[45837] in North American Network Operators' Group
RE: [nsp] Cisco DS3 Questions..
daemon@ATHENA.MIT.EDU (Martin, Christian)
Fri Feb 22 15:27:54 2002
Message-ID: <94B9091E1149D411A45C00508BACEB35015F2BD0@entmail.gnilink.net>
From: "Martin, Christian" <cmartin@gnilink.net>
To: 'Bill Woodcock' <woody@zocalo.net>,
Stephen Sprunk <ssprunk@cisco.com>
Cc: "Gyorfy, Shawn" <sgyorfy@elinkny.com>, nanog@merit.edu,
cisco-nsp@puck.nether.net
Date: Fri, 22 Feb 2002 15:23:02 -0500
MIME-Version: 1.0
Content-Type: text/plain;
charset="iso-8859-1"
Errors-To: owner-nanog-outgoing@merit.edu
> link in a controlled way. Not saying that's a particularly
> good use, just
> that that's the most common reason I've seen it deployed on otherwise
> simple point-to-points. The idea behind frame relay is that
> it gives you
> a multipoint layer-2 protocol to use on a more complicated network of
> circuits.
>
> -Bill
It can also be used to 'equalize' two links of different speeds in such a
way that you can do reasonable equal-cost load-balancing. For example, if
you have a DS3 and an OC3, you can create 3 FR subinterfaces on the OC3 and
add the DS3 to the mix to give you essentially 4 DS3s. There is a slight
speed difference, but it is minimal. This can be done for 2 OC-12s and an
OC-48, for example.
Another reason for virtualizing a ptp circuit is for differentiate billing
in a MPLS VPN environment with an Internet offload component. You can
direct VPN traffic on one VC and Internet on the other, and then take
advantage of basic MIB-II stats for billing and per-(sub)interface CAR for
enforcement of contract and reclassification, etc.
regards,
chris
