[c-nsp] Assigning VLANs on a per-subnet basis

[Frank Bulk]

We basically found out that a Fujitsu FlashWave 4500 shelf 2 cannot do the
same thing the ONS15454 can in regards to routing.  It would be possible to
put everyone on the same VLAN, but then the routers would:
A) share the same broadcast traffic
B) it wouldn't be possible to rate-limit on a per-company basis
C) a bad network event, such as a worm, could starve the other companies

We're leaning toward a 3750 because there are models with 4 SFP's, while the
4948 only has up to 2, I believe.  There's also consideration for a Extreme
switch.  Does anyone have an opinion on the 3750's horsepower to route up to
a 1 Gbps in what are likely mostly small-sized packets?  We're planning on
using the Fujitsu to perform QoS (each company, for example, will say they
need x Mbps with 20% burst), but perhaps we should put QoS on the VLAN
egress rather than then Fuji ingress.

Regards,

Frank

-----Original Message-----
From: Robert Blayzor [mailto:rblayzor at inoc.net] 
Sent: Sunday, April 16, 2006 8:46 PM
To: frnkblk at iname.com
Cc: bep at whack.org; cisco-nsp at puck.nether.net
Subject: Re: [c-nsp] Assigning VLANs on a per-subnet basis

Frank Bulk wrote:
> At this point I have to admit my ignorance.  I'll have to talk to the P.E.
> at our consultancy to find out if an RPR without VLAN tags (or with just
one
> VLAN tag) acts like a hub or if it does have the intelligence that you're
> describing.  


I think the big misconception is that RPR is just an ethernet handoff.
The only part of that is true is the port you're connecting to the
network with, in your case 100BaseTX/FX.

Again, I really only have experience with RPR on the Cisco platforms,
mostly being the ONS15454 via the ML card.  If you look at the ML card
it's basically a layer3 switch on a blade that has two virtual POS ports
that tie the card into the SONET network.  I guess that's where the ML
shines because you then have the flexibility to route or bridge over the
SPR interface (RPR interface to the ML card).

I guess where I'm getting confused is that you're the customer, I'm
looking at it from the transport side.  If four ISP's came to me and
wanted to use a packet ring and have an aggregation point where they can
share the entire alloted bandwidth they can be VLAN tagged (internal to
the transport provider) and then each customers interface would exist in
that VLAN.  Customers could then use a common subnet and route to each
other and the upstream.  It's a really easy application.

The ML will also do QinQ if you needed to do your own tagging around the
ring.  Another plus on the ML is that you can use service policies to
rate-limit traffic at each customers port, should you need to do that.

-- 
Robert Blayzor, BOFH
INOC, LLC
rblayzor\@(inoc.net|gmail.com)
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