IXP

Fri Apr 17 21:10:32 UTC 2009

On Fri, Apr 17, 2009 at 09:00:53PM +0200, Arnold Nipper wrote:
> Large IXP have >300 customers. You would need up to 45k vlan tags,
> wouldn't you?

Not only that, but when faced with the requirement of making the vlan 
IDs match on both sides of the exchange, most members running layer 3 
switches with global vlan significance are going to hit major layer 8 
hurdles negotiating the available IDs very quickly.

A far better way to implement this is with a web portal brokered virtual
crossconnect system, which provisions MPLS martini pwe or vpls circuits
between members. This eliminates the vlan scaling and clash issues, as
it shifts you from as 12-bit identifier to a 32-bit identifier with vlan
tag handoffs to the clients being arbitrarily mapped as the client
wishes. Such a system has significant advantages over traditional flat
layer 2 switches, in things like security, reliability, flexibility,
scalability (in members, traffic, and number of locations within the
network), and multiservice use (since you can accurately bill with snmp
counters per vlan-ID instead of just guestimating w/sflow).

Of course trying to deploy such a system in the current IX market space 
(especially in the US) has its own unique challenges. :)

-- 
Richard A Steenbergen <ras at e-gerbil.net>       http://www.e-gerbil.net/ras
GPG Key ID: 0xF8B12CBC (7535 7F59 8204 ED1F CC1C 53AF 4C41 5ECA F8B1 2CBC)