[c-nsp] Switch recommendation

Wed Nov 9 18:23:19 EST 2005

What you need to look at is L3 roaming. There are many solutions out there
[from companies such as BlueSocket] that allow you to roam across multiple
IPs and still keep the same IP.
On a network with a few hundred/thousand hosts, your arp traffic alone may
saturate all the wireless bandwidth you have. As a user of your service, I
dont want to see arp broadcats from thousands of users.

On 11/9/05, Vincent De Keyzer <vincent at dekeyzer.net> wrote:
>
> Chuck,
>
> as I said, we will split the city into several VLANs - not 1 VLAN per BS,
> but one VLAN per group of, say, 500 users: does that sound like a good
> figure to you?
>
> Vincent
>
>
> > -----Original Message-----
> > From: cisco-nsp-bounces at puck.nether.net [mailto:cisco-nsp-
> > bounces at puck.nether.net] On Behalf Of Church, Chuck
> > Sent: mercredi 9 novembre 2005 17:54
> > To: Vincent De Keyzer
> > Cc: cisco-nsp at puck.nether.net
> > Subject: RE: [c-nsp] Switch recommendation
> >
> > Yeah, this has potential for a total meltdown. If it was a controlled
> > enterprise, it'd be one thing. But you're providing ISP functionality
> > to normal home users. That means that at least one out of every 10 of
> > your customers will be infected with something. So you'll have
> > worm-type traffic from day one. If you can put a number on what
> > percentage of your customers would actually be roaming and need a
> > non-changing IP address, you could use something like IP Mobility to
> > cater to them, while keeping your base stations each in their own
> > subnet/VLAN. It's certainly safer. To think what would happen to a
> > wireless network with 10,000 users in one broadcast domain the next time
> > a Nimda/slammer/etc hits makes me shudder...
> >
> >
> > Chuck
> >
> >
> > -----Original Message-----
> > From: Vincent De Keyzer [mailto:vincent at dekeyzer.net]
> > Sent: Wednesday, November 09, 2005 11:41 AM
> > To: 'Tim Durack'
> > Cc: cisco-nsp at puck.nether.net; Church, Chuck
> > Subject: RE: [c-nsp] Switch recommendation
> >
> > Well, OK, I see your point - and I got the same question off-list too,
> > so
> > here is the situation:
> >
> > This is for a (pre-)Wimax service. We need to cover the whole city with
> > 100
> > base stations, with up to 200 users per BS - that's what gives the
> > 20,000
> > figure.
> >
> > The L2 domain has to spread over the whole city, because a user might
> > roam
> > across BSs, and he should be able to continue working without renewing
> > his
> > IP address (we made a test on a tramway recently, and it worked fine
> > over a
> > journey of several kilometers).
> >
> > But indeed we will slice this into several flat L2 networks, just to
> > limit
> > the size of the broadcast domain.
> >
> > Still, the switches close to the default gateways will need to know all
> > these MAC addresses (even if in separate VLANs).
> >
> > Vincent
> >
> >
> > > -----Original Message-----
> > > From: cisco-nsp-bounces at puck.nether.net [mailto:cisco-nsp-
> > > bounces at puck.nether.net] On Behalf Of Tim Durack
> > > Sent: mercredi 9 novembre 2005 17:15
> > > To: Vincent De Keyzer
> > > Cc: cisco-nsp at puck.nether.net; Church, Chuck
> > > Subject: Re: [c-nsp] Switch recommendation
> > >
> > > I think what Chuck is trying to say is: How big is your L2 broadcast
> > > domain!!??
> > >
> > > I know we had severe pain when we were running large, flat L2 domains
> > > in the 1000+ MAC range. I shudder to think what 10,000+ would be like.
> > >
> > > But maybe your environment is much more controlled...
> > >
> > > Tim:>
> > >
> > > On 11/9/05, Vincent De Keyzer <vincent at dekeyzer.net> wrote:
> > > > A handful. Today 2, tomorrow maybe 10?
> > > >
> > > > Vincent
> > > >
> > > > > How many VLANs? (Please don't say '1')...
> > > > >
> > > > >
> > > > > Chuck Church
> > > > > Lead Design Engineer
> > > > >
> > > > > -----Original Message-----
> > > > > From: cisco-nsp-bounces at puck.nether.net
> > > > > [mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Vincent De
> > > > > Keyzer
> > > > > Sent: Wednesday, November 09, 2005 7:19 AM
> > > > > To: cisco-nsp at puck.nether.net
> > > > > Subject: [c-nsp] Switch recommendation
> > > > >
> > > > > Hello,
> > > > >
> > > > >
> > > > >
> > > > > I have the following requirements for a switch :
> > > > >
> > > > > * ability to handle over 20,000 MAC addresses
> > > > > * a few GigE ports (1 now, maybe 4 later)
> > > > > * a few FE ports (6 now, maybe 12 or 16 later)
> > > > > * no layer 3 required
> > > > >
> > > > >
> > > > >
> > > > > I have the feeling that those requirements are somewhat unusual -
> > a
> > > few
> > > > > ports vs. a large number of MAC addresses.
> > > > >
> > > > >
> > > > >
> > > > > Is the 4503 a good choice for those requirements? What cards
> > should I
> > > > > stick
> > > > > in there?
> > > > >
> > > > >
> > > > >
> > > > > Is there anything cheaper that would do the job?
> > > > >
> > > > >
> > > > >
> > > > > Vincent
> > > > >
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