Does peering at an ATM MAE require a router that does ABR?
I have been told by various people that to peer at an ATM MAE point I must have a router that can do ABR? Can anyone verify if this is the case at any of the ATM MAE peering points? Thanks, Julian _________________________________________________________________ Get your FREE download of MSN Explorer at http://explorer.msn.com
In the past, the MAE ATM switches ran ABR where you specified the MCR and traffic was policed at a PCR of 2xMCR, although almost no one at the MAEs actually used ABR on their connections. Almost everyone used VBR-nrt and many did not even realize that the use of ABR could have been beneficial. With "best effort" PVCs, this really becomes moot although these are still technically ABR. R. Kevin Oberman, Network Engineer Energy Sciences Network (ESnet) Ernest O. Lawrence Berkeley National Laboratory (Berkeley Lab) E-mail: oberman@es.net Phone: +1 510 486-8634
On Thu, Mar 01, 2001 at 01:36:03PM -0800, Kevin Oberman wrote:
In the past, the MAE ATM switches ran ABR where you specified the MCR and traffic was policed at a PCR of 2xMCR, although almost no one at the MAEs actually used ABR on their connections. Almost everyone used VBR-nrt and many did not even realize that the use of ABR could have been beneficial.
To be even more precise, MAE-ATM runs ABR nternally, but didn't speak the protocol over the UNI to the routers. In this mode, the switches being used would emulate VBR-nrt but actually do some input buffering and shaping to smooth out bursts. This came in very handy for older router interfaces which couldn't shape on their own. I never had an ABR-speaking router to try it with.
With "best effort" PVCs, this really becomes moot although these are still technically ABR.
Agreed, though I'm not famiiliar with details of the "best effort" service. And I'm pretty sure the reserved and policed service is still there for folks who still want to use it. Steve (former target-carrier)
Yes. They are still there. They are both ABR services. The 'guaranteed' as they call is, has the PCR at 2x MCR. The 'best-effort' is MCR of 100 cps, PCR being somewhere around 1/2 port speed. On Thu, 1 Mar 2001, Steve Feldman wrote:
On Thu, Mar 01, 2001 at 01:36:03PM -0800, Kevin Oberman wrote:
In the past, the MAE ATM switches ran ABR where you specified the MCR and traffic was policed at a PCR of 2xMCR, although almost no one at the MAEs actually used ABR on their connections. Almost everyone used VBR-nrt and many did not even realize that the use of ABR could have been beneficial.
To be even more precise, MAE-ATM runs ABR nternally, but didn't speak the protocol over the UNI to the routers.
In this mode, the switches being used would emulate VBR-nrt but actually do some input buffering and shaping to smooth out bursts. This came in very handy for older router interfaces which couldn't shape on their own.
I never had an ABR-speaking router to try it with.
With "best effort" PVCs, this really becomes moot although these are still technically ABR.
Agreed, though I'm not famiiliar with details of the "best effort" service. And I'm pretty sure the reserved and policed service is still there for folks who still want to use it.
Steve (former target-carrier)
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