nanog mailing list archives

Re: UBR at MAE-East ATM, anyone?


From: Alex Rubenstein <alex () nac net>
Date: Tue, 18 Apr 2000 12:53:59 -0400 (Eastern Daylight Time)



Yes.

To me, it seems that WCom is policing the amount of traffic one can shove
into a ATM port, so the giga-fiasco doesn't occur again, which I guess is
somewhat of a legitmate cause. However, the difference between the giga
and the atm solution is (obviously) there is no such thing as
'head-of-line' blocking on the ATM.

Moving to the UBR will allow you to more smartly fill your pipe, and not
have arbitrary restrictions on the flows you send in; essentially, the
bottle neck with the PCR = 2 * SCR is the PVC, not the port. Considering
the nature of internet traffic, this seems silly.

However, the ability to build multiple PVC's in parallel from/to the same
ports is important to us, and BeerMaker allows us to do this; we'd like to
not lose this functionality. 





On Tue, 18 Apr 2000, Lauren F. Nowlin wrote:

Thanks for your update Steve and to Alex for getting the ball rolling.

ONYX would also like to see this change implemented.

The model the AADS team uses is far superior to any other scheme to 
'monitor' interactions between peers at the PVC level.  Hands-off full mesh 
build is the easiest to activate rapidly without botched PVCs trickling in 
one-by-one or stuck in a random queue of a departed employee...  The 
PeerMaker method is too human intensive for little to no gain from an 
operational sense.  A negative if you can't use the capacity for fear of 
artificial caps being exceeded with other peers, which is the case noted 
below.

Also, I've never understood why PBNAP PVC build requests between two 
customers - approved by both customers - have to be sent to PacBell 
Marketing for approval...

Alex, let me know if I can help your efforts in any way.

Thanks again,
-Ren

At 10:15 PM 4/17/00 -0700, Steve Feldman wrote:

When I left wcom, there was a project starting to
implement an option to provision UBR PVCs.
It required non-trivial changes to Peermaker,
so would take some time.

I'll let the current MAE crew answer as to current state,
availability, etc.
        Steve

On Mon, Apr 17, 2000 at 10:37:17PM -0400, Alex Rubenstein wrote:


I've been talking to the WCom MAE folk, and the explained to me that the
the VC's between beers are built as ABR, with PCR being twice SCR. Also,
the port you lease from them has a non-oversubscription policy, i.e., the
sum of all SCR's combined cannot be more than port speed.

From what I can tell, PBNap and Ameritech both build the VC's as UBR, with
no over-allocation protection.

In my travels of contacting other providers for peer information, I have
run across about 5 (albeit out of about 60 who responded) that said they
couldn't turn up new VC's across MAE-East ATM, because they have reached
thier subscription allocation, even though thier port is not nearly full.
A few had even expressed they wish that it was the ameritech-like UBR
model.

One person who I spoke to at WCom had said that maybe someday they would
allow UBR PVCs, but there was no timeline.

What are other people's thoughts on this?






-Ren

Lauren F. Nowlin, ren () onyx net
Director, Peering - peering () onyx net
ONYX Networks - http://www.onyx.net/peering/
Office: 650-558-3262,  Fax: 650-558-3160, Cell: 650-281-6963






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