More Questions of Exchange Points

Sun Apr 7 01:58:19 UTC 2002

> > 	are not but that is a nit argument.  There are lots of ways to
> > 	slice the exchange point.
> 
> I did observe 2 exchange points have direct connection between them, does it mean
> they belong to the same switch fabiric?

	What does this mean? 

> > 	If -ANY- isp provides transit off the exchange fabric,
> > 	does that make it a transit exchange?  If not, why not?
> 
> Are those private peering points?

	confusion of terms.   When bits cross an administrative boundary
	that can be called a "peering point".  Often times that administrative
	boundary has a policy associated with it. Policies may be implementated
	via BGP, ACLS, etc.  The pathological case is the T1 between
	Sprint and my home network.  The two endpoints of that circuit 
	comprise a peering point. Sprint controls one end, I control the
	other and we have agreed to fate share a common communications 
	path to swap bits.

	Multiple parties can agree to share a layer 2 media for exchanging
	bits.  For Internet, I make the distinction that the layer 1 media
	(glass, copper, freq.) must implement a shared broadcast domain, e.g.
	I can ARP between the MAC addresses of the connecting devices.
	Again, for Internet, the presumption is IP.  It is conceivable
	that an operator might get a big'ol switch (layer one) and configure
	it so that ports 1-10 are one broadcast domain, 11 & 12 are a second
	broadcast domain, and 13-20 are a third, leaving 21-24 for the fourt
	broadcast domain.  Or... four VLANS.   One switch, four networks.
	Assign an IP subnet for each.  That would be four exchanges.
	Now Zocalo & JAM, running on the first VLAN/exchange are assigned
	192.168.10.4 and 192.168.10.5 & can ping/peer with everyone else
	on VLAN 1-10.  HOWEVER, Zocalo & JAM want to do some nifty/cool 
	things that they really don't want anyone else to sniff out.
	So they create a VPN (extra credit for defining at least four
	ways to do this... over the SAME VLAN) and use 10.168.10.4 and
	10.168.10.5 for their private VPN.

	So.  Is this one exchange point (one switch), four exchange points
	( 4 VLANS), or five exchange points ( 5 subnets)?  Which ones are
	public? Which ones are private?  and why?

> Regards,
> 
> Ruomei
>