asadovnikov" <asadovnikov@comcast.net>
> To: "'Conte, Charles'" <Charles.Conte@nasdaq.com>;
> <ccielab@groupstudy.com>
> Sent: Tuesday, February 01, 2005 12:57 AM
> Subject: RE: Simple Design Question
>
> > 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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