[c-nsp] advice for L2 switches

[Sridhar Ayengar]

Kevin Blackham wrote:
> Did I mention this is spread out over 20,000 square feet?   I'll have to 
> do some math on huge wads of non-reusable cable.  I had avoided the 
> big-and-dense option due to that hassle.

Would it be possible to locate the switches in two central locations? 
That way, all you would need would be one or two (preferably gigabit) 
fiber trunks connecting the two switches together, and you would run a 
metric buttload of Cat 5e out in a star configuration from each of the 
switches.  You might end up with one or two places where you need ports 
that are too far from the nearest switch, but for those exceptions, 
there would be nothing to stop you from running fiber out to those points.

There has to be a way to make it work.  It would get you down about an 
order of magnitude in cost.  We're only talking about one day.

Peace...  Sridhar

> On 6/22/07, *Sridhar Ayengar* <ploopster at gmail.com 
> <mailto:ploopster at gmail.com>> wrote:
> 
>     Kevin Blackham wrote:
>      > We're promoting a one day event that requires around 500 FE
>     access ports.  I
>      > need to filter at layer 4 (block DHCP serving) and perform some
>     QoS duties
>      > to ensure a good experience.  40x 2950T-24 will do the job, but
>     even on the
>      > grey market I'm looking at a $20k project (including larger agg
>     switch).  On
>      > the lower end, I might be able to use 2924XL with protected port/port
>      > blocking (effectively isolated private-vlan), as long as I can
>     perform a
>      > U-turn after filtering (sorta breaks split-horizon doesn't it,
>     perhaps local
>      > proxy-arp at L3) and instead have more intelligence at the
>     aggregator.  I
>      > would lose out on DHCP snooping and full control over QoS by this
>     plan
>      > though.  I'm willing to give up QoS at the access port, and apply
>     to the agg
>      > switch, but I really need option-82 so I know exactly who has
>     what IP when
>      > the time comes to kick someone in the head.
>      >
>      > Recommendations?  The only hard requirements are low cost (grey
>     market ok),
>      > SNMP stats, option-82, and 24-25 100M ports.  Preferred are L4
>     QoS marking,
>      > two egress queues per port, L4 filtering.  No L3 forwarding is
>     needed.
> 
>     A pair of Cisco 5513s should get you to the number of ports and do it on
>     the cheap on the used market.  They do have Layer 4 filtering features,
>     but what I don't know is whether you need the Route Switch Module + IOS
>     to use them.
> 
>     Peace...  Sridhar
> 
>