From: Leigh Harrison (ccileigh@gmail.com)
Date: Wed Mar 01 2006 - 13:30:39 GMT-3
Gents (and indeed, Ladies),
The more I think about routing at the edge, the more I like the idea of
it. In the designs that I do now I will usually specify 3550/3560
switches at the access layer. Mainly for feature reasons.
I have built many switched networks over the years, but to be honest,
find routing more interesting. I feel that a lot more could be
accomplished with routing rather than switching, for example, you can't
stack a 3550/3560, but I usually have a couple of them in a cabinet
using gig sfp's to connect them. Routing in this instance would be as
fast as switching (using CEF) and I could use all sorts of equal cost
routing and I would no longer have redundant links, just 2 ways of
getting somewhere and maybe using them both.
As far as the use of ip ranges into single closets, then that is not too
much of a problem, this can be sorted with some good ip design, or
running ospf and using mobile ip and shipping around /32 addresses where
need be.
My main concerns do lie around rspan and the copying of data for thing
like call recording. Again, I suppose that this can all be sorted with
careful design to begin with and knowing where nodes needs to be placed
Thanks for all of the comments so far,
LH
James Ventre wrote:
> > Many Cisco docs talk about L3 ACL's in the access layer so how else
> >would this be accomplished?
>
>
> It doesn't have to be L3 switch to put L3 ACL's on an interface. You
> can put an extended ACL on a 2950!
>
> James
>
>
>
>
>
> Guyler, Rik wrote:
>
>> 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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